Improvements in or relating to the Separation of Liquid from Bodies Containing or Mingled with the same.
Year: 1897

page_text: Date of Application, 29th July, 1897
Complete Specification Left, 29th Apr., 1898-Accepted, 29th July, 1898
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Separation of Liquid from Bodies
Containing or Mingled with the same.
We, WILLIAM ADOLPH KONEMAN, of 22, Southolm Street, Queens Road, Batter-
sca, in the County of Middlesex, and WILLIAM HENRY HARTLEY, of 23, Moor-
fields, in the City of London, Civil and Mining Engineers, do hereby declare
the nature of this invention to be as follows:―
"
The object of this invention is to enable the abstraction of a clear and non-
turbid liquid from slime-bearing materials, say the abstraction of, water or solu-
tions from slime-bearing ores in the hydro-metallurgical treatment of the same,
or the removal of water from ore for use again, or the removal of solutions or
wash water from other industrial products such as paper pulp, etc. For the
purpose of illustration we will describe this invention as employed in the treat-
ment of ore; a similar proceeding answers for the other uses to which the inven-
tion may be put, and which therefore will not need to be specifically referred to.
The essence of this invention lies in part in the discovery that compacting of
a slime-containing mass is readily effected by subjecting the same, when contained
in a suitable apparatus, to surface pressure, induced by the direct introduction of
a fluid gaseous medium (such as air) above the surface of the charge contained in a
closed vessel (hereinafter termed the tank") preferably one having a filter-
bottom with open discharge, or induced by a vacuum, created and maintained in
a closed chamber below a filter-bottom, the surface-pressure created by either
of these methods compacting the solid matter of which the charge is composed,
and separating out the solution on top of the solid matter. Another important
feature of the invention in combination with the before-mentioned treatment, is
the discovery that such abstraction of solution and its conversion to a clarified
state, suitable for use, may be hastened by abstracting the liquid separated out
above the compacted mass, by means of a movable surface-filter (i.e. a filter at or
near the surface of the expressed liquid) before the said liquid has reached a
state of absolute clearness (the liquid being caused to pass through such surface-
filter either by pressure within the apparatus or by a vacuum created in the filter-
casing) and subjecting the turbid liquid so abstracted to subsequent clarification
by filtration in an auxiliary filtering-apparatus. The surface filter may be con-
structed as a float and may deliver the liquid through a suitable flexible hose to
the exterior of the tank or it may be provided with a hollow vertical stem, which
stem may pass through a stuffing box in the centre of the cover of the tank;
the cover of the tank may be given sufficient interior space to allow of the filter
being raised into that space, and held there in such manner as to be properly
housed so as to allow of the simultaneous removal of both tank-cover and filter;
this latter arrangement assures a central position of the filter during operation
and renders it unnecessary to remove the filter from the tank during the filling
of the latter and the subsequent agitation of its contents. It may, under certain
conditions, be advisable to hold the filter submerged at any desired depth in the

page_text: liquid or to move it downward therein by mechanical means; this can be readily
effected by passing the filter stem through a stuffing box in the tank cover and
providing it with a screw or other adjusting gear; this provision for downward
movement is especially advisable when it is desired to remove liquid from a very
thick or muddy mixture without allowing much time for separation. It is also
advisable to give the surface filter the greatest possible area to ensure a quiet
inflow and also to arrange the air and water supply to the tank in such a manner
that air or water may be injected through the filter-casing in case the filtering
fabric requires cleaning; or mechanical means may be provided for removing any
deposit of slime which may gather on the surface of the filtering fabric, but we
prefer to assure the removal of a deposited slime coating from the fabric by the
employment of a slack and weighted filter-fabric arranged and operating as herein-
after explained.
"We have set forth the description of the surface-filter because by its use it is not
essential to wait for the complete separating out of the liquid from the solid
substance mixed with it, and because by its use the auxiliary-filter is retained
in a good working condition for a greater length of time than if turbid liquid
were delivered into it without preliminary filtration by the surface-filter, but it
is not necessary to employ a surface-filter, as a simple syphon pipe carried by a
float, or other discharging device may be used to draw off the liquid whenever it
is not necessary to force the apparatus and when time can be given to allow of
an approximately complete separation of solid from liquid to take place within
the same.
To facilitate observation of the contents of the apparatus it may be
provided with suitable gauge-glasses and draw-off cocks along its side.
We are aware of the fact that fluid pressure directly applied, and also induced
by a vacuum, is and has been employed for the purpose of causing solution to
percolate through a porous filter-bottom. Fluid pressure has also been employed
for the purpose of removing slime from the surface of an ore charge so as to
enable percolation to take place through the residual porous material, but both
of these methods of treatment have proved to be absolutely ineffectual when the
slime percentage is at all great, so that it is common practice at the present time
to remove the slimes from the ore either by screening or washing or various
other means, before treatment of the coarser and permeable portion is attempted,
and this treatment has always been a separate treatment by percolation, the simul-
taneous treatment of coarse ore and slimes having never before been accomplished,
either by direct pressure or that induced by a vacuum. We draw attention to the
fact that our method is distinguished by the distinctly different procedure, of pro-
ducing, to the maximum extent, impermeability and density of the material under
treatment, in order to collect the bulk of the contained liquid on top of the.com-
pacted material, and removing the liquid from the top of the charge for clarifica-
tion. Thus we induce the very condition which all existing methods must, and
do, avoid, as they create porosity to enable and induce filtration through a bottom
filter, whereas we create density, to enable and induce the collection of the liquid
on top of a densified and compacted mass; and further, they all aim at the removal
of, and avoid, the presence of slimes, whereas its presence and retention in the
charge are absolutely necessary for the successful working of our method.
We have found in practice, treating pure ore slimes mixed with an equal
weight of liquid, that a compacting of the slime-bearing material takes place in
less than one hour, when about 25 pounds gauge pressure is maintained, and the
outlet of the filter bottom is left open, and that, during this period of compacting
the slime mass there is at first a free flow through the filter bottom which, how-
ever, rapidly diminishes and soon stops, so that the greater portion of the liquid
gathers and gradually clarifies on the top of the charge. While the compacting
of the ore and slimes takes place as quickly as is above stated, the liquid separated
in that period is in a more or less turbid condition and requires for perfect clarifi-
cation a rest of from two to five hours additional. While this is very rapid work
compared with gravity separation, which is not complete even after 36 hours

page_text: "
with the same material, and in which there is no compacting of the surface layers
of slime and but slight settling down and compacting of the lower layers, and
no definite demarcation between solid and liquid such as we obtain, we have
nevertheless succeeded in discovering a means of shortening the duration of our
method of treatment, which rests in the facts that clarification takes place from the
top of the contents of the apparatus downward and that a thin layer of slimes is
permeable to liquid or air under pressure. We therefore abstract the liquid from
the top of the charge by means of a surface-filter” while the liquid is still
turbid or opaque, and cause its immediate clarification in an auxiliary filter. It
will be readily seen that the surface-filter, being at or near the top of the liquid
which is only in a slightly turbid condition, can never gather a very thick layer
of obstructing slime, as the percentage of slime in a slightly opaque liquid 'is too
slight to cause a thick layer to form; a current of water or blast of air to clear
the filter can be occasionally directed through the thin layer on the filtering fabric
in a direction opposite to that in which the solution passes through it during
filtration, or a mechanical scraper could be used for a like purpose, but it is pre-
ferred to employ a filter with a slack and weighted fabric such as is hereinbefore
referred to. The turbid solution delivered from the surface filter is readily and
quickly clarified in an auxiliary sand or other filter, so that by using the surface
and auxiliary filters the efficiency of the separating tank is more than double
that which it would possess in their absence, and as one auxiliary filter will
serve several separating tanks, the cost of installation of the whole plant is greatly
diminished. Another object of the auxiliary filter is to create a "safety factor"
against turbid solutions being accidentally produced, which, for instance, in the
case of gold solutions would be detrimental and objectionable in the final precipi-
tation. Such production of turbid solution has to be especially guarded against
when the float in the separating tank comes into close contact with the upper-
most layer of compacted slimes on top of the charge, as will hereinafter appear.
An important feature of the apparatus employed according to this invention
in the case of ore treatment, is the manner of agitating the material under treat-
ment; this is an especially valuable point as it is advisable to cause the slimes
to gather on top of the charge, and the coarse portion of the sand to collect at
the bottom of the charge, so as to produce impermeability for liquid on top of the
concentrated residue and a good filtering layer at the bottom thereof, in order to
assure the clearness of that portion of the liquid which passes through the filter-
bottom during the "compacting" period of the treatment; moreover, the bottom
layer of sand removed from the tank will conveniently serve as filtering material
for use in the auxiliary filter. To assure such a condition, we prefer to agitate
the mass under treatment by means of a mechanical agitator or stirrer, such as is
hereinafter described with reference to the accompanying drawings, as this causes
graduated settling of the coarser particles, that is to say there is an automatic
arrangement of the particles such that their size or fineness (assuming material of
equal specific gravity throughout) gradually decreases from a maximum in the
lower, to a minimum in the upper, layers. But when materials of greater specific
gravity than that of the main charge are present this agitation brings about
another very important result, namely the concentration and gathering of all
coarse gold and the contained metal-bearing compounds, such as sulphides,
arsenites of lead, copper, or iron or any other compounds, which, owing to their
specific gravity, will gather on the bottom during agitation and there be compacted
by the applied pressure. This concentrate can be removed after the withdrawal
of the filter bottom while the body of the charge is held up, say, by supporting
bars in the manner hereinafter explained. To effect the removal of such con-
centrates in an easy manner, the supporting-bars are set at such a height above the
filter-bottom, that a free space will be left between them and the filter-bottom
of the size necessary to accommodate the quantity of concentrates approximately
known to be contained in the charge. This arrangement causes the bulk of the
charge to break off or stop short at the bars, thus leaving the concentrates on the

