U.S. Department of the Interior

U.S. Geological Survey

Copper Recycling in the United States in 2004

By Thomas G. Goonan

U.S. GEOLOGICAL SURVEY CIRCULAR 1196–X

FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES
II

U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2010

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Suggested citation:

Goonan, T.G., 2009, Copper recycling in the United States in 2004, chap. X of Sibley, S.R., Flow studies for recycling 

metal commodities in the United States: U.S. Geological Survey Circular 1196–X, p. X1–X30, available only at 

http://pubs.usgs.gov/circ/circ1196x/.
III

FOREWORD

As world population increases and the world economy expands, so does the demand 

for natural resources. An accurate assessment of the Nation’s mineral resources must 

include not only the resources available in the ground but also those that become available 

through recycling. Supplying this information to decisionmakers is an essential part 

of the USGS commitment to providing the science that society needs to meet natural 

resource and environmental challenges.

The U.S. Geological Survey is authorized by Congress to collect, analyze, and 

disseminate data on the domestic and international supply of and demand for minerals 

essential to the U.S. economy and national security. This information on mineral 

occurrence, production, use, and recycling helps policymakers manage resources wisely.

USGS Circular 1196, “Flow Studies for Recycling Metal Commodities in the 

United States,” presents the results of flow studies for recycling 26 metal commodities, 

from aluminum to zinc. These metals are a key component of the U.S. economy. Overall, 

recycling accounts for a significant portion of U.S. metal supply.

Marcia K. McNutt

Director
IV

CONTENTS

Foreword .......................................................................................................................III

Abstract........................................................................................................................X1

Introduction.....................................................................................................................1

Global Geologic Occurrence of Copper .........................................................................6

Production Processes ......................................................................................................8

Primary Production Processes....................................................................................8

Pyrometallurgical and Electrorefining Processes..................................................8

Hydrometallurgy and Electrowinning Processes.................................................10

Semifabrication Processes........................................................................................11

Uses of Copper-Containing Materials...........................................................................13

Copper End-Use by Economic Sector......................................................................13

Copper End-Use as Alloys and Chemicals ..............................................................14

Copper Metal.......................................................................................................14

Copper Chemicals...............................................................................................14

High-Copper Alloys............................................................................................14

Copper-Aluminum and Aluminum-Copper Alloys.............................................15

Copper-Nickel and Nickel-Copper Alloys..........................................................15

Copper-Tin Alloys...............................................................................................15

Copper-Zinc Alloys.............................................................................................15

Prices.............................................................................................................................15

Sources and Disposition of Copper Scrap ....................................................................18

Old Scrap..................................................................................................................20

Old Scrap Generated ...........................................................................................20

Old Scrap Unrecovered .......................................................................................22

Old Scrap Recovered and Used...........................................................................22

New Scrap ................................................................................................................22

Scrap Recycling Efficiency...........................................................................................22

Scrap Receipts at U.S. Primary and Semifabrication Copper Producers......................23

Processing of Copper Scrap..........................................................................................23

Copper Scrap Trade ......................................................................................................23

Outlook .........................................................................................................................25

References Cited ...........................................................................................................25

Appendix—Definitions.................................................................................................28
V

FIGURES

1. U.S. copper-containing materials flow in 2004 .............................................X2

2. U.S. refined copper supply in 2004 ..................................................................4

3. Copper flow to and through semifabrication producers in 2004 ......................5

4. Pyrometallurgical smelting and electrorefining process steps..........................9

5. Hydrometallurgical solvent-extraction and electrowinning process...............10

6. Process flow chart (unquantified) for copper scrap ........................................11

7. U.S. end-use consumption, by economic sector, from 1980 through 2004....13

8. Indexed prices from 1954 through 2007.........................................................16

9. Monthly dealer prices from 1997 through 2007.............................................17

10. U.S. scrap generation and flow in 2004..........................................................19

11. U.S. exports of old copper scrap, by country, in 2004....................................24

12. Chinese imports of U.S. old copper scrap from 1995 through 2004 ..............24

13. U.S. imports of old copper scrap, by country, in 2004 ...................................25

TABLES

1. Salient copper flow statistics for the United States in 2004 ..........................X3

2. Principal characteristics of significant porphyry copper deposits ....................7

3. World copper mine production in 2004 ............................................................8

4. Average annual growth rates for U.S. consumption of copper.......................14

5. Copper scrap classifications and most likely users.........................................18

6. The development of the estimate for old scrap generated in 2004 .................20
VI

CONVERSION FACTORS

Multiply By To obtain

Length

micrometer (μm) 0.00003937 inch (in.)

inch (in.) 2.54 centimeter 

Volume

cubic meter (m3

) 35.31 cubic foot (ft3)

Mass

microgram (μg) 0.00000003527 ounce avoirdupois (oz)

kilogram (kg) 2.205 pound (lb)

metric ton (t, 1,000 kg) 1.102 short ton (2,000 pounds)

ton, short (2,000 lb) 0.9072 megagram (Mg) or metric ton (t)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as 

follows:

°F=(1.8×°C)+32

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as 

follows:

°C=(°F-32)/1.8
X1

FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

Copper Recycling in the United States in 2004

By Thomas G. Goonan

scrap stock decrease to produce an old scrap supply containing 

855,000 t of copper. This supply of contained copper was 

distributed as 633,000 t to old scrap exports (74 percent of 

supply), 167,000 t to U.S. copper processor receipts (20 percent 

of supply), and 54,000 t for U.S. noncopper processor receipts 

(6 percent of supply).

In 2004, collection and receipts of new scrap amounted 

to 735,000 t of contained copper, which was consumed in 

U.S. production of copper-containing products. A total of 

965,000 t of copper contained in copper scrap was consumed 

by U.S. production activities, of which 88 percent (845,000 t) 

was consumed by semifabrication copper producers, 7 percent 

was consumed by noncopper producers, and 5 percent (51,000 

t) was consumed by primary copper production.

In 2004, the old scrap recycling efficiency for copper was 

estimated to be 43 percent of theoretical old scrap supply, the 

recycling rate for copper was 30 percent of apparent supply, 

and the new-scrap-to-old-scrap ratio for U.S. copper product 

production was 3.2 (76:24).

INTRODUCTION

Copper has been used by humans for more than 10,000 

years. There is evidence of copper smelting in the Middle 

East around 5000 BCE. On average, between 13 million and 

14 million metric tons of copper worldwide was added each 

year into usage from mine production for the years 2000 

through 2004. This study provides a snapshot, shown in figure 

1, of the flow through the U.S. economy of recoverable copper 

contained in various copper-containing materials in 2004. It 

identifies sources of the U.S. copper supply and its distribution 

with particular emphasis on the flow2 of copper contained in 

scrap. Figure 1 provides an overall view of the flow of copper 

and copper-bearing materials through the economy of the 

United States for 2004.

In 2004, copper semifabricators (brass and wire rod 

mills, ingot makers, and foundries and other manufacturing) 

2

As a general rule, flow information (numbers associated with arrows in the 

diagrams) is derived from disparate data sources with differing levels of quality 

and is not as precise as the reporting might indicate. One should view the reported 

values relative to each other rather than for the precision of the data. 

ABSTRACT

As one of a series of reports that describe the recycling of 

metal commodities in the United States, this report discusses 

the flow of copper from production through distribution and 

use, with particular emphasis on the recycling of industrial 

scrap (new scrap1

) and used products (old scrap) in the year 

2004. This materials flow study includes a description of 

copper supply and demand for the United States to illustrate 

the extent of copper recycling and to identify recycling trends. 

Understanding how materials flow from a source through 

disposition can aid in improving the management of natural 

resource delivery systems.

In 2004, the U.S. refined copper supply was 2.53 million 

metric tons (Mt) of refined unalloyed copper. With adjustment 

for refined copper exports of 127,000 metric tons (t) of copper, 

the net U.S. refined copper supply was 2.14 Mt of copper. With 

this net supply and a consumer inventory decrease of 9,000 t 

of refined copper, 2.42 Mt of refined copper was consumed by 

U.S. semifabricators (brass mills, wire rod mills, ingot makers, 

and foundries and others) in 2004.

In addition to the 2.42 Mt of refined copper consumed 

in 2004, U.S. copper semifabricators consumed 853,000 t of 

copper contained in recycled scrap. Furthermore, 61,000 t of 

copper contained in scrap was consumed by noncopper alloy 

makers, for example, steelmakers and aluminum alloy makers.

In 2004, 3.20 Mt of copper was delivered to U.S. 

manufacturers. Of this amount, about 22 percent (699,000 t) 

was recycled as manufacturing or new scrap, and 78 percent 

(2.50 Mt) entered the U.S. copper products reservoir. From the 

same reservoir, 1.92 Mt of copper as old scrap theoretically 

became available (by reaching theoretical end of life), a net gain 

to the reservoir of 578,000 t of copper contained in products 

having a useful life. Of the 1.92 Mt of copper contained in old 

scrap generated, about 40 percent (772,000 t) was recovered, 

and 60 percent (1.15 Mt) was unrecovered.

In 2004, the 772,000 t of copper contained in old scrap 

recovered was supplemented by 80,000 t of copper contained in 

imports of old scrap and 3,000 t of copper contained in an old 

1

Definitions for selected words and terms are found in the Appendix.
X2 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

Figure 1. Diagram showing the flow of copper-containing materials in the United States in 2004. Values are rounded to the nearest thousand metric ton of contained 

copper. The sum of the parts may not equal the totals shown owing to independent rounding. Greater detail of parts of this flow can be found in figures 2, 3, and 10. The sources and distribution of U.S. copper supply and scrap recycling are understood to be in terms of “recoverable” copper. Dissipative losses are not identified, though they are understood to exist. Sources: International Copper Study Group, 2005a, b; Jolly, 2006; Kelly and Matos, 2006; Baker, 2007; Edelstein, 2007.

Old scrap generated:

Construction.................................... 563

Electrical, electronic ....................... 532Industrial......................................... 309

Transportation................................. 261

Consumer, general.......................... 254 Total .......................................... 1,920

DOMESTIC FLOWS OF COPPER-CONTAINING MATERIALS TO 

PRIMARY PRODUCERS AND SEMIFABRICATORS

Refined copper supply for 

U.S. semifabricators

2,410

Semifabrication

(includes brass and wire rod mills, 

chemical plants, foundries, others)

3,270

New (prompt) scrap received and 

consumed by copper producers

728

New (prompt) scrap consumed

735

Net copper stock 

decrease

(refined and in scrap)

18

Old scrap 

theoretical 

supply

2,000

728

735

735

35

16

712 133

54 7

1,920

3,230 36 2,410

51

3,510

1,920

3,200

Products

2,500

Scrap

699

317

761 479

36 845 18

Manufacturing

3,200

Semifabricated 

product imports

761

Semifabricated 

product exports

479

Net product stock 

increase

317

Semifabricated 

product supply

3,510

Noncopper production

61

Copper products reservoir, 

net change

578

DOMESTIC FLOWS OF

COPPER-CONTAINING PRODUCTS

Old scrap receipts at 

copper producers

167

Old scrap stock change

3

Old scrap imports

80

Old scrap exports

633

Old scrap unrecovered

1,150

633

167

80

1,150

3

Recoverable copper from U.S. mined materials

1,190

Net imports

666

Net stock decrease

514

Slag losses

16

1,190

666

514

16
COPPER RECYCLING IN THE UNITED STATES IN 2004 X3

consumed 2.42 Mt of refined copper in their operations. For 

the purposes of this study, even though the semifabrication 

sector called foundries and others produces both finished and 

semifabricated products, the entire production of the sector 

is attributed to semifabrication of copper and copper alloy 

products. Semifabricators consumed 853,000 metric tons 

(t) of scrap copper, which amounted to a total consumption 

of copper by semifabricators of 3.27 Mt. Semifabricators 

generated new scrap containing 36,000 t of copper. Therefore, 

the net flow of copper from U.S. semifabricators was 3.23 

Mt of copper in 2004, which was augmented by imports that 

contained 761,000 t of copper and was depleted by exports 

that contained 479,000 t of copper such that the supply of 

semifabricated copper products contained 3.51 Mt of copper 

in 2004. This supply of semifabricated copper products was 

distributed as 3.20 Mt of copper (91 percent of supply) to 

U.S. manufacturers and 317,000 t (9 percent of supply) to a 

product stock increase.

Manufacturing of copper products generated new 

scrap, which contained 699,000 t of copper (22 percent of 

manufacturing throughput), and useful products for the U.S. 

copper products reservoir,3

 which contained 2.50 Mt of 

copper. The product reservoir theoretically (estimate details 

are discussed below) generated 1.92 Mt of copper as old 

scrap, 40 percent of which was recovered and 60 percent 

of which was unrecovered (unaccounted flows to landfills, 

stocks left-in-place, and dissipative losses).

After adjustments for imports and stock changes, the U.S. 

theoretical supply of old scrap contained 2.00 Mt of copper, 

of which 1.15 Mt was unrecovered and 855,000 t represented 

actual supply of copper contained in old scrap. Most of the 

recovered copper, 633,000 t of copper (74 percent), was 

exported. Of the remaining 26 percent, 167,000 t of copper 

(20 percent of recovered copper) was recovered at U.S. 

smelters and semifabricators, and 54,000 t of contained 

copper (6 percent) was recovered by noncopper producers. 

Most of the 633,000 t of copper that was exported went to 

Asia, particularly China. Copper contained in exported scrap 

was assumed to be 100 percent recovered in the recipient 

countries.

