IMPROVEMENTS IN THE WET TREATMENT OF SILICATE ORES OF COPPER, NICKEL, AND COBALT TO OBTAIN THE METALS OR METALLIC SALTS
Year: 1876

page_text: LETTERS PATENT to Sydney Pitt, of Sutton, in the County of Surrey, for the
Invention of "IMPROVEMENTS IN THE WET TREATMENT OF SILICATE ORES OF
COPPER, NICKEL, AND COBALT TO OBTAIN THE METALS OR METALLIC SALTS." A
communication from abroad by Mieczyslas Kamienski, of Paris, in the Republic
of France.
Sealed the 12th January 1877, and dated the 10th August 1876.
PROVISIONAL SPECIFICATION left by the said Sydney Pitt at the Office of
the Commissioners of Patents on the 10th August 1876.
SYDNEY PITT, of Sutton, in the County of Surrey. "JMPROVEMENTS IN THE
WET TREATMENT OF SILICATE ORES OF COPPER, NICKEL, AND COBALT TO OBTAIN THE
METALS OR METALLIC SALTS." (A communication from abroad by Mieczyslas
Kamienski, of Paris, in the Republic of France.)
This Invention has for its object improvements in the wet treatment of silicate
orcs of copper, nickel, and cohalt to obtain the metals or metallic salts.
The Invention consists in treating the natural silicates of the form Cu O Si O, HO
with a strong acid which displaces the silica, and produces a soluble salt of the
metal. The hydrate of silica which results from the reaction is also soluble. This
silica is separated by dehydrating it at a dull red heat. This heat ought to be
such that the metallic salt will not be decomposed whilst the silica is dehydrated.
The dehydrated silica now being insoluble is precipitated when water is added, and
it is now only necessary to decant or filter, and wash the precipitate of silica, and
the whole of the metallic salt is thus separated; such is the system of treatment.
The operation is as follows:-Suppose that silicate of copper (Cu O Si O, HO) is
to be treated. The mineral is ground, and a quantity of sulphuric acid proportional
to the amount of copper in the ore is mixed with it. It is then exposed to the air
for the time necessary for it to form into a pasty and gelatinous mass. The magma
is then placed in an iron pan, and submitted to a dull red heat in any convenient
furnace. The completion of the reaction is shewn by the cessation of all volatilisa-
tion, vaporisation of water, or acid in excess in the magma. The resulting cake is
treated with water; it disintegrates, the sulphate of copper dissolves, the tempera-
ture augments, the silica which has been dehydrated. hy the heat, and has become
insoluble, remains in the form of an excessively fine powder.
Daine 71

page_text: All that now need be done is to filter with bags, and a limpid liquor is obtained
which contains all the copper in the form of sulphate.
The precipitate of silica is easily washed without the necessity of agitation, so as
to remove the last traces of sulphate of copper.
The bags, if they are sufficiently large, can, before the final washing of the pre-
cipitate, receive successively large quantities of the silica.
Sulphuric acid, nitric, hydrochloric, acetic, &c., may be used indifferently, but will
produce the corresponding metallic salts.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Sydney Pitt in the Great Seal Patent Office on the 9th February
1877.
SYDNEY PITT, of Sutton, in the County of Surrey. "IMPROVEMENTS IN THE WET
TREATMENT OF SILICATE ORES OF COPPER, NICKEL, AND COBALT TO OBTAIN THE
METALS OR METALLIC SALTS." A communication from abroad by Mieczyslas
Kamienski, of Paris, in the Republic of France.
This Invention has for its object improvements in the wet treatment of silicate
ores of copper, nickel, and cobalt to obtain the metals or metallic salts.
The Invention consists in treating the natural silicates of the forni Cu O Si O, HO
with a strong acid which displaces the silica, and produces a soluble salt of the
metal. The hydrate of silica which results from the reaction is also soluble. This
silica is separated by dehydrating it at a dull red heat. The heat ought to be such
that the metallic salt will not be decomposed whilst the silica is deliydrated. The
dehydrated silica now being insoluble is precipitated when water is added, and it
is now only necessary to decant or filter and wash the precipitate of silica, and the
whole of the metallic salt is thus separated; such is the system of treatinent.
The operation is as follows:-Suppose that silicate of copper (Cu O Si O, HO) is
to be treated, the mineral is ground, and a quantity of sulphuric acid proportional
to the amount of copper in the ore is mixed with it; it is then exposed to the air,
for the time necessary for it to form into a pasty and gelatinous mass.
The magma
is then placed in an iron pan, and submitted to a dull red heat in any convenient
furnace. The completion of the reaction is shown by the cessation of all volatiliza-
tion vaporization of water or acid in excess in the imagina. The resulting cake is
treated with water; it disintegrates, the sulphate of copper dissolves, the tempera-
ture augments, the silica which has been dehydrated by the heat, and has become
insoluble, remains in the form of an excessively fine white powder.
All that now need be done is to filter with bags, and a limpid liquor is obtained
which contains all the copper in the form of sulphate.
The precipitate of silicate is easily washed without the necessity of agitation, so
as to remove the last traces of sulphate of copper.
The bags, if they are sufficiently large, can, before the final washing of the pre-
cipitate, receive successively large quantities of the silica.
Sulphuric acid, nitric, hydrochloric, acotic, &c., may be used indifferently, but
will produce the corresponding metallic salts.
If it be required to treat silicate of nickel, such as is found in the minerals of
New Caledonia, having the composition of a double salt, silicate of nickel with the
silicate of magnesia mixed with the oxide or the silicate of iron, the operation is
conducted as follows:-The mineral in question is dissolved in muriatic acid of
commerce diluted with double its weight of water. For this operation the mineral
should be finely powdered, and passed through a sieve. The quantity of acid should
represent the equivalent corresponding to the nickel the magnesia and the iron
contained in the mineral. The solution is made in stoneware vessels heated by an