page_text: filter-bottom ready for removal. The removal of such concentrates may be effected
either after the withdrawal of the wash-water used as a preliminary, or after the
treatment of the charge with solution, as desired.
A further safeguard against the production of turbid solution, in addition to
the "safety factor" hereinbefore referred to, is the provision of a water seal" in
the filter bottom during the periods of filling and agitating the charge, that is to
say the employment of a body of still water to fill the space in the apparatus
below the filter bottom, as by this seal the percolation of agitated and turbid solu-
tion into that space is prevented and all the solution (except the trifling preliminary
discharge before referred to and being principally the liquid contained in the
coarser bottom layers of the charge) is compelled to ascend through the charge
as before described; this space should also be arranged to communicate with the
auxiliary filter, and if this be done no turbid solution can pass from the tank
either at top or bottom without being intercepted in the auxiliary filter.
Owing to the great degree of solidity to which the solid matter of the charge is
compacted during the aforesaid treatment, the question of the discharge thereof
is of great importance; removal by shovel is out of the question as the mass is
almost impenetrable by pick or spade, and a great amount of labour would be in-
volved if its removal by these means were attempted, therefore, removal through
the bottom is advisable, and, as the removal of the filter bottom is necessary
to accomplish this, it becomes advisable to support the compressed charge and
prevent it from dropping out or from interfering with the removal of the filter
bottom; this may be done by making the shell of the tank conical with the smaller
diameter at the base, but we prefer to support the compressed charge by a remov-
able perforated bottom, or by a series of carrier bars as hereinafter described, for
these bars can be so operated as to release only so much of the charge as it may
be desired to remove.
Of the two methods of treatment hereinbefore described for compacting slime-
bearing material and expressing upward the contained liquid, we prefer the use
of the direct pressure method, but, inasmuch as many installations are now in use
for pulverised ore filtration where it would be desirable to use existing apparatus,
it may be advisable to "water wash" the ore by means of the vacuum procedure,
and abstract the gold solution by means of a direct application of fluid pressure,
or vice versa. It is also possible to apply a vacuum below the filter bottom of a
tank having a closed top, and apply direct pressure on top of the charge at the
same time. The auxiliary filter may receive pressure for the surface of its contents
either direct from the separating tank (i.e. the tank") or otherwise, or it may
be caused to act by a vacuum produced below its own filter bottom, or it may be
actuated by both pressure and vacuum, or it can be given a sufficient filtering
area for filtration to occur under the action of gravity alone.
It is found, however, that the whole process of extraction herein before referred
to need not be carried out in apparatus of great strength, for it is not necessary,
during the earlier stages of the treatment of the ore, to employ pressure exceeding
that of approximately one atmosphere; consequently, in view of the fact that
this preliminary part of the process is one of considerable duration as compared
to that of the final separation part of the treatment which requires higher pres-
sure, it becomes convenient and economical to employ a large number of light and
cheap vessels made portable, as auxiliaries to one high-pressure vessel which
cannot be conveniently made portable. For instance, ore impregnated with a
re-agent may be delivered by a loading spout into a series of these vacuum vessels,
such vessels being moved from under the spout as fast as they are loaded, into
proximity to a vacuum-chamber, to which they are coupled, remaining thus con-
nected for a period sufficiently long to enable the wash-water to be extracted.
Then the necessary solvent for the metal to be extracted is added to each residual
mass, and the solution so added is allowed to remain in contact with the ore for a
maceration-period sufficiently long to dissolve the metal or metals to be abstracted.
It is then desirable to agitate the contents of the vessel for a short period, and

page_text: then to remove it into proximity to the high pressure vessel, into which the
contents are discharged for the briefer final treatment under high pressure.
It will of course be understood that, if desired, the whole process can be carried
out in a vacuum vessel, but not so satisfactorily as if initiated in a vacuum-vessel
and finished in a pressure vessel.
In the accompanying drawings,
Figure 1 is a vertical central section illustrating diagrammatically one con-
struction of apparatus employed in carrying this invention into effect;
Figure 2 is a similar view illustrating an alternative construction according to
this invention,
Figure 3 being an underside view of the vessel illustrated in Figure 2.
Figure 4 is a vertical central section of an additional construction of apparatus
according to this invention;
Figure 5 illustrates a construction of stirrer or agitator arranged to opérate in
succession on the contents of a series of separating tanks intended to be arranged
in a circle about it.
Figure 6 shows a tank top provided with one device according to this inven-
tion for forcing downward a filter, housed in the cavity of the top.
Figure 7 is a view, half in section and half in elevation showing a surface
filter with a slack and weighted fabric such as is hereinbefore referred to;
Figure 8 is an underside view partly in elevation and partly in section of the
surface filter shown in Fig. 7; and
Figure 9 shows an alternative construction of trolley for moving the filter-bottom
as hereinafter described.
Like letters indicate like parts throughout the drawings.
With reference first to Figure 1 which illustrates diagrammatically a separat-
ing tank into which a mixture of slime-bearing substances with liquid is delivered
and subjected to pressure to compact the solid constituents of the mixture and
cause the liquid portion to separate out on top of them, and which illustrates
also other apparatus for use in conjunction with the tank, A is a spout down which
ore can be delivered into a vessel C mounted on wheels C¹ so as to run upon rails A².
The vessel is provided with a coned bottom C². D is a filter-bottom supported
within the vessel C a short distance above the bottom 02, the rails A2 being
arranged so that one is at a higher level than the other and consequently the filter
bottom D slopes as shown towards an outlet sluice valve E.
The space F below the filter bottom forms a vacuum-chamber, and at its
lowest portion is provided with a drain cock C5 and a little above that level with
an air exhaust pipe G which at its outer end has a cock G and an "air brake'
coupling G2 or other means by which it may be readily put into connection with
a vacuum main leading to an air pump, or other apparatus, by which a vacuum
may be produced and maintained in the space F.
When a charge of slime-bearing material is delivered into the vessel C and a
vacuum is produced in the space under the filter bottom D a little liquid will
percolate through the latter and should be led to the auxiliary filter, but if the
material under treatment is of proper consistence, that is to say, if it contain a
sufficient percentage of slime such percolation amounts to only a slight percen-
tage of the contained liquid, as the slime which is in more or less immediate
contact with the filter bottom is rendered more dense than the superincumbent
material at the commencement of the operation and thus prevents all but a very
slight further downward passage of liquid. After the filter-bottom has thus
become almost entirely sealed or clogged maintenance of the vacuum below it
will have the effect of causing the resulting pressure above to precipitate and
aggregate the solid constituents forcing the liquid into the space above the solid
or semi-solid residue.
In the drawing I is the layer of thick sediment on the filter bottom, a larger
body of solid residue J being above it, and the expressed liquid K being shown
above the latter.

