IMPROVEMENTS IN TREATING WASTE SOLDUPTONS OBTAINED from Burnt CUPREOUS PYRITES
Year: 1866

page_text: LETTERS PATENT to Frederic Claudet, of Nos. 6 and 7, Coleman Street,
in the City of London, for the Invention of "IMPROVEMENTS IN TREATING
WASTE SOLDUPTONS OBTAINED from Burnt CUPREOUS PYRITES."
Sealed the 30th April 1867, and dated the 3rd November 1866.
PROVISIONAL SPECIFICATION left by the said Frederic Claudet at the
Office of the Commissioners of Patents, with his Petition, on the
3rd November 1866.
I, FREDERIO CLAUDET, of Nos. 6 and 7, Coleman Street, in the City of
London, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS. IN TREATING WASTE SOLUTIONS OBTAINED FROM BURNT CUPREOUS PYRITES,"
to be as follows:-:
In the treatment of Portugese, Spanish, and other burnt cupreous pyrites
by the wet method after re-calcination with salt the waste solutions that
remain after the precipitation of the copper contain a large proportion of
soda and iron salts, and some other metallic salts in very small quantity,
amongst which are those of cobalt. I propose employing these waste solutions
for the purpose of extracting the small quantity of cobalt contained, and at
the same time making sulphate of soda and a crystalline peroxide of iron,
both products of commercial value. The salts consist essentially of 'sulphate
of soda, chloride of sodium, and protosulphate of iron, varying in their relative
proportions according to the amount of common salt mixed with the burnt

page_text: ore previous to the re-calcination, and the amount of the sulphur and copper
contained in the latter. In addition to these salts the liquors hold in solution
a little lead, antimony, arsenic, bismuth, zinc, manganese, cobalt, and nickel.
I find it is advantageous to regulate the proportion of common salt added to
the burnt ore, or I increase the sulphur when deficient in the burnt ore by the
addition of raw. pyrites before the re-calcination, so that the salts in the waste
liquors should consist of not more than 1 equivalent of chlorides to every
2 equivalents of sulphates.
I now proceed as follows:-The solutions are either concentrated in case-
iron or boiler plate pans constructed and heated on the same principal as
those employed in Cheshire for the brines, and the salts raked out as deposited,
or they are evaporated down to dryness in a reverberatory furnace as more
economical, and in works where waste heat is available I apply it for the
same purpose. The salts or residual mass thus obtained, consisting of an
intimate mixture of all the alkaline and metallic salts originally in solution
are now charged in a calcining furnace and subjected at first to a low heat,
which is increased gradually to bright red, taking care to renew the surfaces
by repeated and prolonged stirring; a reaction ensues, the iron of the
sulphate becomes peroxidized, the chloride of sodium is transformed into
sulphate of soda with the ebolution of hydrochloric acid, chlorine, and
sulphurous acid; these gases are made to pass through the same tower that
serves for the condensation of similar gases evolved in roasting the ore with
salt, and are thereby condensed and serve for the lixiviation of the calcined
ores. The tower liquors becoming more charged with acid than heretofore
the quantity of salt used in the first operation may be without inconvenience
materially decreased. I find that by keeping the charges at a red heat the
sulphate of iron is completely decomposed, whilst the sulphate of cobalt in
presence of a large amount of alkaline sulphate resists a much higher
temperature, and remains in a soluble state. When no more fumes are
given off, and the mass which at first was nearly liquid has become quite
pasty it is withdrawn and lixiviated in the same way as black ash in the
inanufacture of soda. Sulphate of soda, sulphate of cobalt, and some other
metallic sulphates dissolve and are filtered from the peroxide of iron, which
remains in a beautiful scaly or crystalline form of a dark reddish colour. This
oxide of iron is washed, and if necessary levigated and dried, and may be
employed to advantage for polishing and several other purposes. To the clear
solution I now add a slight excess of sulphide of sodium (prepared by
decomposing the sulphate at a strong heat by coal), whereby the metals are
precipitated as sulphides. After standing some time the clear fluid which is

page_text: a strong and very pure solution of sulphate of soda is syphoned off or filtered
from the precipitate, and either concentrated to the crystallizing point of
sulphate of soda, or evaporated down to dryness for salt ash. The precipitate,>
consisting of sulphides of zinc, cobalt, nickel, and other metals, is treated for
cobalt and nickel by the process employed for the extraction and separation of
these metals from their ores.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frederic Claudet in the Great Seal Patent Office on
the 3rd May 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERIC
CLAUDET, of Nos. 6 and 7, Coleman Street, in the City of London, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters-
Patent, bearing date the Third day of November, in the year of our Lord One
thousand eight hundred and sixty-six, in the thirtieth year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said Frederic
Claudet, Her special licence that I, the said Frederic Claudet, my executors,
administrators, and assigns, or such others as I, the said Frederic Claudet, my.
executors, administrators, and assigns, should at any time agree with, and
no others, from time to time and at all times thereafter during the term.
therein expressed, should and, lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN TREATING
WASTE SOLUTIONS OBTAINED FROM BURNT CUPREOUS PYRITES," upon the condition
(amongst others) that I, the said Frederic Claudet, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Frederic Claudet, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
In the treatment of Portuguese, Spanish, and other burnt cupreous pyrites
by the wet method after re-calcination with salt, which is a well known

