U.S. Department of the Interior 

U.S. Geological Survey 

Platinum Recycling in the United States in 1998 

By Henry E. Hilliard 

U.S. GEOLOGICAL SURVEY CIRCULAR 1196–B 
U.S. DEPARTMENT OF THE INTERIOR 

GALE A. NORTON, Secretary 

U.S. GEOLOGICAL SURVEY 

CHARLES G. GROAT, Director 

U.S. GEOLOGICAL SURVEY, RESTON, VIRGINIA : 2001 

Version 1.0 

Published online in the Eastern Region, Reston, Va., 2001. 

Manuscript approved for publication May 3, 2001. 

Any use of trade, product, or firm names in this publication is for 

descriptive purposes only and does not imply endorsement by 

the U.S. Government. 
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 more than half of the U.S. metal supply by weight 

and roughly 40 percent by value. 

Charles G. Groat 

Director 

III 
CONTENTS


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


Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B1


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


Sources of PGM Ore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3


Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3


South Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3


Russia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3


United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4


Sources of Platinum Scrap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4


Old Scrap Generated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4


Automobile Catalysts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4


Reforming Catalysts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5


Chemical-Process Catalysts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6


New Scrap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6


Home Scrap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6


Disposition of Platinum Scrap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6


Scrap Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6


Unrecovered Old Scrap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7


Old Scrap Recycling Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7


Infrastructure of Platinum Scrap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7


Scrap Collection Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7


Trade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7


Processing of Platinum Scrap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7


Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8


References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8


Appendix—Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9


FIGURES 

1. Flow diagram showing U.S. platinum materials flow in 1998 . . . . . . . . . . . . . . . . . B2 

2. Graph showing U.S. platinum consumption by end-use sector from 1978 to 1998 . . . 4


TABLE 

1. Salient statistics for U.S. platinum scrap in 1998 . . . . . . . . . . . . . . . . . . . . . . . . . . B3 

IV 
CONTENTS V 

CONVERSION FACTORS 

Most measurements in this report are in metric units, but a few terms are in customary units. 

Conversion factors are provided below. 

Multiply By To obtain 

Length 

kilometer (km) 0.6214 mile 

inch (in.) 25.4 millimeter 

Volume 

cubic foot (ft3

) 0.02832 cubic meter 

Mass 

microgram (μg) 0.00000003527 ounce avoirdupois 

gram (g) 0.03527 ounce avoirdupois 

kilogram (kg) 2.205 pound avoirdupois 

kilogram (kg) 32.1507 troy ounce 

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

troy ounce (troy oz) 31.10 gram 

Pressure 

kilopascal (kPa) 0.1450 pound force per square inch 

kilopascal (kPa) 0.009869 1 atmosphere 

Other 

gram per metric ton (g/t) 0.0292 troy ounce per short ton 

For temperature conversions from degrees Celsius (°C) to degrees Fahrenheit (°F), use the following: 

°F = (1.8 × °C) + 32 
FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES 

Platinum Recycling in the United States in 1998 

By Henry E. Hilliard 

ABSTRACT 

In the United States, catalytic converters are the 

major source of secondary platinum for recycling; about 

25,500 kilograms of platinum-group metals from automobile catalysts was available for recycling in 1998. Other 

sources of platinum scrap include reforming and chemical-process catalysts. The glass industry is a small but significant source of platinum scrap. In 1998, an estimated 

7,690 kilograms of platinum was recycled in the United 

States. The U.S. recycling efficiency for old scrap was 

calculated to have been 76 percent in 1998; the recycling 

rate was estimated at 16 percent. 

INTRODUCTION 

World resources of platinum appear ample for the foreseeable future. Political and economic events in the past 

decade, however, have raised concerns about the availability 

and reliability of the supply of platinum and other metals in 

this group. This report discusses the 1998 flow of platinum 

in the United States from mining, through metallurgical and 

chemical applications, to recycling (fig. 1, table 1). Factors 

influencing the rate and availability of material for recycling 

are described, especially areas where significant losses 

occurred. 

Platinum-bearing scrap is a heterogeneous material that 

may also contain one or more of the other platinum-group 

metals. This report deals primarily with platinum, which was 

the most valuable and abundant platinum-group metal 

(PGM) found in scrap materials at the time of this study. The 

annual recycling rate for platinum, which represents the fraction of the metal’s apparent supply that is scrap, was estimated at 16 percent in 1998. The balance of apparent supply 

was primary platinum (see appendix). This study also indicates that materials containing about 8,500 kilograms (kg) of 

platinum were unrecovered in 1998, representing about 14 

percent of U.S. apparent consumption. 

Six elements of group VIII in the periodic table of the 

elements have been collectively designated the platinumgroup metals; they are palladium (Pd), platinum (Pt), iridium 

(Ir), osmium (Os), rhodium (Rh), and ruthenium (Ru). 

Sometimes called noble metals because of their resistance to 

oxidation, these precious metals are found in the Earth’s 

crust in very low concentrations. PGM’s are conveniently 

separated into two subgroups; the light PGM’s (those of 

lower atomic weight) are Ru, Rh, and Pd, and the heavy 

PGM’s are Os, Ir, and Pt. 

The PGM’s are strongly siderophilic and chalcophilic; 

that is, they occur predominantly as pure metals and alloys 

and, to a much lesser extent, combined with sulfur, tellurium, 

and arsenic. They occur in rock-forming silicates in small to 

negligible amounts. For the most part, PGM’s are concentrated in the early stages of magmatic differentiation and, 

consequently, are most abundant in magmatic mafic and 

ultramafic bodies and associated ore deposits. Under certain 

conditions, as yet imperfectly known, the PGM’s are carried 

through the differentiation process because of their lack of 

affinity for the silicate minerals and are then concentrated in 

the products of late hydrothermal solutions (Wright and 

Fleischer, 1965, p. A2). 

