AU678519B2

AU678519B2 - Process for concentrating ore and a device for carrying out said process

Info

Publication number: AU678519B2
Application number: AU75098/94A
Authority: AU
Inventors: Boris Petrovich Sadkovsky
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-04-29
Filing date: 1994-08-02
Publication date: 1997-05-29
Anticipated expiration: 2014-08-02
Also published as: CA2188894A1; WO1995029757A1; RU2034662C1; AU7509894A; BR9408575A; CN1048430C; CN1149263A

Description

METHOD AND DEVICE FOR DRESSING USEFUL MINERALS Technical Field The present invention relates in general to equipment for and technology of dressing useful minerals, predominantly, gravity concentration of gold-bearing ores and more specifically to a method and device for dressing useful minerals.

Background Art The heretofore-known methods and devices for dressing useful minerals, in particular, for gravity concentration of gold-bearing ores are based on establishing a trapping coating in the pulp processing zone, filling said coating with the grains of a valuable component from the pulp under processing, restoring the trapping capacity of the coating in the course of its filling, and rinsing out the coating carrying the accumulated valuable component.

There exist nowadays a number of diverse trends in approaching the issue of restoring the trapping capacity of the covering. This is attainable by, e.g, a constructional modification of the elements of the concentration devices (in particular, their bottom) aimed at dressing useful minerals (DE, A, 719,647), or due to the provision cf additional movable elements in the construction of concentration devices, such as baffled riffles (SU, A, 724,194), or else an actuator to impart vibratory or I 2 shaking motion to the bottom (DE, A, 285,909).

The aforementioned known technical solutions, however, suffer either from a low degree of extraction of the valuable component (DE, A, 719,647), or from a cumbersome construction involving a great number of movable elements and/or power-consuming units (SU, A, 724,194, DE, A, 285,909), which affects operating reliability of the process of dressing useful minerals and renders said process more expensive. One prior-art method for dressing useful minerals is known (SU, A, 1,540,085) to comprise establishing a trapping coating in the pulp processing zone made of heavy magnetic concentrates of the valuable component, feeding the pulp under processing to the working zone, filling the trapping coating with the grains of the valuable component from the pulp under processing in a variable-intensity magnetic field, restoring the trapping capacity of the coating by its loosening with a pulsating magnetic field in the course of filling, and rinsing out the trapping coating carrying the accumulated valuable component.

The method discussed above is capable of restoring the trapping capacity of a coating without mecha'nical action thereon. The method, however, requires establishing an artificial trapping coating from heavy magnetic concentrates of the valuable component that have preliminarily been extracted from ores and distributed, after having been class ified, between the areas of the pulp a -3processing zone prior to feeding the pulp thereto.

Moreover, practical application of the aforesaid method involves much power to be consumed to build up a magnetic field and a complicated system for control of the intensity of said field, said system requiring the use of precision-accuracy measuring, monitoring, and actuating instruments, apparatus, and mechanisms, which makes the process much more costly and affects the reliability thereof.

Furthermore, as the pulp stream advances over the processing zone, its turbulence is considerably attenuated, which rules out selective settling of the valuable component grains and affects the degree of extraction and hence the concentration thereof. In addition, as the stream of pulp makes its headway along the processing zone, the particles of barren rock concomitant with the valuable component are being accumulated along the periphery of said zone and on the surface of the trapping covering, with the result that the thus-accumulated barren-rock layer gets cemented due to reduced turbulence of the pulp stream, which likewise affects the degree of extraction and concentration of useful minerals.

After all, the method in question Is unacceptable for dressing hard-to-wash argillaceous rock, a well as rock that is liable to form agglomerates, and also boulder rook because agglomerates and boulders both are 4able to destruct an artificial trapping covering, thus preventing its filling with the grains of the valuable component.

A device for dressing useful minerals (of. the textbook "Gravity concentration methods" by V.N.Shokhin and A.G.Lopatin, 1980, Nedra PH, Moscow, pp.285-288 (in Russian) is known to comprise an inlet section and an additional section consecutively butt-joined together and arranged parallel to each other at an angle to the horizontal plane in the direction of the pulp feed, Each of the sections has straight side walls and a bottom whereon baffled riffles are detachably installed, the baffles making right angles with the side walls of the section and being inclined towards the bottom in the direction of pulp motion.

Use of said device makes it possible to establish a natural trapping coating in the riffles at the bottom of its sections for accumulating the valuable component.

However, said construction arrangement of the sections fails to establish an alternating force exertion upon the trapping coating aimed at restoring its trapping capacity, and also rules out any possibility of producing a selective action on the grains of the valuable component so as to accelerate their settling. As a result, the trapping coating gets filled with the substance concomitant with the valuable component (that is, barren rock particles) which in turn leads to their I I I rapid accumulation, due to absence of an alternating load applied to the pulp stream, at the side walls of the sections and on the surface of the covering. The result is a decrease in the turbulization of the pulp stream, which affects adversely the degree of extraction of the valuable component and might impair serviceability of the device.

Disclosure of the Invention It is therefore a primary and essential object of the present invention to provide a method for dressing useful minerals featuring such an action upon the stream of pulp, and a trapping coating and a device for dressing useful minerals featuring such a lay-out and construction arrangement of the sections that make it possible to increase the degree of extraction (recovery) of the valuable component of useful minerals.

The foregoing object is accomplished due to the provision of a method for dressing useful minerals, predominantly, gold-bearing ores, consisting in that the pulp under processing is fed to the processing zone, said pulp containing a liquid phase and a solid phase that incorporates the grains of the valuable component to be trapped during pulp processing, and barren-rook particles to be removed during pulp processing, a stream of said pulp under processing is established, then accelerated and is made to advance lengthwise the processing 6 zone, wherein a trapping coating is established, the trapping coating is filled with the valuable component grains, the trapping capacity of the coating is restored concurrently with its being filled with the valuable component grains, whereupon the trapping coating filled with the accumulated valuable component is rinsed out; according to the invention, in order to restore the trapping capacity of the coating, developing stationary vortices in the course of the stream advancement over the initial section at the lower boundary thereof, said vortices having an axis of rotation oriented square with the direction of the pulp stream feed, filling the trapping coating with the grains of the valuable component concurrently with restoring the trapping capacity of the covering, and rinsing out the trapping coating carrying the accumulated valuable component; according to the invention, in order to restore the trapping capacity of the coating a flow resistance is built up in the processing zone to the stream longitudinal motion, said flow resistance being nonuniform as for stream length and width; stationary vortices are established at the lower stream boundary, the ais of rotation of said vortices being oriented at an angle to the direction of the stream feed, said vortices being aimed at acting upon the particles of the pulp solid phase at an orbital velocity that exceeds the fall velocity of the barren-rock particles but are lower than the velocity of i 1.

7valuable-component grains being trapped; when the pulp stream advances over the processing zone it is deflected crosswise from the direction of its feed, a dynamic action is exerted upon the lateral stream boundaries, and a spiral flow is established whose axis aligns with the direction of the deflected pulp stream.

Practical application of the proposed method enables one to impart an increased specially established turbulence to the stream of the pulp under processing throughout the extent of the processing zone which provides for loosening of the trapping coating due to kinetic energy of the pulp stream and rules out any possibility of cementing said coating and accumulating barren rock particles concomitant with the valuable component, throughout the width and length of the processing zone. As a result, settling of the grains of the valuable component is facilitated and reliability of such settling is increased, which leads ultimately to a higher degree of extraction and concentration of useful minerals.