Smelters, refiners, and semifabricators recovered 

728,000 t of copper from new scrap and 167,000 t of copper 

from old scrap. Smelters and refiners recovered 6 percent 

of copper contained in recycled scrap, and semifabricators 

recovered 94 percent.

In 2004, the old scrap recycling efficiency for copper was 

estimated to be 43 percent of theoretical old scrap supply, 

the recycling rate for copper was 30 percent of U.S. apparent 

copper supply, and the new-scrap-to-old-scrap consumption 

3

This addition to the U.S. copper product reservoir is trade adjusted for 

semifabricated products but does not include any adjustment for net imports 

of assembled products that may contain copper (for example, automobiles 

and appliances).

ratio for U.S. copper product production was approximately 

3.2. Salient copper flow statistics for 2004 are summarized 

in table 1.

Figure 2 shows the sources and distribution of U.S. 

refined copper supply in 2004.

The sources for the estimated flow of refined (unalloyed) 

copper to U.S. copper processors are U.S. mining operations 

(adjusted for slag losses), 49 percent; net imports of various 

copper-bearing materials (anode, ash, blister, concentrate, 

matte, ore, and refined copper), 28 percent; stock decreases 

(producer stocks, including anode and blister stocks, exchange 

stocks, mine stocks, and refinery stocks), 21 percent; and scrap, 

2 percent. U.S. copper-refining operations produced 1.31 

Mt of unalloyed copper (45 percent electrowon, 51 percent 

electrorefined, and 4 percent fire refined). With adjustment 

of refined-copper production for net imports (577,000 t of 

copper) and net stock decreases (522,000 t of copper), the 

total net refined-copper flow to U.S. semifabricators was 2.41 

Mt of copper in 2004.

Figure 3 shows in detail the flows of refined copper and 

recycled copper (contained in scrap) to and through U.S. 

semifabricators.

Brass mills consumed 1.26 Mt of copper, of which 

45 percent was refined copper, 54 percent was from copper 

contained in scrap, and 1 percent was copper contained in 

ingot (essentially from scrap). Adjusting for 174,000 t of 

copper contained in net imports, 64,000 t of copper contained 

in a brass mill stock decrease, and 20,000 t of copper contained 

in new scrap generated, 1.48 Mt of copper contained in brass 

mill products was supplied to U.S. manufacturers.

Table 1. Salient copper flow statistics for the United 

States in 2004. 

[Values are in thousand metric tons of contained copper, unless otherwise 

specified. Sources: International Copper Study Group, 2005a, b; Jolly, 

2006; Kelly and Matos, 2006; Baker, 2007; Edelstein, 2007]

Old scrap theoretically generated............................................ 1,920

Old scrap consumed (received ± inventory change) .............. 230

Value of old scrap consumed ................................................. $305 million

Recycling efficiency ............................................................... 43.1 percent

Old scrap supply ..................................................................... 2,000

Old scrap unrecovered ............................................................ 1,150

New scrap generated and consumed ....................................... 735

New-to-old-scrap ratio ........................................................... 76:24

Recycling rate ........................................................................ 29.9 percent

U.S. net exports of scrap ......................................................... 553

Value of U.S. net exports of scrap .......................................... $694 million

Apparent consumption............................................................ 2,500

Refined-to-scrap-borne-copper ratio for U.S. copper 

consumption.......................................................................

71:29

Apparent supply...................................................................... 3,230
X4 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

Ingot makers consumed 95,000 t of copper, 5 percent of 

which was refined copper, and 95 percent was from copper 

contained in scrap. After generating 5,000 t of copper contained 

in process scrap, 91,000 t of copper in ingot products (ingots, 

hardeners, and master alloys) was distributed to brass mills, 

of which 81,000 t (89 percent) of copper went to foundries 

and others, and 10,000 t (11 percent) went to brass mills.

Foundries and others (chemical plants and powder 

manufacturers) consumed 196,000 t of copper, of which 

41 percent was contained in ingot (essentially from scrap), 

30 percent was scrap copper, and 29 percent was refined 

copper. After generating 11,000 t of copper contained in 

process scrap, 186,000 t of copper contained in foundries 

and other products was enhanced with 40,000 t of copper 

contained in net imports and depleted by 94,000 t of copper 

Wire semifabrication4 consumed 1.81 Mt of copper, of 

which 98 percent was refined copper and 2 percent was scrap 

copper. Net imports of wire rod and wire mill products (taken 

together) contained 67,000 t of copper (113,000 t of copper 

contained in net imports of wire rod minus 46,000 t of copper 

contained in net exports of wire). Stocks, in contained copper 

terms, at wire rod mills increased by 16,000 t and, at wire 

mills, by 273,000 t—a total of 289,000 t. Therefore, the flow 

of copper to U.S. manufacturers of copper contained in wire 

product was 1.58 Mt in 2004.

4

Depending on the use, wire may be considered to be a semifabricated 

or manufactured product. In this report, wire is considered to be the 

semifabricated product of a two-step process—wire rod-making and wiremaking from trade and stock adjusted rod production.

Figure 2. Diagram showing sources and distribution of U.S. refined copper supply in 2004. Values are rounded to the nearest 

thousand metric ton of contained copper. The sum of the parts may not equal the totals shown owing to independent rounding. 

The sources and distribution of U.S. copper supply and scrap recycling are understood to be in terms of “recoverable” copper. 

Dissipative losses are not identified, though they are understood to exist. Sources: International Copper Study Group, 2005a, b; 

Jolly, 2006; Kelly and Matos, 2006; Baker, 2007; Edelstein, 2007.

Smelter production

from primary materials

593

Electrowon production

584

Primary electrolytic production

671

Imports

704

Anode/blister 

imports

151

Exchange stock

decrease

521

5

35 Old scrap

New scrap 16

Refined copper supply

2,530

Exports

127

Net U.S.

refined copper

supply

2,410

Electrolytic and fire-refined

production from scrap

51

Anode/blister

stock change

51

24 584

Recoverable copper available

from primary sources

1,220

584

51

2 671

Refinery stock

decrease

Imports of ash

ore, concentrate, 

and matte

515

Mine stock

increase

14593

1,190

16

16

Exports of matte, ash

Losses (slag)

Exports of ore

and concentrate

24

Recoverable copper

from U.S. mined

copper-bearing

materials and ores

Anode/blister 

exports

46
COPPER RECYCLING IN THE UNITED STATES IN 2004 X5

Figure 3. Diagram showing the flow of refined and scrap copper to and through semifabrication copper producers in 2004. 

Values are rounded to the nearest thousand metric ton of contained copper. The sum of the parts may not equal the totals shown 

owing to independent rounding. The sources and distribution of U.S. copper supply and scrap recycling are understood to be in 

terms of “recoverable” copper. Dissipative losses are not identified, though they are understood to exist. Sources: International 

Copper Study Group, 2005a, b; Jolly, 2006; Kelly and Matos, 2006; Baker, 2007; Edelstein, 2007.

26 679

90

58

10

81

57 573 1,780

20

11

281

186

5

1,240

1,810

91

319

9

9

2,410

712

133

New scrap

Old scrap

3,200 5

Ingot makers

Wire rod and

wire mills

Foundries

and others

Consumption of copper contained in scrap

853

To U.S. manufacturers as:

Brass mill products ...................... 1,480

Wire mill products ....................... 1,580

Foundry and other products............ 132

 Total .......................................... 3,200

New stock 

change

-9

New stock 

change

-9

Net U.S. refined 

copper supply

2,410

Consumption of refined copper

2,420

New scrap generated

36

Net imports of:

Wire rod and wire mill products....... 67

Brass mill products ......................... 174

Foundry and other products.............. 40

 Total ............................................. 281

Stock increase at:

Brass mills............................ (64)

Wire mills............................. 289

Foundries and others ............. 94

 Total................................... 319

Brass mills
X6 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

contained in product stock increases, such that 132,000 t of 

copper flowed to U.S. manufacturers for further processing.

GLOBAL GEOLOGIC OCCURRENCE

OF COPPER

Copper is a chemical element of group II–B of the 

periodic table; it has atomic number 29 and atomic weight 

of 63.546, consisting of isotopes 63Cu (69.09 percent) and 65Cu (30.91 percent) (Cox and others, 1973). It occurs in 

nature as the native element, as compounds of Cu+1 and Cu+2. 

Copper is a strongly sulfur-seeking (chalcophile) element, 

and it tends to be concentrated in sulfide deposits; in igneous 

rocks, it occurs mainly as finely divided sulfides, principally 

chalcopyrite and bornite. Copper is concentrated in basaltic 

and gabbroic igneous rock [30–160 parts per million (ppm), 

average 90 ppm] and in sedimentary clays, sandstones, 

shales, and soils (2–120 ppm, average 45 ppm). The crustal 

abundance for copper is about 50 ppm (Parker, 1967).

Copper occurs in at least 160 minerals. In order of 

abundance, chalcopyrite (CuFeS2), bornite (Cu5FeS5), 

and chalcocite (Cu2S) are the principal ore minerals. 

The sulfarsenides enargite (Cu3AsS4) and tennantite 

[(Cu,Fe)12As4S13] and the sulfantimonides tetrahedrite 

[(Cu,Fe)12SbS13] and famatinite (Cu3SbS4) are generally rare, 

but each makes up a major part of at least one large orebody. 

Malachite [Cu2(OH)2(CO3)], azurite [Cu3(OH)2(CO3)2], and 

chrysocolla [CuSiO3•5H2O] are the most common copper 

minerals in weathered and oxidized environments (Cox and 

others, 1973).

Most copper deposits fall into one of the following five 

major types:

1. porphyry copper deposits and vein and replacement 

deposits, which account for almost two-thirds of the 

world’s copper resources and are discussed together 

because of their common genetic association with 

granitic and intermediate intrusive rocks;

2. sedimentary rocks, which account for one-quarter of the 

world’s identifiable resources;

3. volcanic rocks, such as massive sulfide deposits, which 

account for about 5 percent of the world’s resources;

4. nickel-copper ores formed by magmatic processes in 

mafic intrusives contain smaller portions of the world 

resources;

5. in native copper ores of the Keweenaw type.

Porphyry copper deposits, which are characterized by 

large mass, relatively uniform dissemination, and averageper-ton (often less that 1 percent) copper content (U.S. Bureau 

of Mines, 1968, p. 848), are typical in the Southwestern 

United States. They contain upwards of 150 Mt of ore that 

averages 0.8 percent copper and 0.15 percent molybdenum. 

On average, 70 percent of the ore body is in the intrusive 

rock, and 30 percent is in the country rock. Sulfide minerals in 

descending order of abundance are pyrite (FeS), chalcopyrite 

(CuFeS2), molybdenite (MoS2), and bornite (Cu5FeS5) (Cox 

and others, 1973).

The U.S. Geological Survey (USGS) has published a 

database of world porphyry copper deposits (Singer and 

others, 2002). Table 2 lists some of the principal characteristics 

of the world’s largest porphyry copper deposits.

Vein, pipe, and replacement deposits may be associated 

with porphyry deposits or may be found within otherwise 

barren felsic intrusive rocks. According to Cox and others 

(1973, p. 171–173):

“Veins are formed when metal-rich solutions, emanating 

from a crystallizing intrusion, deposit minerals in 

faults or fractures. They are tabular in form and may 

show mineral textures indicating growth of crystals in 

open cavities as well as replacement of wallrocks5

 by 

copper minerals. Many veins show several generations 

of mineral deposition related to opening and reopening 

fault zones by tectonic movements. Hydrothermal 

alteration envelopes may accompany the veins, 

indicating chemical reactions between wallrocks and 

hydrothermal solutions.

“Ore pipes are rodlike in form as contrasted to tubular 

veins. They may form in fractured or brecciated rock 

at the intersections of faults or by explosive release 

of gases derived from intrusive magmas. These latter 

are called breccia pipes because of the broken rock 

associated with them. At many places copper deposits 

in breccia pipes show a close spatial and genetic relation 

to porphyry intrusions....

“Replacement deposits form in reactive host rocks near 

the intrusive contacts or along mineral veins. These hosts 

may be sedimentary rocks such as limestone, dolomite, 

or calcareous6

 sandstone or even diabase sills... . 

Replacement deposits tend to be tabular in form... . 

Vein, pipe, and replacement deposits have a more varied 

mineralogy than porphyry deposits. Calchopyrite and 

bornite are the most common hypogene7

 minerals... .

“Strata-bound deposits in sedimentary rocks include 

some of the world’s largest sources of copper8

... .”

The stratabound copper deposits can be from new 

sediments or old sediments enclosed by new sediments. 

Additionally, there can be mineral alterations caused by 

precipitation from solutions or chemical reactions, such as 

oxidation or reduction. The type of alteration is governed by 

gradients of pH, pressure, temperature, and other physical 

conditions within the sediments. 

5

Wallrock is the country rock immediately adjacent to the vein or load.

6

Calcareous rocks are ones containing limestone.

7

Hypogene are mineral deposits that are formed by ascending hot waters.

8

These are Congo (Brazzaville) (formerly Zaire), Russia, and Zambia.
COPPER RECYCLING IN THE UNITED STATES IN 2004 X7

Copper and nickel ores of commercial grade are found 

in mafic rocks, and the copper is a byproduct of nickel 

production. Australia, Canada, and Russia produce byproduct 

copper in this fashion. Such deposits are generally interpreted 

to have been formed by a magmatic-segregation process as 

part of the intrusion of the bodies of mafic rock. Variation 

in the nickel-to-copper ratio in different ore bodies makes it 

possible for the mining company to adapt the ratio in the ore 

produced to metal-market conditions (Cox and others, 1973, 

p. 179).