page_text: L is a surface filter through which the expressed liquid K passes to the shorter
leg M of a syphon M, the longer leg M² discharging the liquid to any place
desired, and both filter and syphon being readily removable. The leg M², if
sufficient height is not available for automatic syphon discharge can be connected
to a vacuum chamber or exhaust pump. The construction of this filter will be
hereinafter particularly described.
The upper end of the tank or vessel C is provided with an inturned flange C to
turn back any of the contents which may tend to over-flow under the action of
the stirrer hereinafter described.
The travelling tank C is run under the spout A, filled with the material and
liquid to be treated, and then run under the stirring apparatus N which com-
prises a square shaft O, carrying at its lower end vanes 01; the upper end of
the shaft O is journalled in a swivel P in which it can be rotated freely by
means of the bevel wheel Q, which is made to revolve in fixed bearings R by
the driving shaft S and pinion S¹. The central hole in the bevel wheel Q
through which the shaft O passes and the hole in the collar R rotating in the
bearing R² are made rectangular to fit the square-section shaft 0, so that the
latter though compelled always to rotate in company with the bevel wheel Q
may be freely moved endwise therethrough in order that the vanes or stirrers 01
may be lowered to the desired extent into and readily withdrawn from the vacuum
vessel below it, as for instance by a wire rope T passing over pulleys U to a
counter-balance N₁, the pulleys U being supported upon stationary supports.
The stirrer being stationary and the tanks C movable, one stirrer will serve
any desired number of tanks.
After the contents of each tank C have been agitated and mixed by the stirring
apparatus N the tank is run into proximity to a vacuum main provided with
couplings by which ready connection may be made with similar couplings G2
on the pipes G leading to the several spaces F of the different portable vacuum-
vessels, assuming that a series of such vessels is being used as aforesaid.
Upon the production of pressure on the surface of the charge, the slime is
acted upon in the manner hereinbefore described so that the liquid is separated
out on top thereof.
If the residue J is re-converted into a fluid by the addition of suitable liquid
it can be run off or pumped out through the discharge valve E, or the contents
may be discharged by means of a centrifugal pump or otherwise while under
agitation, or afterwards, as desired.
In the alternative construction of apparatus illustrated in Figure 2 the tank C
is stationary, and tapered so as to be of larger diameter at the bottom than at the
top, and it is provided with a coned bottom C2 which is suitably packed around its
edges and removable from the bottom of the tank when the compacted charge J
is to be expelled therefrom. The filter-bottom I is carried by the bottom Č² so
that when the latter is lowered and run out from beneath the tank C upon the
screw-jack trolley C³ provided for that purpose, the filter 1) is carried with it
and the residual compacted mass in the tank C is supported by the bars C which
extend across the bottom of the tank as shown in Figure 3, and are each held in
position at one end by a hinge e and at the opposite end by a hinged hook c¹. By
knocking aside the hook under one end of any bar such bar can turn about the
hinge at the other end, the portion of the charge previously upheld by this bar
then descending and being received in a trolley run in beneath the tank.
Or
By suitably operating these bars C the compacted mass J can be discharged
more or less gradually from the tank C instead of dropping out as one mass.
the residual mass can be removed by other means. The supporting-bars C are
however a general feature in each and every apparatus where the discharge of
the treated material is by way of the bottom of the tank, although a perforated
hinged bottom might be substituted therefor.
Or the apparatus may be arranged as in Figure 4 in which the tank C is mounted
on wheels to run on track rails A2 between which is a vacuum chamber F, over

page_text: which a succession of tanks such as C can be run for treatment. The filter D
which in previous examples forms the bottom of the tank C forms in this con-
struction the top of the vessel F, and bars C such as are shown in Figures 2 and 3
are provided at the bottom of the tank C for the purpose of regulating the dis-
charge as hereinbefore explained.
The bottom of the tank C and the top of the vessel F are made to fit closely
upon each other, and are provided with suitable packing to ensure a tight joint
between them.
To enable the tank C, Figure 4 to be readily lifted clear of the top of the cham-
ber F so as to be run away from the it along the rails A2, it is provided with
suitable raising and lowering devices, such as four lugs C each of which retains a
screw-threaded rod C8 as shown; it is to be understood that in this construction,
the screw-threaded portion of each rod does not engage with the lug through
which it passes but serves to receive a nut C situated on the rod below the lug.
The lower part of each rod is formed as a fork to retain a wheel C¹º, flanged to
engage with and run upon
the rails A². By operating the
C the lugs C7 and with them the tank C can be readily forced
up or lowered down. When it is slightly lifted from the top end of the
chamber F it can be readily carried away along the track, or it may be run back
again and lowered into place at any future time with equal facility.
nuts
This construction of apparatus illustrated in Figures 2, 3 and 4 is equally suit-
able when treating material either by pressure fluid delivered into the tank C or
by a vacuum set up in the chamber F, or simultaneously by pressure in the tank C
and vacuum in the chamber F. The chamber F in addition to serving as a
vacuum chamber, serves as a receptacle for any liquid descending into it through
the filter D.
It is to be understood that where in the description of the drawings reference
has been made to vacuum processes and apparatus, the vessels illustrated could if
desired be provided with a closely fitting top below which fluid under pressure
could be introduced into the vessel for use either alone or simultaneously with a
vacuum set up in the space F, to effect the treatment of the charge as described.
Figure 6 shows one example of such a top for the tank, so shaped that the
filter L can be drawn up into it and protected by it from any risk of damage which
might otherwise occur, when the cover is removed in the manner presently to be
described. The cover C2 is provided with lugs C7 screw rods C³, nuts C and
wheels Co, by which it may be raised and lowered and moved from over the
tank C, on track rails A2 in a manner similar to that described with reference
to the raising and lowering, and removal of the tank C, Figure 4. The surface-
filter tube M is carried through a stuffing box C, in the top of the cover and
provided with rack and pinion mechanism or other gear by which it can be
moved to hold the filter at any desired level within the tank C.
In Figure 5 the stirrer shaft O is carried in a frame V which is rotatable about
the line XY so that the stirrer can be brought in turn over any one of a series
of separating tanks which can be arranged in a circle about the said line X Y at
the same distance therefrom as the radial distance of the shaft O. In this con-
struction the shaft S supported in bearings V1 in the frame V carries at its inner
end a gear-wheel S2 which meshes with a gear-wheel W which with the gear
wheel W is rotatable about the central pillar V2 of the apparatus and driven
The hoist-
by the wheel W³, which latter is rotated by any convenient means.
ing rope T for raising and lowering the stirrer is carried over pulleys U to a
winch V3 secured on the frame V in proximity to the stirrer shaft, so that the
attendant, by whom the raising and lowering of the stirrer is to be controlled
can, whilst standing at the winch handle, look into the vessel over which the
stirrer at any time is situated.
Or a stirrer capable of being raised and lowered, can be arranged to travel along
a railway to act in succession on a series of tanks placed alongside each other.
For the purpose of avoiding the adherence of slimes to the filtering fabric of

page_text: the surface filter and to accomplish the ready removal of such slimes in case they
have a tendency to choke the fabric we prefer to provide the filter case with a
filter cover having a certain amount of slack, and to attach a suitable weight to
the filtering fabric such as a circlet of lead. A filter thus fitted operates as
follows:-
While the filter is in operation the fluid pressure in the tank holds the filtering
fabric against a support such as a well braced and suitably covered wire screen;
when the filtering action becomes slow or sluggish on account of the formation of
a slime layer which has deposited on the fabric the pressure is let off the tank
and the lead or other weight attached to the filter fabric drops as far as the
slack of the fabric allows thus causing a movement of the fabric sufficient to
cause the accummulated slime layer to drop off and leave the fabric clean in
condition for further operation.
In the surface filter shown separately in Figures 17 and 8, the underside thereof
is covered with a slack layer L² of filtering fabric weighted by a heavy ring L³,
this slack and weighted fabric being provided in order to enable slimes accumu-
lated thereon to be shaken from it by causing the fabric to pulsate or flap. Above
the fabric a layer or screen L6 of wire gauze or the like is provided, backed with
radial ribs L7; the spaces between the ribs form channels which direct fluid
drawn through the gauze towards the exit from the filter afforded by the lower
end of the pipe M¹.
The ribs L of the filter are so shaped that the layer L6 of gauze is coned as
shown. The lowest portion or apex of the gauze L6 should not be at any higher
level than that of the lowest part of the circumference of the filter so that when
this form of filter settles upon the residue J of compacted material below it no
such stoppage of the withdrawal of surface liquid such as would occur if the
filter were flat-bottomed, will take place, for only the centre of the filter will touch
the compacted material beneath it thus leaving a circumferential clearance space
past the circumference of the apparatus until practically the whole of the surface
liquid is extracted by way of the delivery pipe M of the filter which is led to
the lowest point of the interior above the gauze in order that the mouth of the
pipe may remain immersed to the last.
The method of working which is preferred with the apparatus hereinbefore
described, in the case for example of an ore treated by the cyanide process of
gold extraction is as follows:-
Charges of ore are delivered into a series of vacuum tanks C such as are illus-
trated in Figure 1. These vessels are filled to within say 18 inches of the top and
when so filled are removed to a place in the working establishment at which a
vacuum connection can readily be effected with the vacuum space F by means
of a coupling, such as G2. A more or less complete vacuum is then established
in this space F and the outlet C is connected with a suitable receiving chamber,
or the space F may itself be made sufficiently large, as in the chamber Fin
Figure 4, to retain any liquid which may percolate into it through the filter-
bottom D. Establishment of the vacuum as described will cause a drainage of
liquid from the lower part of the charge and a compacting of the ore and slimes
contained in the tank. While such compacting is progressing the surface filter L
is introduced and the outlet M thereof is connected with an exhausting pump or
a receiving chamber in which a vacuum has been established. When the valve M³
in the pipe M2 is thereafter opened a vacuum is set up in the hollow interior of
the filter L, and the collected liquid K is thus caused to percolate through the
filtering layer of the filter, and enter the interior of the filter body, and thence
pass to the delivery pipe M¹ and to the vacuum pump or the receiving chamber.
This operation removes what is termed the " wash-water" from the ore. The
various vacuum connections are now removed, the filter L is taken out of the
tank G, and a suitable amount of say cyanide solution is then added on the sur-
face of the residual charge J.
The tank C (Figure 1) is next run under the stirring apparatus N, the stirrer