Pulp stream transverse deflection provides for displacement of at least superficial layer of the trapping coating towards the direction of the stream deflection and establishing excess-pressure and rarefaction areas in the various portions of the processing zone, which promotes restoring the trapping capacity of the coating due to removal lighter barren rook particles therefrom and accumulating heavier grains of the valuab- II e7, -p~ 8 le component, in particular, those of gold, therein.

Provision of a flow resistance offered to the stream longitudinal motion and nonuniform as for stream length and width results in a relative displacement of the solid phase particles in the pulp stream under the inertia forces. This in turn gives rise, among other consequences, to formation of local turbulent vortices at the surface of the solid phase particles, said vortices being the more intense the higher is the density of said particles, as well as to an increased number of particle-to-particle collisions which the higher the greater is the mass of the particles. As a result, the particles of the valuable component which possess a maximum density and, with a relative homogeneity of the solid phase fractional composition, also a maximum mass, experience a maximum flow resistance to their longitudinal motion, lose kinetic energy, settle down in the field of gravitational forces, thus approximating the trapping coating to get trapped by the latter, which intensifies the process of filling the trapping coating with the valuable component, thereby adding to the deg-, ree of extraction of the latter component.

Formation of said stationary vortices at the lower stream boundary makes it possible to loosen the trapping covering, that is, to bring the settled-out barren rock particles to a suspended state, whereas establishing said spiral flow of the pulp stream facilitates longitu- Iu rrrr~-~ rm~il rra~ r 9dinal motion of the barren-rock particles over the entire stream cross-section without settling out. This conduces to their being carried away from the processing zone, thereby adding to the degree of ePtraction and concentration of useful minerals.

It is expedient that to build up Jptimum force exerting upon the solid phase of the pulp under processing and high enough for the barren rook particles to move but insufficient for establishing the conditions for hydraulic entrainment of the grains of the valuable component, the pulp stream be deflected to an angle of from 0.5 to 450 in transverse direction.

It is desirable that the axis of rotation of each stationary vortex in the deflection stream portion be oriented towards the axis of rotation of each stationary vortex in the initial stream portion at an angle substantially equal to the angle of the stream deflection in transverse direction.

The aforementioned feature favorites the conditions for sliding the barren-rook particles under the action of the near-bottom transverse current flowing from the periphery towards the central stream portion, maintaining said particles in a suspended state followed by removal of said particles from the processing zone by the main current, and ruling out transverse displacement and carry-over of the settled grains of the valuable component, fine ones insolusive. This in turn makes it 10 possible, with an appropriate granulometrio composition of the valuable component grains, to add to the degree of extraction of said component due to retaining its fine particles, as well as to increase the degree of ooncentration of the material being processed due to a more intense carry-over of the barren-rock particles from the processing zone.

As the pulp stream advances over the processing zone the spiral flow may lose its kinetic energy. That is why it is desirable, for periodically enhancing said energy, to additionally deflect the stream crosswise as it advances over the processing zone while alternating the orientation of said deflection. This intensifies carry-over of the barren-rook particles without their settling throughout the length of the processing zone, which adds to the degree of extraction and concentration of useful minerals.

When the length of the processing zone is increased the pulp stream advancing along said zone loses its velocity. To increase the latter it is expedient to locally accelerate the stream additionally as it advances over the processing zone. This intensifies all the aforementioned processes proceeding in the pulp stream and adds to the degree of extraction and concentration of useful minerals.

To increase the degree of turbulization of the pulp stream as it advances lengthwise over the processing zo- E i I IP 11 ne and to add to the efficiency of the aforesaid processes proceeding in the pulp stream an'd in the trapping covering, it is expedient that, as the pulp stream advances over the processing zone, flow resistance offered to its longitudinal motion be either decreased or increased locally, or else the stream be deflected vertically by curving its lower boundary.

Thus, practical application of the proposed method enables the degree of extraction and concentration of the valuable component of useful minerals to be increased.

The foregoing object is accomplished also due to the provision of a device for dressing useful minerals, comprising an inlet section and at least one additional section consecutively butt-joined together and arranged at an angle to the horizontal plane in the direction of the pulp feed, each of the sections heaing side walls and a bottom which carries detachable riffles, having baffles inclined towards the bottom in the direction of the stream feed, the baffles of the inlet section making right angles with the side walls thereof and being parallel to one another, according to the invention, the additional section is so turned transversely either side with respect to the inlet section so that an acute angle between the longitudinal axes of both sections is within and 450, and the baffles of the riffles of the additional sections are turned to the side opposite to

I

12 the direction of turn of said section relative to the inlet section and are arranged at an acute angle to the side walls of the additional section so as to make up an acute angle with the baffles of the inlet section.

The proposed construction arrangement of the device makes it possible to carry into effect the herein-proposed above-described method for dressing useful minerals.

The device is maximally simple and is devoid of any power-consuming or movable units and components. Use of the proposed device makes it possible to accelerate the pulp stream, provides for restoration of the trapping capacity of the coating due to establishing a flow resistance offered to the stream longitudinal motion and being nonuniform as for the stream length and width, said drag being due to installing the aforesaid baffled riffles capable of forming stationary near-the-bottom vortices between the baffles, the axis of rotation of said vortices being oriented along the respective baffles, and an orbital rotational velocity exceeds the fall velocity of the barren-rook particles being removed but is less than the fall velocity of the valuable component grains. In addition, the proposed device allows of deflecting the pulp stream transversely in the course of its advancement over the processing zone, makes it possible to build up a dynamic action on the stream in the zone of its- impingement upon the side wall and to establish a transverse motion of the pulp in the -Y I 13 near-bottom area directed along the baffles which motion, while being combined with the deflected stream, forms a spiral flow directed along the deflected stream.

Said spiral flow prevents barren-rook particles being removed from settling in the near-wall zone and between the baffles and provides for motion of said particles over the entire stream cross-section which adds to the degree of extraction and concentration of useful minerals.

Thus, it is due to the provision of the stationary elements alone with the use of kinetic energy of the pulp stream that the herein-proposed device enables the degree of extraction and concentration of useful minerals to be increased.

It is expedient that the acute angle between the baffles of the inlet and additional sections be substantially equal to the acute angle between the longitudinal axes of said sections. This improves the conditions for motion of the barren-rook particles in the interbaffle space under the action of the transverse near-bottom flow and rules out transverse motion and carry-over of the valuable component grains, fine ones inclusive, which makes it possible, with an appropriate granulometrio composition of the valuable component grains, to increase the degree of extraction of the valuable component due to retention of its fine particles, as well as to add to the degree of concentration of the material 14 under processing due to a more intense carry-over of the barren-rook particles from the processing zone.

It is also expedient that when making use of at least two additional sections, a second section be positioned with respect to the preceding one with a transverse turn to either side so that an angle between the longitudinal axis of the second additional section and that of the inlet section be within 0.5 and 45°, and the baffles of the riffles of the second additional section be turned in a direction opposite to the direction of turn of said section relative to the preceding additional section and be arranged at an acute angle to the side walls of its section so as to make up an acute angle with the baffles of the inlet section.