Native copper (Keweenaw type) deposits are stratabound, 

having been introduced into vesicles, fractures, and interstitial 

pore spaces after deformation of the rocks (Cox and others, 

Massive sulfide deposits are typically found in volcanic 

rocks. Copper is more abundant in basalt (highest relative 

calcium content) and andesite (next highest relative calcium 

content) than in other volcanic rocks. A small but locally 

important part of the world’s copper resources is found in 

lava flows and pyroclastic rocks deposited in the marine 

environment. Different magma chemistries give rise to 

deposits of different mineralogy. For example, pyritepyrrhotite-chalcopyrite (iron-copper-sulfur systems) deposits 

are commonly associated with mafic volcanics, and sphalerite 

(zinc-sulfur)- and galena (lead-sulfur)-bearing deposits tend 

to be found in silicic volcanic rocks (Cox and others, 1973, 

p. 179).

Table 2. Principal characteristics of the world’s most significant porphyry copper deposits.

[Values are in metric tons of contained copper, unless otherwise specified. NA, not available; XX, not applicable. Source: Singer and others 2002]

Deposit name Country Discovery

year

Startup

year

Age,

in millions of

years

Tonnage,

in millions

of metric 

tons of ore

Grade,

in percent of

copper

Tonnage,

in percent of 

known porphyry 

deposits

Tonnage,

in cumulative 

percent of known 

porphyry deposits

Chuquicamata ............... Chile................ 1911 1915 31.5 17,100 0.65 7.37 7.37

El Teniente .................... Chile................ 1706 1906 4.5 11,800 0.92 5.09 12.46

Safford........................... United States... 1886 1959 52.5 7,260 0.44 3.13 15.59

Cananea......................... Mexico ............ NA 1899 55.5 7,140 0.42 3.08 18.67

Morenci-Metcalf ........... United States... 1872 1942 56.0 6,470 0.52 2.79 21.46

Almalyk......................... Uzbekistan....... 1925 1958 289.5 6,080 0.39 2.62 24.08

Continental/Butte .......... United States... NA 1864 60.5 5,220 0.67 2.25 26.33

Rio Blanco .................... Chile................ 1864 1970 6.0 5,000 0.80 2.16 28.29

La Escondida................. Chile................ 1981 1990 35.0 4,860 0.97 2.10 30.58

Grasberg........................ Indonesia ......... 1936 1973 3.0 4,000 0.60 1.72 32.31

Cerro Colorado.............. Chile................ 1970 NA 5.0 3,730 0.39 1.61 33.92

Los Pelambres............... Chile................ 1914 1992 9.5 3,300 0.63 1.42 35.34

Bingham Canyon .......... United States... 1863 1904 36.0 3,230 0.88 1.39 36.73

Ray ................................ United States... 1846 1911 60.5 3,230 0.49 1.39 38.12

Aktogai.......................... Kazakhstan...... NA NA 333.0 3,120 0.39 1.38 39.50

Collahausi ..................... Chile................ 1978 1999 32.0 3,100 0.86 1.34 40.84

Chino............................. United States... 1801 1911 55.5 3,030 0.47 1.31 42.15

La Granja ...................... Peru ................. 1969 NA 12.0 3,000 0.56 1.29 43.44

Tampakan...................... Philippines....... NA NA NA 2,500 0.48 1.08 44.52

Toquepala...................... Peru ................. NA 1959 57.0 2,320 0.55 1.00 45.52

Sierrita........................... United States... 1895 1907 55.0 1,830 0.26 0.79 46.31

La Caridad..................... Mexico ............ 1896 1905 51.0 1,800 0.45 0.78 47.08

Glacier Peak1

................. United States... 1900 NA 21.0 1,710 0.33 0.74 47.82

Agua Rica...................... Argentina......... 1900 1965 5.5 1,710 0.43 0.74 48.56

Batu Hijau ..................... Indonesia ......... 1987 1999 3.7 1,640 0.44 0.71 49.27

Cuajone ......................... Peru ................. 1939 1976 51.0 1,630 0.69 0.70 49.97

Subtotal (26) ............. XX XX XX 116,000 2

0.57 49.97 XX

Others (355) ................. Worldwide...... XX XX XX 116,000 2

0.49 50.03 100.00

Total (381) ................ Worldwide....... XX XX XX 232,000 2

0.50 100.00 100.00

1

This deposit will not be developed because it is within the Glacier Peak Wilderness Area, Wash.

2

Average for the deposits within the group.
X8 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

1973, p. 179–180). While copper mining in the Keweenaw 

[Mich.] province is presently inactive, the copper resource is 

still extensive.

Table 3 lists 2004 worldwide copper mine production 

distributed by type of production and by country. Table 3 also 

shows the worldwide recovery of copper from leached ores 

(hydrometallurgy) in 2004.

In 2004, 13 countries accounted for nearly 91 percent 

of world copper production. Chile, which has the largest 

deposits, also has the highest grade deposits (0.74 percent 

average copper, versus the average for all porphyry copper 

deposits of 0.50 percent copper). Chile produced about 

37 percent, which is more than four times the amount of the 

next largest producer, the United States. 

Chile also leads the world in the production of copper 

from leached ore (1.64 Mt of copper), but the percentage 

of total Chilean production as electrowon copper is only 

30 percent. Electrowinning is a process that recovers copper 

leached from copper oxide and sulfide ores.

The United States, which had copper mine production 

(concentrates, adjusted for 16,000 t copper in slag loss, 

and electrowon) of 1.18 Mt of copper, was the number two 

producer of copper in the world in 2004. However, production 

in the United States was only one-fifth that of Chile. The 

United States is a major producer of copper concentrates 

(about 4 percent of total world mined copper production) and 

leads the world in the percentage of total copper produced 

as electrowon copper (50 percent). The United States does 

import copper because it is economically efficient to do so, 

but it can function as import independent.

PRODUCTION PROCESSES

PRIMARY PRODUCTION PROCESSES

Copper ore is generally processed either by a 

pyrometallurgical route (application of heat) or by 

hydrometallurgical (treatment of copper-bearing solutions) 

methods to produce a suitable feedstock for refining by electrical 

methods to ultimately obtain refined copper of greater than 

99.9 percent purity (Anchor Bronze and Metals, Inc., 2007). 

In 2004, 81.5 percent of world refined copper was processed 

initially through pyrometallurgical circuits, and 18.5 percent 

was processed through hydrometallurgical circuits.

PYROMETALLURGICAL AND

ELECTROREFINING PROCESSES

Copper sulfides are the chief copper minerals, which 

are mined and concentrated for pyrometallurgical smelting. 

Process steps include mining, crushing and grinding, 

concentration by flotation, pyrometallurgical processing 

(smelting, converting, and refining), and electrolytic refining 

(electrorefining) of the smelter product anodes into cathodes 

of greater than 99.9 percent copper. Figure 4 shows the process 

flow steps for copper produced by the pyrometallurgical 

processing route.

To obtain anode copper from pyrometallurgical smelting, 

one must first mine copper ore. Based upon the productionweighted average operating statistics of a hypothetical world 

copper smelter in 2002, for every 1 t of anode copper metal 

produced, 326 t of material is mined, of which 116 t is 

Table 3. World copper mine production in 2004, by type of production and country.

[—, zero. Calculated from original data reported by Edelstein, 2007, p. 21.29–21.30]

Country Copper content, in metric tons of contained copper Percentage of 

world production

Cumulative 

percentage Concentrate production Electrowon production Total production

Chile.............................. 3,780,000 1,640,000 5,410,000 36.95 36.95

United States1

................ 576,000 584,000 1,160,000 7.92 44.86

Peru ............................... 869,000 167,000 1,040,000 7.07 51.93

Australia........................ 796,000 58,300 854,000 5.83 57.76

Indonesia....................... 840,000 — 840,000 5.74 63.50

China............................. 742,000 10,000 752,000 4.61 68.11

Russia............................ 675,000 — 675,000 5.06 73.17

Canada........................... 563,000 — 563,000 3.85 77.02

Poland ........................... 531,000 — 531,000 3.62 80.64

Kazakhstan.................... 461,000 — 461,000 3.15 83.79

Zambia .......................... 344,000 82,600 427,000 2.91 86.70

Mexico .......................... 334,000 72,200 406,000 2.77 89.47

Argentina....................... 177,000 — 177,000 1.21 90.68

Other ............................. 1,310,000 87,600 1,400,000 9.32 100.00

Total .......................... 11,900,000 2,770,000 14,700,000 100.00

1

Recoverable copper content.
COPPER RECYCLING IN THE UNITED STATES IN 2004 X9

useable ore, and 210 t is mine waste. The useable ore, which 

contains about 0.50 percent copper, then must be crushed, 

ground, and processed in flotation circuits to produce copper 

concentrate (containing roughly equal amounts of copper, 

iron, and sulfur), which is the primary feed for smelting 

furnaces. For every 1 t of anode copper metal produced, 

flotation circuits produce 3 t of copper concentrate and 113 t 

of disposable mill tailings (Goonan, 2004). Pyrometallurgical 

smelting occurs in suitable furnaces where oxygen and slagmaking fluxes are added to aid the separation of copper 

metal from iron-containing slag and sulfur-containing gas. 

The sulfur in the copper concentrate reacts chemically 

with the oxygen to produce SO2 gas and heat. The iron in 

the copper concentrate reacts chemically with the oxygen 

and flux materials to produce a slag (calcium-iron-siliconoxygen), which also releases some heat. The heat release 

from both reactions is sufficient to melt the reaction product 

(matte) and fluidize the slag. The slag is tapped from the 

smelting furnace and often reprocessed through grinding 

and flotation to recover entrained copper units. The matte, 

which contains 50 to 70 percent copper, is transferred to a 

converter furnace to produce blister copper. Oxygen is added 

to further the separation of copper from the remaining iron 

and sulfur by means of the same reactions as smelting. The 

sulfur from both steps leaves the system as a SO2 gas, which 

is collected and most often processed into sulfuric acid 

(2.3 t of sulfuric acid per 1 t of copper contained in anodes). 

A refining furnace (the third step) receives converter copper 

(about 98 percent copper), oxygen is added to obtain 99 

percent copper (complete sulfur removal), and then carbon 

is added to reduce oxygen in the copper metal. The copper is 

usually cast into moulds shaped as copper anodes. Smelting 

and refining together produces 2 t of slag per 1 t of copper 

contained in anodes (Goonan, 2004).

Figure 4. Diagram showing the pyrometallurgical smelting and electrorefining process steps for the production of 

refined copper. The sources and distribution of U.S. copper supply and scrap recycling are understood to be in terms 

of “recoverable” copper. Dissipative losses are not identified, though they are understood to exist. Values are in mass 

units per one mass unit of copper cathode. Source: Goonan, 2004.

Mine deposit Mine waste

Crushing and grinding

Flotation Mill tailings

Copper concentrate (30 percent copper) 

Smelting furnace Converting furnace Refining furnace

Electrolytic refining Anode casting

Slag (iron separation)

Gas (sulfur separation)

Acid plant Sulfuric acid

Oxygen

Flux

Oxygen

Flux

Oxygen

Carbon

210

116

113

3

1.5

0.3

0.3

0.1

2

1

2.3

1

Matte recycle

0.13

Ore (0.5 percent copper)

Blister copper

(98 percent copper)

Matte

(50–70 percent copper)

Cathode

(99 .99 percent copper)

Fire-refined copper

(99 percent copper)

Anode

(99 percent copper)
X10 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

The anodes are transported to a different facility 

for electrolytic refining to obtain 99.99 percent copper 

cathode. Electrolytic refining cells dissolve copper from a 

copper anode into the electrolyte and plate copper from the 

electrolyte to the copper cathode. Trace metals either collect 

(antimony, bismuth, gold, lead, platinum, selenium, silver, 

tellurium, and tin) in anode slimes, which drop to the bottom 

of the cell and are physically removed and further processed, 

or remain (cobalt, iron, nickel, and zinc) in solution in the 

electrolyte, thus requiring a bleed stream offtake to remove 

and recover the residuals and reconstitute the electrolyte 

(Vlaamse Technische Kring, 2006).

HYDROMETALLURGY AND ELECTROWINNING 

PROCESSES

The world copper industry’s most widely used and 

productive hydrometallurgical process for recovering copper 

directly from ore is solvent-extraction/electrowinning 

(SX–EW). Figure 5 shows the process flow steps for the SX–

EW process.

Leaching and SX–EW processing for direct copper 

cathode production is very effective for recovering copper 

metal from the oxide ores of copper. These ores occupy the 

upper reaches of porphyry copper-sulfide deposits, where the 

sulfide mineralization has been oxidized under near-surface 

physical conditions. Some ore is mined and placed directly 

on leach pads, a small amount is leached in situ, but most is 

crushed to expose more surface area for chemical reaction. 

Leaching pads are usually lined with high-density polyethylene 

to prevent losses of valuable copper-bearing solutions and to 

restrict release of solutions that contain contaminants to the 

environment. The piles of copper ore (ranging from 0.1 to 

1.0 percent copper) being leached are called lifts. A typical 

leaching lift ranges in height from 30 to 150 meters. The top 

surface area is frequently more than 15,000 square meters, 

and the timeframe for leaching to reach optimum completion 

(about 60 percent copper recovery for the first exposure to 

leaching fluids)9

 ranges between 90 and 120 days.

9

The ultimate copper recovery is greater than 60 percent when residual 

leaching (multiple exposures to leaching fluids) is considered.

Figure 5. Diagram showing the hydrometallurgical solvent-extraction and electrowinning process 

steps for the production of refined copper. Except for sulfuric acid, flow values are in mass units of 

contained copper per one mass unit of copper cathode. The value of sulfuric acid is in mass units for 

93-percent sulfuric acid per one mass unit of copper cathode. Lifts are 30 to 150 meters high, greater 

than 15,000 square meters in top area, and there are 90 to 120 leach days per list.