page_text: blades are dropped through the cyanide solution on to the top of the charge J
and the stirrer is set in motion being gradually lowered into the said charge J as
the same becomes mixed with the overlying liquid; and such lowering is con-
tinued until the stirrer blades O¹ have reached approximately the bottom of the
tank C at a point near the filter bottom D. As soon as a thorough mixture of
cyanide solution with the charge has been thus effected, the stirrer N is with-
drawn and the connection G2 is coupled to a pipe supplying air under pressure;
such air is allowed to percolate upward through the charge, from time to time
for short periods, whenever the contained charge shows any signs of settling or
of any separating out of the liquid from the charge. In this manner thorough
maceration of the ore with the contained solvent liquid is ensured; the duration
of such maceration varies with the condition of the ore and the fineness of the
contained gold, but is rarely less than 12 hours; and it is on account of the long
period of time which is required for dissolving out the gold during the maceration
treatment that we prefer to use in the operation of maceration tanks of compara-
tively cheap construction, such as are exemplified by Figure 1, in conjunction
with say a single pressure tank such as shown in Figure 2 or Figure 4, for it is
more economical to keep a series of cheap tanks idle during maceration than to
perform the maceration in the costlier pressure-tank which might more advan-
tageously be kept in continuous work on material discharged from the vacuum
tanks, in a manner which will presently be described.
When a test of the contents of the tank C (Figure 1) shows that solution of the
gold has practically taken place, we prefer to again drop the stirrer N into the
charge and agitate the same for a period of from 1 to 3 hours, by which means
certain gold slimes which have gathered and are partially locked up, so to speak,
in the interstices and crevices of the minute particles of ore become released by
the agitation, and a correspondingly greater metal extraction is therefore due to
this additional agitation. As soon as this agitation is finished the apparatus is
ready to be discharged into the pressure separator (Figure 2 or Figure 4) for the
removal of the gold containing solution, and we prefer to accomplish this removal
under a high pressure on the surface of the charge in the pressure separator, and
it is advisable with certain slimes to add a vacuum below the filter beneath the
charge, because by such pressure and vacuum combined the ore compacted to
a greater degree of density than is otherwise possible, and the solution is there-
fore abstracted in greater perfection, that is to say a higher percentage of the
contained solution is thereby abstractable.
It can of course be readily understood that the preliminary abstraction as well
as the maceration might be carried out in one and the same apparatus, say in
the apparatus such as shown in Figure 2 and Figure 4, as both these construc-
tions are susceptible of being used either by vacuum in the bottom section or
by vacuum in the bottom and pressure in the top section, or by pressure in the
top section alone, but for reasons of economy as hereinbefore explained it is not
advisable to perform the whole process in one tank.
When the contents of the tank C (Figure 1) have been discharged into the
apparatus such as is shown in Figure 2 or Figure 4, the stirrer should be again
dropped to a point near the bottom of the charge for the purpose of causing a
proper classification and concentration of the ore contents, it being rotated at
some moderate velocity sufficient to allow a proper settling or descent of the
coarser particles of the charge down through the current caused by the agitator.
The agitator is gradually withdrawn from the charge and when completely re-
moved therefrom the cover is placed on and properly fastened to the shell C, air
under pressure is admitted through the pipe C12, the water seal is drawn off from
below the filter bottom D and the cock C5 is left open, and these conditions are
maintained until solution drawn through the upper test cocks C13 shows that the
liquid K superincumbent on the charge J is but slightly opaque at the upper
'section; when this condition has been arrived at valve M³ is opened and the
pressure within the tank C will then force the liquid-K through the delivery pipe M¹

page_text: .
of the filter L. The liquid so abstracted by the filter L through the pipe M¹ is
delivered (as also is any turbid solution forced through the filter bottom D) into
the auxiliary filter W which is merely indicated diagrammatically, and which
should be open so that the ends of the pipes delivering into it and the material
they discharge can be conveniently observed. The turbid or opaque solution
leaving the auxiliary filter W is clarified by passing through the porous sand
layer Wand after passing such filtering layer W₁ and filtering fabric W2 it is
ready for subsequent treatment which is well understood and will result in the
precipitation of the gold therein contained. When the layer of liquid above the
compacted charge is reduced to a minimum by the filter the charge cracks up or
shrinks in such a manner that the small amount of liquid remaining therein can
be forced out by the pressure of the air which penetrates the charge. Figure 9
illustrates an alternative construction of trolley C³ provided with a ram C15 adapted
to be raised and lowered by compressed air (always available in the working of
this invention) and serving to remove and replace the filter bottom D and tank
bottom C as herein before described. It will be readily understood that the
apparatus herein described is applicable also for causing percolation by pressure
through ores of a permeable character in which case of course the surface filter is
dispensed with and we desire it to be understood that we claim the use of the
apparatus as described and shown for percolation as fully within the scope of our
invention.
Dated this 20th day of July 1897
BOULT & WADE,
Agents for the Applicants.
Improvements in or relating to the Separation of Liquid from Bodies
Containing or Mingled with the same.
We, WILLIAM ADOLPH KÖNEMAN, of 22, Southolm Street, Queen's Road, Batter-
sea, in the County of Middlesex, and WILLIAM HENRY HARTLEY, of 23, Moor-
fields, in the City of London, Civil and Mining Engineers, 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:-
The object of this invention is to enable the abstraction of a clear and non-
turbid liquid from slime-bearing materials, say the abstraction of water or solu-
tions from slime-bearing ores in the hydro-metallurgical treatment of the same,
or the removal of water from ore for use again, or the removal of solutions or
wash water from other industrial products such as paper pulp, etc. For the
purpose of illustration we will describe this invention as employed in the treat-
ment of ore; a similar proceeding answers for the other uses to which the inven-
tion may be put, and which therefore will not need to be specifically referred to.
The essence of this invention lies in part in the discovery that compacting of
a slime-containing mass is readily effected by subjecting the same, when contained
in a suitable apparatus, to surface pressure, induced by the direct introduction of
a fluid gaseous medium (such as air) above the surface of the charge contained in a
closed vessel (hereinafter termed "the tank") preferably one having a filter-
bottom with open discharge, or induced by a vacuum, created and maintained in
a closed chamber below a filter-bottom, the surface-pressure created by either
of these methods compacting the solid matter of which the charge is composed,
and separating, out the solution on top of the solid matter. Another important
feature of the invention in combination with the before-mentioned treatment, is
the discovery that such abstraction of solution and its conversion to a clarified