Despite their limited availability, these metals and 

chemical compounds containing them are extremely useful 

as catalysts in the automobile, chemical, and petroleum 

industries, as conductors in the electrical and electronic 

industries, in extrusion devices, in dental and medical prostheses, and in jewelry. Also, the glass industry takes advantage of platinum’s high melting point, its noncontaminating 

behavior, and its chemical inertness and resistance to corrosion in the manufacture of high-quality optical and special 

glasses. 

Platinum is primarily an industrial metal. There are, 

however, small quantities in the possession of speculators 

and investors. In 1998, there was strong demand for the platinum American Eagle coin, launched by the U.S. Mint in 

1997. Domestic and foreign sales of this coin totaled 5,443 

kg in 1998 (U.S. Mint, 1999, p. 7–13). Although Eagle coin 

sales were concentrated in the United States, the coin also 

found a market in Japan. Demand in Japan was mainly for 

smaller coins, weighing 0.10 or 0.25 troy ounce (troy oz), 

many of which were incorporated into watches and other 

items of jewelry. There are no reliable statistics available 

about the quantity of platinum held by speculators and 

investors. Probably stocks are held in banks and private holdings. This material, held for speculation and profitmaking, is 

B1 
B2 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES
 DISTRIBUTION OF DOMESTIC SUPPLY OF DOMESTIC SUPPLY OF PRIMARY PRIMARY AND SECONDARY PLATINUM Government stockpile shipments of platinum . . . 4,510 Old scrap consumed . . . . . 7,690 Old scrap exported . . . . 19,700 Old scrap generated: Automobile catalysts . . . . . . . 25,500 Chemical-process catalysts . . . 2,500 Reforming catalysts . . . . . . . . 14,700 Total . . . . . . . . . . . . . . . . . 42,700 Old scrap unrecovered . . 8,500 Platinum products reservoir net change 

. . . +46,000 

Exports of refined platinum metal, concentrates, ores, and coins . . . . . . . . . 15,000 

Platinum products to U.S. market . . . . 92,700 

New scrap generated . . . . 5,600 

118,000 

U.S. investment: 

Platinum coins . . . . .4,520 

Other . . . . . . . . . . . . . . 480 

Total . . . . . . . . . . 5,000 

Platinum metal, prefabricated . . . . . . 10,000 

AND SECONDARY PLATINUM 

Processing losses . . . . 20 

Dissipative uses . . . . 4,000 

Old scrap supply . . . . . . . 48,100 

Old scrap imported . . . 5,390 

Old scrap stock increase at collection centers . . . . . .12,200 

4,510 

97,300 

16,500 

15,000 

5,000 10,000 

88,300 

10,000 82,700 

5,600 

4,000

12,200 8,500 

42,700 

7,690 

19,700 

3,240 

5,600 

7,690 

20 

88,700 

Platinum metal fabrication . . . . 88,300 

Domestic production of Pt in concentrates . . . . 

Refinery production of platinum metal . . . . 16,500 

Home scrap 

Imports of platinum metal: 

Unwrought . . . . . . 75,400 

Prefabricated . . . . 10,200 

Other . . . . . . . . . . . 11,700 

Total . . . . . . . . . 97,300 42,700 

3,240 

U.S. platinum materials flow in 1998. 

Values are in kilograms of contained platinum, and totals have been rounded to three significant figures. Sources of data are 

described in the section titled “Sources of Platinum Scrap.” 

Figure 1. 
PLATINUM RECYCLING IN THE UNITED STATES IN 1998 B3 

put on the market infrequently, depending upon price and 

price outlook. The material is usually of high purity and is 

not likely to be found in the recycling circuit, except as home 

scrap during its manufacture. 

SOURCES OF PGM ORE 

Canada, South Africa, Russia, and the United States 

account for nearly all of the world’s primary production of 

PGM ore. The relative amounts of the individual elements in 

ores vary from deposit to deposit and from country to country. The ratio of platinum to palladium in ores can vary from 

3:1 in the Bushveld Complex in South Africa to 1:3.5 in the 

Noril’sk deposit in Russia and 1:3 in the J-M Reef of the 

Stillwater Complex in the United States and the Sudbury 

Complex in Canada (Conradie, 1997). 

CANADA 

Small amounts of silver, gold, and PGM’s are present in 

most sulfide deposits of nickel. In Canada, PGM’s are mainly a byproduct of copper-nickel production. Most of the 

nickel ores are located in the Sudbury Complex in Ontario. 

The complex is a large stratiform, oval intrusion with dimensions along the axes of 50 and 23 kilometers (km). The copper-nickel deposits of the Sudbury area are peripherally 

located around the structure of an elliptical basin-shaped 

stratiform complex referred to as the Nickel Irruptive or the 

Sudbury Basin. The Nickel Irruptive consists of an outer part 

of noritic rocks and an inner part of granophyre (micropegmatite) (Cabri and Laflamme, 1976, p. 1159). The concentration of PGM’s averages about 0.9 to 1.0 gram per metric 

ton (g/t), with about 40 percent Pd, 40 percent Pt, and 20 percent Ir, Os, Rh, and Ru. Canada also produces nickel-copper 

ores with byproduct PGM’s from the entire spectrum of 

ultramafic and mafic complexes that occur in Manitoba, 

Ontario, and Quebec (Allen, 1960, p. 1–26; Page and others, 

1973; Sutphin and Page, 1986, p. 2–7). 

SOUTH AFRICA 

South Africa is the world’s largest source of platinum. 