SX loading SX stripping

Leach lift

1.0

Water

Acid leach solution

(applied at 0.24 liters per 

minute per square meter)

Acid makeup 

for pH control

Selected, proprietary 

organics to facilitate 

copper separation

(~1 liter per liter of 

electrolyte flowing)

Lean electrolyte

1.9

Copper cathode

Copper ore

(0.1–1.0 

percent copper)

5.1 Sulfuric acid

15.3

Raffinate

0.2

Pregnant

leach solution

3.1

Loaded 

organics

2.9

Unloaded 

organics

1.9

Copper electrowinning

Rich electrolyte

1.9
COPPER RECYCLING IN THE UNITED STATES IN 2004 X11

The pile is usually preconditioned chemically, based on 

the chemical makeup of ore and host rock, surface disturbed, 

and then saturated with a dilute sulfuric acid solution (at a rate 

of about 0.24 liters per minute per square meter) to dissolve 

copper into a copper-enriched solution that gravitationally 

migrates to the bottom of the pile where it collects in a 

lined pond. The pregnant leach solution (PLS) contains high 

concentrations of dissolved metals.

The PLS pond is continually tapped for a designed 

flow into a solvent-extraction facility. There, the PLS is 

mixed with a combination of organic materials designed 

(on a facility-specific basis) to preferentially uptake copper. 

The copper-depleted PLS (raffinate) returns to the leaching 

area where it is mixed with water and sulfuric acid and is 

reapplied to the ore on the leach pad. The organics, now 

loaded with copper, are mixed, in another tank, with pHadjusted lean electrolyte from the electrowinning process 

in order to strip copper from the organics. The resulting 

rich electrolyte flows to the electrowinning cells, and the 

depleted organics are recycled to the solvent-extraction 

loading tanks.

The copper is stripped from the electrolyte through 

electrowinning. Electrowinning is different from electrolytic 

refining, which is downstream from pyrometallurgical 

processing. The electrowinning cell has a cathode starter plate 

and an inert (instead of copper) anode made of a lead alloy. 

The copper to be collected at the cathode is withdrawn (by 

chemical reduction of copper ions) from the electrolyte, so the 

electrolyte needs to be continually replenished with copper 

ions, which are obtained from the solvent-extraction process.

Hydrometallurgical adaptations and technology 

advancements have extended the applicability of 

hydrometallurgy beyond oxide ores (Taylor and Jansen, 

2000). Pressure leaching at elevated temperatures in 

autoclaves and additions of biologic bacterial agents into the 

process allow hydrometallurgical treatment of sulfide ores 

and standard sulfide concentrates from flotation mills (Taylor, 

2002; Phelps Dodge Corporation, 2007).

SEMIFABRICATION PROCESSES

Figure 6 is a stylized representation of the processing 

paths for copper scrap as it is collected and processed to 

Smelting

furnace

Converter

Fire

refining

Blister copper

Sweating furnace

Melting and

alloying furnace

Holding

furnace

Casting

Slag Fuel

Flux

Copper or copper alloys

Copper or copper alloys

Exports

Byproducts

Supply of recoverable copper from sorted copper and copper alloy scrap

Fuel

Flux

Wire chopper Picking and

other

Anode

Copper and copper-alloy 

scrap requiring no 

upgrading

Copper rod, copper, 

and copper alloy 

shapes

Copper and copper-alloy scrap requiring upgrading

Copper and 

copper-alloy scrap

Lead, solder, 

babbitt metal

Copper scrap Copper scrap

Copper

Air

Fuel

Air

Fuel

Flux

Air

Fuel

Flux

Wire burner

Brass and bronze scrap

Brass and bronze

Electrorefining

Refined copper 

from scrap

Copper Copper and 

copper alloys

Copper Slag

Figure 6. Process flow chart (unquantified) for copper scrap. Adapted from U.S. Environmental Protection Agency, 

1995.
X12 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

support production of refined copper, copper rod and wire, 

copper alloys and chemicals, and alloyed castings and shapes.

Before use, copper scrap may or may not require some 

upgrading in terms of identity and (or) physical character. 

Processing scrap through picking and sorting processes, 

sweating furnaces, wire burners, and wire choppers will 

accomplish the upgrading task. The sum of the product of 

scrap upgrading and the scrap that does not require any 

upgrading is the supply of recoverable copper from sorted 

copper and copper alloys, which is taken by smelters, fire 

refiners, brass mills, wire rod mills, ingot makers, foundries, 

and other manufacturers to make copper-bearing products.

Scrap upgrading can be undertaken by scrap-handling 

specialists or by scrap consumers that have the capability. 

Typical sources of copper scrap include construction 

demolition debris, junked automobiles, and electronic scrap 

collection. Electronic and auto scrap may be processed 

through shredding and sorting (screening, magnetic, and 

other) to produce a copper-bearing fraction. Wire goes 

through a chopping operation10 to remove the insulation from 

the copper, and the copper is ready to proceed to a consumer’s 

melting or alloying furnace. Copper alloy scrap may be 

passed through a sweating furnace, which provides enough 

heat to melt and recover lead from solder and babbitt metal. 

The remaining copper alloy is then ready to be processed 

directly in a melting or alloying furnace.

At the melting or alloying furnace, the copper, copper 

alloy, and makeup alloys are blended to make a new alloy to 

a desired chemical specification. This product is then cast to a 

desired form. In the case of wire rod production, the melting 

furnace handles mainly copper and produces rod for further 

processing to wire in a wire mill. In the case of brass mill and 

foundry production, the scrap entering the alloying furnace 

is more likely to be already alloyed. The following section 

describes some of the furnace types that can participate in the 

flows pictured in figure 6.

Types of Furnaces Used in Semifabrication of Copper 

and Copper Alloy Products.—As described by Jolly (2006, 

p. 34–36), semifabrication copper production uses various 

types of scrap melting furnaces, depending on the material 

being melted. Electric arc furnaces were once popular,but 

have lost favor, in part because hydrogen absorbed from the 

air shortened electrode life.

ASARCO Incorporated (Asarco) shaft furnaces are used 

for melting pure copper cathodes for feed to continuous wire 

rod casting. Under certain circumstances, limited quantities of 

high-grade scrap may be added to the melt without previous 

refining. Asarco shaft furnaces were first built in the 1950s 

and are manufactured in many sizes. They are shaft furnaces 

shaped internally like an inverted cone, about one-half as wide 

at the bottom as at the top. The fuel-to-air mixture, where the 

fuel can be a variety of gases, is kept slightly reducing.

10Historically the insulation on wire was burned off.

Crucible furnaces are used for a fairly large amount of 

secondary copper production. They are fired by hydrocarbon 

gases and oils. They are used for melting clean, well 

segregated scrap, mostly in foundries. Scrap is usually melted 

in crucibles by puddling—that is by melting enough to make 

a liquid puddle, then submerging additional scrap into the 

melt to become part of the molten material. Such furnaces 

can be stationary or tilting.

Blast furnaces are used for melting low-grade copper and 

brass scrap, refinery slags, drosses, and skimmings. In such 

cases, the material is melted under reducing conditions, and 

the product is a copper matte and slag. When a furnace is used 

for melting only scrap, with no chemical reduction required, 

it is called a cupola. These furnace operations are carried out 

in a shaft furnace mode with unmelted material charged at the 

top and countercurrent air forced upwards through the charge. 

The melted material collects at the bottom and is periodically 

collected. Oxides of the base metals other than copper dissolve 

in the slag, fume off, or are reduced and dissolved in the copper 

melt. The product of the blast furnace is called black copper 

and may contain any or all of the elements commonly found in 

copper alloy scrap. Fumed materials are recovered in baghouses 

and treated for their metal content. A typical product may 

contain 75 to 88 percent copper, 4 to 10 percent zinc, 1.5 percent 

tin, 1.5 percent lead, 0.5 to 1.5 percent iron, 0.5 to 1.25 percent 

sulfur, and 0.1 to 0.7 percent antimony. The calcium-iron-silica 

slag may also contain up to 1.5 percent copper.

Reverberatory furnaces are box-like refractory-lined 

structures designed to heat the charge by both conduction and 

radiation. They are called reverberatory furnaces because the heat 

from the bath (molten metal plus slag) is radiated (reverberated) 

from the roof back to the bath. These furnaces can be quite large 

and are used for melting scrap containing more than 40 percent 

copper. A few of these types of furnaces are operated by fire 

refiners associated with tube mills. All the former large-scale 

reverberatory furnace operations in the United States have been 

shut down because of the high cost of operation under current 

pollution control requirements. The closure of reverberatory 

furnaces has reduced U.S. recycling of low-grade scrap.

Converters, which are part of the stepwise process for 

producing primary copper, use copper scrap as feed and for 

cooling and process temperature control. Converters are also 

used to process the black copper product of blast furnaces. 

The product of the converter is called blister copper.

Top-blown rotary converters are sometimes used to 

smelt and refine copper-bearing materials. Some believe that 

they are more flexible than reverberatory furnaces and can be 

operated in semicontinuous mode. They can accommodate a 

wide variety of change materials. These furnaces can meet 

stringent environmental standards. Capacities run about 45 

metric tons per day of alloy.

Low-frequency electric induction furnaces are used by 

brass mills and ingot makers to melt high-quality scrap and 

zinc slab in small batches (about 5 t of metal). Melting rates are 
COPPER RECYCLING IN THE UNITED STATES IN 2004 X13

high, and pollution losses are small. These furnaces produce 

alloys to specification for casting into billets and other shapes.

Sweating is the name given to heating (below the melting 

point of copper and copper alloys) scrap types that contain 

low-melting lead alloys, such as borings, lead-sheathed cable, 

radiators, and auto shredding, which contain valuable lowmelting point metals. Sweating recovers the valuable lead 

alloys while upgrading the scrap for smelting or direct melt 

applications. Reverberatory, muffle, and sloping and vibrating 

hearth-fired furnaces have been used for this purpose.

USES OF COPPER-CONTAINING 

MATERIALS

Copper has been useful to humankind for thousands 

of years because of the metal’s attractiveness, conductivity 

(electrical11 and thermal), corrosion resistance, ductility, 

malleability, and strength. It is readily alloyed with other 

metals and forms many useful chemicals. Bronze, a family of 

alloys of copper and tin, has even given its name to a historical 

timeframe called the “Bronze Age,” variously experienced by 

different cultures within a general time bracket from 3300 

through 600 BCE; the time period came to be known by this 

name because tools and weapons were made of bronze rather 

than the previously used stone (Cowen, 2008).

COPPER END-USE BY ECONOMIC SECTOR

From 1980 through 2004, the U.S. consumption of 

copper by sector end-use is shown in figure 7.

11Electrical applications account for more than 70 percent of U.S. 

consumption.

Figure 7. Chart showing U.S. end-use consumption of copper by economic sector from 1980 through 2004. Values are in 

metric tons of copper contained. Sources: Copper Development Association Inc., 2005; Kelly and Matos, 2006. END USE, IN THOUSANDS OF METRIC TONS

TIME INTERVAL, IN YEARS

EXPLANATION

3,500

1980 1985 1990 1995 2000 2005

3,000

2,000

2,500

1,000

1,500

500

0

Consumer and general uses

Transportation equipment

Industrial machinery and equipment

Electrical infrastructure and electronic devices

Building and construction
X14 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

In 2004, copper consumed by the building and 

construction sector amounted to 49 percent of the market; 

correspondingly, electrical and electronic applications 

comprised 21 percent; industrial machinery and equipment, 9 

percent; transportation equipment, 11 percent; and consumer 

and general use, 11 percent (Edelstein, 2007).

Table 4 lists the annual growth rate trends for various 

consumer and industrial end-use sectors of the economy for 

copper contained in semifabricated products for the period 

from 1980 through 2004.

For the period from 1980 through 1999, all sectors with 

the exception of industrial machinery experienced average 

annual growth rates between 2 and 5 percent. Building 

and construction (5 percent) and electrical and electronics 

(3 percent) showed the most robust growth. For the period 

from 2000 through 2004, every sector declined with building 

and construction showing the least decline (1 percent). 

Electrical and electronics declined by 8 percent, industrial 

machinery declined by 4 percent, and consumer and general 

declined by 3 percent.

COPPER END-USE AS ALLOYS AND CHEMICALS

Copper, whether pure, alloyed, or combined into a 

chemical formulation, is of great economic importance. 

In this section, some of the more common copper-bearing 

products are discussed.

COPPER METAL

After silver, copper has the highest electrical 

conductivity (95 percent of the electrical conductivity of 

silver) among metals. Because silver prices range from 50 

to 80 times that of copper, copper is a preferred material 

for electricity production and distribution in such products 

as building wire, telecommunications cables, magnet 

(winding) wire, printed circuit board conductors and a host 

of other electrical applications. It has sufficient strength, 

ductility, and hardness for these applications at operating 

temperatures up to 100°C (Callcut, 2006). The addition of 

alloy elements, while diminishing the electrical properties 

somewhat, adds strength and higher temperature service, 

often an acceptable tradeoff. Small (less than 1 percent) 

additions of phosphorous and tellurium increase the 

toughness and machineability of copper intended for use as 

liquid conduits (plumbing pipe and tube) (Anchor Bronze 

and Metals, Inc., 2007).

