IMPROVEMENTS IN PRECIPITATION OF COPPER AND OTHER METALS FROM SOLUTION
Year: 1875

page_text: LETTERS PATENT to George Tomlinson Bousfield, of Sutton, in the.
THE
County of Surrey, for the Invention of "IMPROVEMENTS IN
PRECIPITATION OF COPPER AND OTHER METALS FROM SOLUTION."-A com-
munication from abroad by the Société Anonyme du Cuivre
Tennis of Panic in the Republic of France.
Sealed the 18th January 1876, and dated the 6th November 1875.

page_text: NOW KNOW YE, that I, the said George Tomlinson Bousfield, 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:-
This Invention has for its object improvements in the precipitation of
copper and other metals from solution.
The method for the precipitation of copper at present in use is subject
to the great disadvantage that the precipitate of metallic copper is found
mixed with a whole series of basic salts and other impurities, which are
formed during the operation by the decomposition of sulphates other
than the sulphate of copper contained in the liquid under treatment.
I have found by experience that the copper is the first to precipitate,
and that the other salts do not yield up their bases to form basic salts
until the liquid which contains them has already parted with the copper.
I have thus been led to modify the process of precipitation by conducting
it under conditions in which the liquid is gradually heated and is kept
in motion, so as to circulate through a series of vessels from top to
bottom, thus bringing the molecules in succession into contact with the
iron provided to precipitate them.
I work with an apparatus arranged substantially in the manner shown
in the annexed Drawing.
A, A, A, open vats of wood lined with lead or other material which
will not be attacked by the liquid under treatment. B, B, B, siphons
connecting together the several vats, and arranged with this object in
the manner shown in the Drawing. C a Giffard's injector constructed
(so far as it is exposed to contact with the solution) of lead alloyed with
antimony. It is supplied with steam by the pipe c, it draws the liquid
from the first vat through the pipe D, and it delivers it by the pipe E
into the last vat.
The vats are all of the same size, their number and their dimensions
depending on the quantity of liquid to be treated, but to obtain a recular

page_text: How it is advisable to employ one viaru s injector ion cach twenty Cubic
metres of vat capacity.
The liquor should be previously clarified by means of sulphuric acid
in order to eliminate or modify the arseniates, arsenites, silicates, and
aluminates, which may be in suspension in the liquor, and which would
otherwise oppose to the precipitation of the copper.
After having filled all the vats to a level at least ten centimetres over
the mouths of the shorter branches of the siphons, and having placed
in the vats the iron, by preference bar iron, to effect the precipitation I
open the siphons. Then I place the suction tube D in the first vat, and
the end of the tube E into the last vat. The circulation commences in
the direction indicated by the arrows marked on the Drawing so soon as
the Giffard's injector is set to work, and the temperature of the liquid
rises slowly until it attains 6° centigrade or thereabout. The heat
generally attains its maximum after about six hours' work, then the
Giffard's injector stops of itself, the steam is shut off, the movement
becomes less and less, and when it ceases the precipitation is finished.
.
If the density of the liquid to be precipitated is higher than ten
degrees Beaumé, and if it contains principally sulphates of copper it
may be desirable to repeat the operation; in this case when the Giffard's
injector stops the second time the precipitation is accomplished. The
operation is thus reduced in its duration to about twelve hours, when it
is simple, and twenty to twenty-four hours when it is double. This
process of which I have described specially the employment for the
treatment of sulphates of copper by precipitation with iron is equally
applicable to the precipitation of the precious metals, for example, for
the treatment of solutions of sulphate of silver and of copper in view of
the precipitation of the silver by copper, only it is necessary that the
materials of which the apparatus is constructed should be adapted to the
substances to be treated, thus for the precipitation of copper the Giffard's
injector, the siphons, and the tubes are of lead and caoutchouc, whilst to
precipitate silver it is necessary to make then of glass, or of a metal or
matter which will not be acted upon. By this process independently of
the purity of the products and the economical conditions under which
they are obtained, arising especially from the great acceleration of the
operation, it should be remarked that the copper is precipitated in
regular octahedric crystals, which (after they have been washed in
.

page_text: the property of uniting together when hammered cold.
Having thus described the nature of the Invention, and the manner
of performing the same, I would have it understood that I claim the
precipitation of copper and other metals from solution by the means
substantially as described.
In witness whereof, I, the said George Tomlinson Bousfield, have
hereunto set my hand and seal, this Sixth day of November, in
the year of our Lord One thousand eight hundred and seventy-
five.