This enables one to increase the degree of extraction and concentration of the valuable component due to a repeated intensification of the transverse motion of the pulp flow in the near-bottom area gradually attenuating within the first additional section, and of the spiral flow along the deflected stream moving within the second additional section so as to prevent the light barren-rock particles being removed from settling in the zone of impingement of the stream upon the side walls within the second additional section and to provide settling-free motion of said particles between the baffles and over the entire cross-section of the pulp stream.

P 15 It is desirable that the acute angle between the baffles of the inlet section and of the second additional section be substantially equal to the acute angle between the longitudinal axes of said sections. This improves the conditions for motion of the barren-rook particles in the interbaffle space under the action of the transverse near-bottom flow from the side walls towards the center, followed by removal of said particles beyond the limits of the processing zone by virtue of the main stream, and rules out transverse motion and carry-over of the valuable component grains, fine ones inclusive, which makes it possible, with an appropriate granulometric composition of the valuable component grains, to increase the degree of extraction of the valuable component due to retention of its fine particles, as well as to add to the degree of concentration of the material under processing due to a more intense carry-over of the barren-rock particles from the processing zone.

It is favorable, whenever at least three additional sections are made use of, that each of the next additional sections be butt-joined with the preceding additional section and be turned transversely with respect to the inlet section in a direction opposite to the direotion of turn of the preceding additional section relative to the inlet section.

,This allows of periodically deflecting the pulp 16 stream, as it advances lengthwise the device, in a crosswise direction with different orientations, thus adding to kinetic energy of the spiral flow arising in each additional section and intensifying the carry-over of the barren-rock particles without their settling across the entire width of each section lengthwise the whole device, which adds to the degree of extraction and concentration of useful minerals.

It is favorable that at least one baffle in at least one additional section be either higher or lower than the baffles of the inlet section.

This enables one to carry out an intense local turbulization of the pulp flow so as to provide an active destruction of solid-phase agglomerates containing the valuable component, in the working zone of the device, thus adding to the degree of extraction of said valuable component.

It is expedient that the bottom of at least one additional section be at least partially convex or concave; it is most preferable that the bottom be sinusoidal.

This makes it possible to deflect the stream vertically, to curve its path, and build up additional vertical centrifugal forces acting on the pulp solid phase and contributing to separation and settling of the valuable component grains, as well as to carrying-over 17 the barren-rook particles to be removed, which allows of increasing the degree of extraction and concentration of the valuable component.

It is practicable that at least one of the next additional sections be butt-joined with the preceding additional section in such a manner that its slope to the horizontal plane be either greater or lesser than that of the preceding section.

This makes it possible to increase the intensity of the stream turbulization and destruction of the solid-phase agglomerates in the zone of falling of the pulp stream onto a next additional section featuring a smaller slope so as to promote stream acceleration and increase the intensity of stationary vortices in the interbaffle space when the stream passes over to a next additional section featuring a larger slope, which enables one to increase the degree of concentration and extraction of the valuable component.

It is expedient that at least one baffle in at least one additional section be so positioned that its slope towards the respective bottom be either greater or lesser than the slope of each baffle of the inlet section towards the respective bottom.

This makes it possible to insert an additional local perturbation into the stream, to enhance the degree of nonuniformity of flow resistance lengthwise the stream, establish an additional stream turbulization, I a -c 18 thus increasing the degree of concentration and extraction of the valuable component.

It is desirable that in at least one of the additional sections the baffled riffles be provided on a part of the bottom thereof.

This makes it possible to accelerate the stream in order to increase its kinetic energy in those portions of the additional sections which are devoid of baffles, thus enabling one to intensify a transverse flow resulting from impingement of the stream upon the side wall after its been deflected crosswise, and to restore the operating capacity of the stationary v'rtJ s in the interbaffle space with such an orbital r~tational velocity that is sufficient for carrying over the barren-rook particles to be removed and for separation of the valuable component grains therefrom.

It is desirable that at least one additional section have the side walls curved and parallel to each other, and that each baffle of the riffles in said additional section run along a line the tangent to which passes at each point at an acute angle to the baffles of the inlet section, and said acute angle should be substantially equal to an angle between the longitudinal axis of the inlet section and the longitudinal axis of said additional axis passing through said point.

.his makes it possible to further intensify de- I 19 struction of the solid-phase agglomerates containing the valuable component, in the working zone of the device due to the effect of alternating centrifugal forces arising from the stream flowing about the curved side walls. In addition, this enables one to establish such stream conditions that provide uniform distribution of the pulp solid phase across the width of the processing zone, thus adding to the degree of concentration and extraction of the valuable component.

It is favorable that at least the outlet portion of the bottom of the last section be perforated and the perforations can be shut up periodically.

This facilitates rinsing out the trapping coating containing the valuable component due to the provision of a possibility of their separate discharge, which adds to the reliability and quality of operation of the device.

Thus, use of the herein-proposed device for dressing useful minerals is capable of increasing the degree of extraction and ooncenration of the valuable component. In addition, practical application of the present invention makes it possible to render the process of dressing useful minerals cheaper and more reliable.

The proposed invention can be used under conditions of dissected topography, using various embodiments thereof.

The herein-proposed method is carried into effect I e 20 as follows.

The ore being concentrated, an auriferous one, containing the g'rains of the valuable component and barren-rook particles, is mixed with a liquid, water to obtain a pulp which is then fed to the processing zone, wherein a stream of the pulp to be processed in formed by virtue of one of there commonly known physical actions by arranging a system of sections positioned at a slope to the horizontal plane) and is let to move leng'thwise the processing zone, wherein a trapping coating is established, containing the pulp solid phase settling in the processing zone. The stream of the pulp under processing, while passing along the processing zone, gradually fills the trapping coating g'unfig'ht the grains of the valuable component which are separated from the pulp under processing in the field of gravitational forces. Simultaneously with the g'rains of the valuable component settled in the trapping coating are the barren-rook particles which affect the trapping capacity of the covering. To improve the trapping capacity of the coating the streamn of the pulp under processing is accelerated at the initial instant of At8 feeding to the processing zone (that is, in the initial portion of the processing zone) so as to increase the 26 stream kinetic energy. The Atreazn can be aocelerated by, appropriately selecting the operating conditions of the pulp stream feeder or by acting on the stream by 21 the boundaries of the processing zone. By using the thus-increased pulp stream kinetic energy one restores the trapping capacity of the coating by developing an intense stream turbulization. To this end, as the pulp stream advances over the processing zone, a flow resistance nonuniform as for stream length and width is offered to the stream longitudinal motion. The pulp stream, while passing along the processing zone, interacts with local flow resistances, whereby its turbulization is increased due to which the barren-rook particles are extracted from the trapping coating and brought to a suspended state, with the result that the capacity of said coating to trap the grains of the valuable component is restored.

It is due to establishing a flow resistance nonuniform as for stream length and width and offered to its.

longitudinal motion due to, modifying the roughness at the lower and side boundaries of the processing zone and inserting a variety of flow restrictions that a system of stationary vortices is created at the lower stream boundary, the axis of rotation of said stationary vortices being oriented at an acute angle to the axis of rotation of the stationary vortices in the initial stream pcrtion. By establishing a nonuniform flow resistance with the aid of the aforementioned action on the pulp stream, one imparts to the system of stationary vortices an orbital rotational velocity which exceeds 22 the fall velocity of the barren-rook particles being removed but is lower than that of the minutest grains of the valuable component which can be trapped by applying the method proposed herein.