COPPER CHEMICALS

Though they constitute a small percentage of total 

copper demand, copper chemicals (acetates, chlorides, 

cyanides, hydroxides, nitrates, oxides, and sulfates) are used 

as algicides, antifouling agents, disinfectants (for seed), 

(animal) feed additives, fertilizers, fungicides, inorganic 

dyes, pesticides, and wood preservatives. Copper chemicals 

are also used in electroforming, medicines, pharmaceuticals, 

and photography (Department of Environment and Water 

Resources, Australia, 2007). By volume, copper sulfate is the 

most prevalent chemical and is frequently used as feedstock 

for other copper chemical production. Copper sulfate and 

oxide can be produced either from primary or scrap materials. 

In 2004, 12,000 t of copper was contained in copper-bearing 

chemicals produced from scrap materials in the United States 

(Edelstein, 2007, table 6).

HIGH-COPPER ALLOYS

High-copper alloys usually contain more than 94 percent 

copper. The addition of beryllium (0.5–2.0 percent by weight) 

to copper produces alloys that exhibit high electrical and 

thermal conductivity, good corrosion and fatigue resistance, 

high strength and hardness, and nonmagnetic properties. 

Copper-beryllium alloys average about 70 percent of annual 

U.S. consumption on a beryllium metal equivalent basis 

(Cunningham, 2003). The alloys are used for such applications 

as bearings, brake drums, electrical connectors, molds, 

springs, and welding electrodes (Automation Creations, Inc., 

2007). In 2004, the U.S. consumption of copper-beryllium 

alloys accounted for about 5,000 t of copper and 91 t of 

beryllium contained therein (Shedd, 2008).

The addition of cadmium (0.8–1.2 percent by weight) 

to copper nearly doubles the mechanical strength and wear 

resistance of pure copper while retaining 90 percent of its 

conductivity. Major uses for such alloys include contact wire 

and catenary strand for railway overhead electrification, 

electrical components (such as contact strips), special cables 

for military and aerospace uses, and telephone drop wire 

(International Cadmium Association, 2007). The United 

States consumed about 500 t of cadmium in 2004, of which 

about 0.3 percent was in the form of copper-cadmium 

alloy (98 percent copper and 1.0 percent cadmium), which 

computes to about 2,000 t of copper and 1.5 t of cadmium 

contained in such alloys (Morrow, 2005).

Table 4. Average annual growth rates for U.S. 

consumption of copper as contained in semifabricated 

products from 1980 through 2004, by industrial sector.

[Values are in average annual percentage change. Calculated from original 

data reported in Copper Development Association Inc., 2005a; and Kelly 

and Matos, 2006]

Economic sector 1980–1999 2000–2004 1980–2004

Building and construction........ 4.77 -0.65 3.76

Electrical and electronic........... 2.77 -7.68 1.27

Industrial machinery ................ 0.00 -3.93 -0.61

Transportation equipment ........ 1.74 -2.18 0.64

Consumer and general.............. 1.50 -2.90 1.52
COPPER RECYCLING IN THE UNITED STATES IN 2004 X15

The addition of chromium (0.6–1.2 percent chromium 

by weight) nearly doubles the mechanical strength of pure 

copper, while retaining 85 percent of its conductivity, 

and improves corrosion resistance (Copper Development 

Association, 2007a). Major uses for such alloys include 

resistance welding electrodes, seam welding wheels, switch 

gears, connectors, circuit breaker parts, molds, spot welding 

tips, and electrical and thermal conductors that require 

strength (Copper Development Association, 2007a). Copperchromium alloy consumption data are unavailable; however, 

the amount of copper associated with copper-chromium alloy 

consumption is estimated to be on the order of thousands of 

metric tons.

COPPER-ALUMINUM AND ALUMINUM-COPPER 

ALLOYS

The copper content of copper-aluminum alloys ranges 

from about 70 to 90 percent copper (average copper content is 

about 85 percent by weight), the balance being aluminum and 

perhaps small amounts of other elements. Bolts, bushings, 

cams, and gears made from these materials are corrosion 

resistant with good strength (Anchor Bronze and Metals, 

Inc., 2007). In 2004, the United States produced 6,000 t of 

aluminum bronze materials that contained about 5,000 t of 

copper (Edelstein, 2007, table 8).

Aluminum bronze is a type of bronze in which 

aluminum is the main alloying element added to copper. 

Aluminum bronzes are most valued for their higher strength 

and corrosion resistance compared with other bronze alloys. 

They have low oxidation rates at high temperatures and low 

reactivity to sulfurous compounds and other exhaust products 

of combustion. They are also resistant to sea water corrosion. 

Aluminum bronze castings have exceptional corrosion 

resistance; high strength, toughness, and wear resistance; 

and good casting and welding characteristics (Copper 

Development Association, 2008). Aluminum-copper alloys 

contain copper in the range of 1 to 6 weight percent and do 

not represent a significant flow of copper.

COPPER-NICKEL AND NICKEL-COPPER ALLOYS

The copper-nickel alloys include cupronickels 

(68–88 percent copper and 10–30 percent nickel) and nickel 

silvers (55–65 percent copper, 12–25 percent nickel, and 

3–27 percent zinc) (Anchor Bronze and Metals, Inc., 2007). 

Because copper-nickel alloys are corrosion and oxidation 

resistant and thermally stable, they are used in marine and 

powerplant applications, such as condenser tubes, valves, 

pumps and fittings (Copper Development Association, 

2007b).

Nickel silvers (referring to their luster, not silver 

content) or nickel brasses have moderately high strength 

and good corrosion resistance (Copper Development 

Association, 2007d). They are most often used for 

housewares and giftware (Smiths Metal Centers, 2006). 

In 2004, U.S. manufacturers produced 3,000 t (containing 

about 2,000 t of copper) of nickel silvers (Edelstein, 2007, 

table 8; Kuck, 2007, table 4).

Nickel-copper alloys are called monels (30–33 percent 

copper and 63–65 percent nickel), and these, like cupronickels, 

are used largely in marine applications where the properties 

sought are resistance to biofouling, corrosion, and erosion 

(Greetham, 2003). In 2004, U.S. manufacturers produced 

27,000 t (containing about 19,000 t of copper) of cupronickel 

alloys (Kuck, 2007, table 4).

COPPER-TIN ALLOYS

The copper-tin alloys or tin bronzes (70–90 percent 

copper, 5–12 percent tin, balance other metal) have good 

corrosion resistance and are stronger and more ductile 

than brass. Additions of lead (6–12 percent) diminish alloy 

strength but enhance machineability (Copper Development 

Association, 2007c).

Bronze alloys (22–24 weight percent copper) are used for 

making bells, cymbals, and cast metal sculpture (Bhadeshia, 

2005). When struck against a hard surface, bronze will not 

generate sparks. Bronze hammers, mallets, wrenches, and 

other durable tools can be used in explosive atmospheres or 

in the presence of flammable vapors (Canadian Centre for 

Occupational Health and Safety, 1999). In 2004, 36,000 t 

(containing about 29,000 t of copper, 3,000 t of tin, and 4,000 

t of other metals) of copper-tin alloys was produced in the 

United States (Carlin, 2006).

COPPER-ZINC ALLOYS

Copper-zinc alloys normally, though not always, called 

brasses include between 10 and 40 percent zinc and often other 

elements (lead, tin, other) to provide special characteristics. 

The average copper content of copper-zinc alloys is about 73 

percent.

Brass is used in decorative and artistic applications, 

hardware, munitions, and plumbing. Leaded brasses contain 

from 0.5 to 3 percent lead and are used as pump cylinder 

liners, plumbing accessories, gears, and pinions because the 

addition of lead improves the alloy’s machineability (Anchor 

Bronze and Metals, Inc., 2007). In 2004, 322,000 t of brass 

(containing about 226,000 t of copper and 97,000 t of zinc) 

was produced by U.S. brass producers (Jorgenson, 2007).

PRICES

Copper metal (99.99 percent pure cathode) is traded 

on the London Metal Exchange (LME), the New York 

Merchantile Exchange’s COMEX Division (COMEX), and 

the Shanghai Commodity Exchange. Prices established by 

the exchanges are the basis for most physical transactions, 

with producers and merchants adding a premium to the 
X16 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

exchange price to cover shipping and storage costs and profit. 

Prices on the COMEX and LME track closely (usually not 

varying more than 5 cents per pound on any given day), the 

differences being attributable to local market conditions 

and changes in currency exchange rates. Copper scrap is 

not traded on these exchanges. However, scrap prices are 

negotiated as either a discount from or premium addition to 

the price of refined copper as determined by the commodity 

exchanges (Burghardt, 2004).

There are many factors that determine copper scrap 

prices including local supply and demand for a particular 

type of scrap. conversion costs, transportation costs, and 

current prices for the metals contained in the scrap (copper, 

zinc, other). Competition for domestic copper scrap from 

Chinese companies has shrunk scrap discounts below what 

they might have been, prior to their entry into the market, 

for material delivered to U.S. brass mills and others, thereby 

increasing their relative raw material costs (Burghardt, 

2004).

Figure 8 shows market price indices12 for primary copper 

metal and its major alloying elements (aluminum, lead, 

nickel, tin, and zinc) for the period from 1954 through 2007. 

The base year for the price indices is 1991. Temporal datasets 

are of interest for context and projection. In this particular 

temporal dataset, prices (in terms of indices) fall into three 

fairly distinct regions in figure 8. For the period from 1954 

through 1973, the prices for all metals are relatively stable 

(flat line) with low volatility (little variance). The index 

averages (which reflect price level compared with the average 

price during the base year) plus or minus (±) a standard 

deviation (which reflects price volatility) for the 1954–73 

12The index for the commodity is defined as the nominal annual average 

price for the commodity in a given year divided by the nominal annual 

average price for the commodity in 1991. The base year 1991 was selected 

because it was a year where volatility (variability around the average) for 

most of the selected commodities was low. The reason for constructing a 

price index, rather than just plotting prices, was to represent all commodities 

at the same scale to facilitate comparison.

INDEX OF NOMINAL METAL PRICES FROM 1954 THROUGH 2007, IN 1991 U.S. DOLLARS

TIME INTERVAL, IN YEARS

5.0

1954 1959 1964 1969 1974 1979 1984 1989 1994 1999 2004

4.0

3.0

1.0

2.0

0.0

Decoupling of U.S. 

dollar from gold Index year

Increased demand for 

metals from China begins

Aluminum

Lead

Tin

Copper

Nickel

Zinc

EXPLANATION

Figure 8. Chart showing indexed prices for copper and its major alloying elements from 1954 through 2007. Base year is 

1991. Values represent the index of the selected commodity’s nominal price for the year in question divided by its price in 1991. 

The values for copper metal prices are in dollars per kilogram metal as reported by the COMEX Division of the New York 

Mercantile Exchange. Sources: U.S. Geological Survey, 1999, 2004, 2005, 2006. 
COPPER RECYCLING IN THE UNITED STATES IN 2004 X17

period for each element were aluminum, 0.42 ±0.03; copper, 

0.36 ±0.09; lead, 0.40 ±0.05; nickel, 0.25 ±0.07; tin, 0.21 

±0.06; and zinc, 0.26 ±0.05.

In 1973, the dollar was decoupled from gold. The result 

was an increase in the price levels and the price volatility for 

the metals in question. For the period from 1974 through 2004, 

the index averages ± standard deviation for the elements were 

aluminum, 1.11 ±0.27 (a price level increase of 160 percent 

and a volatility increase of 870 percent); copper, 0.84 ±0.24 

(a price level increase of 136 percent and a volatility increase 

of 161 percent); lead, 1.11 ±0.31 (a price level increase of 

179 percent and a volatility increase of 302 percent); nickel, 

0.86 ±0.37 (a price level increase of 247 percent and a 

volatility increase of 410 percent); tin, 0.73 ±0.22 (a price 

level increase of 246 percent and a volatility increase of 283 

percent); and zinc, 0.91 ±0.22 (a price level increase of 249 

percent and a volatility increase of 375 percent).

After 2004, China became a heavy user of these elements, 

and figure 8 shows the resulting price increases from the 

previous period’s averages. These Chinese demand-driven 

prices may or may not be sustainable in the long run. Since 

January 1, 2006, nominal prices for nickel rose to peak in May 

2007 at four times the price in January 2006, followed by a 

decline by August 2008 to 40 percent more than the January 

2006 price. The nominal price for copper, on the other hand, 

has held steady at roughly 60 percent higher than the January 

2006 level for the period from May 2006 through August 2008.

 “No. 1 heavy and wire” copper scrap is an unalloyed 

copper scrap. “Automobile radiators (unsweated)” is a 

medium quality brass scrap. Figure 9 compares monthly 

dealer prices for these two copper scrap types with COMEX 

copper metal prices for the period from January 1997 through 

February 2007.

Copper scrap has historically closely followed copper 

metal prices. Based on the data underlying figure 9, for the 

period from January 1997 through September 2003, the ratio of 

the price for “No. 1 heavy and wire” copper scrap to the price 

for copper metal averaged 0.73 ±0.07 (one standard deviation); 

the ratio of the price for “automobile radiators (unsweated)” 

copper scrap to the price of copper metal averaged 0.41 

±0.03 on a copper-content basis and 0.59 ±0.05 on a copperequivalent basis. On the basis of contained copper, the two 

DEALER PRICES FOR THREE SCRAP TYPES BY MONTH 

FROM 1997 THROUGH 2007, IN DOLLARS PER KILOGRAM

TIME INTERVAL, IN MONTHS AND YEARS

9.00

8.00

7.00

6.00

5.00

4.00

3.00

2.00

1.00

Jan. 97 Jan. 98 Jan. 99 Jan. 00 Jan. 01 Jan. 02 Jan. 03 Jan. 04 Jan. 05 Jan. 06 Jan. 07

0.00

Copper

No. 1 wire

Radiators

EXPLANATION

Figure 9. Chart showing monthly dealer prices of “no. 1 heavy and wire,” “automobile radiators (unsweated),” and copper 

metal from 1997 through 2007. The values for scrap prices are dealer purchasing prices in dollars per kilogram at Chicago, Ill. 