page_text: state, suitable for use, may be hastened by abstracting the liquid separated out
above the compacted mass, by means of a movable surface-filter (i.e. a filter at or
near the surface of the expressed liquid) before the said liquid has reached a
state of absolute clearness (the liquid being caused to pass through such surface-
filter either by pressure within the apparatus or by a vacuum created in the filter-
casing) and subjecting the turbid liquid so abstracted to subsequent clarification
by filtration in an auxiliary filtering-apparatus. The surface filter may be con-
structed as a float and may deliver the liquid through a suitable flexible hose to
the exterior of the tank or it may be provided with a hollow vertical stem, which
stem may pass through a stuffing box in the centre of the cover of the tank;
the cover of the tank may be given sufficient interior space to allow of the filter
being raised into that space, and held there in such manner as to be properly
housed so as to allow of the simultaneous removal of both tank-cover and filter;
this latter arrangement assures a central position of the filter during operation
and renders it unnecessary to remove the filter from the tank during the filling
of the latter and the subsequent agitation of its contents. It may, under certain
conditions, be advisable to hold the filter submerged at any desired depth in the
liquid or to move it downward therein by mechanical means; this can be readily
effected by passing the filter stem through a stuffing box in the tank cover and
providing it with a screw or other adjusting gear; this provision for downward
movement is especially advisable when it is desired to remove liquid from a very
thick or muddy mixture without allowing much time for separation. It is also
advisable to give the surface filter the greatest possible area to ensure a quiet
inflow and also to arrange the air and water supply to the tank in such a manner
that air or water may be injected through the filter-casing in case the filtering
fabric requires cleaning; or mechanical means may be provided for removing any
deposit of slime which may gather on the surface of the filtering fabric, but we
prefer to assure the removal of a deposited slime coating from the fabric by the
employment of a slack and weighted filter-fabric arranged and operating as herein-
after explained.
We have set forth the description of the surface-filter because by its use it is not
essential to wait for the complete separating out of the liquid from the solid
substance mixed with it, and because by its use the auxiliary-filter is retained
in a good working condition for a greater length of time than if turbid liquid
were delivered into it without preliminary filtration by the surface-filter, but it
is not necessary to employ a surface-filter, as a simple syphon pipe carried by a
float, or other discharging device may be used to draw off the liquid whenever it
is not necessary to force the apparatus and when time can be given to allow of
an approximately complete separation of solid from liquid to take place within
the same.
To facilitate observation of the contents of the apparatus it may be
provided with suitable gauge-glasses and draw-off cocks along its side.
We are aware of the fact that fluid pressure directly applied, and also induced
by a vacuum, is and has been employed for the purpose of causing solution to
percolate through a porous filter-bottom. Fluid pressure has also been employed
for the purpose of removing slime from the surface of an ore charge so as to
enable percolation to take place through the residual porous material, but both
of these methods of treatment have proved to be absolutely ineffectual when the
slime percentage is at all great, so that it is common practice at the present time
to remove the slimes from the ore either by screening or washing or various
other means, before treatment of the coarser and permeable portion is attempted,
and this treatment has always been a separate treatment by percolation, the simul-
taneous treatment of coarse ore and slimes having never before been accomplished,
either by direct pressure or that induced by a vacuum. We draw attention to the
fact that our method is distinguished by the distinctly different procedure, of pro-
ducing, to the maximum extent, impermeability and density of the material under
treatment, in order to collect the bulk of the contained liquid on top of the com-
pacted material, and removing the liquid from the top of the charge for clarifica-

page_text: tion. Thus we induce the very condition which all existing methods must, and
do, avoid, as they create porosity to enable and induce filtration through a bottom
filter, whereas we create density, to enable and induce the collection of the liquid
on top of a densified and compacted mass; and further, they all aim at the removal
of, and avoid, the presence of slimes, whereas its presence and retention in the
charge are absolutely necessary for the successful working of our method.
We have found in practice, treating pure ore slimes mixed with an equal
weight of liquid, that a compacting of the slime-bearing material takes place in
less than one hour, when about 25 pounds gauge pressure is maintained, and the
outlet of the filter bottom is left open, and that, during this period of compacting
the slime mass, there is at first a free flow through the filter bottom which, how-
ever, rapidly diminishes and soon stops, so that the greater portion of the liquid
gathers and gradually clarifies on the top of the charge. While the compacting
of the ore and slimes takes place as quickly as is above stated, the liquid separated
in that period is in a more or less turbid condition and requires for perfect clarifi-
cation a rest of from two to five hours additional. While this is very rapid work
compared with gravity separation, which is not complete even after 36 hours
with the same material, and in which there is no compacting of the surface layers
of slime and but slight settling down and compacting of the lower layers, and
no definite demarcation between solid and liquid such as we obtain, we have
nevertheless succeeded in discovering a means of shortening the duration of our
method of treatment, which rests in the facts that clarification takes place from the
top of the contents of the apparatus downward and that a thin layer of slimes is
permeable to liquid or air under pressure. We therefore abstract the liquid from
the top of the charge by means of a surface-filter" while the liquid is still
turbid or opaque, and cause its immediate clarification in an auxiliary filter. It
will be readily seen that the surface-filter, being at or near the top of the liquid
which is only in a slightly turbid condition, can never gather a very thick layer
of obstructing slime, as the percentage of slime in a slightly opaque liquid is too
slight to cause a thick layer to form; a current of water or blast of air to clear
the filter can be occasionally directed through the thin layer on the filtering fabric
in a direction opposite to that in which the solution passes through it during
filtration, or a mechanical scraper could be used for a like purpose, but it is pre-
ferred to employ a filter with a slack and weighted fabric such as is hereinbefore
referred to. The turbid solution delivered from the surface filter is readily and
quickly clarified in an auxiliary sand or other filter, so that by using the surface
and auxiliary filters the efficiency of the separating tank is more than double
that which it would possess in their absence, and as one auxiliary filter will
serve several separating tanks, the cost of installation of the whole plant is greatly
diminished. Another object of the auxiliary filter is to create a
safety factor"
against turbid solutions being accidentally produced, which, for instance, in the
case of gold solutions would be detrimental and objectionable in the final precipi-
tation. Such production of turbid solution has to be especially guarded against
when the float in the separating tank comes into close contact with the upper-
most layer of compacted slimes on top of the charge, as will hereinafter appear.
An important feature of the apparatus employed according to this invention
in the case of ore treatment, is the manner of agitating the material under treat-
ment; this is an especially valuable point as it is advisable to cause the slimes
to gather on top of the charge, and the coarse portion of the sand to collect at
the bottom of the charge, so as to produce impermeability for liquid on top of the
concentrated residue and a good filtering layer at the bottom thereof, in order to
assure the clearness of that portion of the liquid which passes through the filter-
bottom during the "compacting" period of the treatment; moreover, the bottom
layer of sand removed from the tank will conveniently serve as filtering material
for use in the auxiliary filter. To assure such a condition, we prefer to agitate
the mass under treatment by means of a mechanical agitator or stirrer, such as is
hereinafter described with reference to the accompanying drawings, as this causes

page_text: graduated settling of the coarser particles, that is to say there is an automatic
arrangement of the particles such that their size or fineness (assuming material of
equal specific gravity throughout) gradually decreases from a maximum in the
lower, to a minimum in the upper, layers. But when materials of greater specific
gravity than that of the main charge are present this agitation brings about
another very important result, namely the concentration and gathering of all
coarse gold and the contained metal-bearing compounds, such as sulphides,
arsenites of lead, copper, or iron or any other compounds, which, owing to their
specific gravity, will gather on the bottom during agitation and there be compacted
by the applied pressure. This concentrate can be removed after tlie withdrawal
of the filter bottom while the body of the charge is held up, say, by supporting
bars in the manner hereinafter explained. To effect the removal of such con-
centrates in an easy manner, the supporting-bars are set at such a height above the
filter-bottom, that a free space will be left between them and the filter-bottom
of the size necessary to accommodate the quantity of concentrates approximately
known to be contained in the charge. This arrangement causes the bulk of the
charge to break off or stop short at the bars, thus leaving the concentrates on the
filter-bottom ready for removal. The removal of such concentrates may be effected
either after the withdrawal of the wash-water used as a preliminary, or after the
treatment of the charge with solution, as desired.
A further safeguard against the production of turbid solution, in addition to
the "safety factor" hereinbefore referred to, is the provision of a water seal" in
the filter bottom during the periods of filling and agitating the charge, that is to
say the employment of a body of still water to fill the space in the apparatus
below the filter bottom, as by this seal the percolation of agitated and turbid solu-
tion into that space is prevented and all the solution (except the trifling preliminary
discharge before referred to and being principally the liquid contained in the
coarser bottom layers of the charge) is compelled to ascend through the charge
as before described; this space should also be arranged to communicate with the
auxiliary filter, and if this be done no turbid solution can pass from the tank
either at top or bottom without being intercepted in the auxiliary filter.
Owing to the great degree of solidity to which the solid matter of the charge is
compacted during the aforesaid treatment, the question of the discharge thereof
is of great importance; removal by shovel is out of the question as the mass is
almost impenetrable by pick or spade, and a great amount of labour would be in-
volved if its removal by these means were attempted, therefore, removal through
the bottom is advisable, and, as the removal of the filter bottom is necessary
to accomplish this, it becomes advisable to support the compressed charge and
prevent it from dropping out or from interfering with the removal of the filter
bottom; this may be done by making the shell of the tank conical with the smaller
diameter at the base, but we prefer to support the compressed charge by a remov-
able perforated bottom, or by a series of carrier bars as hereinafter described, for
these bars can be so operated as to release only so much of the charge as it may
be desired to remove.
"
Of the two methods of treatment hereinbefore described for compacting slime-
bearing material and expressing upward the contained liquid, we prefer the use
of the direct pressure method, but, inasmuch as many installations are now in use
for pulverised ore filtration where it would be desirable to use existing apparatus,
it may be advisable to "water wash the ore by means of the vacuum procedure,
and abstract the gold solution by means of a direct application of fluid pressure,
or vice versa. It is also possible to apply a vacuum below the filter bottom of a
tank having a closed top, and apply direct pressure on top of the charge at the
same time. The auxiliary filter may receive pressure for the surface of its contents
the tank") or otherwise, or it may
either direct from the separating tank (i.e.
be caused to act by a vacuum produced below its own filter bottom, or it may be
actuated by both pressure and vacuum, or it can be given a sufficient filtering
area for filtration to occur under the action of gravity alone.