To ensure against accumulation of the barren-rook particles on the trapping coating and nearby the lateral stream boundaries, where the local pulp stream velocity is low and the orbital rotational velocity of the stationary vortices decreases, the pulp stream in the course of its advancement is deflected crosswise from the direction of feed, a dynamic action is built up on the lateral stream boundaries, and a transverse pressure gradient is established, under the effect of which a transverse pulp motion arises, which while being combined with the translational motion of the stream, establishes a spiral flow whose axis aligns with the direction of the deflected stream. The abovesaid dynamic action on the lateral stream boundaries caused by its deflection, as well as the transverse flow compensate for an undesirable decrease in the stream velocity nearby its boundaries and rules out accunuiation of the barren-rock particles in said zones. The spiral flow established in this case provides for motion of the barren-rock particles as for the stream width and length till their complete removal outside the processing zone, while holding the trapped valuable-component grains fixed stationary. An optimum angle of the stream trans- 23 verse deflection is within 0.5 and 450, said angle building up an optimum force acting on the solid phase of the pulp under processing and being high enough to displace the barren-rock particles but insufficient to provide conditions for hydrodynamic carry-over of the valuable-component grains. To improve the sliding conditions for the barren-rook particles and maintain them in a suspended state for subsequent removal from the processing zone the stationary vortices are established in nuch a manner that the axis of rotation of each stationary vortex in the deflected stream portion be oriented to the axis of rotation of the stationary vortices in the initial stream portion at an angle substantially equal to the angle of the transverse stream deflection.

All stated above, adds to the degree of extraction and concentration of the valuable component.

The aforementioned effect produced by the spiral flow can be augmented by the fact that as the stream advances longitudinally it is further deflected transversely from time to time, with alternating orientation of the stream deflection, thus boosting the action of centrifugal forces on the solid pulp particles.

Additional centrifugal forces are developed by deflecting the pulp stream vertically from the direction of feed, by curving its path along, a sinusoid by acting on the lower stream boundary by any p I 24 known method, e.g. mechanical exertion, said additional centrifugal forces being applied to the pulp solid phase so as to promote separation and settling of the valuable-component grains and carry-over of the barren-rock particles.

An additional effect of separating the valuable component and carrying-over the barren-rook particles being removed is attained due to local stream turbulization as it advances over the processing zone, said turbulization being carried out by a local decrease or increase of the flow resistance offered to the stream longitudinal motion, by acting on the stream with the aid of flow restrictions installed locally in any portion of the processing zone, or by a local decrease in the angle of the pulp stream feed.

It is due to heavy loss of the stream kinetic energy for overcoming local resistances, maintaining stationary vortices, and local stream turbulization as the stream advances over the processing zone that the stream kinetic energy decreases, especially in case of a gentle stream slope to the horizontal plane. In such a case the stream is additionally accelerated locally either by eliminating all flow resistances on specially provided acceleration sections within the processing zone or by inoreasing the local stream slope on some individual portions of the processing zone.

The aforesaid action on the pulp stream provides i 25 for separation of the valuable-component grains from the barren-rook particles being removed, as well as accumulation of the valuable-component grains in the trapping covering, thus adding to the degree of concentration and extraction of the valuable component.

Once the trapping coating has become filled completely with the valuable component it is rinsed out by feeding a liquid, water to the processing zone at a rate high enough to wash out and remove a layer of barren-rock particles that have been caught during the operating process, whereupon the valuable component is extracted, and the entire technological cycle is repeated. In what follows the herein-proposed method is described in more detail with reference to the description of operation of the proposed device carrying said method into effect.

Brief Description of the Drawings To promote understanding of the invention, given below are some specific exemplary embodiments thereof with reference to the accompanying drawings, wherein: FIG.1 is a schematic plan view of a two-section device, according to the invention; FIG.2 is a side fragmentarily cutaway view of a two-section device, according to the invention; FIG.3 is a plan view of a five-section device, according to the invention; i L ql4IClb l 26 FIG.4 is a side partly cutaway view of a five-section device, according to the invention; and is a fragmei tar, pla view of a device, according to the invention.

Best Method of Oarrying Out the Invention The device for dressing useful minerals, predominantly, gold-bearing ores, according to the invention, consists essentially of an inlet section I (FIG.1) and an additional section 2, both being tandem-joined together. The sections i and 2 (FIG.2) are arranged at a slope T (FIG.2) to the horizontal plane in the direction of pulp feed. Each of the sections i and 2 (FIG.1) has side walls 3, 4 and a bottom 5, 6 (FIG.2) on which are detachably mounted riffles 7, 8 provided with baffles 9, 10, i01 arranged at angles wi; w3, respectively to the corresponding bottom 5, 6 in the direction of pulp feed. The additional section 2 (FIG.1) is turned transversely with respect to the inlet section 1. Angle of turn of the additional section 2 relative to the inlet section I (that is, an acute angle ai between their respective longitudinal axes a and bi is from 0.5 to 450 Such a construction arrangement enables the pulp stream interact, while entering the additional section 2, with the side wall 4 of said section 2, with the result that the pulp stream acquires a transverse component of 27 its motion which co:responds to the tangent of the angle ci of turn of the additional section 2 with respect to the inlet section 1.

Said angle ai is selected so as to make it possible to build up a force acting on the solid-phase particles of the pulp under processing and high enough for displacing the barren-rock particles but insufficient for providing conditions for hydrodynamic carry-over of the grains of the pulp valuable component.

When the angle ri of turn of the sections 1 and 2 is below 0.50, the transverse component of the stream velocity is such that the force developed by the stream and acting on the pulp particles on the trapping covering, is lower than the force of friction between said particles and cannot provide their mutual displacement, thus failing to provide loosening the trapping coating and restoring its trapping capacity and affecting adversely the degree of extraction of the valuable component.

When the angle dl of turn of the sections 1 and 2 is above 450, the transverse component of the stream velocity exceeds the longitudinal component thereof which results in destruction of the trapping coating and its being carried over by the stream of the processing zone togethei with the grains of the valuable component.

The baffles 9 of the riffles 7 in the inlet section 1 are set square with the side walls 3 of said section 1 i i c-b Y- 28 and parallel to one another, which enables one to establish stationary vortices at the lower boundary of the stream, the axis of rotation of each of said stationary vortices being oriented square with the stream feed.

The baffles 10 of the riffles 8 in the additional section 2 are turned in the direction opposite to that of turn of the additional section 2 wherein said baffles are installed, relative to the inlet section 1, which iO enables one to establish stationary vortices at the lower boundary of the stream as the latter advances over the processing zone, the axis of rotation of said stationary vortices being oriented at an acute angle to the axis of rotation of the stationary vortices in the initial portion.

The baffles 10 in the additional section 2 are arranged at an acute angle Bi to its side walls 4 and make up an acute angle Yr with the baffles 9 of the inlet section 1, said acute angle yj between the baffles 9 of the inlet section 1 and the baffles 10 of the additional section 2 being substantially equal to the acute angle ~i between the respective longitudinal axes a and bi. This provides for establishing a nonuniform flow resistance offered to the stream longitudinal motion, while the fact that the baffles 10 are turned in the direction opposite to that of turn of the additional section 2 relative to the inlet section 1

I

29 enables one to uniformly distribute the pulp solid phase across the width of the processing zone and to establish local turbulent vortices capable of separating the barren-rook particles from the valuable-component grains that feature a higher density in order to intensify their settling on the trapping covering.