The values for copper metal prices are in dollars per kilogram metal as reported by the Commodity Exchange, Inc. division of 

the New York Mercantile Exchange. Sources: American Metal Market, 2007; Futures Trading Charts, 2007.
X18 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

scrap classes are discounted from high-grade refined copper, 

on average, by 27 and 41 percent respectively.

From October 2003 through February 2007, prices for 

all copper metal and alloys have increased markedly. During 

this period of increasing prices, the relative ratios have also 

changed. The new ratio of “No. 1 heavy and wire” copper 

scrap price to copper metal price averaged 0.66 ±0.07, and 

the new ratio of “automobile radiators (unsweated)” copper 

scrap price to copper metal price averaged 0.32 ±0.03.

The Institute of Scrap Recycling Industries, Inc. (ISRI) 

recognizes about 53 classes of copper and copper alloy scrap 

(Jolly, 2006, p. 19). Table 5 lists some of the more significant 

ISRI copper scrap classifications and their most likely 

recycling user.

Dealer prices are paid to those delivering scrap to the 

dealer’s scrap yard. Consumer prices are those paid by 

purchasers of processed scrap. Copper scrap prices vary by 

grade and with local conditions.

SOURCES AND DISPOSITION

OF COPPER SCRAP

There are two conditions necessary for recycling to occur. 

First, there must be a supply of material. Many materials 

dissipate with use and cannot be recycled (for example, 

fertilizer). While small amounts of copper are dissipated in 

use, the vast majority of the mass of copper placed in service 

is conserved, losing only its economic utility with use. These 

copper sources are candidates for recycling, and there is a 

ready supply. Second, the cost of identifying, collecting, 

processing, and transporting scrap materials must be low 

enough to provide a profit margin for the entity performing 

that task to do so. Metals are relatively scarce and thus 

generally have prices high enough to cover the recycler’s costs 

and provide the recycler’s required margin. During periods of 

low prices, margins decrease, and the cost of collection for 

certain scrap types may become prohibitive, which leads to 

Table 5. Copper scrap classifications and most likely users.

[Values are denominated in column headings. NA, not available. Source: Jolly, 2006, p. 20–21, 69]

ISRI scrap type

Copper 

content,

in percent

Other metal content, in percent Priority users

Unalloyed copper scrap

No. 1 copper.................................................................... 99.5 Brass and wire rod mills.

No. 2 copper, mixed, light............................................... 96.8 Fire refiners, ingot makers.

Other ............................................................................... 96.5 NA.

Copper-base alloy scrap

High coppers: beryllium, cadmium, or chromium.......... 96.4 Nickel or cobalt, 1.5; other, 1.4

Red brass......................................................................... 92.5 Lead, 1.45; zinc, 7.0 Ingot makers and foundries.

Tin bronze, phosphor bronze .......................................... 82.1 Tin, 13.0; zinc, 2.6; nickel or cobalt, 1.3 Foundries.

Leaded red and semired brass......................................... 80.5 Tin, 4.0; lead, 5.3; zinc, 10.5 Foundries.

Copper-nickel alloys....................................................... 80.1 Nickel or cobalt, 17.5; manganese, 1.5 Foundries.

Silicon bronze and brass ................................................. 78.5 Zinc, 18; manganese, 0.75 Foundries.

Tin brasses....................................................................... 72.5 Tin, 2.1; lead, 1.3; zinc, 23.2 Brass mills.

High leaded tin bronzes .................................................. 68.5 Tin, 7.8; lead, 20.5; zinc, 2.0 Brass mills.

Yellow leaded and heavy brass ....................................... 66.0 Tin, 1.4; lead, 2.6; zinc, 30.5 Brass mills.

Yellow and low brass, and other copper-zinc brasses..... 73.8 Zinc, 24.5; aluminum, 4.0 Brass mills, foundries.

Copper-nickel-zinc alloys............................................... 57.8 Tin, 3.5; lead, 5.6; zinc, 13; nickel or cobalt, 

15.5; manganese, 1.5

Foundries.

Manganese bronze .......................................................... 51.8 Tin, 1.0; zinc, 32.0; aluminum, 4.0; nickel or 

cobalt, 2.0; manganese, 2.5

Foundries.

Aluminum bronze ........................................................... 79.5 Aluminum, 9.75; nickel or cobalt, 2.8; manganese, 7.0; other, 2.5Foundries.

Common scrap groups

Water meters ................................................................... 63.5 Lead, 1.2; zinc, 34.7 Foundries.

Auto radiators (ocean)..................................................... 69.0 Tin, 4.0; lead, 9.5; zinc, 12.5 Foundries.

Cocks and faucets (grape)............................................... 59.0 Tin, 1.0; lead, 4.0; zinc, 24.0 Foundries.

Cartridge cases and brass................................................ 70.0 Zinc, 29.9 Brass mills.

Refinery brass (drink) .................................................... 61.3 Other, 39.0 Brass mills, ingot makers, and foundries.

Aluminum or copper radiators........................................ 45.6 Aluminum, 54.0 Foundries and brass mills.

Copper-bearing material ................................................. 40.0 Other, 60.0 Ingot makers and chemical plants.
COPPER RECYCLING IN THE UNITED STATES IN 2004 X19

declines in the recovery of copper from scrap. When scrap 

prices are high enough to cover the cost of recycling and 

provide a suitable profit, one can expect copper recovery 

from scrap to increase. In some instances, disposal costs may 

serve as a credit to the value of recovered metal and provide 

additional margin or incentive for recovery. Recycling can be 

increased if subsidized through policy.

This section examines the sources and distribution of 

recyclable copper scrap, both new and old.

Figure 10 shows sources and distribution of new and 

old scrap in the United States in 2004. It was assumed that 

old scrap supplied the export market and that new scrap was 

returned to U.S. smelters and first-use consumers (if not 

entirely, then almost so).

In 2004, 1.92 Mt of copper was contained in old scrap 

derived from the U.S. product reservoir based on estimates of 

loss of utility for sectors within the reservoir, and 735,000 t of 

copper was contained in new scrap. Of the copper contained 

in new scrap, 95 percent was generated by manufacturers 

using semifabricated products, and 5 percent was generated 

from semifabrication processing by brass, wire rod and wire 

mills, ingot makers, foundries, and others. The 735,000 t of 

copper contained in new scrap was returned (recycled) to U.S. 

semifabricated product producers (97 percent), refined copper 

producers (2 percent), and noncopper producers (1 percent). 

Of the old scrap generated, 1.15 Mt of copper (60 percent) was 

unrecovered (left in place pending more favorable economic 

conditions, or landfilled), and 772,000 t (40 percent) was 

recovered. The copper contained in recovered old scrap 

was augmented by 80,000 t of copper contained in scrap 

imports and 3,000 t of copper contained in stock drawdown, 

to provide a total of 855,000 t of copper contained in old 

scrap processed. This supply of old scrap to be processed 

was distributed as 74 percent for exports, 20 percent for U.S. 

copper processors, and 6 percent for noncopper producers. 

U.S. copper processors received 895,000 t of copper as scrap, 

81 percent of which was new scrap, and 19 percent was 

old scrap. Semifabricators received 94 percent of the total, 

of which 84 percent was new scrap and 16 percent was old 

scrap. Primary refined copper producers received 6 percent of 

the total, of which 31 percent was new scrap and 69 percent 

was old scrap.

U.S. supply of semifabricated 

copper-bearing products after 

net trade and stock increase

Generated from U.S. 

semifabricator 

production

Exports

80

845

712

699

735

728

633

167

133

54

51

35

36

16

772

772

1,150

1,920

3,200 2,500

3

7

Imports

To

semifabricators

Stock 

change

To

smelters and 

fire refiners

Manufacturing

3,200

U.S. copper-based product 

reservoir net change

578

Theoretical old 

scrap generated

1,920

Old scrap 

unrecovered

1,150

Old scrap 

recovered

772

Noncopper 

processing

61

New scrap 

recovered/supply

735

Old copper 

scrap supply

855

Copper 

(contained in 

scrap) receipts 

(at U.S. 

smelters and 

semifabricators)

895

Copper product

New scrap

Old scrap

EXPLANATION

Figure 10. Diagram showing copper scrap generation and flow in the United States in 2004. Values are rounded to the nearest 

thousand metric ton of contained copper. The sum of the parts may not equal the totals shown owing to independent rounding. 

Sources: International Copper Study Group, 2005a, b; Jolly, 2006; Kelly and Matos, 2006; Baker, 2007; Edelstein, 2007.
X20 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

OLD SCRAP

Old scrap recycling efficiency shows the relation 

between what is theoretically available for recycling and 

what was actually recovered, and recycling rate is that 

fraction of apparent metal supply that is derived from 

scrap. In 2004, the domestic old scrap recycling efficiency 

for copper was estimated to be 43 percent of theoretical 

old scrap supply, and the recycling rate was 30 percent of 

apparent copper supply.

OLD SCRAP GENERATED

The USGS estimated that, in 2004, 1.92 Mt of copper 

contained in old scrap was generated as end-of-life material 

from the U.S. copper products in-service reservoir. The 

development of the estimate is shown in table 6, which 

considers the distribution of copper to defined economic 

sectors with annual variance included, the average life of 

products within sectors, and an assumption (in conformance 

to common practice) of Gaussian decay of economic utility 

of the scrap.

In table 6, the method for estimating old scrap generated 

is shown completely for the sector building and construction, 

and only the results are reported for the remaining sectors. 

The historic sector consumption data13 are from Kelly and 

Matos (2006), and the average life estimates for the sectors 

are from the report of the International Copper Study Group 

(2005a).

Most of the material from building and construction that 

loses economic utility, and therefore theoretically becomes 

available after an average 40-year life (averaged from data 

provided in International Copper Study Group, 2005a, 

p. 17–18), is derived from construction that consumed those 

materials about 40 years ago; the amount of old scrap generated 

decreases more and more as the year of consumption deviates 

from the 40-year lifecycle. In 2004, 563,000 t of copper 

13The data set published by Kelly and Matos (2006) covers the period 1975 

through 2004. To apply the Gaussian distribution for a longer lifetime and 

a larger spread, it was necessary to extrapolate the USGS data set to earlier 

years by application of selected sector participation fractions to total reported 

apparent consumption for those earlier years.

Table 6. The development of the estimate for old scrap generated in 2004.

[Consumption and old scrap generated are in metric tons of copper. The information in row “2004” is old scrap generated through 2003 and available for use 

in 2004, by sector, with the total at the lower far right corner of the table. —, zero; NA, not available. Sources: International Copper Study Group, 2005a; 

Jolly, 2006; Kelly and Matos, 2006]