South Africa’s PGM output is derived mostly from the 

Bushveld Complex, with only a small amount coming from 

the Evander Gold Field and the Phalaborwa Complex. Currently, 10 mines are producing platinum in the Bushveld 

Complex (South Africa Department of Minerals and Energy, Minerals Bureau, 1997, p. 34–40). Of these, nine 

exploit the Merensky Reef and UG2 Chromite Layer, and 

one, Potgietersrust Platinum Ltd., the only open-cast operation, exploits the Platreef on the northern limb of the complex. Eight of the mines are located on the western limb of 

the Bushveld Complex; Atok Mine, of Lebowa Platinum 

Mines Ltd., is currently the only producer on the eastern 

limb. Beneficiation of PGM ore through milling, flotation, 

and smelting (to form a matte containing PGM’s, gold, silver, and the base metals cobalt, copper, and nickel) is 

Table 1. Salient statistics for U.S. platinum scrap in 1998.


[Values in kilograms of contained platinum, unless otherwise specified]


Old scrap: 

Generated1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42,700 

Consumed2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7,690 

Value of old scrap consumed . . . . . . . . . . . $117 million 

Recycling efficiency3 . . . . . . . . . . . . . . . . . . . 76 percent 

Supply4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48,100 

Unrecovered5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8,500 

New scrap consumed6 . . . . . . . . . . . . . . . . . . . . . . . . . 5,600 

New-to-old-scrap ratio7 . . . . . . . . . . . . . . . . . . . . . . . . 42:58 

Recycling rate8 . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 percent 

U.S. net exports of scrap9 . . . . . . . . . . . . . . . . . . . . . . 14,310 

Value of U.S. net exports of scrap . . . . . . . . . . . $200 million 

1Platinum content of products theoretically becoming obsolete in the 

United States in 1998. Net U.S. imports of semifinished products containing 

platinum in 1998 are included. Dissipative uses are excluded. 

2Platinum content of products that were recycled in 1998. 

3(Old scrap consumed plus old scrap exported) divided by (old scrap 

generated plus old scrap imported plus any old scrap stock decrease or minus 

any old scrap stock increase). 

4Old scrap generated plus old scrap imported plus old scrap stock 

decrease. 

5Old scrap supply minus old scrap consumed minus old scrap exported 

minus old scrap stock increase. 

6Including prompt industrial scrap but excluding home scrap. 

7Ratio of quantities consumed, in percent. 

8Fraction of the metal apparent supply that is scrap, on an annual basis. 

9Trade in scrap is assumed to be principally in old scrap. Net exports 

are exports of old scrap minus imports of old scrap. 

undertaken at the various mines. Further refining of the 

matte, including extraction of the base metals and recovery 

of the precious metals, takes place at refineries near 

Rustenburg, Brakpan, and Springs. Some matte is sent to 

refineries outside the country for toll refining. In 1998, 

South Africa produced about 117,000 kg of platinum and 

57,300 kg of palladium (Hilliard, 2000b, p. 58.7). 

RUSSIA 

Probably more than 97 percent of Russia’s mine output 

of PGM’s is a byproduct of nickel-copper mining. The nickel-mining complex at Noril’sk, in northwestern Siberia, 

accounts for about 95 percent of total Russian production, 

and the mines at Pechenga on the Arctic coast account for 

most of the remainder. Modes of occurrence and composition of PGM’s in different types of ores vary significantly at 

Noril’sk. In disseminated ores, the main PGM minerals are 

represented by isoferroplatinum and cooperite, whereas in 

massive ores, very diverse palladium intermetallic compounds and tetraferroplatinum occur (Genkin and 

Evstigneeva, 1986, p. 1204). PGM’s are refined at the metallurgical complex in Krasnoyarsk, East Siberia. In 1998, 

Russia produced about 17,000 kg of platinum and 47,000 kg 

of palladium (Hilliard, 2000b, p. 58.7). 
B4 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES


40 

CONSUMPTION, IN THOUSANDS OF KILOGRAMS 

35 

30 

25 

20 

15 

10 

5 

End-use sector 

Automobile catalysts 

Chemical-process catalysts 

Electrical and electronic industries 

Reforming catalysts 

Other 

0 

1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 

YEAR 

Figure 2. U.S. platinum consumption by end-use sector from 1978 to 1998. 

UNITED STATES 

The Stillwater Mine near Nye, Mont., is the only primary PGM producer in the United States. The Stillwater 

Complex is an elongated assemblage of intrusive rocks that 

occurs in Sweetwater County, Mont., and extends into Park 

and Stillwater Counties. In its annual report, the Stillwater 

Mining Company reported its 1998 production as 10,575 kg 

of palladium and 3,235 kg of platinum (Stillwater Mining 

Company, 1999). In 1998, the company mined 653,184 metric tons (t) of ore. In conjunction with the operation of the 

mine, the average throughput at the mill facility was 1,196 

metric tons per operating day (t/d) with a recovery rate of 91 

percent. The mill head grade was 23.7 grams (g) of combined palladium and platinum per metric ton of ore. 

The Stillwater Mining Company operates a smelter and 

base-metals refinery (BMR) at the company’s metallurgical 

complex in Columbus, Mont. At the smelter, concentrate is 

treated to produce matte containing approximately 22.3 kg 

of palladium and platinum per metric ton. The matte is subsequently sent to the BMR, which produces a filter cake that 

is about 60 percent palladium and platinum. The filter cake 

is sent to metal refiners in New Jersey, California, and Germany, where it is converted into palladium and platinum 

sponge for sale to end users. 

In 1998, the Stillwater Mining Company restarted its 

program to process spent automobile catalysts for the recovery of PGM’s. In 1998, approximately 139 t was processed 

in the BMR at a rate of 1 t/d. The usual procedure was to 

blend spent catalysts with concentrate from the mill (Stillwater Mining Company, 1999). 

SOURCES OF PLATINUM SCRAP 

Typical sources of platinum for secondary refining 

include spent automobile, reforming, and chemical-process 

catalysts; electronic scrap; jewelry; and used equipment 

from the glass industry (fig. 2). Spent automobile catalysts 

have emerged as the major source of secondary platinum, 

palladium, and rhodium. In the United States, about 25,500 

kg of PGM’s from automobile catalysts was available for 

recycling in 1998 (see p. B5). 

OLD SCRAP GENERATED 

Old scrap generated is defined as the platinum content 

of products theoretically becoming obsolete in the United 

States in 1998. Total platinum old scrap generated in 1998 in 

the United States from automobile catalysts, reforming catalysts, and chemical-process catalysts was estimated as 

42,700 kg (table 1). Old scrap consumed, defined as the platinum content of products recycled, was estimated at about 18 

percent of old scrap generated or 7,690 kg. 

AUTOMOBILE CATALYSTS 

Spent automobile catalysts have emerged as the major 

source of secondary platinum, palladium, and rhodium. The 

amount of platinum that is recovered from automobile catalytic converters depends upon the following factors: (1) the 

average loading of platinum in the converters, which will not 

be a constant, (2) the probability that vehicles from each of 

the previous model years will be taken out of service in the 

year under consideration, (3) the percentage of the vehicles 

that are taken out of service in that year and are scrapped, 
PLATINUM RECYCLING IN THE UNITED STATES IN 1998 B5 

and (4) the percentage of platinum that is recoverable from a 

used converter. The first of these factors can only be estimated, but industry-based statistics are available for the second 

factor. A value for the third factor depends upon the returns 

expected in the scrap market. Annual figures for automobiles 

scrapped are influenced by the strength or weakness of the 

scrap metal market. Thus, vehicles retired in years when the 

price of scrap is depressed may not reach the scrap yard until 

there is sufficient economic incentive. In the long run, however, it is likely that most vehicles withdrawn from service 

end up as scrap. As for the fourth factor, research has shown 

that the high recovery rates typical of PGM recycling in the 

chemical, petroleum, and electronic industries can also be 

achieved with automobile catalysts (Dhara, 1983). 

Beginning with the 1974 model year, new automobiles 

sold in the United States have been equipped with catalytic 

converters that chemically convert polluting substances in 

automobile exhaust to nontoxic materials. Automobile catalysts were developed to remove carbon monoxide (CO), 

hydrocarbons (HC), and the oxides of nitrogen (NOX) that 

cause air pollution from vehicle exhausts. Small amounts of 

platinum, either alone or combined with other PGM’s, were 

used to oxidize and reduce the exhaust gases, thereby significantly lowering harmful emission levels. 

The first catalytic converters used a monolithic system 

that incorporated palladium and platinum as the active constituents to oxidize the CO and HC. NOX was controlled by 

modifications to the engine. In addition to monoliths, highly 

porous pelleted materials were also used. All converters now 

use monolithic supports because of the monolith’s high geometrical surface area and low pressure drop during operation. 

Since the introduction of the basic catalytic converter in 

1974, the technology has advanced in response to tightening 

air-quality-control regulations; for example, the three-way 

oxidation-reduction converter (TWC) was developed. In the 

TWC system, all three pollutants—CO, HC, and NOX—are 

converted in one reactor using a platinum-rhodium catalyst 

coated on a ceramic monolith. Thus, a reducing-type catalyst, based on rhodium for the reduction of NOX, is combined with a conventional oxidation catalyst to provide 

three-way emission control of the pollutants. In TWC’s, the 

platinum-to-rhodium ratio is generally about 10:1. The 

amount of PGM’s used in the manufacture of these devices 

is more than the total amount consumed in all other U.S. uses 

combined (Roskill Information Services Ltd., 1991, p. 99). 

At the beginning of the 1980’s, General Motors suggested that a typical TWC might contain 1.555 g Pt, 0.622 g 

Pd, and 0.156 g Rh (Roskill Information Services Ltd., 1991, 

p. 100). The oxidizing units of early TWC’s are thought to 

have contained platinum and palladium in the ratio of 2:1. 

The palladium content subsequently has risen considerably. 

Newer TWC’s may contain about 1.8 kg (58 troy oz) PGM’s 

per cubic meter of monolith. A catalytic converter measuring 

10 centimeters (cm) in diameter by 15 cm in length would 

contain 2.3 g (0.074 troy oz) PGM’s. A typical mean level of 

1.5 g (0.048 troy oz) was suggested. 

In 1998, about 200 million automobiles were in circulation in the United States, and about 17 million automobiles 

were scrapped. If each catalytic converter in the scrapped 

automobiles contained an average of 1.5 g of platinum, then 

about 25,500 kg of platinum was available for recycling 

from this source. Of the 17 million scrapped automobiles, 

about 12 million were recycled through shredders (Fenton, 

1999, p. NN1). If it is assumed that the catalytic converters 

were collected from the automobiles prior to shredding, then 

18,000 kg of platinum was available for recycling. 

REFORMING CATALYSTS 

Heterogeneous catalysts containing platinum are widely 

used in the petroleum-refining industry for a variety of 

hydrocarbon conversion processes, including reforming. The 

products made by these processes, such as motor fuels and 

aromatic hydrocarbons, are of great economic value to the 

United States. For example, increasing the aromatic hydrocarbon content of gasoline raises the octane rating and 

lessens knocking. 

Catalysts in this service can be deactivated by several 

different mechanisms, but deactivation is primarily the result 

of deposition of carbonaceous materials onto the catalyst 

surface during hydrocarbon processing at elevated temperature. This deposit, known as coke, results in substantial deterioration in catalyst performance (Fung, 1993, p. 91–96). 