It is practicable that at least one baffle (FIG.2) of the additional section 2 have a height hi exceeding a height H of the baffles 9 of the inlet section 1, or that the baffle 10 1 have a height h2 lower than the height H of the baffles 9 of the inlet section 1. In addition, it is practicable that at least one baffle 10 in the additional section 2 be arranged at the angle we to the respective bottom 6 which exceeds the angle wi of incline of each baffle 9 of the inlet section 1 to the bottom 5, or at the angle s3 of incline of the baffle 10 1 lower than the angle wi of incline of the baffle 9 of the inlet section 1.

The degree of nonuniformity of the flow resistance offered to the stream longitudinal motion can be increased or decreased depending on a preset pulp stream longitudinal flow velocity in order to build up the field of inertial forces high enough for the valuable-component grains to settle but also to maintain soaring of the barren-rock particles in the pulp stream, by means of the aforementioned adjustment of the height hi, h2 of the baffles 10, 10 1 of the additional section i I- 30 2, and/or the angle W2, ws of slope of said baffles 101 towards the respective bottom 6.

The herein-proposed device may incorporate at least one more additional section 1i butt-joined with the preceding additional section 2 (FIG.3) and turned transversely either side with respect thereto so that the angle ag between the longitudinal axes b 2 of the inlet section 1 and of the second additional section 11 is between 0.5 and 450. In this case baffles 12 of riffles 13 of the second additional section 11 are turned in the direction opposite to that of turn of said section 11 relative to the preceding additional section 2 and are arranged at an acute angle 02 to side walls 14 of its own section 11 so as to define an acute angle ye with the baffles 9 of the inlet section 1. The acute angle y2 confined between the baffles 9 of the inlet section 1 and the baffles 12 of the second additional section il is substantially equal to the acute angle (2 between the longitudinal axes a and b2 of said sections.

FIG.3 illustrates the herein-proposed device, wherein the inlet section 1 and four additional sections 2, 11, 15, and 16 are butt-joined successively in such a way that each of the following additional sections 11, 15, and 16 is butt-joined with the preceding additional section 2, 11, 15, respectively, with a transverse turn relatively to the inlet section in the direction opposiliPPI~ e9 II 31 te to that of turn of the preceding additional section 2, 11, and 15 relative to the inlet section 1. Otherwise speaking, each of the additional sections 2, 11, and 16 is turned in the opposite directions with respect to the inlet section 1. Upon each change in the direction of flow of the pulp stream the solid-phase particles of the pulp under processing undergo dynamic load which is the higher the greater the absolute value of a change in the direction of pulp stream velocity vector. As a result, the clayey agglomerates are destruoted and the particles of the valuable component are released therefrom, thus adding to the degree of extraction of said valuable component.

All described before with regard to the turn of the preceding additional section 11 and installing the corresponding baffles 12 therein refers equally to the following additional sections 15 and 16 and their baffles 17, 18.

A bottom 19 (FIG.4) of at least one additional section 15 can be at least partially convex or concave.

In a particular case depicted in FIG.4, the bottom 19 of the additional section 15 is sinusoidal in shape, that is, partly convex and partly concave., Each of th6- additional sections 2, 11, 15, and 1D" can be butt-joined with the preceding section 1, 2, 111 or 15 so that an angle T2, 93j, 94, 9p5 of its slope be greater or lesser than an angle ep1, 'p2, 9p31 941 of slope 32 of the preceding section 1, 2, 11, By changing the shape of the bottom 19 and/or the magnitude of the angle p2, T3, 94, p5, of slope of the additional sections 2, 11, 15, 16, one sets the pulp stream longitudinal flow velocity that provides, with a preset flow resistance, building-up the aforesaid field of inertial forces acting on the valuable-component grains and the barren-rook particles. Depending on the size and shape of the valuable-component grains present in a given ore, and on the degree of its washability, the stream longitudinal flow velocity can be increased or decreased at a high or low recurrence rate by changing the shape of the bottom 19 or varying the angle 92, s3, 4, T5, of slope of the additional sections 2, 11, 15, 16, respectively.

When the ore being processed features a high content of the valuable-component grains having a large specific surface, and/or with small overall dimensions of the device as a whole, necessity arises, with the purpose of increasing the stream turbulization and the efficiency of loosening the trapping covering, for establishing on a small area of the processing zone a periodical change in the direction of the transverse component of the stream flow. In this case side walls 27 (FIG.5) of at least one additional section 21 can be curved, that is, bent or broken, and parallel to each other. Each baffles 22 of riffles 23 of said additional I s I ud IS~S~S 33 section 21 must run along the line the tangent to which at each point passes at an acute angle -3 to the baffles of the inlet section 1, said angle rS being substantially equal to the angle a3 between the longitudinal axis of the inlet section 1 and the longitudinal axis (b 3 of said additional section 21 passing through the given point With the purpose of a higher acceleration of the pulp umder processing on its longitudinal flow, riffles 24 (FIG.3) with baffles 12 may be provided in at least one additional section 11 only on part of a bottom The bottom 6 (FIG.1) and a bottom 26 (FIG.3) of the last section 2 (FIGA.), and 16 (FI.3) at least on the outlet portion thereof can be perforated, and perforations 27 (Fl1.4) can be periodically shut up by, e.g., placing mats 28 on the bottom 26 of the perforated portion of the last additional section 16.

The number of the additional sections 2, 11, 15, 16 and the magnitudes of the angles cx, T are selected in their respective ranges mentioned above depending on technological considerations so as to establish optimum hydraulic conditions for the stream bf pulp having a definite granulometrio composition, depending on the degree of washability of the ore being processed, and/or with due account of the terrain on which the aforedescribed device is installed so as to provide the 34 highest possible degree of extraction and concentration of the valuable component.

The herein-proposed device operates as follows.

To produce pulp the ore under processing is mixed with water and fed to the bottom of the inlet section 1, wherein disintegration and final formation of the structural composition of the pulp stream is carried out as a result of interactic between the ore-and-water mixture and the baffles 9 of the riffles 7, which baffles are arranged square with the walls 3 of the inlet section 1, said structural composition being characterized by a granulometrio curve of the barren-rook particles and a granulometrio curve of the valuable-component grains contained in a given pulp. As a result, stationary vortices arise in the initial pulp stream portion at the lower stream boundary, the axis of rotation of each of said stationary vortices being oriented perpendicularly to the direction of the pulp stream feed. Further on the stream arrives at the additional section 2. At the initial instant of pulp stream advancement along the sections 1 and 2 of the device, a flow resistance developed by the baffles 9 and 10 and the bends of the butt-joint areas of the sections 1 and 2, results in establishing a trapping coating on the bottom 5 and 6 of each section 1 and 2, said coating containing the pulp solid phase settling down in the interbaffle space. The thus-obtained natural trapping coating on the bottoms -L ~i Ip I A 35 and 6 of the sections 1 and 2 has a loose structure due to differently shaped pulp solid-phase particles and possesses a high trapping capacity at the initial time lapse. Further feeding of the pulp stream to the sections 1 and 2 of the device results, due to gravity separation of the solid-phase particles as for density, in loading the trapping coating with the densest particles of the valuable component.