Year

Product 

life,

in years

Building and construction Electrical and 

electronic 

products, 

old scrap 

generated

Industrial 

machinery and 

equipment,

old scrap

generated

Transportation 

equipment, old 

scrap generated

Consumer and 

general 

products, 

old scrap 

generated

Old scrap 

generated 

through 2003 

and available 

in 2004

Consumption Gaussian

distribution

Old scrap 

generated

1928...... 76 300,000 0.0000 3 — — — — 3

1929...... 75 310,000 0.0000 5 — — — — 8

1930...... 74 350,000 0.0000 8 — — — — 16

1931...... 73 330,000 0.0000 12 — — — — 28

1932...... 72 370,000 0.0001 21 — — — — 49

1933...... 71 400,000 0.0001 35 — — — — 84

1934...... 70 310,000 0.0001 39 — — — — 123

1935...... 69 230,000 0.0002 42 — — — — 165

1936...... 68 140,000 0.0003 38 — — — — 203

1937...... 67 180,000 0.0004 72 — — — — 275

1938...... 66 140,000 0.0006 75 — — — — 350

1939...... 65 250,000 0.0008 193 — — — — 543

1940...... 64 330,000 0.0011 354 — — — — 897

1941...... 63 330,000 0.0014 483 — — — — 1,380

1942...... 62 210,000 0.0019 416 — — — — 1,800

1943...... 61 320,000 0.0026 818 — — — — 2,610

1944...... 60 420,000 0.0034 1,403 — — — — 4,020

1945...... 59 660,000 0.0043 2,852 — — — — 6,870

1946...... 58 590,000 0.0055 3,244 — — — — 10,100

1947...... 57 590,000 0.0069 4,054 — — — — 14,200

1948...... 56 580,000 0.0086 5,000 — — — — 19,200

1949...... 55 550,000 0.0105 5,806 — — — — 25,000

1950...... 54 570,000 0.0127 7,271 — — — — 32,200

1951...... 53 540,000 0.0152 8,166 — — — — 40,400

1952...... 52 540,000 0.0178 9,614 — — — — 50,000
COPPER RECYCLING IN THE UNITED STATES IN 2004 X21

Year

Product 

life,

in years

Building and construction Electrical and 

electronic 

products, 

old scrap 

generated

Industrial 

machinery and 

equipment,

old scrap

generated

Transportation 

equipment, old 

scrap generated

Consumer and 

general 

products, 

old scrap 

generated

Old scrap 

generated 

through 2003 

and available 

in 2004

Consumption Gaussian

distribution

Old scrap 

generated

1953...... 51 440,000 0.0207 9,230 — — — — 59,300

1954...... 50 450,000 0.0238 10,666 — — — — 69,900

1955...... 49 520,000 0.0269 13,967 — — — — 83,900

1956...... 48 540,000 0.0301 16,312 — — — — 100,000

1957...... 47 520,000 0.0332 17,325 — — — — 118,000

1958...... 46 440,000 0.0361 15,958 — — — — 133,000

1959...... 45 550,000 0.0388 21,174 — — — — 155,000

1960...... 44 550,000 0.0412 22,593 — — — — 177,000

1961...... 43 490,000 0.0431 20,910 — — — — 198,000

1962...... 42 440,000 0.0445 19,518 — — — — 218,000

1963...... 41 520,000 0.0454 23,551 — — — — 241,000

1964...... 40 490,000 0.0457 22,176 — — — — 263,000

1965...... 39 510,000 0.0454 23,095 — — — — 286,000

1966...... 38 550,000 0.0445 24,435 — — — — 311,000

1967...... 37 570,000 0.0431 24,659 — — — — 336,000

1968...... 36 600,000 0.0412 24,522 — — — — 360,000

1969...... 35 660,000 0.0388 25,720 6 4 3 — 386,000

1970...... 34 740,000 0.0361 26,839 20 12 9 — 413,000

1971...... 33 620,000 0.0332 20,434 44 26 19 — 433,000

1972...... 32 640,000 0.0301 19,232 114 68 48 — 453,000

1973...... 31 690,000 0.0269 18,563 285 170 121 — 472,000

1974...... 30 610,000 0.0238 14,486 550 328 234 — 487,000

1975...... 29 470,000 0.0207 9,749 798 570 433 — 499,000

1976...... 28 610,000 0.0178 10,888 2,109 1,362 1,274 — 515,000

1977...... 27 660,000 0.0152 10,006 4,296 2,625 2,307 — 534,000

1978...... 26 780,000 0.0127 9,914 8,391 5,143 4,195 — 562,000

1989...... 25 780,000 0.0105 8,204 14,274 8,434 6,920 — 599,000

1980...... 24 700,000 0.0086 6,013 19,804 12,012 7,792 — 645,000

1981...... 23 730,000 0.0069 5,055 29,301 17,856 11,446 — 709,000

1982...... 22 600,000 0.0055 3,306 29,720 16,983 11,524 — 770,000

1983...... 21 740,000 0.0043 3,202 37,742 22,645 18,116 2 852,000

1984...... 20 780,000 0.0034 2,616 46,772 26,475 24,710 12 952,000

1985...... 19 860,000 0.0026 2,207 47,492 29,077 27,139 52 1,060,000

1986...... 18 880,000 0.0019 1,705 49,000 30,000 26,000 182 1,170,000

1987...... 17 950,000 0.0014 1,372 49,431 28,108 23,262 635 1,270,000

1988...... 16 910,000 0.0011 967 45,007 27,357 23,827 1,976 1,370,000

1989...... 15 890,000 0.0008 687 37,742 23,400 19,626 4,764 1,450,000

1990...... 14 870,000 0.0006 481 32,753 18,196 15,770 9,787 1,530,000

1991...... 13 880,000 0.0004 344 22,892 12,362 10,530 16,355 1,590,000

1992...... 12 950,000 0.0003 260 18,830 9,740 9,090 26,722 1,660,000

1993...... 11 1,030,000 0.0002 194 14,057 6,488 7,137 33,971 1,720,000

1994...... 10 1,100,000 0.0001 141 9,067 4,331 4,331 43,200 1,780,000

1995...... 9 1,040,000 0.0001 89 5,251 2,387 2,228 36,925 1,830,000

1996...... 8 1,160,000 0.0001 66 3,251 1,494 1,362 32,531 1,870,000

1997...... 7 1,230,000 0.0000 46 1,732 798 729 22,585 1,890,000

1998...... 6 1,270,000 0.0000 31 911 367 333 13,346 1,910,000

1999...... 5 1,350,000 0.0000 21 412 173 158 6,713 1,910,000

2000...... 4 1,300,000 0.0000 13 182 68 68 3,323 1,920,000

2001...... 3 1,150,000 0.0000 7 57 20 20 794 1,920,000

2002...... 2 1,250,000 0.0000 5 19 9 9 249 1,920,000

2003...... 1 1,170,000 0.0000 3 6 3 3 66 1,920,000

2004...... 0 NA NA 563,000 532,000 309,000 261,000 254,000 1,920,000

Table 6. The development of the estimate for old scrap generated in 2004—Continued.

[Consumption and old scrap generated are in metric tons of copper. The information in row “2004” is old scrap generated through 2003 and available for use 

in 2004, by sector, with the total at the lower far right corner of the table. —, zero ; NA, not available. Sources: International Copper Study Group, 2005a; 

Jolly, 2006; Kelly and Matos, 2006]
X22 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

contained in old scrap was theoretically generated from the 

building and construction sector from material placed in 

service during the period from 1928 through 2003, with the 

majority of the contributions for each year from a spread of 

35 years about the average life of 40 years for material in 

that sector. In like manner, the consumption datasets for the 

other sectors were superimposed with Gaussian distributions 

to generate old scrap generation statistics for 2004 as follows:

• Electrical and electronic products—

• dataset from 1969 through 2003

• average life, 18 years

• spread 16 years

• copper contained in old scrap generated, 532,000 t

• Industrial machinery and equipment—

• dataset from 1969 through 2003

• average life, 18 years

• spread 16 years

• copper contained in old scrap generated, 309,000 t

• Transportation equipment—

• dataset from 1969 through 2003

• average life, 18 years

• spread 16 years

• copper contained in old scrap generated, 261,000 t

• Consumer and general products—

• dataset from 1983 through 2003

• average life, 10 years

• spread 10 years

• copper contained in old scrap generated, 254,000 t

In 2004, the total old scrap theoretically generated from 

these five sectors contained 1.92 Mt of copper.

Uncertainties in the estimate for old scrap theoretically 

generated can arise from several factors including:

• average life and variance about the average are 

themselves estimates

• the datasets for sector consumption may be inaccurately 

reported

• the datasets for U.S. economic sector consumption 

may appear to be decreasing with time, which may be 

an inaccurate snapshot because the copper contained in 

net imports of finished goods (such as automobiles and 

appliances) does not appear in consumption accounting, 

leading to underestimating old scrap generated14.

OLD SCRAP UNRECOVERED

Old scrap unrecovered could be located in several places. 

It could be abandoned in place (hibernating) pending suitable 

economic incentives (scrap prices) to warrant collection and 

processing. It might have been collected and placed in landfills, 

which would potentially conserve it for a time of better prices. 

14A fact that may be more so in the future than presently because the lifetimes 

for copper-containing goods are greater than the time period that bounds the 

shift from domestic to foreign production of U.S. consumer goods.

It might have been dissipated (that is, dispersed or scattered) 

during use (for example, as in paints and fertilizers), making 

it exceptionally difficult and costly to recycle or recover the 

metal. Lastly, if the method for estimating old scrap generated 

is wrong, then it may exist in greater or lesser quantities 

depending on the direction of the estimate error.

Spatari and others (2005) studied copper flows over time 

with a dynamic model and estimated that the recycling rate 

for copper from postconsumer waste was 40 percent and that, 

over the past century, 130 kilograms per capita for the current 

North American population has been added to landfills.

In figure 10, the term reported as old scrap unrecovered 

is the amount that closes the material balance after summing 

inputs and outputs. It is therefore an artifact of the materials 

flow accounting process. In 2004, copper contained in old 

scrap unrecovered amounted to 1.15 Mt of copper (about 

60 percent of theoretical old scrap generated).

OLD SCRAP RECOVERED AND USED

Old scrap recovered and reused is based on reported 

data and is therefore more reliable than the previously 

discussed estimates pertaining to old scrap generation 

and disposal. In 2004, 772,000 t (40 percent of old scrap 

theoretically generated) of copper contained in old scrap 

was recovered. This was supplemented by 3,000 t of copper 

contained in a drawdown of old scrap stocks and 80,000 t 

of copper contained in scrap imports. Of this U.S. supply 

of old scrap containing 855,000 t of copper, 633,000 t of 

copper (74 percent of U.S. old scrap supply) was exported, 

167,000 t of copper (20 percent of U.S. old scrap supply) 

was returned to U.S. primary refined copper producers and 

semifabricators, and 54,000 t of copper (6 percent of U.S. 

old scrap supply) was consumed by noncopper producers. 

Gomez and others (2007) studied the relatively low rate of 

old scrap recovery and suggested that the low rate may be 

explained by reduced secondary production capacity owing 

to environmental control costs and the successful efforts of 

primary producers to reduce their production costs. The study 

also found that the existence of old scrap stocks was not a 

driver for old scrap recycling.

NEW SCRAP

Figure 10 shows that 735,000 t of copper contained in 

new scrap (5 percent from semifabrication copper production 

and 95 percent from manufacturing operations) was recovered 

in 2004, of which 712,000 t of copper (97 percent of new 

scrap supply) was recovered by wire rod mills, brass mills, 

foundries, and from chemical production; 16,000 t of copper 

(2 percent of new scrap supply) was recovered in primary 

refined copper production; and 7,000 t of copper (1 percent 

of new scrap supply) was recovered in noncopper operations.

In 2004, the new-scrap-to-old-scrap ratio with respect 

to scrap consumed in U.S. manufacturing activities was 3.2 
COPPER RECYCLING IN THE UNITED STATES IN 2004 X23

(table 1). Home scrap, which is scrap generated and recovered 

within the same plant, was not included in this analysis.

SCRAP RECYCLING EFFICIENCY

Based on the amount of copper contained, old scrap 

recycling efficiency was estimated to be 43 percent of 

theoretical old scrap supply (fig. 1) from the following 

formula:

consumption of old scrap + exports of old scrap

old scrap generated + imports of old scrap + decrease of old scrap stocks

or

230,000 t + 633,000 t

1.92 Mt + 80,000 t + 3,000 t .

When the new scrap recovery and consumption are 

considered, 735,000 t of additional copper from scrap is 

recovered, and the overall scrap recycling efficiency is 

58 percent of the copper contained in the theoretical supply 

of old and new scrap combined.

SCRAP RECEIPTS AT U.S. PRIMARY AND 

SEMIFABRICATION COPPER PRODUCERS

In 2004, total U.S. supply of copper recoverable from 

scrap (new and old) was 1.59 Mt of contained copper, 

composing 772,000 t of copper recovered from old copper 

scrap generated, 3,000 t of copper from reduced stocks, 80,000 

t of copper from imports, and 735,000 t of copper contained 

in new scrap generated. Of the 1.59 Mt of recoverable copper, 

895,000 Mt of recoverable copper (56 percent of supply) 

was received by U.S. mills for consumption and inventory 

adjustment, 633,000 t of contained copper (40 percent of 

supply) was exported, and 61,000 t of recoverable copper (4 

percent of supply) was received and consumed by noncopper 

producers.

Of the 895,000 t of copper recoverable from scrap 

that was received at U.S. refined-copper producers and 

copper-product semifabricators, 845,000 t (94 percent) was 

consumed by semifabricators, and 51,000 t (6 percent) was 

consumed to produce refined copper. The 845,000 t of copper 

consumed by semifabricators was supplemented with 9,000 t 

of copper contained in a drawdown of semifabricators’ scrap 

inventories for a total input to semifabrication of 853,000 t 

of recoverable copper, which was distributed for production 

among semifabricators as follows: brass mills consumed 

679,000 t (79 percent), ingot makers consumed 90,000 

t (11 percent), foundries and others consumed 57,000 t 

(7 percent), and wire rod mills consumed 26,000 t (3 percent).

PROCESSING OF COPPER SCRAP

The collection and handling of new copper scrap 

are fairly straightforward. New scrap is generated during 

manufacturing operations and consists of items such as 

clippings, stampings, and turnings. These are usually 

segregated by material specification and returned to furnace 

operations where the scrap is matched and melted for reuse 

based on its chemistry. Some new scrap enters the open 

market, but the major portion is returned to the primary and 

secondary mills through buy-back arrangements.

Old scrap originates from product aging within the 

reservoir of products-in-service. Old scrap requires more 

handling, including operations such as collection, manual 

sorting, stripping, shredding, and magnetic separation. The 

scrap may be compacted into a bundle or briquette.

Copper wire scrap contains about 60 percent metal 

and 40 percent polyvinylchloride insulation, which must 

be separated before the copper wire can be recovered 

completely. Insulation can be removed from wire with very 

fine chopping. The process produces a fine-particle mixture 

of insulation and wire, which is passed over a fluidized bed 

to facilitate the separation of the insulation (overflow) from 

the wire (underflow). Another separation process is cable 

stripping, which is a much slower process, where the cable is 

passed through a machine that separates the insulation from 

single strands of wire (Bureau of International Recycling, 

2008). The product of wire stripping/chopping operations is 

usually a high-quality scrap, “bare bright” as listed by ISRI, 

and may trade at a premium to refined cathode as its size 

distribution makes it easier to process.

Cell phones and computers are sources of electronic 

scrap. In 2004, about 2,900 t of copper was contained in 

cell phones in-use (Sullivan, 2006). In 1999, Noranda, Inc. 

of Canada received 50,000 t of electronic scrap from more 

than 300 suppliers in 18 countries for addition to its smelting 

furnaces; in 1998, about 4,600 t of copper was recovered 

from such scrap (Bleiwas and Kelly, 2001). Electronic scrap 

is also attractive for its content of precious metals.

Complicated residues, such as drosses, liquors, 

skimmings, slags, and spent electrolytes, are usually treated 

in specially designed recovery circuits with chemical control 

and assorted separation technologies.

