A Process for the Manufacture of Sulphate of Copper.
Year: 1898

page_text: Date of Application, 23rd May, 1898-Accepted, 21st Jan., 1899
COMPLETE SPECIFICATION.
A Process for the Manufacture of Sulphate of Copper.
I, JULES LAGACHE, of 22, Rue des Allamandiers, Bordeaux, in the Republic of
France, Engineer, 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 :-
Sulphate of copper has hitherto been obtained in the industry by one of the
following processes:
Treatment by dilute sulphuric acid alone of oxidised or carbonated copper ores,
or of copper filings or waste previously submitted to an oxidising roasting.
Treatment by a mixture of nitric acid and sulphuric acid of copper waste or
precipitates.
Treatment by dilute sulphuric acid alone of copper submitted alternately to
the action of air and of the acid.
These three processes are lengthy and necessitate a costly plant. Considerable
manipulation and important losses of material occur, whilst the cost of main-
taining the apparatus is heavy.
The methods or means hereinafter described, considered as a whole, constitute
a novel process.
When commercial sulphuric acid at 66° Baume in which copper is immersed
is heated, the acid is partially decomposed; the copper is transformed first into
a sulphide then into an oxide, sulphurous acid and steam being liberated. The
un-decomposed sulphuric acid unites with the oxide of copper and transforms
it into a sulphate. By continuing the heating operation, the excess of sulphurie
acid, if any, volatilises anhydrous sulphate mixed with a small quantity of
sulphide of copper_remains. On again treating the mass with hot water the
sulphate dissolves; the liquor is decanted and crystallises on cooling. The copper
still unattacked, if such exists is collected and again enters the cycle of opera-
tions, the same applies to the sulphide.
These operations as a whole may be effected commercially in a muffle furnace
or a stove of any suitable kind. For this purpose an apparatus similar to those
employed for the manufacture of hydrochloric acid is particularly adapted.
The form of apparatus which I prefer for carrying out this operation in the
most convenient manner is represented in the accompanying drawings in which
Figure 1 is a vertical longitudinal section of the improved apparatus.
Figure 2 is a horizontal section of the same and
Figure 3 is a cross section thereof.
The copper is introduced either in the state of fragments, granulated, pre-
cipitated or the like into a cast metal pan A into which the concentrated acid
is poured. This pan supports a cast metal vertical shaft C to which a movement
of rotation is imparted from the outside. It carries two horizontal arms BB¹
provided with toothed ribs in the form of plough-shares capable of sliding vertically
along the driving shaft in such a manner as to constantly clean the bottom of the
pan and prevent the adhesion of material whatever their degree of wear may be,

page_text: This pan is heated. When almost the whole of the copper has combined with
the acid, the contents of the pan are transferred by the operatives to a sole
plate 1, which is also heated and where the reaction is completed. When this
has taken place, the mass is caused to fall into a vault or cellar E of dimensions
varying with the magnitude of the operations. Cooling takes place in this cellar
and the mass is then removed by the operatives to the dissolution vessel. There
are always two operations in progress in the furnace, one in the pan and the other
upon the sole plate. The sole plate and the pan are heated by the grate F; if
there exists at hand a sufficient source of waste heat, the bars of the grate may be
removed when once the furnace has been started and the door of the grate and
of the ash pit may be walled up. All that is necessary is to slide in the slab I
in the form of a damper which covers the stove G.
The sulphuric acid produced by the reaction is raised, at the same time as the
steam, by the pipe H which acts as a syphon directly at the outlet of the furnace,
in order to prevent the condensations which would be produced there from falling
back into the furnace. This pipe may be provided with a suction device for increa-
ing the draught if necessary.
The sulphuric acid is collected and may; after purification, be disposed of com-
mercially either in a liquid state after compression or in solution or it may be
employed in a manufacturing process.
When sulphurous acid does not flow freely it may be found preferable to pass
the gases arising from the reaction into a Glover tower and thence into a condensa-
tion chamber, these apparatus having either been constructed specially to corres-
pond with the quantity of sulphate manufactured, or on the other hand, the
manufacture of the sulphate being adapted to an existing sulphuric acid apparatus.
In this case, in place of fuel a portion of the heat given off by the combustion
of the pyrite may be utilized.
The sulphurous acid which is removed through the pipe H and also the sulphuric
acid in excess are collected by the usual means, and they may be placed upon the
market in the natural state or utilized in other manufactures, or finally re-intro-
duced in the manufacture of the sulphate of copper.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
-
1. The oxidation of copper and its transformation into sulphate by heated
concentrated sulphuric acid alone.
2. The volatilisation of the sulphuric acid in excess for the purpose of obtain-
ing first a commercially neutral and anhydrous sulphate and subsequently a
crystalized sulphate.
3. The recuperation of the sulphurous and sulphuric acids in excess either
for placing upon the market in the natural state or for utilizing them for other
manufactures or finally for re-introducing them into the manufacture of sulphuric
acid and sulphate of copper.
4. The employment of a furnace provided with a pan and sole plate and with
a mechanical mixing device, such furnace being heated directly either by means
of a grate or by the waste heat arising from another manufacturing process, that
from pyrite furnaces being particularly adapted for this purpose.
Total this 00 1
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.