The catalyst activity, or its ability to convert reactants, is 

adversely affected by this coke deposition, and the catalyst is 

referred to as “spent.” 

The original performance of the fresh catalyst can be 

restored by proper regeneration to remove this coke (Kim 

and others, 1992, p. 39–46). Regeneration allows continued 

use of the same catalyst for many years. The actual loss of 

platinum during use by the petroleum industry is very small, 

and this efficient metal recovery contributes greatly to the 

economics of platinum use. There is a limit, however, to the 

number of times that a catalyst can be regenerated, and eventually the catalyst must be replaced. Many reforming and 

selective hydrogenation catalysts are regenerated two or 

more times. As a general rule, after a catalyst can no longer 

be regenerated to at least 75 percent of its original activity, it 

is reclaimed or discarded (Chang, 1998). 

When the catalysts are removed from service, they are 

sent to a toll refiner for recovery of the metal values, which 

are returned to the owner. About 70 percent of the replacement market is for the bimetallic form commonly consisting 

of 0.3 percent platinum and 0.3 percent rhenium. 

Monometallic catalysts average 0.4 percent platinum 

(Burke, 1979). It is estimated that the amount of platinum 

used in catalytic reforming in 1998 was over 40,200 kg and 

was increasing by about 6,200 kg each year. Because PGM’s 

are valuable, great care is exercised in monitoring all 

streams entering and leaving catalyst manufacturing sites to 

ensure that no significant amounts of material are lost. Yearly overall materials recovery rates of about 99.8 percent are 

attainable. 
B6 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES


CHEMICAL-PROCESS CATALYSTS 

A typical use of a PGM catalyst in a chemical process is 

the production of nitric acid. During the manufacture of 

nitric acid by the oxidation of ammonia, platinum-rhodium 

and platinum-palladium-rhodium alloy gauzes are used as 

catalysts. Traditionally, the process is carried out at temperatures of 750°C to 950°C and at pressures of 101.3 to 1,013 

kilopascals. The amount of platinum lost from catalyst 

gauzes during nitric acid production depends upon the properties of the catalyst alloys, the operating conditions (temperature and pressure), and the technical control. The rate of 

platinum loss from a binary gauze consisting of 90 percent 

platinum and 10 percent rhodium varies from 0.05 g of platinum per metric ton of nitric acid produced in plants operated at atmospheric pressure (101.3 kilopascals) to 0.45 g of 

platinum for each metric ton of nitric acid produced in some 

high-pressure plants (Platinum Metals Review, 1999). In 

1998, the United States produced 9.3 million metric tons of 

nitric acid (Chemical & Engineering News, 1999). With that 

rate of nitric acid production, about 2,300 kg of platinum is 

estimated to have been consumed in this process. Not all of 

this material was allowed to escape into the atmosphere. Various filters and “gettering” devices allowed recovery of perhaps half of the lost metal. Of the platinum that escaped, 

most was probably trapped in absorption towers and ended 

up in the nitric acid. 

About 200 kg of platinum was consumed in other industrial or commercial catalytic applications. 

NEW SCRAP 

New scrap is defined as 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. Typical sources of 

platinum new scrap are used equipment from the glass industry, jewelry, and electronic scrap (fig. 2). Platinum and platinum-rhodium alloys are basic to the glass industry and are 

used in a variety of glass-handling and -forming equipment. 

Platinum is used in these applications because of its high 

melting point, high-temperature strength, low oxidation rate, 

and noncontaminating behavior. Pure platinum is used to 

make stirrers and tanks and crucibles for melting glasses. 

Alloys of 90 percent platinum and 10 percent rhodium are 

used for the bushings and baskets needed in the production 

of glass fibers. This use represents a large application for 

platinum-rhodium alloys. Similarly, alloys of platinum and 

10 to 40 percent rhodium are used for crucible liners, structures conveying molten glass, fiber-optics-forming devices, 

laser-glass melters, and stirrers for glass homogenization. 

Very low metal losses are experienced in these uses. Worn 

parts are recycled on a toll basis, and the recovered metals 

are returned to the industry for fabrication into new parts. 

The platinum used in jewelry is theoretically available 

as an aboveground resource, but there is very little recycling, 

apart from machining chips and grindings resulting from 

jewelry fabrication. The machining chips and grindings are 

efficiently recycled. 

Precious metals in the electrical and electronic industries are dispersed in the assemblies, and until recently, little 

effort was made to recycle discarded scrap. Electronic scrap 

may contain recoverable amounts of gold, palladium, and 

silver but only trace levels of platinum (Hilliard and Dunning, 1983). The amount of platinum in electronic scrap may 

change dramatically as hard disk drives from computers 

manufactured after 1996 are scrapped. The first hard disk 

drives used 50 disks, each measuring 61 cm in diameter, to 

store just 5 megabytes of data. A typical modern personal 

computer can store 15 megabytes on a hard disk drive containing two or three disks that are only 9 cm in diameter. This 

efficiency was achieved by incorporating a platinum-cobalt 

magnetic layer on the surface of the disk to improve storage 

capacity. About 50 percent of the hard drives manufactured 

in 1998 used platinum, and it was estimated that in 2000 

more than 90 percent of the hard drives used magnetic thin 

films containing platinum (Johnson Matthey, 1999, p. 26). It 

will be several years, however, before these hard drives begin 

appearing in scrap streams for recycling. 

Almost all new PGM scrap generated is consumed. As 

shown in table 1, new scrap consumed in 1998 was estimated to have a platinum content of 5,600 kg, and the new-toold-scrap ratio was 42:58. 

HOME SCRAP 

In every company that manufactures semifinished and 

final PGM products, virtually all of the scrap generated is 

reprocessed for precious-metals recovery. Casting scrap, 

such as croppings of castings, is recovered simply by adding 

it to melt charges. This scrap is not counted as material consumed because it is endlessly recycled and never leaves the 

plant. Grindings, ingot scalping, and machining chips, which 

are processed through toll refining, are not home scrap. 