COPPER SCRAP TRADE

Large quantities of copper contained in various forms 

and mixtures move through the international scrap trade. 

In 2004, 633,000 t of copper contained in 714,000 t of old 

scrap15 was exported from the United States, which was the 

15It is assumed that old scrap is what is being traded because new scrap 

tends to flow backwards through the production process by agreement and 

contract.
X24 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

leading source of global copper scrap exports, accounting 

for 19 percent of global scrap trade (Edelstein, 2007, p. 

21.5). Figure 11 shows the distribution of those exports by 

country.

Most of the old copper scrap exported by the United 

States goes to Asia, and China, by far, is the largest consumer. 

The emergence of China as a significant importer of U.S. old 

scrap is a relatively new phenomenon driven by increasing 

Chinese demand for copper raw materials and the reduction 

of domestic demand because of the closure of significant 

scrap smelting capacity for economic and environmental 

reasons. Figure 12 shows the growth of exports to China of 

both unalloyed and alloyed U.S. old copper scrap from 1995 

through 2004.

From 1995 through 2004, total U.S. old copper scrap 

exports to China grew by about 50 percent per year. Unalloyed 

scrap exports grew by about 70 percent per year, and alloyed 

scrap exports, by about 34 percent per year. The value of this 

trade increased to $477 million in 2004 from $90 million in 

1995 (48 percent per year).

The United States is also an importer of old copper 

scrap. In 2004, 80,000 t of copper contained in such scrap 

was imported. Figure 13 shows the distribution of sources for 

U.S. imports of old copper scrap.

Most U.S. imports of old copper scrap originate in North 

America and Central America. Overall, the United States 

Figure 11. Chart showing the distribution of exports of 

old copper scrap from the United States in 2004, by country. 

Values are in percentage of total exports. Source: Edelstein, 

2007.

Figure 12. Chart showing Chinese imports of U.S. old copper scrap from 1995 through 2004, by type. Values are in metric 

tons of contained copper. Source: Edelstein, 1998–2007.

EXPLANATION
COPPER RECYCLING IN THE UNITED STATES IN 2004 X25

was a net exporter of copper (553,000 t) contained in scrap 

in 2004.

OUTLOOK

Because of the superior electrical properties of copper, it 

should continue to be in demand worldwide. In-ground copper 

resources seem adequate because copper prices, which should 

be rising under a condition of supply and demand mismatch, 

are near their 100-year averages in terms of constant dollars. 

High prices for copper will enhance recovery of copper from 

scrap. Economic globalization seems to be redistributing 

flows for all copper-bearing materials—anode, concentrate, 

ore, product, and scrap.

The reduction of production costs by means of 

incremental technological improvements should continue 

as a typical response to the pressure of the increasing costs 

of energy, labor, and material inputs. Stakeholders could be 

expected to push for improved resource efficiencies through 

recycling mandates where the economics may not justify 

recycling. The loss of U.S. copper processing capacity may 

not necessarily decrease copper recycling. Recycling should 

continue but may increasingly occur in foreign countries, 

which would be importing U.S. scrap. Competition from 

other material streams should continue to create challenges 

for securing the energy and material inputs necessary to 

sustain copper production. Competition of other materials for 

the traditional share of copper in market end uses should help 

to provide a counterbalance.

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X28 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

APPENDIX—DEFINITIONS

anode. The positive terminal in an electrolytic cell where 

electrons leave a device to enter the external circuit. A 

copper anode at 99 percent purity will dissolve.

anode slimes. A mixture of metals and some insoluble 

compounds that originate in and dissolve from the anode 

during electrolysis and precipitate from the electrolyte 

onto the cell floor. These are processed for the metal 

content. In copper electrolysis, gold, silver, selenium, 

tellurium, and other metals are recovered.

apparent consumption. Primary plus secondary production 

(old scrap) plus imports minus exports plus adjustments 

for U.S. Government and industry stock changes.

apparent supply. Apparent consumption plus consumption 

of new scrap.

blister copper. The product of a converting furnace. It is 

an intermediate, more concentrated (with respect to 

the desired metal) material than matte, from which it is 

made, and is usually transferred to another furnace for 

further concentration. Blister copper contains about 98 

percent copper, the exact percentage depending on the 

process parameters. Blister copper is sometimes cast into 

ingot forms and placed into worldwide trade. Most often 

it is fire-refined onsite.

cathode. The negative terminal in an electrolytic cell where 

copper is plated during electrowinning or electrolytic 

refining. Copper so plated is referred to as “cathode” and 

is generally about 99.99 percent pure.

catenary. The name of the curve formed by a uniform cable 

strung between two points. It is mathematically described 

by a hyperbolic function.

copper concentrate. A product of flotation milling. It 

composes sulfide minerals and entrained material 

and contains one-third each copper, iron, and sulfur. 

It can be processed pyrometallurgically in a smelter 

to produce matte or hydrometallurgically (pressure 

leaching) to produce pregnant leach solution, both 

products requiring further processing to obtain 

copper metal. Copper concentrate may participate 

in worldwide trade or be smelted domestically in its 

country of origin.

electrolyte. An acidic solution containing copper ions. In 

electrorefining, the concentration of copper ions remains 

relatively constant, in balance with copper dissolution 

at the anode and copper precipitation at the cathode. 

In electrowinning, the copper concentration is more 

variable but in relative equilibrium with new copper 

ions introduced by rich (copper-loaded) electrolyte 

from the solvent extraction facility and with the copper 

precipitation at the cathode.

electrorefining. An electrolytic refining process where 

less pure copper anodes are dissolved, and high-purity 

copper is plated at the cathode.

electrowinning. An electrolytic refining process where 

the anode is inert, and rich (copper-loaded) electrolyte 

continually replaces lean (copper-depleted) electrolyte 

as copper is plated at the cathode.

fire-refined copper. The product of a fire-refining furnace. 

It is an intermediate, more concentrated (with respect to 

the desired metal) material than blister, from which it 

is made. Because oxygen is added in the processing to 

upgrade the copper content by oxidizing the impurities 

in the furnace charge materials, the resulting copper must 

be deoxidized, usually by stirring it with natural gas, with 

the carbon in the natural gas reacting with the excess 

oxygen. Fire-refined copper contains about 99 percent 

copper, the exact percentage depending on the process 

parameters. Fire-refined copper is sometimes cast into 

ingot forms and placed into worldwide trade. Often it 

is transferred to another same-company electrorefining 

facility for processing into 99.99 percent copper cathode. 

Fire-refining is also used to purify high-grade copper 

scrap consumed at brass mills in the production of tube 

and sheet products.

flotation. A method of mineral separation in which air and a 

variety of reagents are injected to create a froth in water. 

Some finely crushed minerals float and other minerals 

sink. The preferential flotation of sulfide minerals and 

sinking of the gangue materials is used to concentrate the 

copper for economic smelting. The resulting product is 

called “concentrate.”

flux. Slag-making materials, such as sand, lime, limestone, 

that are added to high-temperature metal and metaloxide emulsions to fuse the oxides into a relatively low 

melting-point material that can be readily separated from 

the molten metal.

Gaussian distribution. The utility of materials in service 

is assumed to decay, thereby generating old scrap, 

according to a Gaussian distribution. The distribution is 

generated from the following formula:

where y is the year for which the distribution value is being 

calculated, a is the average life of the material, and b

is the spread, a value that is subjectively adjusted but 

is about two times the average life of the material.

hibernating scrap. Scrap that has reached the end of its 

useful economic life but has not been collected (remains 

in place) pending economic conditions that warrant the 

effort to collect it.

home scrap. Scrap generated as process or runaround scrap 

and consumed in the same plant where generated. It does 

not enter into trade and is not considered in this study.

hydrometallurgy. A process of separating desired metals 

from aqueous solutions.
COPPER RECYCLING IN THE UNITED STATES IN 2004 X29

lift. The portion of a heap leach that is currently being leached. 

In common practice, lifts vary in height between 30 and 

150 meters and can actively accommodate leaching 

fluids for 90 to 120 days. The top area of a lift is usually 

greater than 15,000 square meters.

master alloys (of copper). Alloys with other elements 

containing more than 10 percent by weight copper. 

Master alloys serve as an intermediate material source 

in the manufacture of other alloys or to deoxidize liquid 

metal baths. The copper content on average ranges 

between 30 and 90 percent in master alloys.

matte. Is an intermediate, more concentrated (with respect 

to the desired metal) material than concentrate, from 

which it is made, and is usually transferred to another 

furnace for further concentration. Copper mattes contain 

between 50 and 70 percent copper, depending on the 

process parameters.

mine waste. Rock materials that are not ore grade and are 

removed to provide access to ore and disposed.

new scrap (prompt scrap). Scrap produced during the 

manufacture of metals and articles for both intermediate 

and ultimate consumption, including all defective 

finished or semifinished articles that must be reworked, 

and is obtained from a facility separate from the 

recycling refiner, smelter, or processor. Examples of new 

scrap are borings, castings, clippings, drosses, skims, 

and turnings. Included as new scrap is prompt industrial 

scrap—scrap obtained from a facility separate from the 

recycling refiner, smelter, or processor. Excluded from 

new scrap is home scrap that is generated as process 

scrap and used in the same plant.

new-to-old-scrap ratio. New scrap consumption compared 

with old scrap consumption in the United States, 

measured in weight and expressed as new scrap divided 

by old scrap.

nominal price. The price at the time of sale.

obsolete (end-of-service-life). A material becomes obsolete 

when it no longer provides the desired services or when 

other services are valued more than those provided by 

the material in question.

old scrap. Scrap including (but not limited to) metal articles 

that have reached the end of their service life. Old scrap 

may be collected or stored for recycle, disposed in landfills, 

simply abandoned, or retained (hibernating scrap) in 

place. Typical examples of old scrap are electrical wiring, 

lead-acid batteries, silver from photographic materials, 

metals from shredded cars and appliances, used aluminum 

beverage cans, spent catalysts, and tool bits. This is also 

referred to as postconsumer scrap and may originate from 

industry or the general public. Expended and obsolete 

materials used dissipatively, such as paints and fertilizers, 

are not included.

old scrap exports. The amount of old scrap exported from 

the United States in a subject year.

old scrap generated. The metal content of obsolete products 

from the U.S. product reservoir that theoretically 

becomes available for recycling in a subject year.

old scrap imports. The amount of old scrap imported to the 

United States in a subject year.

old scrap recovered and used. Equals old scrap reported as 

recovered.

old scrap recycling efficiency. The amount of old scrap 

recovered and reused relative to the amount available to 

be recovered and reused. Defined as [consumption of old 

scrap (COS) plus exports of old scrap (OSE)] divided 

by [old scrap generated (OSG) plus imports of old scrap 

(OSI) plus a decrease in old scrap stocks (OSS) or minus 

an increase in old scrap stocks], measured in weight and 

expressed as a percentage as follows:

old scrap unrecovered. Scrap that might have been 

abandoned in place (hibernating), collected and 

landfilled, or dissipated during use. It is the difference 

between theoretical scrap generated and actual scrap 

collected and processed for sale to the global pool of 

manufacturers.

organics. Is a term used to describe a mixture of kerosene 

and proprietary hydrocarbons that specifically adhere 

to copper in copper hydrometallurgical processes. The 

organics preferentially load copper from the pregnant 

leach solution in one tank and unload the copper to lean 

electrolyte in another tank.

pH. Hydrogen concentration in an acidic solution, a measure 

of acidity, and a process control parameter in electrolytic 

processes.

pregnant leach solution. The metal-loaded acidic solution 

collected in a lined pond following percolation of acid 

through leachable ore piles. It is the feedstock for 

solvent-extraction operations.

primary copper. Copper extracted from ores and recovered 

as copper metal or copper-bearing chemicals.

product reservoir. The stock of copper-bearing materials 

serving consumer needs. When materials within the 

product reservoir reach their end of life (end of utility), 

they become eligible for utility upgrade, one method of 

which is recycling as old scrap.

pyrometallurgy. A process of separating desired metals 

from materials under conditions of high heat.

raffinate. The copper-depleted flow back to the heap leach 

after the copper-rich pregnant leach solution has been 

stripped of its copper load through solvent extraction.

recoverable copper. The flows reported here are flows of 

recoverable copper; that is, they are reported in terms of 

the copper contained in products. There are dissipative 

losses to air, water, and land throughout the system, but 

these are not quantified. This approach makes the system 
X30 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES

COS + CNS

AS

×100

scrap consumption. Scrap added to the production flow of a 

metal or metal product.

secondary copper. Copper recovered from scrap and waste. 

Scrap types include clippings, cuttings, grindings, 

turnings, flue dust, slag, filter cakes, and spent electrolyte 

solutions.

supply of recoverable copper. The sum of new (prompt) 

scrap, old scrap recovered, old scrap imports, and old 

scrap stock decrease. This supply serves the domestic 

and foreign demand for scrap.

appear to balance, but the reality is that more copper (to 

cover the dissipative losses) than is reported is required 

to produce the product reported.

recycling. A process to reclaim a metal (for example, copper) 

in a useable form from scrap or wastes. This includes 

recovery as the refined metal or as alloys, compounds, 

or mixtures that are useful. Examples of recycling are 

recovery of copper from such copper-bearing alloys as 

brass, from spent, from copper-sulfate solutions, and 

even from low-grade wastes, such as drosses, dusts, 

skimmings, and slag.

recycling rate. The fraction of the apparent metal supply that 

is scrap on an annual basis. It is defined as [consumption 

of old scrap (COS) plus consumption of new scrap 

(CNS)] divided by apparent supply (AS), measured in 

weight and expressed as a percentage: