A Process for Recovering Copper and Nickel from Ores or Mattes Containing these Metals.
Year: 1892

page_text: Date of Application, 20th Sept., 1892
Complete Specification Left, 3rd May, 1893—Accepted, 29th July, 1893
PROVISIONAL SPECIFICATION.
A Process for Recovering Copper and Nickel from Ores or Mattes
Containing these Metals.
I, JULES STRAP, of No. 1, Boulevard St. Denis, Paris, France, do hereby
declare the nature of this invention to be as follows:-
Ores or mattes containing copper and nickel usually contain also iron. My
invention relates to the treatment of such ores or mattes so as to separate first the
copper, then, after clearing the residue from iron, to deposit the nickel from it.
For this purpose, I first pulverise the ore or matte, then oxidise while roasting,
preferably with an oxidising gas flame, first at a temperature of not more than
300° C. for several hours, and afterwards up to about 600°. Thus the sulphides
are converted into anhydrous sulphates, and the sulphate of iron formed is decom-
posed and converted into peroxide. The roasting should be effected in two ovens
provided with means of thoroughly raking the material and of regulating the
currents of air for oxidising, particularly when the heat results from the conversion
of the sulphides into sulphates.
As
After oxidation the material is thrown into tanks, which may be of wood with
sand filters at the bottom, with water slightly acidulated and preferably warmed to
effect solution rapidly. The liquor is transferred from tank to tank until it attains
a strength of 25° to 30° Beaumé, in which condition it contains about 60 kilo. of
copper and 55 kilo. of nickel to the cubic metre, in the state of sulphates. There
is a solid residue, peroxide of iron, which can be utilised as purple ore. The liquor,
is run into wooden tanks with double bottoms and treated with scrap and cast iron,
being preferably heated by a steam jet to about 60° C. The copper is thus
deposited, and can be collected. The liquor now containing sulphate of nickel and
sulphate of protoxide of iron, has air then biown through it while carbonate of lime
is added in numerous small doses. This causes precipitation of sulphate of lime
and peroxide of iron, leaving the liquor containing only sulphate of nickel.
the precipitate is of a very spongy character, it should be washed to recover the
liquor with which it is saturated. The sulphate of nickel is converted into
chloride by adding calcium chloride or sodium chloride. When the former is
added, sulphate of lime is precipitated and separated by filtration; leaving nickel
chloride only; when the latter is added, the liquor is a mixture of nickel chloride
and sodium sulphate. On treating this liquor with milk of lime, nickel oxide is
precipitated and can be separated by filtration from the solution of calcium
chloride. Metallic nickel may be obtained electrolytically in the following manner.
I employ a bath of the sulphate of nickel solution at 12° Bé., to which I add
30 per cent. of sulphate of ammonia; I use carbon anodes and thin nickel cathodes,
and I maintain agitation during the electrolysis, adding freshly precipitated nickel
oxide which combines with the sulphuric acid liberated from the sulphate to form
fresh sulphate. Metallic nickel is deposited on the cathodes.
Dated this 20th day of September 1892.
ABEL & IMRAY,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
A Process for Recovering Copper and Nickel from Ores or Mattes
Containing these Metals.
I, JULES STRAP, of No. 1 Boulevard St. Denis, Paris, France, do hereby
declare the nature of this invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement :-
The object of my invention is the treatment of cupronickel pyrites or sulphide
ores containing copper and nickel mixed with iron or other metals. The process is
applicable to native pyrites or to the mattes obtained by roasting and melting. As
in these the metals are more or less concentrated, the process may be best described
as applied to them. I first finely pulverise the matte so that it passes a sieve of
2 millimetres mesh, and I roast it, taking care that it does not reach or certainly
does not exceed the temperature at which copper sulphate is decomposed, and
afterwards the higher temperature at which nickel sulphate is decomposed, and
thus obtain these sulphates by simple solution in water acidulated with
1 per cent. of sulphuric acid. At these temperatures the iron sulphate formed is
decomposed and can be separated.
to
Some metallurgical works, especially Crookes & Köhrig's treatise, describe a
treatment which at first sight appears to resemble this in some respects, but on
closer examination, differences will be found which characterise my invention. In
the Crookes & Köhrig's process the roasting temperature is only approximate,
whereby a small quantity of copper sulphate and even of nickel sulphate is decom-
posed, so that afterwards only the undecomposed portions can be dissolved, and the
residue must be attacked by dilute acids, that is to say, water containing about
15 per cent. of acid. By my process I entirely avoid decomposition of copper
sulphate and nickel sulphate, and consequently the solution can be made practically
without acid. I operate in the following manner.
The matte or ore, first pulverised as above mentioned, is subjected to an oxidising
roasting, and should therefore be charged as fine powder in a thin layer of 25 to
30 kilos. on each square metre. During 5 hours, at first, the temperature should
not exceed 300° C., after which it should be raised to 580° to 600° C. The
sulphides are thus converted into anhydrous sulphates, and the sulphate of iron
formed is decomposed. I maintain the required uniformity of temperature by using
producer gas and regulating the temperature of the gas current maintained with
excess of oxygen before it enters the oven. After about 18 hours, the matte,
rabbled about every hour, to renew the surface exposed, presents the following
conditions. The iron is converted into peroxide Fe2O3, the copper and the nickel
are converted into sulphates, CuOSO2, and NiOSO³. Part of the copper has
passed to the condition of basic sulphate. The completion of the operation and
the absence of all sulphides are ascertained by known tests.
For carrying on the operation properly, the roasting should be divided into two
parts so as not to agglomerate the matte nor exceed the temperature of 600° C.
A gas current that freely oxidises is absolutely necessary. The roasting can be
effected in two ovens. In the first the matte is brought to a state such that it
cannot mass itself when it is heated to 600° C. But, with an oven of Maletia-Perret
kind as commonly used in the manufacture of sulphuric acid from iron pyrites
properly arranged, the operation can be effected in one oven. In this case, the
lower slabs should be brought together so as to increase the temperature at the
lower part of the oven and so that the radiation of the slabs on each other may
keep up sufficient heat.
The upper slabs, where the charging begins, should, on the contrary, be separated
with air openings arranged so as to keep down the temperature at the upper part

