s.WASHING ORES AND OTHER MINERALS
Year: 1886

page_text: Minerals.
I, ANDREW RUTHERFORD GRAY, of 15, Maitland Street, Edinburgh, in the
County of Mid-Lothian, Scotland, Engineer do hereby declare the nature of my
invention for WASHING ORES AND OTHER MINERALS and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
My invention consists of an improved machine for the hydraulic concentration
of the heavier particles in mineral products whose granules are too fine to be
dressed by jigging.
The principle of the operation of the machine is the separation of the lighter
from the heavier particles of nearly uniformly fine granular mineral products, by
artificially increasing the relative buoyancy of the lighter particles, by the upward
dynamic action of numerous jets of water upon a stratum of the granular stuff' in
a jet chamber so constructed that the hydraulic action is always directed upon the
gravitating particles while the gravitating particles are continually guided into the
range of the effective action of the jets, the lighter particles being carried off in
the overflow, while the concentrating stratum is continually moving onward over
the active jets to a concentrate receiver. The concentrate is run off when necessary
by means of a valve in the bottom of the receiver. The receiver is of sufficient
size to hold several hours' production of concentrate, so that one attendant is able
to look after a number of machines.
The mineral product, of the fiueness that this machine is intended to treat, is
produced in the ordinary crushing of the ores, at all crushing mills, and is commonly
called fines and slimes. These fines are classified to a uniform fineness of particles,
and the hydraulic pressure used has to be different for different sizes of granules.
The fine ore material is delivered from the classifiers into a hopper connected to
the machine, so arranged that its rate of delivery can be regulated by the
attendant.
The jet chamber is a rectangular vessel open at the top, and with the sides partly
of glass to enable the attendant to observe the action. The bottom of the jet.
chamber is the jet plate, preferably of gun metal, formed with alternate straight

page_text: parallel ridges and furrows leading from the entering end to the concentrate
receiver at the opposite end of the chamber. Issuing from the entering end of the
chamber and beneath the hopper delivery, there is a row of nearly horizontal
nozzles from which a jet is directed into and along each furrow. Along the bottom
of each furrow and along the top of each ridge, there is a row of numerous fine
apertures through which water under the suitable pressure is continually flowing in
a multitude of upward jets whose dynamic effect is an artificially increased relative
buoyancy of those mineral particles having the less specific gravity. These are
borne up with more effect over the ridges, and the heavier particles tend to
gravitate into the furrows, but the latter are compelled to move on in these furrows,
being continually agitated, washed, and freed from impurities along their whole
course until they reach the entrance to the concentrate receiver beyond the
extremity of the jet plate. The onward motion of translation is begun by the
horizontal jets; it is assisted by gravitation through the jet plate being set with
declivity, and by the thereby slightly inclined onward direction of its jets, and
finally by an induced current produced by a regulable outflow pipe from the
receiver. This outflow is by a swivel pipe fitted so that its discharge aperture can
be elevated or depressed by the attendant, to regulate the current into the concentrate
receiver.
The water chamber below the jet plate is made of sufficient depth to insure
practically uniform pressure over the whole of its area. Any fine ore which may
drop through the jet apertures when the water pressure is off, is run by pipe and
cock into the receiver. The pressure of water is varied according to the size and
specific gravities of the granules, so as to suitably maintain the stratum of heavy
ore in agitation, and to impel the lighter minerals upwards into the overflow.
For ore material of 30 mesh, consisting of galena, blende, and silicious gangue,
15 pounds per square inch is found to be a suitable pressure. The most advan-
tageous pressure for any ore can be very readily determined by observation by the
attendant; previous training is unnecessary. The classification may be effected in
any of the well known ways; the inventor uses the "knotter plate," which gives a
range of classification from 11th to Tirth of an inch. The advantage of this
classification of fines such as those of galena aud blende ores, is to enormously
reduce the amount of buddle work.
Ore concentrating machines of this construction can be worked in series; the
overflow from one machine passing into another similar jet chamber, the successive
concentrates being of effectively diminishing specific gravities. When the valuable
product has the less specific gravity, as when coal dross is operated on, the process
is the same in principle, but the machine will then be much larger.
It is obvious that mechanical agitation may be superadded in the jet chamber
without affecting the substance of this invention.
On the accompanying sheet of drawings, Fig. 1 is a longitudinal vertical section
through the jet chamber A, the jet plate B, and the receiver K.
Fig. 2 is a plan, sectional through the jet chamber sides A A, and through the
horizontal nozzles D D, showing the receiver K externally, but with a part of one
side K in section through the glass pane. The numerous dots on the jet plate B B
represent the minute jet apertures in the furrows and ridges.
Fig. 3 is a plan of the jet chamber, with the hopper end Q for attachment to the
classifier delivery, C in fig. 1.
Fig. 4 is an end view showing the concentrate receiver in section.
Fig. 5 is a transverse vertical section of the jet chamber A A and jet plate B B
and water chamber R R.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
(1st) The horizontal nozzles D D, substantially as described and for the purpose

page_text: (2) The jet plate B B, substantially as described and for the purpose set
forth.
(3d) The manner in which the onward motion of the concentrate is obtained,
substantially as described and for the purpose set forth.
(4th) The ridge and furrow formation of a jet plate, substantially as described
and for the purpose set forth.
(5th) The combination of horizontal and vertical jets with an overflow and a
concentrate receiver, substantially as described and for the purpose set forth.
Dated this third day of May one thousand eight hundred and eighty six.