page_text: process,
the waste solutions that remain after the precipitation of the copper
contain a large proportion of soda and iron salts, and some other metallic
salts in very small quantity, amongst which are those of cobalt. I propose
employing these waste solutions for the purpose of extracting the small
quantity of cobalt contained, and at the same time making sulphate of soda
and a crystalline peroxide of iron, both products of commercial value. The salts
consist essentially of sulphate of soda, chloride of sodium, and proto-sulphate
of iron, varying in their relative proportions according to the amount of
common salt mixed with the burnt ore previous to its re-calcination, and the
amount of the sulphur and copper contained in the latter; in addition to
these salts the liquors hold in solution a little lead, antimony, arsenic, bismuth,
zinc, manganese, cobalt, and nickel. I find it is advantageous to regulate
the proportion of common salt added to the burnt ore, or I increase the
sulphur when deficient in the burnt ore by the addition of raw pyrites before
the re-calcination so that the salt in the waste liquors should consist of not
more than 1 equivalent of chlorides to every 2 equivalents of sulphates.
.
I now proceed as follows:-The solutions are either concentrated in cast
iron or boiler plate pans constructed and heated on the same principle as
those employed in Cheshire for the brines, and the salts raked out as
deposited, or they are evaporated down to dryness in a reverberatory furnace
as more economical, and in works where waste heat is available I apply it
for the same purpose. The salts or residual mass thus obtained, consisting
of an intimate mixture of all the alkaline and metallic salts originally in
solution, are now charged in a calcining furnace, and subjected at first to a
low heat, which is increased gradually to bright red, taking care to renew
the surfaces by repeated and prolonged stirring; a reaction ensues, the iron
of the sulphate becomes peroxidized, the chloride of sodium is transformed
into sulphate of soda with the evolution of hydrochloric acid, chlorine, and
sulphurous acid; these gases are made to pass through a condensing tower,
it may be the same tower that serves for the condensation of similar gases
evolved in roasting the ore with salt, the gases thereby condensed serve for
the lixiviation of the calcined ores. The tower liquors becoming more
charged with acid than heretofore the quantity of salt used in the first
operation may be without inconvenience materially decreased. I find that
by keeping the charges at a red heat the sulphate of iron is almost completely
decomposed, whilst the sulphate of cobalt in presence of a large amount of
alkaline sulphate resists a much higher temperature, and remains in a soluble
state. When no more fumes are given off, and the mass which at first was
nearly liquid has become quite pasty it is withdrawn and lixiviated in the

page_text: same way as black ash in the manufacture of soda. Sulphate of 'soda,
sulphate of cobalt, and some other metallic sulphates dissolve and are filtered
from the peroxide of iron which remains in a beautiful scaly or crystalline
form of a dark reddish color; this oxide of iron is washed, and if necessary
levigated and dried, and may be employed to advantage for polishing and
several other purposes. The clear solution may be evaporated, and an impure
sulphate of soda obtained from it, which may be more or less purified by
crystallization; I prefer, however, to add to the clear solution a slight excess of
sulphide of sodium (prepared by decomposing the sulphate at a strong heat
by coal) whereby the metals are precipitated as sulphides. After standing
some time the clear fluid, which is a strong and very pure solution of sulphate
of soda, is syphoned off or filtered from the precipitate, and either concentrated
to the cystallizing point of sulphate of soda, or evaporated down to dryness
for salt ash. The precipitate, consisting of sulphides of zinc, cobalt, nickel,
and other metals, is treated for cobalt and nickel by the process employed for
the extraction and separation of these metal from their ores.
What I claim is the treating waste solutions obtained from burnt cupreous
pyrites by evaporating the said solutions, and obtaining salts therefrom, then
calcining these salts and dissolving out the sulphates from the calcined salts,
leaving peroxide of iron uudissolved.
I also claim the precipitating from the solution of these calcined salts tho
cobalt and other metals it contains by means of alkaline sulphides, leaving a
solution of sulphate of soda in a nearly pure state.
In witness whereof, I, the said Frederic Claudet, have hereunto set
my hand and seal, this Thirtieth day of April, in the year of our
Lord One thousand eight hundred and sixty-seven.
FRED. CLAUDET. (LS.)
FRED. CLAUDET. (L.S.)