IMPROVEMENTS IN THE TREATMENT OF COPPER AND NICKEL ORES
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by Hector Auguste Dufrené at the
Office of the Commissioners of Patents, with his Petition, on the 11th
July 1865. A communication from Viscount Charles de Secqueville,-
Mining Engineer, residing at Milan, in the Kingdom of Italy.
I, HECTOR AUGUSTE DUFRENÉ, of the General Patent Offices, 10, Rue de la
Fidélité, Paris, in the Empire of France, and 4, South Street, Finsbury,
London, Civil Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE TREATMENT OF COPPER AND NICKEL ORES," to be as
follows, that is to say:-
The Invention communicated to me consists of improvements in the
treatment of copper and nickel ores by several operations.
First operation. The ground ore or the schlick thereof is to be roasted in
an oven or furnace built of a certain shape, and this ground ore or schlick is
to be mixed at the time of roasting with about five per cent. (or such other
proportion as the variable produce of metal in the ore may require) of the
residuum of the manufacture of nitric or azotic acid, the flue of this said
furnace or oven being put into communication with a tower or shaft 8. yards
high, and filled up with coke in a manner to obtain the condensation of acid
vapours with the assistance of water.
Second operation.-After the ore or mineral has been roasted in the manner
berein-before described it must be reduced to small pieces by means of rollers

page_text: or any other crushing apparatus, then roasted again in the before-mentioned
furnace or oven, and mixed at the same time with a proportion equal to
about 15 per cent. of a compound mixture of equal parts of common sea salt,
bi-oxyde of manganese, and of the residuum of the manufacture of nitric acid.
It is to be understood that the proportion of every one of the constituents
of this compound mixture may be altered according to the variable nature of
the ore or ores to be treated.
Third operation. The ore or ores or their schlick having thus undergone
the second roasting process, as herein-before explained, may be arranged in
large heaps, and for the term of a week or so these heaps are to be sprinkled
over, once each day or thereabouts, with the acid waters coming from the
tower containing coke as above mentioned for the condensation of the acid
vapours.
Fourth operation.-The regular washing of the ore, ores, or schlick, prepared
as above, having thus taken place, the concentration of the saturated waters
must be proceeded with after they have been drawn off by way of decantation,
leaving free the gold which first of all is precipitated under the action of the
dissolved salts of iron, provided however that the ore is an auriferous one.
The copper is afterwards precipitated from its solution by means of granulated
pig iron.
Fifth operation. Reduction of the said copper precipitate in ingots after
fusing it in an appropriate furnace or crucible.
Sixth operation. Concentration of the remaining solutions containing the
salt of iron, and production by crystallisation of the green vitriol or sulphate
of iron. The mother waters may be used again to sprinkle over the above
mentioned heaps of calcined or roasted ore,
Seventh operation.-When the ore, ores, or schlick to be treated contain at
the same time copper and nickel, the preceding operations remain exactly
the same with the following variation or difference, videlicet, that after having
obtained by previous cementation the copper precipitate, and likewise by
crystallisation the first portion of the sulphate of iron, the mother waters
must be submitted to the following treatment, in order to extract the nickel
contained therein :-
(a.) Evaporation of the mother waters in order to bring the liquor to a
density of 30 degrees of Beaume's areometer.
(b.) Saturation of the said liquor by means of powdered marble or of any
sort of carbonate of lime. The same is afterwards to be set to boil for one
hour, then allowed to settle, then again drawn clear by means of decantation.
(c.) Dissolution in the above liquor, so decanted, of bypochlorite of lime,

page_text: such as is made use of in the trade, in the proportion of 771 grains or
thereabouts for every quantity of 10 quarts of the liquor, with the successive
addition of 925 grains or thereabouts of sulphuric acid of the trade at 50
degrees of Baume's areometer, or a proportional quantity of the acid water
coming from the condensing tower may be used.
(d.) The clarified liquor is afterwards to be treated hot with caustic sodaic
lime in a suitable proportion, as, for instance, 5 ounces 4 drachms or there-
abouts for every 10 quarts of the liquid.
(e.) The precipitate resulting from the above treatment is dried at a heat
of about 302 degrees Fahrenheit, then washed cold with hydrochloric acid
such as is found in the trade, but diluted with water and reduced to 8 degrees
of Baume's areometer. The portion remaining undissolved is again submitted
to the drying process at a beat of about 248 degrees Fahrenheit, then mixed
up into a paste by means of common nut oil with wheat flour to which
black flux and dry carbonate of soda have been added, the whole being
combined in the following proportions or thereabouts, videlicet, 100 parts of
the said dry residuum, 20 parts of wheat flour, 75 parts of black flux, and 75
parts of dry carbonate of soda.
I reserve to myself the right of making use of different reducing agents,
such as oxalic acid, simple hydrogen, or the various known hydrocarburets,
and also the right of combining the above-mentioned parts in different
proportions. The powdered residuum mixed up as above is formed into a
sort of cake, which after being dried is cut into small fragments which are
put into a crucible or a set of crucibles, which are to be well covered with a
mixture of black flux and dry carbonate of soda and well luted; they are
then submitted to the heat of burning coke in a proper oven for 2 hours or
thereabouts, after which spongious nickel is obtained which is to be remelted
and reduced into regulus by the ordinary means.