page_text: of the oven. A fire in the bottom of the oven about 15 metre distant from the
slabs, with excess of air to give a thoroughly oxidising atmosphere, can maintain
the temperature. As the formation of sulphates evolves much heat, once the action
is started, the fire may be extinguished, leaving the oxidation to go on with the
heat evolved by the reaction. The roasted matte is put in large basins or tanks,
which may be of wood, having sand filters at the bottom. Pure water is first
This water may
poured on the material, then water acidulated to 1 to 2 per cent.
be cold, but it is preferably heated as solution is more quickly effected; and the
solution is made to flow from tank to tank until it attains 25° to 30° Bé. When
the liquor is at this strength (at which it crystallises) each litre contains 450
to 500 grammes of copper and nickel sulphates and consequently about 60 grammes
of metallic copper and 55 grammes of nickel, or, in the cubic metre of liquor,
60 kilos. of copper and 55 kilos. of nickel. The solution contains the whole of the
copper and nickel in the state of sulphates. Basic sulphates are obtained by
lixiviating with water containing per cent. of sulphuric acid. For this solution
may be also employed the water of condensation of the sulphurous acid coming
from the towers connected to the roasting ovens.
TL 11 1
annnxide which is utilised as purple ore.
SEPARATION OF THE NICKEL AND IRON.
To effect this the sulphate of iron protoxide is connected into sulphate of iron
peroxide and treated with carbonate of lime. Hitherto iron has been peroxidised
by calcium chloride, nitric acid or chlorine; peroxidising by blowing in air had
been suggested, but this action which succeeded at first, stopped as soon as a
certain proportion of sulphate of peroxide was formed. I avoid this inconvenience
by blowing cold air into the liquor containing the iron and nickel sulphates, and, at
the same time, adding pulverised carbonate of lime, there being thus formed
sulphate of iron peroxide which precipitates as it is formed. In order that the
reaction may be complete, the carbonate of lime has to be added frequently in
small doses. The operation is completed in 5 or 6 hours, giving precipitates of
sulphate of lime and of sulphate of iron peroxidised and leaving the liquor con-
taining only very pure sulphate of nickel. The precipitate is very spongy and the
water which it holds is charged with sulphate, it is therefore washed and the
washing water is collected.
I transform the sulphate of nickel into chloride by adding sodium or calcium
chloride. When the latter is used there is a precipitate of sulphate of lime which
When sodium
is separated by filtering leaving solution of nickel chloride alone.
chloride is used, the liquor is a mixture of nickel chloride and sulphate of soda.
The liquor is treated with milk of lime which gives a precipitate of nickel oxide
and solution of calcium chloride. The nickel oxide is separated by filtering. I
obtain metallic nickel electrolytically by forming a bath of nickel sulphate of 12° Bé.
strength to which I add 30 per cent. sulphate of ammonia; I use carbon anodes
and cathodes of thin nickel, and transmit a current of 2 volts and 20 ampères for
each square metre of the cathode surface. The nickel sulphate is decomposed and
nickel is deposited. I keep up constant agitation in the bath, adding freshly pre-
cipitated nickel oxide. The sulphuric acid set free by the current combines with

page_text: the nickel oxide which should be kept in suspension in the liquor, producing nickel
sulphate which is decomposed in its turn.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The herein described process for recovering copper and nickel by roasting
finely pulverised matte or ore containing their sulphides, taking care not to exceed
the temperature at which their sulphates decompose, lixiviating in slightly acidulated
water so as to produce solution of the sulphates, depositing the copper by treatment
with iron, blowing cold air into the residual liquor while adding frequent small
doses of pulverised carbonate of lime to bring the iron to condition of insoluble
sulphate of peroxide and thus cause its precipitation leaving nickel sulphate alone
in solution, then depositing the nickel electrolytically from a bath consisting of
nickel sulphate with addition of sulphate of ammonia, substantially as herein
described.
2. Treating the nickel sulphate solution obtained as set forth in the preceding
claim with sodium or calcium chloride so as to convert it into nickel chloride, and
converting this into nickel oxide by adding milk of lime, substantially as described.
Dated this 3rd day of May 1893.
ABEL & IMRAY,
Agents for the Applicant.