A NEW AND USEFUL IMPROVEMENT OR PROCESS OF SMELTING AND REFINING COPPER ORES AND METALLIC COPPER
Year: 1875

page_text: LETTERS PATENT to Samuel Leonard Crocker, of the State of Massa-
chusetts, of the United States of America, for the Invention of
** A NEW AND USEFUL IMPROVEMENT OR PROCESS OF SMELTING AND REFINING
COPPER ORES AND METALLIC COPPER"
Sealed the 21st May 1875, and dated the 2nd March 1875.
COMPLETE SPECIFICATION filed by the said Samuel Leonard Crocker
at the Office of the Commissioners of Patents, with his Petition
and Declaration, on the 2nd March 1875, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SAMUEL
LEONARD CROCKER, of the State of Massachusetts, of the United States
of America, send greeting.
WHEREAS I am in possession of an Invention for "A NEW AND
USEFUL IMPROVEMENT OR PROCESS OF SMELTING AND REFINING COPPER ORES AND
METALLIC COPPER," and have petitioned Her Majesty to grant unto me,
my executors, administrators, and assigns, Her Royal Letters Patent

page_text: for the same, and have made solemn Declaration that I am the first
and true Inventor thereof.
NOW KNOW YE, that I, the said Samuel Leonard Crocker, do hereby
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the said Invention and
in what manner the same is to be performed in and by the following
statement:
The object of this Invention is to provide a practicable and useful
method of removing such impurities as arsenic and antimony during the
process of smelting copper ore or of refining metallic (crude or pig)
copper in the furnace.
It is well known to smelters of copper ore and refiners of metal that
it is impossible to completely remove these impurities by any process of
smelting or refining heretofore in common use; and ores or coppers
known to contain either arsenic or antimony, or both, are generally
rejected by smelters as being of inferior value.
I have discovered that by the aid of zinc, added in small quantity in
the furnaces to the ores, or to the partially refined metallic copper con-
taining arsenic and antimony, these impurities can be readily removed
at very small cost. I have found that zinc in any of its forms, either
refined or crude material, such as spelter, "hard spelter" (an alloy of
zine and iron made in the so-called process of galvanizing iron), brass,
and other alloys, oxides, scoria, slag, natural ores of zinc, etc., may be
used for this purpose, the value of the material depending upon the
proportion of zinc contained in it.
I have employed the following modes of practicing my Invention, and
find them to yield good results :-When smelting an ore containing
about thirty per cent. of copper and four or five per cent. of arsenic, I
put into the smelting furnace with the copper ore about one-quarter as
much zinc slag as of ore, and run them together as in the ordinary
method of smelting copper ore alone. The zine slag is such as is
commonly made in founderies where zinc and brass are melted; it
contains about twenty-five per cent. of zinc, the remainder being iron,
copper, silica, etc. During the smelting of the copper ore and zinc slag
together fumes and vapors of zinc will be seen passing off from the
furnace, and it is my belief that the arsenic, antimony, and other volatile

page_text: metals are carried off with them. The copper taken from furnaces
charged in this way, after refining in the usual manner, yields a soft
malleable metal containing no appreciable arsenic, and but traces of
zinc, if there be any at all.
When refining pig copper or crude copper containing arsenic I melt
with it from two to six per cent. of its weight of spelter or metallic zinc
in the refining furnace, and conduct the refining process in the usual
manner. The zinc is driven off, in this case also apparently carrying the
volatile impurities with it.
I do not confine myself to these exact modes of practicing my Inven-
tion, nor to these proportions of zinc or materials containing zinc, nor
do I confine myself to any particular form of furnace in which to make
the meltings. It will be evident to persons familiar with the art that
zinc should not be added in quantity so large as to produce an alloy
instead of nearly pure copper. The office of the zinc being to remove
impurities and volatile metals from the copper, it should only be used in
such quantites as may be found necessary to accomplish this result.
Having thus described my discovery and Invention, I claim as new,
and desire to secure by Letters Patent, the described art or process of
removing arsenic, antimony, and other volatile metals from copper in a
smelting or refining furnace, such being by the employment of zinc
substantially as herein specified.
In witness whereof, I, the said Samuel Leonard Crocker, have
hereunto set my hand and seal. this Fifteenth day of February.
SAMUEL LEONARD CROCKER. (L.S.)
SAMUEL LEONARD CROCKER. (L.S.)