DISPOSITION OF PLATINUM SCRAP 

SCRAP CONSUMPTION 

Recovery of PGM’s from spent automobile catalysts is 

growing in the United States, where a network of recycling 

facilities is being put in place. This growth is due to the higher PGM loadings in automobile catalysts in recent years. 

Nevertheless, the amount of PGM’s recovered from catalysts 

remained only a fraction of the total amount consumed. In 

1998, more than 6,000 kg of PGM’s was recovered from 

spent automobile catalysts and other sources in the United 

States (Hilliard, 2000a). This represented about 8 percent of 

U.S. apparent consumption in 1998. More than 19,000 kg of 

platinum in spent automobile catalysts and other scrap materials was exported to other countries (fig. 1) where the metal 

values were recovered and the recovered platinum sold back 

to the United States. 
PLATINUM RECYCLING IN THE UNITED STATES IN 1998 B7 

UNRECOVERED OLD SCRAP 

Only about 64 percent of the catalytic converters 

scrapped in the United States are being collected (Dhara, 

1983). Of these scrapped converters, less than 30 percent are 

being processed domestically for recovery of PGM content; 

about 30 percent are shipped to collection centers to await 

more favorable economic conditions before processing; 20 

percent are unrecovered. The remaining catalytic converters 

(20 percent) are exported to Japan and Europe for processing. 

OLD SCRAP RECYCLING EFFICIENCY 

Old scrap recycling efficiency shows the relation 

between old scrap materials recovered and reused and old 

scrap that is available to be recovered and reused. By definition, this relation is (the amount of old scrap consumed plus 

old scrap exported) divided by (old scrap generated plus old 

scrap imported plus any decrease in old scrap stocks or minus 

any increase in old scrap stocks). Platinum-bearing scrap 

materials consist mostly of spent catalysts from the automobile, chemical, and petroleum industries. In 1998, the chemical and petroleum industries recycled spent catalysts with 

recovery rates above 98 percent. Overall recycling efficiency 

for platinum was lower because of the many automobile catalysts that were not being recycled in 1998. Uncertainty in 

the exact value for recycling efficiency is increased because 

of lack of data on stocks of platinum-bearing material, but 

old scrap recycling efficiency is estimated at 76 percent. 

INFRASTRUCTURE OF PLATINUM SCRAP 

SCRAP COLLECTION SYSTEMS 

Anyone who owns a car manufactured in the United 

States after January 1, 1974, also owns a certain amount of 

automobile catalyst. Although spent automobile catalysts are 

readily available, collecting the material systematically is a 

complicated task. Because the catalysts are unevenly distributed, it is assumed that 20 to 40 percent of the total available 

catalysts will be either uncollected or unaccounted for 

(Dhara, 1983, p. 86). The flow of the material is unpredictable, as many factors, such as PGM prices, govern the 

collection effort. 

The low PGM content in automobile catalysts and the 

nature of the monoliths used as support have required the 

development of specialized recovery techniques, as well as 

the establishment of an infrastructure of collection centers. 

These factors have slowed the development of an automobile 

catalyst recycling industry. 

TRADE 

In 1998, the United States imported 103,000 kg of prefabricated platinum, unwrought platinum, platinum scrap, 

and other platinum materials. The value of these imports was 

$603 million. South Africa (69 percent), the United Kingdom (12 percent), and Germany (4 percent) were the major 

foreign sources of imports. The United States exported 

14,300 kg of refined platinum and 20,447 kg of platinum in 

scrap, ores, and concentrates. The value of these exports was 

$240 million (Hilliard, 2000b, p. 58.6). These quantities differ from those given in figure 1 because the U.S. Census 

Bureau reports some imports and exports as gross weight 

and estimates were made for the platinum content of these 

materials for inclusion in figure 1. 

In the first half of 1998, delayed shipments from Russia 

caused platinum prices to rise by more than $60 to reach a 

peak of $434 per troy oz on April 14. Prices began to fall 

soon afterward, following news that Russian export quotas 

had been approved. Platinum prices declined sharply from 

May through October 1998 because of the economic crisis in 

Asia and renewed financial and political uncertainty in Russia. As a result, the price of platinum sank to a 5-year low of 

$337 per troy oz in October. In 1998, the average annual 

price was $372.50 per troy oz (Hilliard, 2000b, p. 58.3). 

PROCESSING OF PLATINUM SCRAP 

Automobile and catalyst-canister manufacturers arrange 

to recover in-house stainless steel and PGM-bearing scrap 

materials. Once a canister containing PGM’s is mounted on 

a car that is sold, however, it is not regarded as an item for 

recovery by the manufacturers. Initially, each canister contains about 1.5 to 3 g of PGM’s; 1 to 3 micrograms of PGM’s 

are emitted per 1.6 kilometers from the exhaust systems of 

automobiles equipped with the canisters. For the present, the 

economic conditions of salvage through automobile scrap 

yards limit the amount of PGM’s recovered from this source. 

Several processes are available for recovering platinum from 

spent automotive industry catalysts: 

•	 Selective dissolution of the PGM’s from ceramic support 

in aqua regia. Soluble chloro-complexes of platinum, palladium, and rhodium are formed, and reduction of these 

compounds yields crude PGM’s for further refining. 

•	 Dissolution of the catalyst support in sulfuric acid, in 

which PGM’s are insoluble. This technique is widely 

used for the treatment of reforming and isomerization catalysts in which γ-alumina is the substrate but is not suitable for dissolution of the cordierite honeycomb substrates used in many automotive catalysts. 