As has been stated before, it is in the inlet seotion 1 that the ore agglomerates get disintegrated on the cross baffles 9, and the structural composition of the pulp stream solid phase is formed. After the pulp stream has got in the additional section 2, a transverse component of the velocity vector is established in the direction of deflection of the longitudinal axis (bj) of the additional section 2 from the longitudinal axis (a) of the inlet section 1, this being due to said additional section 2 being turned at the angle ai to the inlet section 1 upon interaction between the stream and the side walls 4 of said section 2.

A nonuniform flow resistance to the longitudinal motion of the pulp stream established in the device by the baffles 9, 10 installed in the additional section 1 and the additional section 2 thereof, enables one to create stationary near-bottom vortices resulting from collision of the stream with the baffles 9, 10, the axis of rotation of said stationary vortices being oriented 36 lengthwise the baffles 9, 10 at an acute angle to the axis of rotation of the stationary vortices in the initial stream portion.

The conditions (that is, flow depth and velocity) of the stream over the baffles 9 and 10 are selected such that the orbital rotational velocity of the vortices exceed the fall velocity of the barren-rook particles being removed and be lower than the fall velocity of the valuable-component grains to be trapped.

The stationary vortices are aimed at loosening the trapping coating and performing hydraulic classification of the pulp solid phase by raising the barren-rook particles and providing a possibility of settling the valuable-component grains in the interbaffle space.

While advancing longitudinally towards the additional section 2 the stream is transversely deflected, due to the section 2 being turned crosswise relative to the axis of the stream feed, and a dynamic action is produced on the stream by the side walls 4 of the additional section 2. The barren-rook particles are prevented from settling in the near-wall zone close to the side wall 4 of the additional section 2 due to the stream impinging upon said side wall 4, so that the stream depth there increases, whereas the stream depth at the opposite side wall 4 of the additional section 2 remains unaffected. A difference between the stream depths in a transverse section thereof establishes a I- as II 37 transverse pressure gradient under the action of which a transverse flow is established in the near-bottom zone of said section, said flow carrying the barren-rook particles raised by the stationary vortex away from the interbaffle space and displacing the barren-rook particles from the near-wall zones with reduced flow velocities. While being combined with the deflected stream flowing along the additional section 2, the transverse flow creates a spiral flow carrying over the barren-rook particles from the working zone of the device.

When concentrating medium-washable, hard-to-wash, or boulder-like rock, it is expedient to intensify the process of loosening the trapping coating and increasing dynamic loads on the solid phase of the pulp stream. In this case it is also favorable to increase the overall length of the device, that is, to make use of the additional sections 11, 15, and 16 butt-joined with the preceding additional section 2.

Upon arriving the pulp stream at the following additional sections 11, 15, and 16, the aforedescribed processes proceeding in the stream, which are being attenuated as the pulp advances over the processing zone of the device, are intensified.

Interaction between the pulp stream and the baffles 10 and 101 of the additional section 2 which have a larger and/or a smaller height hi and h2, respectively, compared with the height H of the baffles 9 of the inlet II U 38 section 1, intensifies turbulence of the pulp stream, which can also be intensified when the pulp stream passes over from the additional section 2 featuring a greater slope Tp towards the horizontal plane, to the additional section 11 having a lesser slope T3 to the horizontal plane.

Insofar as kinetic energy of the pulp stream is lost after its impingement upon the higher baffle 10 and is then consumed, upon subsequent stream impact against the side wall 3 of the additional section 2, for maintaining rotation of the system of stationary vortices, generating the stream turbulence, and overcoming frictional forces, the stream capacity to separate the pulp solid phase into the valuable-component grains and the barran-rook particles is being lost as the stream advances longitudinally. This occurs especially quickly in case of a gentle slope of the stream to the horizontal plane. The stream restores its lost kinetic energy due to conversion of the potential energy of position when it gets on the portion of the bottom 25 of the additional section 11 devoid of the riffles 24 with the baffles 12 with the purpose of reducing flow resistarne and loss of kinetic energy there.

Tho lost stream kinetic energy can also be restored by positioning the further additional section 16 at an angle 95 of dip to the horizontal larger than that of the preceding additional section 15, or by reducing the i i 1 r I 39 flow resistance and increasing the angle of dip simultaneously. This makes it possible to intensify the transverse flow and restore the working capacity of the stationary vortices in the interbaffle space with an orbital rotational velocity high enough for raising the barren-rook particles being removed and separating the valuable-component grains therefrom for their settling on the trapping coating.

Oarry-over of the barren-rook particles from the interbaffle space can be stimulated by such an orientation of the baffle 10' of the additional section 2 that provides for a positive angle w3 of dip of the baffle relative to the horizontal plane with a preseleoted transverse derlection of the additional section 2 from the direction of the pulp stream feed and a preset angle p of dip of the direction of the stream feed. A positive angle W3 of dip of the baffle 10' is to be set not in excess of the natural angle of slope of the bulk of the valuable-component grains in a water-saturated state which rules out their sliding along the baffle and may approximate the natural angle of slope of the bulk of the barren-rook particles in a water-saturated state which promotes their sliding along the baffle and carrying over from the interbaffle space.

Oprration of the device for separating the solid pulp phase into the valuable-component grains and the barren-rook particles can be further intensified on the 40 additional section 15 whose bottom 19 has a sinusoidal longitudinal profile. Bending of the stream path in a vertical plane upon its getting onto the additional section 15 having the curvilinear bottom 19, allows of developing extra vertical centrifugal forces acting on the pulp solid phase and contributing to separation and settling of the valuable-component grains and to carrying-over of the barren-rook particles, which enables one to increase the degree of concentration and extraction of the valuable component.

Provision of the additional sections with curvilinear walls and a convex, concave, or sinusoidal bottom, changing the slope of the additional section relative to the horizontal plane, changing the inclination and height of the baffles, installing the riffles on a part of the bottom, or any other of the aforesaid features of the construction arrangement allows of increasing the dynamic load on the solid phase of the pulp stream, thus ensuring destruction of clayey agglomerates and separation of the particles of the pulp valuable component, and the greater number of the aforesaid changes is provided by the construction of the device the more efficiently proceeds the aforementioned process.

Once the trapping coating has got filled with the valuable-component grains completely, the coating is subjected to rinsing out together with the valuable component. To this end, the riffles 7, 8, 28, and 24 _I

II.

41 with the baffles 9, 10, 12, 17, 18, and 22 are detached from the bottoms 5, 6, and 25 of all the sections 1, 2, 11, 16, and 21 (with the presence of the perforations 27 in the outlet portion of the last section 16 they are exposed by, removing the mats 28), whereupon wash water is fed to remove the concentrated ore. Next the mat 28 and the riffles with the baffles are re-placed in position, and the entire operating cycle is repeated.

Example 1 The pulp is prepared from an easily-washable rook in the form of medium sand with a 17 content of particles sized below 0.27 mm and pebble-rook inclusions sized up to 100 mm, with the gold content of 1 g/m 3 in the form of grains sized over 0.1 mm and a 2 fractions of grains sized below 0.1 mm.

When preparing the pulp use is made of water as a liquid phase, the liquid/solid phase ratio being 6:1.

