Improvements in Extracting Metals from their Ores and in Apparatus therefor.
Year: 1898

page_text: Date of Application, 22nd Feb., 1898-Accepted, 6th Aug., 1898
COMPLETE SPECIFICATION.
Improvements in Extracting Metals from their Ores and in
Apparatus therefor.
I, SAMUEL HENRY JOHNSON, of the Engineering Works, Carpenters Road, Strat-
ford, Metallurgical and Chemical 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 : —
This invention has for its object the removal of gold and other metals from
finely ground minerals or slimes by chemical treatment in the wet way; and in
carrying out this my invention I employ an -apparatus for use in the operation of
bringing the metals into solution by treatment with the proper chemical reagents
I have in mind
and removing the solution so obtained completely from the ores.
the existence of Letters Patent No. 19389 A.D. 1891 for improvements in leaching
ores and in apparatus therefor, which were granted in England to the aforesaid
Samuel Henry Johnson and to Christopher Clarke Hutchinson on the 17th Sep-
tember 1892, which had for its object the removal of soluble metallic salts from
finely ground minerals after they had been previously chemically treated so as to
render the metal which it is desired to extract soluble, and I desire to distinguish
that this invention which I now describe differs therefrom in that the ground
minerals or slimes under treatment are to be dealt with in the apparatus, so that
both the operation of chemically treating the ore and of separating from it the
solution of the metal so obtained are performed in the one apparatus, thus reduc-
ing the manipulation and the labour involved in the process.
The apparatus for the purpose of this Specification may be taken to correspond
to the leaching press described in the aforesaid Letters Patent No. 19389/1891,
and the arrangements therein described with respect to the particulars of construc-
tion of same together with the mode of filling same and apparatus therefor so as
to produce cakes of ore or slimes uniformly permeable should be employed. In-
stead of passing the solution through a single machine, to work economically when
treating the ore chemically in the apparatus, in some cases it may be necessary
to combine several sets of such apparatus together. so that the excess of the chemical
reagent passing through the first apparatus may act on the ore in the second and
the excess from the second through that in the third, and so on, the flow of the
solution of chemical reagent being maintained until the solution of the metal in
the apparatus is sufficiently effected. The liquor from each or any of the series
of apparatus may sometimes with advantage be aerated before being passed through
the ore again. The solution remaining in the cakes may then be pushed out with
wash water, and the displaced solution passed through the series of machines until
the whole of the chemical solution has been removed from the first apparatus of
the series, which may then be discharged and refilled with ore and in its turn
it becomes the last of the series, with regard to the circulation of the solvent, the
direction of flow of solvent in the series being such that it traverses successive
presses in reverse order to that in which they are filled by such systematic treat-
ment the maximum effect may be obtained from the chemicals employed. It will

page_text: of course be understood that when forcing the liquids consecutively through the
apparatus above described a proportionately greater pressure will be required than
is necessary when working with a single apparatus. It will thus be seen that in
the first stage of the operation of extraction the machine is first filled so as to form
cakes possessing the requisite permeability. These cakes are then percolated with
the chemical solutions which are capable of dissolving the metals which it is
desired to extract. Then when this operation has been effected, the residue of the
solution which the cakes contain is displaced with water, leaving the ore freed from
metal, which is then contained in solution in the effluent from the apparatus.
DESCRIPTION OF THE DRAWINGS.
In the drawing appended to this Specification V represents a mixing vat with
agitator for mixing the finely pulverised ore with liquid which may or may not
contain chemicals for the treatment of the ore, as may be desired. R represents
a pneumatic forcing receiver into which the thin slurry resulting from such mix-
ture is introduced, and from which it is forced by means of compressed air intro-
duced from the compressed air main indicated with stop valve at A. From thence
it is forced by the pressure of the compressed air through the delivery main M
into whichever of the leaching presses is next intended to form the first in the
series. F, F, F3, F and F are a series of filter presses arranged to be worked
consecutively in rotation, from which the filtrate is discharged by the two top outlet
cocks shown in each case on the head of the filter press, arranged so that the filtrate
from one passes by the delivery pipes El to E5 into the feed sumph S1 S2 S3 S4 or $5
of the next of the series, and from thence is fed in by means of the pumps P1, P2, P³, P4
and 15 into the next press of the series. The first of the feed sumphs is shown
dotted below the ground level. The pipe with branches C to C5 is for supplying
the fresh chemicals in rotation to whichever sumph in the cycle becomes the first
of the series. The water main with its branches is lettered W to W, and is simi-
larly used for supplying wash water by means of the pumps to the presses.
represents a truck on a tram line for carrying away the spent ore when discharged
from the presses.
T
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:-
1) The chemical treatment of permeable cakes of ore or slimes in the chambers
of an apparatus of the kind described so as to bring the metal to be extracted there-
from into solution therein, together with the washing of same substantially as
described.
2) The employment of two or more such apparatus in series, to effect a con-
tinuous systematic treatment of the ores, and to effect the economic removal of the
metal in the process of chemical treatment and washing, substantially as described.
3) The treatment of powdered or finely divided ores in the form of permeable
cakes with chemical solvents in a filter press together with the further treatment
of the charge of cakes so obtained by washing them with water without removing
them from the filter press in one operation in the manner and for the purpose
herein described.
Dated this 21st day of Robmiom 1808