page_text: It is found, however, that the whole process of extraction hereinbefore referred
to need not be carried out in apparatus of great strength, for it is not necessary,
during the earlier stages of the treatment of the ore, to employ pressure exceeding
that of approximately one atmosphere; consequently, in view of the fact that
this preliminary part of the process is one of considerable duration as compared
to that of the final separation part of the treatment which requires higher pres-
sure, it becomes convenient and economical to employ a large number of light and
cheap vessels made portable, as auxiliaries to one high-pressure vessel which
cannot be conveniently made portable. For instance, ore impregnated with a
re-agent may be delivered by a loading spout into a series of these vacuum vessels,
such vessels being moved from under the spout as fast as they are loaded, into
proximity to a vacuum-chamber, to which they are coupled, remaining thus con-
nected for a period sufficiently long to enable the wash-water to be extracted.
Then the necessary solvent for the metal to be extracted is added to each residual
mass, and the solution so added is allowed to remain in contact with the ore for a
maceration-period sufficiently long to dissolve the metal or metals to be abstracted.
It is then desirable to agitate the contents of the vessel for a short period, and
then to remove it into proximity to the high pressure vessel, into which the
contents are discharged for the briefer final treatment under high pressure.
It will of course be understood that, if desired, the whole process can be carried
out in a vacuum vessel, but not so satisfactorily as if initiated in a vacuum-vessel
and finished in a pressure vessel.
The following description of the arrangement and operation of apparatus accord-
ing to this invention has reference to the drawings accompanying our Provisional
Specification, in which:-
Figure 1 is a vertical central section illustrating diagrammatically one con-
struction of apparatus employed in carrying this invention into effect;
Figure 2 is a similar view illustrating an alternative construction according to
this invention.
Figure 3 being an underside view of the vessel illustrated in Figure 2.
Figure 4 is a vertical central section of an additional construction of apparatus
according to this invention;
Figure 5 illustrates a construction of stirrer or agitator arranged to operate in
succession on the contents of a series of separating tanks intended to be arranged
in a circle about it.
Figure 6 shows a tank top provided with one device according to this inven-
tion for forcing downward a filter, housed in the cavity of the top.
Figure 7 is a central section of a surface filter with a slack and weighted
fabric such as is hereinbefore referred to;
Figure 8 is an underside view partly in elevation and partly in section of the
surface filter shown in Fig. 7; and
Figure 9 shows an alternative construction of trolley for moving the filter-bottom
as hereinafter described.
Like letters indicate like parts throughout the drawings.
With reference first to Figure 1 which illustrates diagrammatically a separat-
ing tank into which a mixture of slime-bearing substances with liquid is delivered
and subjected to pressure to compact the solid constituents of the mixture and
cause the liquid portion to separate out on top of them, and which illustrates
also other apparatus for use in conjunction with the tank, A is a spout down which
ore can be delivered into a vessel C mounted on wheels C¹ so as to run upon rails A²
The vessel is provided with a coned bottom C². D is a filter-bottom supported
within the vessel C a short distance above the bottom C3, the rails A² being
arranged so that one is at a higher level than the other and consequently the filter
bottom D slopes as shown towards an outlet sluice valve E.
The space F below the filter bottom forms a vacuum-chamber, and at its
lowest portion is provided with a drain cock C5 and a little above that level with
an air exhaust pipe G which at its outer end has a cock G¹ and an "air brake'
"

page_text: coupling G or other means by which it may be readily put into connection with
a vacuum main leading to an air pump, or other apparatus, by which a vacuum
may be produced and maintained in the space F.
When a charge of slime-bearing material is delivered into the vessel C and a
vacuum is produced in the space F under the filter bottom D a little liquid will
percolate through the latter and should be led to the auxiliary filter, but if the
material under treatment is of proper consistence, that is to say, if it contain a.
sufficient percentage of slime such percolation amounts to only a slight percen-
tage of the contained liquid, as the slime which is in more or less immediate
contact with the filter bottom is rendered more dense than the superincumbent
material at the commencement of the operation and thus prevents all but a very
slight further downward passage of liquid. After the filter-bottom has thus
become almost entirely sealed or clogged maintenance of the vacuum below it
will have the effect of causing the resulting pressure above to precipitate and
aggregate the solid constituents forcing the liquid into the space above the solid
or semi-solid residue.
In the drawing H is the layer of thick sediment on the filter bottom, a larger
body of solid residue J being above it, and the expressed liquid K being shown
above the latter.
L is a surface filter through which the expressed liquid K passes to the shorter.
leg M of a syphon M, the longer leg M² discharging the liquid to any place
desired, and both filter and syphon being readily removable. The leg M², if
sufficient height is not available for automatic syphon discharge can be connected
to a vacuum chamber or exhaust pump. The construction of this filter will be
hereinafter particularly described.
The upper end of the tank or vessel C is provided with an inturned flange C+ to
turn back any of the contents which may tend to over-flow under the action of
the stirrer hereinafter described.
The travelling tank C is run under the spout A, filled with the material and
liquid to be treated, and then run under the stirring apparatus N which com-
prises a square shaft O, carrying at its lower end vanes 01; the upper end of
the shaft O is journalled in a swivel P in which it can be rotated freely by
means of the level wheel Q, which is made to revolve in fixed bearings R by
the driving shaft S and pinion S¹. The central hole in the bevel wheel Q
through which the shaft O passes and the hole in the collar R₁ rotating in the
bearing R are made rectangular to fit the square-section shaft O, so that the
latter though compelled always to rotate in company with the bevel wheel Q
may be freely moved endwise therethrough in order that the vanes or stirrers O
may be lowered to the desired extent into and readily withdrawn from the vacuum
vessel below it, as for instance by a wire rope T passing over pulleys U to a
counter-balance N₁, the pulleys U being supported upon stationary supports.
The stirrer being stationary and the tanks C movable, one stirrer will serve
any desired number of tanks.
After the contents of each tank C have been agitated and mixed by the stirring
apparatus N the tank is run into proximity to a vacuum main provided with
couplings by which ready connection may be made with similar couplings G²
on the pipes G leading to the several spaces F of the different portable vacuum-
vessels, assuming that a series of such vessels is being used as aforesaid.
Upon the production of pressure on the surface of the charge, the slime is
acted upon in the manner hereinbefore described so that the liquid is separated
out on top thereof.
If the residue J is re-converted into a fluid by the addition of suitable liquid
it can be run off or pumped out through the discharge valve E, or the contents
may be discharged by means of a centrifugal pump or otherwise while under
agitation, or afterwards, as desired.
In the alternative construction of apparatus illustrated in Figure 2 the tank C
is stationary, and tapered so as to be of larger diameter at the bottom than at the