Then the prepared pulp is fed to the processing zone at a specific flow rate of 0.05 m 3 /s per meter of the stream width. When fed to the processing zone the pulp stream is compressed for height, accelerated up to a velocity of 2.0 m/s, and directed orthogonally to the inlet-section baffles in the initial portion of said zone. Next the pulp stream which contains also soil agglomerates is brought in collision with the baffles of the initial zone portion to disintegrate the main proportion of the agglomerates, where-.-r-n the stream is i 4- LIYP- 42 deflected transversely by virtue of dynamic action produced on thereon by the side boundaries of the sections oriented at an angle of 6.65 to the initial direction of the stream flow. In order to restore part of the kinetic energy lost by the pulp stream for disintegration of the soil agglomerates and collision with the inlet-seotion baffles, the pulp stream while being displaced transversely, is also deflected in a vertical plane by changing the slope of its lower boundary by an angle of It is due to the dynamic action produced by the side boundary on the pulp stream when the latter runs against said side boundary upon being deflected transversely that an elevation of 0.2 m of the stream level over its level at the opposite side boundary is established. A transverse pressure gradient is developed by virtue of the resultant difference in the stream levels at the side boundaries thereof, with the aid of which a transverse flow is initiated predominantly near the lower stream boundary at a velocity of up to 0.2 m/s, said flow displacing barren-rook .articles from the side stream boundaries towards its center where they are entrapped and entrained away from the processing zone by the main deflected stream. To attain the best sliding of the barren-rook particles across the stream from its side boundaries under the action of the transverse flow, the stream is directed at a maximum angle of 100 to the horizon line which is I I Is ~pp II 43 selected to be proportional to the natural angle of slope of the soil under processing in the state of a maximum water saturation. Then the transverse flow and the main translational motion of the pulp stream are combined together to form a spiral flow whose axis is aligned with the direction of the deflected stream, said spiral flow transferring the barren-rook particles from the side stream boundaries towards the center and removing them outside the working zone, The velocity of the lower stream boundary equal to 0.2 m/s is quite enough for transversely displacing the barren-rook particles sized below 0.27 mm but is too low for transferring gold grains sized 0.1 mm and over; hence said grains as well as the sand particles sized over 0.27 mm move down towards the lower stream boundary, thus forming a trapping coating (or bed). It is due to a rough surface of said bed that it decelerates the near-bottom stream layers so as to let the valuable-component grains sized 0.1 mm settle out under the preestimated conditions of hydraulic regime. The settling Valuable-component grains fill the pores of the trapping coating, thus making it less rough, whereby the decelerating and trapping capacity of the coating are reduced.

Next a system of stationary vortices is formed due to the provision of a nonuniform flow resistance to the stream longitudinal motion as for the stream length and width by acting on the stream by local resistances, said

I-

44 stationary vortices being formed at each local resistance near the lower boundary of the pulp stream, Said local resistances are so arranged that the axis of each stationary stream be parallel to the direction of the transverse flow. The orbital rotational velocity of each stationary vortex is to be lower than the fall velocity of the gold grains sized 0.1 mm which is equal to 6.6 cm/s but is to exceed the fall velocity of the barren-rook particles being removed which in this particular example equals 2.5 om/s and corresponds to the rate of settling of sand particles equal in weight to the gold grains having the estimated size of 0.1 mm.

Said orbital rotational velocity of the stationary vortices is established due to an average flow velocity which with a preset slope of 90 depends on the depth of the pulp stream and is attained at said depth approximating 0.2 m.

It is the appropriately selected aforesaid hydraulic and geometric pulp stream parameters that provide for transferring cobble up to 100 mm in size without settling in the processing zone, whereby the proposed method is carried into effect in a continuous mode.

With the aforesaid parameters of the proposed method its practical realization under conditions of the aforestated example enables one to attain a degree of gold extraction approximating 98 with a concentration factor equal to 89.

_IM

45 Example 2 The pulp is prepared from an easily-washable rock in the form of coarse sand having particles sized up to 2 mm with the content of large-sized sand particles below 1% and that of small-sized sand fractions having a diameter below 0.1 mm up to 10 featuring pebble-rook inclusions sized up to 100 mm, with the gold content of I. g/m 3 in the form of grains sized over 0.08 mm and a i content of fractions of grains sized below 0.08 mm.

When preparing the pulp use is made of water as a liquid phase, the solid/liquid phase ratio being 1:10.

Then the prepared pulp is fed to the processing zone at a flow rate of 0.15 m 3 /s (which corresponds to 1080 mn 3 of solid phase daily). The processing zone is composed of four sections butt-joined with a mutual transverse turn at an angle of 0.50, shaped as rectangular cross-section troughs positioned at a slope of 80 and provided a trapping coating established in said sections with the aid of riffles with inclined baffles.

With pebble-rook inclusions sized 100 mm the stream depth over' the baffles is assumed to be 100 mm, and the stream velocity is selected to be 2.5 rn/s so as to provide an unobstructed carry-over of the pebble-rock inclusions outside the working zone.

With the limit size of a g~old grain equal to 0.08 mm, the trapping coating is established by making use of riffles having ba ffles 2.5*10-2 m high and 46 spaced 0.1 m apart. With the aforesaid stream and trapping coating parameters, the pulp stream velocity is 3.1 m/s, rhich exceeds the lower limit (2.5 m/s) required for carrying over the pebble-rook inclusions.

With the aforestated pulp stream flow rate, slope, depth, and velocity, the width of each trough is equal to 0.7 m. The slope of the baffles to the horizon line is adopted to be 0.50, equal to the angle of transverse stream deflection, which provides an efficient trapping of the minutest valuable-component grains and adds to the degree of extraction of said component. The angle of transverse deflection of the additional sections equal to 0.50 allows of obtaining a stream near-bottom flow velocity effective in the interbaffle space of up to 0.2 m/s, which is quite sufficient for removing small-size sand fractions and periodically displacement of larger-size fractions thereof so as to transfer them from the side stream zones to the zone of carry-ove- by the main stream.

With the aforespeoified parameters the herein-proposed device carries into effect the herein-proposed method in a way similar to that described in Example 1, whereby the attainable degree of gold extraction approximates 99 with a concentration factor of '8.

Example 3 The pulp is prepared from an easily-washable rock in the form of medium sand having particles sized below i j 47 mm with the content of large-sized sand particles below 1 by volume with the gold content of 1 g/m 3 in the form of grains sized over 0.1 mm and a 2 content of fractions sized below 0.1 mm.

When preparing the pulp use is made of water as a liquid phase, the solid/liquid phase ratio being 1:8.

The pulp is fed to the processing zone at a flow rate of 0.05 m 3 /s (which makes up 450 m 3 of solid phase per day). The processing zone is composed of two sections butt-joined angularly and shaped as rectangular cross-section troughs positioned at a slope of 60 and provided with a trapping coating established in said sections with the aid of riffles with inclined baffles.

With the limit size of a gold grain equal to 0.1 mm, the trapping coating is established by making use of riffles having baffles featuring the spacing/height ratio thereof equal to 2. In this case the stream depth over the baffles equals 2.5*10-2 m and the baffle height is assumed to be 3*10-2 m, the baffle spacing being 6*10-2 m. With said stream and trapping coating parameters the pulp stream velocity is 1.1 m/s.

With the aforestated pulp stream flow rate, slope, depth, and velocity, the width of each trough is equal to 0.93 m. The slope of the baffles to the horizon line is adopted not to exceed 100. The angle of transverse turn of the additional section (that is, the angle of the stream deflection) is adopted to be which allows of -1 48 a near-bottom flow velocity effective in the interbaffle space of up to 0.25 ml/s, which is quite sufficient for displacing the barren-rook grains smaller than 1 mm.