•	 A gas-phase volatilization in which the PGM’s are selectively chlorinated to produce volatile compounds that are 

condensed in a cooler zone. 

•	 Blending of the catalyst with PGM concentrate to be 

refined by the same process as PGM ore (Dhara, 1983, 

p. 89). 

In the United States, A-1 Specialized Services & Supplies, Inc., Croydon, Pa., and Multimetco, Inc., Anniston, 

Ala., are among the leading buyers and processors of scrap 

catalytic converter canisters. These companies have a network of collection points across the country and pay between 

$3.00 and $17.00 per canister (International Precious Metals 

Institute, 2000). 
B8 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES


OUTLOOK 

The amount of platinum recovered from scrapped automobile catalysts continues to climb slowly and is expected to 

increase significantly in the long term because of increased 

demand for catalytic converters and platinum jewelry in 

Japan and China. Catalytic converters are the major source 

of platinum and other PGM’s for recycling. The outer shell 

of the converter is recycled for its stainless steel content, and 

the substrate is shipped to extractors to recover platinum, 

palladium, and rhodium. The U.S. price of steel scrap, a key 

ingredient of the steelmaking process, continues to be 

depressed, primarily because of the import of new foreign 

steel (Fenton, 2000, p. 40.1). With lower steel scrap prices 

there is less incentive to dismantle cars as dismantlers cut 

back in hope of a price rebound, resulting in fewer salvage 

catalytic converters coming to collection centers. In many 

instances, the converters that find their way to collection centers are exported to countries with lower labor cost—recycling catalytic converters is a labor-intensive task—allowing 

for the economic recovery of the PGM’s. The relatively low 

value of the metal content (about $19.00 in each converter), 

the low concentration of PGM’s (less than 0.1 weight percent), and the difficult logistics of returning the material to a 

central recycling location are reasons why recycling of PGM 

catalysts is not yet economically viable in the United States. 

Consequently, it is doubtful that there will be a significant 

increase in the reclamation of metals from automobile emissions control catalysts in the immediate future. 

Significant changes are on the horizon. The U.S. automobile industry has begun to enter the automobile recycling business, which could lead to an improved infrastructure of collection centers. Pending regulations will deter catalysts from 

entering landfills and will redirect spent catalyst traffic from 

disposal to regenerating and reclamation plants. Although the 

number of cars being scrapped in the United States is fairly 

constant, new sources of material, especially from Mexico, 

where new air-quality regulations are being considered, could 

increase significantly the number of catalytic converters available. Beginning in 2001, automobile manufacturers will shift to 

a more palladium-intensive catalyst. It will be 5 to 6 years, 

however, before any change is seen in the relative amounts of 

various PGM’s available for recycling. 

REFERENCES CITED 

Allen, C.C., 1960, The platinum metals: Canada Department of 

Mines and Technical Surveys, Mineral Resources Division, 

Mineral Report 3, 68 p. 

Burke, D., 1979, Catalyst I: Chemical Week, March 18, p. 10. 

Cabri, L.J., and Laflamme, J.H.G., 1976, The mineralogy of the 

platinum-group elements from some copper-nickel deposits of 

the Sudbury area, Ontario: Economic Geology, v. 71, no. 7, p. 

1159–1195. 

Chang, Thi, 1998, Spent catalyst options—1; Regeneration industry helps refiners control costs, limit liabilities: Oil & Gas 

Journal, v. 96, no. 41, October 12, p. 49–52. 

Chemical & Engineering News, 1999, Facts & figures: Chemical & 

Engineering News, v. 77, no. 26, June 28, p. 36. 

Conradie, A.S., 1997, Platinum-group metals, in South Africa’s 

mineral industry, 1996/1997 (14th ed.): Braamfontein, South 

Africa, South Africa Department of Minerals and Energy, 

Minerals Bureau, November, p. 34–40. 

Dhara, S., 1983, The extraction of platinum-group metals from 

automotive catalysts, in Lundy, D.E., and Zysk, E.D., eds., 

The platinum group metals—An in depth view of the industry: 

International Precious Metals Institute 1983 International 

Seminar, Williamsburg, Va., April 10–13, 1983, p. 88–98. 

Fenton, M.D., 2000, Iron and steel scrap, in Metals and minerals: 

U.S. Geological Survey Minerals Yearbook 1998, v. 1, p. 

40.1–40.19. (Also available online at http://minerals.usgs.gov/ 

minerals/pubs/commodities/iron_&_steel_scrap/360498.pdf.) 

Fung, S.C., 1993, Regeneration of supported noble metal catalysts: 

American Chemical Society, Division of Petroleum Chemistry, Inc., v. 38, no. 1, February, p. 91–96. 

Genkin, A.D., and Evstigneeva, T.L., 1986, Associations of platinum-group minerals of the Noril’sk copper-nickel sulfide 

ores: Economic Geology, v. 81, no. 5, p. 1203–1212. 

Hilliard, H.E., 2000a, Platinum-group metals: U.S. Geological Survey Mineral Commodity Summaries 1999, p. 128–129. 

Hilliard, H.E., 2000b, Platinum-group metals, in Metals and minerals: U.S. Geological Survey Minerals Yearbook 1998, v. 1, p. 

58.1–58.7. (Also available online at http://minerals.usgs. 

gov/minerals/pubs/commodities/platinum/550498.pdf.) 

Hilliard, H.E., and Dunning, B.W., 1983, Recovery of platinum 

group metals and gold from electronic scrap, in Lundy, D.E., 

and Zysk, E.D., eds., The platinum group metals—An in depth 

view of the industry: International Precious Metals Institute 

1983 International Seminar, Williamsburg, Va., April 10–13, 

1983, p. 129–133. 

Johnson Matthey, 1999, Platinum 1999: London, Johnson Matthey, 

May, 52 p. 