page_text: top, and it is provided with a coned bottom C which is suitably packed around its
edges and removable from the bottom of the tank when the compacted charge J
is to be expelled therefrom. The filter-bottom D is carried by the bottom C² so
that when the latter is lowered and run out from beneath the tank C upon the
screw-jack trolley. C³ provided for that purpose, the filter I) is carried with it
and the residual compacted mass in the tank C is supported by the bars C which
extend across the bottom of the tank as shown in Figure 3, and are each held in
position at one end by a hinge c and at the opposite end by a hinged hook c¹. By
knocking aside the hook under one end of any bar such bar can turn about the
hinge at the other end, the portion of the charge previously upheld by this bar
then descending and being received in a trolley run in beneath the tank.
By suitably operating these bars C6 the compacted mass J can be discharged
more or less gradually from the tank C instead of dropping out as one mass. Or
the residual mass can be removed by other means. The supporting-bars C6 are
however a general feature in each and every apparatus where the discharge of
the treated material is by way of the bottom of the tank, although a perforated
hinged bottom might be substituted therefor.
Or the apparatus may be arranged as in Figure 4 in which the tank C is mounted
on wheels to run on track rails A2 between which is a vacuum chamber F, over
which a succession of tanks such as C can be run for treatment. The filter D
which in previous examples forms the bottom of the tank C forms in this con-
struction the top of the vessel F, and bars C such as are shown in Figures 2 and 3
are provided at the bottom of the tank C for the purpose of regulating the dis-
charge as herein before explained.
The bottom of the tank C and the top of the vessel F are made to fit closely
upon each other, and are provided with suitable packing to ensure a tight joint
between them.
To enable the tank C, Figure 4 to be readily lifted clear of the top of the cham-
ber F so as to be run away from the it along the rails A2, it is provided with
suitable raising and lowering devices, such as four lugs C7 each of which retains a
screw-threaded rod C8 as shown; it is to be understood that in this construction,
the screw-threaded portion of each rod does not engage with the lug through
which it passes but serves to receive a nut 09 situated on the rod below the lug.
The lower part of each rod is formed as a fork to retain a wheel C10, flanged to
engage with and run upon the rails A². By operating the nuts C
the lugs 07 and with them the tank C can be readily forced up
01' lowered down. When it is slightly lifted from the top end of the
chamber Fit can be readily carried away along the track, or it may be run back
again and lowered into place at any future time with equal facility.
This construction of apparatus illustrated in Figures 2, 3 and 4 is equally suit-
able when treating material either by pressure fluid delivered into the tank C or
by a vacuum set up in the chamber F, or simultaneously by pressure in the tank C
and vacuum in the chamber F. The chamber F in addition to serving as a
vacuum chamber, serves as a receptacle for any liquid descending into it through
the filter D.
It is to be understood that where in the description of the drawings reference
has been made to vacuum processes and apparatus, the vessels illustrated could if
desired be provided with a closely fitting top below which fluid under pressure
could be introduced into the vessel for use either alone or simultaneously with a
vacuum set up in the space F, to effect the treatment of the charge as described.
Figure 6 shows one example of such a top for the tank, so shaped that the
filter L can be drawn up into it and protected by it from any risk of damage which
might otherwise occur, when the cover is removed in the manner presently to be
described. The cover C¹ is provided with lugs C screw rods C8, nuts C9 and
wheels Co, by which it may be raised and lowered and moved from over the
tank C, on track rails A2 in a manner similar to that described with reference
to the raising and lowering, and removal of the tank C, Figure 4. The surface-

page_text: filter tube M is carried through a stuffing box C, in the top of the cover and
provided with rack and pinion mechanism or other gear by which it can be
moved to hold the filter at any desired level within the tank C.
In Figure 5 the stirrer shaft is carried in a frame V which is rotatable about
the line XY so that the stirrer can be brought in turn over any one of a series
of separating tanks which can be arranged in a circle about the said line X Y at
the same distance therefrom as the radial distance of the shaft O. In this con-
struction the shaft S supported in bearings V¹ in the frame V carries at its inner
end a gear-wheel which meshes with a gear-wheel W which with the gear
wheel W is rotatable about the central pillar V² of the apparatus and driven
by the wheel W3, which latter is rotated by any convenient means. The hoist-
ing rope T for raising and lowering the stirrer is carried over pulleys U to a
winch V3 secured on the frame V in proximity to the stirrer shaft, so that the
attendant, by whom the raising and lowering of the stirrer is to be controlled
can, whilst standing at the winch handle, look into the vessel over which the
stirrer at any time is situated.
Or a stirrer capable of being raised and lowered, can be arranged to travel along
a railway to act in succession on a series of tanks placed alongside each other.
For the purpose of avoiding the adherence of slimes to the filtering fabric of
the surface filter and to accomplish the ready removal of such slimes in case they
have a tendency to choke the fabric we prefer to provide the filter case with a
filter cover having a certain amount of slack, and to attach a suitable weight to
the filtering fabric such as a circlet of lead. A filter thus fitted operates as
follows:-
While the filter is in operation the fluid pressure in the tank holds the filtering
fabric against a support such as a well braced and suitably covered wire screen;
when the filtering action becomes slow or sluggish on account of the formation of
a slime layer which has deposited on the fabric the pressure is let off the tank
and the lead or other weight attached to the filter fabric drops as far as the
slack of the fabric allows thus causing a movement of the fabric sufficient to
cause the accummulated slime layer to drop off and leave the fabric clean in
condition for further operation.
Above
In the surface filter shown separately in Figures 17 and 8, the underside thereof
is covered with a slack layer L² of filtering fabric weighted by a heavy ring L³,
this slack and weighted fabric being provided in order to enable slimes accumu-
lated thereon to be shaken from it by causing the fabric to pulsate or flap.
the fabric a layer or screen L6 of wire gauze or the like is provided, backed with
radial ribs L7; the spaces between the ribs form channels which direct fluid
drawn through the gauze towards the exit from the filter afforded by the lower
end of the pipe M¹.
The ribs L of the filter are so shaped that the layer L of gauze is coned as
shown. The lowest portion or apex of the gauze L should not be at any higher
level than that of the lowest part of the circumference of the filter so that when
this form of filter settles upon the residue J of compacted material below it no
such stoppage of the withdrawal of surface liquid such as would occur if the
filter were flat-bottomed, will take place, for only the centre of the filter will touch
the compacted material beneath it thus leaving a circumferential clearance space
past the circumference of the apparatus until practically the whole of the surface
liquid is extracted by way of the delivery pipe M¹ of the filter which is led to
the lowest point of the interior above the gauze in order that the mouth of the
pipe may remain immersed to the last.
The method of working which is preferred with the apparatus hereinbefore
described, in the case for example of an ore treated by the cyanide process of
gold extraction is as follows:-
Charges of ore are delivered into a series of vacuum tanks C such as. are illus-
trated in Figure 1. These vessels are filled to within say 18 inches of the top and
when so filled are removed to a place in the working establishment at which a
C

page_text: vacuum connection can readily be effected with the vacuum space F by means
of a coupling, such as G2. A more or less complete vacuum is then established
in this space F and the outlet C is connected with a suitable receiving chamber,
or the space F may itself be made sufficiently large, as in the chamber F in
Figure 4, to retain any liquid which may percolate into it through the filter-
bottom D. Establishment of the vacuum as described will cause a drainage of
liquid from the lower part of the charge and a compacting of the ore and slimes
contained in the tank. While such compacting is progressing the surface filter L
is introduced and the outlet M2 thereof is connected with an exhausting pump or
a receiving chamber in which a vacuum has been established. When the valve M³
in the pipe M2 is thereafter opened a vacuum is set up in the hollow interior of
the filter L, and the collected liquid K is thus caused to percolate through the
filtering layer of the filter, and enter the interior of the filter body, and thence
pass to the delivery pipe M and to the vacuum pump or the receiving chamber.
This operation removes what is termed the "wash-water" from the ore.
various vacuum connections are now removed, the filter L is taken out of the
tank G, and a suitable amount of say cyanide solution is then added on the sur-
face of the residual charge J.
The
The tank C (Figure 1) is next run under the stirring apparatus N, the stirrer
blades O¹ are dropped through the cyanide solution on to the top of the charge J
and the stirrer is set in motion being gradually lowered into the said charge Jas
the same becomes mixed with the overlying liquid; and such lowering is con-
tinued until the stirrer blades (1 have reached approximately the bottom of the
tank C at a point near the filter bottom D. As soon as a thorough mixture of
cyanide solution with the charge has been thus effected, the stirrer N is with-
drawn and the connection G2 is coupled to a pipe supplying air under pressure;
such air is allowed to percolate upward through the charge, from time to time
for short periods, whenever the contained charge shows any signs of settling or
of any separating out of the liquid from the charge. In this manner thorough
maceration of the ore with the contained solvent liquid is ensured; the duration
of such maceration varies with the condition of the ore and the fineness of the
contained gold, but is rarely less than 12 hours; and it is on account of the long
period of time which is required for dissolving out the gold during the maceration
treatment that we prefer to use in the operation of maceration tanks of compara-
tively cheap construction, such as are exemplified by Figure 1, in conjunction
with say a single pressure tank such as shown in Figure 2 or Figure 4, for it is
more economical to keep a series of cheap tanks idle during maceration than to
perform the maceration in the costlier pressure-tank which might more advan-
tageously be kept in continuous work on material discharged from the vacuum
tanks, in a manner which will presently be described.
When a test of the contents of the tank C (Figure 1) shows that solution of the
gold has practically taken place, we prefer to again drop the stirrer N into the
charge and agitate the same for a period of from 1 to 3 hours, by which means
certain gold slimes which have gathered and are partially locked up, so to speak,
in the interstices and crevices of the minute particles of ore become released by
the agitation, and a correspondingly greater metal extraction is therefore due to
this additional agitation. As soon as this agitation is finished the apparatus is
ready to be discharged into the pressure separator (Figure 2 or Figure 4) for the
removal of the gold containing solution, and we prefer to accomplish this removal
under a high pressure on the surface of the charge in the pressure separator, and
it is advisable with certain slimes to add a vacuum below the filter beneath the
charge, because by such pressure and vacuum combined the ore is compacted to
a greater degree of density than is otherwise possible, and the solution is there-
fore abstracted in greater perfection, that is to say a higher percentage of the
contained solution is thereby abstractable.
It can of course be readily understood that the preliminary abstraction as well
as the maceration might be carried out in one and the same apparatus, say in