page_text: oil bath.
green color.
The operation is complete when the residue carefully washed has lost its
The solution is allowed to settle, and is drawn off; it contains chlorides of nickel,
of magnesia, and of iron. After it has been allowed to stand for some hours the
iron is peroxidised by adding an aqueous solution of chlorine in such quantity that
there may be chlorine equivalent to the iron requiring to be peroxidised. This
quantity of chlorine will be quite small, for it has only to peroxidise the iron found
in a state of protoxide. The rest of the iron exists as peroxide in the mineral.
The iron thus oxidised is precipitated from the solution by carbonate of magnesia;
the magnesia combines with the chlorine of the chloride, and disengages the
peroxide. The quantity of carbonate of magnesia required is an equivalent of
magnesia for each equivalent of iron to be precipitated. This carbonate of magnesia
is obtained in a pure state from the mineral under treatment in the manner herein-
after described.
Air is employed to agitate the liquid, and to remove excess of chlorine to prevent
peroxidation of the chloride of nickel.
After that the liquid has been freed from carbonic acid by the action of the air,
or by agitation, the oxide of iron is found to be completely precipitated. After it
has been left for about twelve hours the liquid is passed through a filter; it then
only contains chloride of nickel and chloride of magnesia, and it is quite neutral.
It is placed in copper bowls, and carbonate of soda is added in quantity almost
equivalent to the nickel contained, and it is heated. The carbonate of soda pre-
cipitates both the nickel and the magnesia in the form of carbonates, but the car-
bonate of magnesia becomes decomposed by heat in the presence of the chlorido of
nickel contained in the liquid, and returns as chloride into the solution, depositing
the nickel in the form of carbonate.
It should be observed that to avoid having carbonate of magnesia in the deposit
it is necessary to have a little less soda than there is nickel in the solution. The
remaining nickel will be recovered, as herein-after described.
The liquid with the deposit is passed a second time through the filter press; the
deposit, which is carbonate of nickel, is carefully washed with water free from
earthy salts; then pressed, dried, and set aside for reduction with wood charcoal in
a close crucible at a white red heat continued for two hours or more. The carbonic
acid of the carbonate of nickel, as well as its oxide at this heat, is reduced by the
carbon forming oxide of carbon which burns, leaving in the crucible pure metallic
nickel mixed mechanically only with carbon, which separates from it when it is
thrown into water. The nickel thus obtained in a spongy state is quite pure, and
may be melted with other metals to form well-known alloys, or it may be employed
in the metallic state.
The liquid obtained from the second filtration containing traces of nickel besides
chlorides of magnesia and of sodium is again treated by carbonate of soda for the
precipitation of the rest of the nickel and of a part of the magnesia; it yields car-
bonate of magnesia and of nickel, which serves in the next operation for the
precipitation of the iron, as has been already described above.
The remaining liquid when submitted to evaporation yields common salt which
represents all the soda employed as carbonate, the mother liquor (which is but
chloride of magnesium) further evaporated and heated in stoneware vessels to a
temperature of about 150c. When a jet of steam is passed through the mass yields
hydrochloric acid. The magnesia thus obtained is also a useful product.
What I claim is,-
First. The separation of the silica from the natural silicates of metals by dis-
placing the silica by another acid, which produces a soluble salt of the inetal,
and by dehydrating the silica, so as to render it insoluble, substantially as
described.
Second. The employment of pure carbonate of magnesia for the precipitation of
the iron, such carbonate of magnesia being obtained from the mineral itself, sub-
stantially as described.

page_text: Third. The employment of carbonate of soda for the precipitation of carbonate
of nickel in presence of carbonate of magnesia, substantially as described.
Fourth. The application of air to agitate the liquid and to expel excess of
chlorine, in order to preserve the chloride of nickel from peroxidization, substantially
as described.
Fifth. The combined process, above described, for obtaining by humid method
pure carbonate of nickel from the New Caledonia mineral employing only hydro-
chloric acid, chlorine water, and carbonate of soda, substantially as described.
The carbonate of nickel so obtained is capable of being reduced into metallic nickel
either by the means above indicated or by any other known method.
In witness whereof, I, the said Sydney Pitt, have hereunto set my hand and
seal, this Sixth day of February, in the year of our Lord One thousand
eight hundred and seventy-seven.
SYDNEY PITT. (L.S.)