Kim, C.-S., Massoth, F.E., and Furimsky, Edward, 1992, Structure 

and catalytic activity of regenerated spent hydrotreating catalysts: Fuel Processing Technology, v. 32, no. 1–2, November, 

p. 39–46. 

Page, N.J, Clark, A.L., Desborough, G.A., and Parker, R.L., 1973, 

Platinum-group metals, in Brobst, D.A., and Pratt, W.P., eds., 

United States mineral resources: U.S. Geological Survey Professional Paper 820, p. 537–545. 

Platinum Metals Review, 1999, Platinum loss from alloy catalyst 

gauzes in nitric acid plants: Platinum Metals Review, v. 43, no. 

2, April, p. 62–69. 

Roberts, J.D., and Caserio, M.C., 1965, Basic principles of organic 

chemistry: New York, W.A. Benjamin, Inc., 1,315 p. 

Roskill Information Services Ltd., 1991, The economics of platinum group metals 1991 (5th ed.): London, Roskill Information Services Ltd., 203 p. 

South Africa Department of Minerals and Energy, Minerals Bureau, 

1997, South Africa’s mineral industry, 1996/1997 (14th ed.): 

Braamfontein, South Africa, South Africa Department of Minerals and Energy, Minerals Bureau, November, 222 p. 

Stillwater Mining Company, 1999, 1998 annual report: Denver, 

Stillwater Mining Company, 98 p. 

Sutphin, D.M., and Page, N.J, 1986, International Strategic Minerals Inventory summary report—Platinum-group metals: U.S. 

Geological Survey Circular 930–E, 34 p. 

U.S. Mint, 1999, 1998 annual report: Washington, D.C., U.S. Mint, 

47 p. 

Wright, T.L., and Fleischer, Michael, 1965, Geochemistry of the platinum metals: U.S. Geological Survey Bulletin 1214–A, 24 p. 
PLATINUM RECYCLING IN THE UNITED STATES IN 1998 B9 

APPENDIX—DEFINITIONS 

γ-alumina. An activated form of alumina, made from Bayer 

α-trihydrate, widely used in adsorption and catalysis, 

where its large surface area, pore structure, and surface 

chemistry play an essential role. 

apparent consumption. Primary plus secondary production 

(old scrap) plus imports minus exports plus adjustments 

for Government and industry stock changes. 

apparent supply. Apparent consumption plus consumption of 

new scrap. 

aqua regia. Royal water, usually a solution of 1 part nitric 

acid and 3 parts hydrochloric acid used to dissolve platinum and other precious metals. 

catalyst. A substance that changes the rate of a chemical reaction but is itself not permanently changed in chemical 

form. 

chalcophilic. Having an affinity for sulfur. 

dissipative use. A use in which the metal is dispersed or scattered, such as paints or fertilizer, making it exceptionally 

difficult and costly to recycle. 

heterogeneous catalysts. Catalysts in which phase boundaries exist between the catalysts and the reacting substances, such as a solid catalyst in a gas or liquid phase 

reaction. 

home scrap. Scrap generated as process scrap and consumed 

in the same plant where generated. 

metal values. The amount of a specified precious metal or 

nonferrous scrap recovered by a refiner plus the cash 

value of other desirable metals recovered minus a penalty 

for undesired metals recovered. 

monolith. [monos, one + lithos, stone] A single ceramic block 

coated with catalytic materials. 

new 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. Examples of new scrap are 

borings, castings, clippings, drosses, skims, and turnings. 

New scrap includes scrap generated at facilities that consume old scrap. 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, measured in weight and 

expressed in percent of new plus old scrap consumed (for 

example, 40:60). 

old scrap. Scrap including (but not limited to) metal articles 

that have been discarded after serving a useful purpose. 

Typical examples of old scrap are electrical wiring, leadacid 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 or obsolete 

materials used dissipatively, such as paints and fertilizer, 

are not included. 

old scrap generated. Metal content of products theoretically 

becoming obsolete in the United States in the year of consideration, excluding dissipative uses. 

old scrap recycling efficiency. 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: 

COS + OSE ×100 

OSG + OSI + decrease in OSS or − increase in OSS 

old scrap supply. Old scrap generated plus old scrap imported plus old scrap stock decrease. 

old scrap unrecovered. Old scrap supply minus old scrap 

consumed minus old scrap exported minus old scrap 

stock increase. 

price. Based on unit value of platinum in materials.


primary platinum. Platinum derived from ore.


recycling. Reclamation of a metal in useable form from


scrap or waste. This includes recovery as the refined 

metal or as alloys, mixtures, or compounds that are useful. Examples of reclamation are recovery of alloying 

metals (or other base metals) in steel, recovery of antimony in battery lead, recovery of copper in copper sulfate, and even the recovery of a metal where it is not 

desired but can be tolerated—such as tin from tinplate 

scrap that is incorporated in small quantities (and 

accepted) in some steels, only because the cost of 

removing it from tinplate scrap is too high and (or) tin 

stripping plants are too few. In all cases, what is consumed is the recoverable metal content of scrap. 

recycling rate. Fraction of the metal apparent 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: 

COS + CNS × 100 

AS 

reforming. A petroleum-refining process that uses a platinum 

catalyst to convert aliphatic hydrocarbons to aromatic 

hydrocarbons. Increasing the aromatic hydrocarbon content of gasoline raises the octane and lessens knocking 

secondary platinum. Platinum derived from or contained in 

scrap. 

siderophilic. Having an affinity for iron. 

toll refining. Custom refining of metal scrap or residue (feedstock) for which the refiner is paid an agreed fee (toll) for 

the recovery of specified precious metals or nonferrous 

scrap. The refined product is returned to the owner of the 

feedstock.