page_text: the apparatus such as shown in Figure 2 and Figure 4, as both these construc-
tions are susceptible of being used either by vacuum in the bottom section or
by vacuum in the bottom and pressure in the top section, or by pressure in the
top section alone, but for reasons of economy as hereinbefore explained it is not
advisable to perform the whole process in one tank.
When the contents of the tank C (Figure 1) have been discharged into the
apparatus such as is shown in Figure 2 or Figure 4, the stirrer should be again
dropped to a point near the bottom of the charge for the purpose of causing a
proper classification and concentration of the ore contents, it being rotated at
some moderate velocity sufficient to allow a proper settling or descent of the
coarser particles of the charge down through the current caused by the agitator.
The agitator is gradually withdrawn from the charge and when completely re-
moved therefrom the cover is placed on and properly fastened to the shell C. air
under pressure is admitted through the pipe C16, the water seal is drawn off from
below the filter bottom D and the cock C is left open, and these conditions are
maintained until solution drawn through the upper test cocks C¹³ shows that the
liquid K superincumbent on the charge J is but slightly opaque at the upper
section; when this condition has been arrived at valve M3 is opened and the
pressure within the tank C will then force the liquid K through the delivery pipe M¹
of the filter L. The liquid so abstracted by the filter L through the pipe M¹ is
delivered (as also is any turbid solution forced through the filter bottom D) into
the auxiliary filter W which is merely indicated diagrammatically, and which
should be open so that the ends of the pipes delivering into it and the material
they discharge can be conveniently observed. The turbid or opaque solution
leaving the auxiliary filter W is clarified by passing through the porous sand
layer Wand after passing such filtering layer W₁ and filtering fabric We it is
ready for subsequent treatment which is well understood and will result in the
precipitation of the gold therein contained. When the layer of liquid above the
compacted charge is reduced to a minimum by the filter the charge cracks up or
shrinks in such a manner that the small amount of liquid remaining therein can
be forced out by the pressure of the air which penetrates the charge. Figure 9
illustrates an alternative construction of trolley C3 provided with a ram C15 adapted
to be raised and lowered by compressed air (always available in the working of
this invention) and serving to remove and replace the filter bottom D and tank
bottom Cas hereinbefore described. It will be readily understood that the
apparatus herein described is applicable also for causing percolation by pressure
through ores of a permeable character in which case of course the surface filter is
dispensed with and we desire it to be understood that we claim the use of the
apparatus as described and shown for percolation as fully within the scope of our
invention.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
1. The method of abstracting liquid from a mixture of slime-bearing substance
or the like with such liquid and simultaneously compacting that substance, which
consists in subjecting the mixture to pressure in a receptacle to compact it into an
impervious mass on a filter bottom therein, abstracting a portion of the liquid
through the filter bottom and expressing the remainder on to the top of the com-
pacted substance, finally forcing it through a filter situated on the top of the liquid.
2. The method of obtaining clear liquid referred to in the preceding claiming
clause but comprising the further filtration of the abstracted liquid in an auxiliary
filtering apparatus.
3. The method of compacting slime-bearing substance and separating it from
liquid mixed with the same which consists in placing the liquid in a receptacle
having a filter bottom and closed top, applying a partial vacuum below the filter

page_text: bottom and positive gaseous pressure above the charge, and withdrawing through
a filter above the compacted mass the liquid expressed upon the top thereof.
4. In the obtainment of a clear liquid from a mixture of slime-bearing sub-
stance with such liquid, the combination of a vessel having a filter-bottom with
a surface-filter and an auxiliary filter.
5. In the described method of compacting a slime-bearing substance, the con-
centration of the heavier particles at the lower portion of the charge by agitation
of the mass substantially as described.
6. The method of recovering slime bearing material in a compacted form from
liquid intermixed therewith, by subjecting the mixture to gaseous pressure above
a removable filter bottom in a vessel having devices for supporting the compacted
substance after removal of the filter bottom, withdrawing the expressed liquid,
removing the filter bottom and controlling the subsequent discharge of the com-
pacted mass by removal of a suitable support substantially as described.
7. In the separation of the solid and liquid constituents of slime-bearing
materials and the like, by means of pressure induced by a vacuum, the combina-
tion of a chamber having a filter bottom and a vacuum chamber below and 'con-
nected with said bottom and a surface filter connected with a vacuum apparatus
for the purpose of abstracting liquid from above the surface of the residual
material substantially as described.
8. In the separation of the solid and liquid constituents of slime bearing
materials and the like, the combination of a receptacle having a filter bottom a
float or filter for abstracting liquid from the top thereof and a mechanical agitator
capable of being raised and lowered, with or without an auxiliary filter, substan-
tially as described.
9. In the separation of the solid and liquid constituents of slime bearing
materials and the like the combination of a receptacle having a filter bottom and
an interior filter vertically adjustable and a top adapted to house and carry the
interior filter substantially as described.
10. In the separation of the solid and liquid constituents of slime bearing
materials and the like a receptacle having a removable filter bottom and a movable
perforated diaphragm or a series of movable supporting bars substantially as and
for the purpose described.
11. In the separation of the solid and liquid constituents of slime bearing
materials and the like a stirrer arranged to rotate or to travel so as to plumb a
series of tanks for the purpose described.
12. In the separation of the solid and liquid constituents of slime bearing
materials and the like the combination of a receptacle having a filter bottom with
an auxiliary filter and means for transferring liquid from said receptacle into the
auxiliary filter substantially as and for the purpose described.
13. In the treatment of ore in a granular or pulpy condition which has been
compacted by pressure, subjecting the compacted mass of ore to air and water
pressure from below for the purpose of breaking up the mass substantially, as and
for the purpose described.
14. The complete process for the treatment of ores of the kind herein before indi-
cated, comprising a primary compacting operation, a subsequent breaking up of
the compacted mass by air and water pressure from below and a repetition of the
primary process for the further recovery of the solution of precious metal con-
tained therein.
15. In the separation of the solid and liquid constituents of slime bearing
materials and the like, the combination of two or more portable vessels such as C,
Figure 1, with stationary apparatus to which they may be connected for the pur-
pose of having a vacuum created within them.
16. In the separation of the solid and liquid constituents of slime bearing
materials and the like, a filter having a slack and weighted filtering fabric for
the purpose described.
17. In the separation of the solid and liquid constituents of slime bearing

page_text: materials and the like a coned filter having a delivery pipe opening into the lower
part of the coned portion, and a slack and weighted filtering fabric for the pur-
pose described.
18. The combination with a portable separation vessel such as C Figure 4 of a
vacuum chamber provided with a filter I) situated below the track on which the
vessel C travels substantially as and for the purpose described.
19. The combination and arrangement of parts constituting the portable vacuum
vessel C substantially as and for the purpose described and illustrated in the
accompanying drawings.
20. The combination and arrangement of parts constituting the complete stir-
ring apparatus N, substantially as and for the purpose described and illustrated
in Figure 1 or Figure 5 of the accompanying drawings.
21. The combination and arrangement of parts constituting the complete separa-
tion apparatus substantially as and for the purpose described and illustrated in
Figures 2 and 3 or Figure 4 of the accompanying drawings.
22. In the separation of the solid and liquid constituents of slime bearing
materials and the like, the surface filter substantially as described and illustrated
in Figures 7 and 8 of the accompanying drawings.
23. The combination and arrangement of parts constituting the improved cover
and surface filter substantially as and for the purpose described and illustrated in
Figure 6 of the accompanying drawings
Dated this 26th day of April 1898.
W. H. HARTLEY,
Boult & Wade,
Agents for the Applicants.