With the aforespecified parameters of the herein- 6 proposed device the herein-proposed method is carried into effect in a way similar to that described in Examnple 1, whereby the attainable degree of gold extraction approximates 98 with a concentration factor of 99.

Example 4 The pulp is prepared from a medium-washable rock in the form of sandy loam including 85 Iv of sand and 15 of clayey and dustlike fractions with the content of large sand grains (over 2.0 mm) up to 1.2 and the gold content of I g/m 3 mainly in the form of grains sized over 1.15 mm (grains sized below 0.15 mm being not more than 1.5 by weight of a total amount of grains).

When preparing the pulp use is made of water as the liquid phase, the solid/liquid phase ratio being selected as 1:15. The pulp is fed at a flow rate of 0.05 m 3 /s (that is, 360 m 3 per day) to the processing zone which appears as a rectangular cross-section inlet section and two additional sections butt-Joined together and with the inlet section and turned transversely at an angle of the direction of turn of the sections with respect to each other alternating periodically. The sections are arranged with a slope of go, 90, and The trapping coating in the sections is established with 49 the aid of riffles with baffles that make up an angle of 850 with the bottom.

With the limit size of a gold grain equal to 0.15 mm, the trapping noating is established by making use of baffles featuring the spacing/height ratio thereof equal to 2.5. In this case the stream depth over the baffles equals 3.5*10 2 m and the baffle height is assumed to be 4*10 2 m, the baffle spacing being 0.1 m.

With said stream and trapping coating parameters the pulp stream velocity in the first and second sections reaches 1.65 m/s. A decreased slope of the third section enables the stream velocity to be reduced to 1.2 m/s, which makes possible intensification of the pulp processing procedure in the first and second sections and ensuring better trapping of small-sized grains in the third section. With the aforestated pulp stream flow rate, slope, depth, and velocity, the width of the first and second sections is 0.85 m, that of the third section, 1.2 m.

The slope of the baffles to the horizon line is adopted for sandy loam not to exceed O8 insofar as the presence of clayey and dustlike fractions in the pulp promotes sliding of the barren-rook particles lengthwise the baffles.

The angle of transverse turn is 6.50 which allows of attaining a near-bottom flow velocity effective in the interbaffle space of about 0.5 m/s, which is quite I- r 50 sufficient for displacing the barren-rock grains smaller than 2.0 mm.

With the aforespecified parameters of the hereinproposed device the herein-proposed method is carried into effect in a way similar to that described in Example 1, whereby the attainable degree of gold extraction approximates 98.5 with a concentration faotor of 82.

Example 110 The pulp is prepared from hard-to-wash rock appearing as clay loam in the form of soil agglomerates including 55 of clay particles, 40 of sand, and 5 of pebble sized under 20 mm. The content of the largest sand particles sized over 2 mm is I by volume, the gold content being 6 g/m 3 largely as grains sized over 0.25 mm (the content of the grains sized below 0.25 mm being not more than .56 by weight of a total amount of the gold grains).

When preparing the pulp use is made of water as the liquid phase, the solid/liquid phase ratio being 1:25.

The pulp is fed at a flow rate of 0.03 rn 3 /s (which corresponds to 1040 mn 3 of rock per day).

The processing zone is shaped as a gradually narrowing inlet section, wherein the pulp stream is accelerated up to a velocity of 3.5 rn/s. With such a velocity stream impingement upon the baffles of the inlet section enables one to effect partial disintegration 51 of the clayey agglomerates. To attain an additional destructive effect with respeot to the agglomerates the four additional sections of the working zone are butt-joined together with a transverse angle of turn of 450' and consecutive alternation of the slope of the additional sections at 130, 811) 130, and 80, which makes it possible to effect additional di~sinteg'ration of the agglomerates at the places of the vertical change in the processing zone. The slope of baffles to the horizon line is assurned to be 450, which allows of creating a near-bottom f low velocity of up to07 ns quite enough for a transverse displacement of pebble and the largest sand particles without an appreciable displacement of the gold grains sized 0.25 mm. The baffles are inclined towards the bottom at an angle of 670 which facilitates displacement of the largest pebble particles by the main stream. The baffles are assumed to be 7/0*10-2 m, the stream depth over the baffles, 3.2*10-2 M, and the baffle spacing, 0.3 mn. With such stream and trapping coating parameters the pulp stream velocity remains to be equal to 3.5 rn/s in the first and third additional sections, and decreases to 2.75 in/s in the second section, and to 2.5 in/s in the fouirth section. To restore the stream kinetic energy, no baff led riffles are installed in the initial portion of the second additional section 1.0 m long. The end portion of the fourth additional section is provided with baffles of 52 the alternating height equal to 7*10 2 m and 5*10-2m and a spacing of 0.1 m, which provides for an efficient trapping of the minutest grains of gold.

With the aforespecified parameters of the hereinproposed device the herein-roposed method is carried into effect in a way similar to that described in Example 1, whereby the attainable degree of gold extraction is equal to 97.5 with a concentration factor of 73.

Thus, the herein-proposed method and device are capable of increasing the degree of extraction and concentration of the valuable component from the pulp of the rook being processed in a simplest way without external power input.

Industrial Applicability The present invention is applicable for concentrating gold- and iron-bearing ores, coal preparation, as well as for dressing any ores that require separation as to density of their components.

The present invention can find most utility when used for concentration of gold-bearing ores of all types of washing.

pl~s*C

Claims

1. A method for dressing useful minerals, predominantly, gold-bearing ores, consisting in that the pulp under pr ~cessing is fed to tL, processing zone, said pulp containing a liquid phase an r a solid phase that incorporates the grains of the valuable component to be trapped during pulp processing, and barren-rook particles to be removed during pulp processing, a stream of said pulp under processing is established, then accelerated and is made to advance lengthwise the processing zone, wherein a trapping coating is established, the trapping coating is filled with the valuable component grains, the trapping capacity of the coating is restored concurrently with its being filled with the valuable component grains, whereupon the trapping coating filled with the acoumulated valuable component is rinsed out; according to the invention, in order to restore the trapping capacity of the coating, developing stationary vortices in the course of the stream advancement over the initial section at the lower boundary thereof, said vortices having an axis of rotation oriented square with the direction of the pulp stream feed, filling the trapping coating with the grains of the valuable component concurrently with restoring the trapping capacity of the covering, and rinsing out the trapping coating carrying the aocumula- a~3 I 54 ted valuable component; according to the invention, in order to restore the trapping capacity of the coating a flow resistance is built up in the processing zone to the stream longitudinal motion, said flow resistance being nonuniform as for stream length and width; stationary vortices are established at the lower stream boundary, the axis of rotation of said vortices being oriented at an angle to the stream feed, said vortices being aimed at acting upon the particles of the pulp solid phase at an orbital velocity that exceeds the fall velocity of the barren-rook particles but are lower than the velocity of valuable-component grains being trapped; when the pulp stream advances over the pro- cessing zone it is deflected crosswise from the direoti- on of its feed, a dynamic action is exerted upon the lateral stream boundaries, and a spiral flow is established whose axis aligns with the direction of the deflected pulp stream.

2. A method according to Claim 1, CHARACTERIZED in that the pulp stream is deflected transversely to an angle of from 0.5 to 32 A method according to Claim 2, CHARACTERIZED in that the stationary vortices are so formed that the angle at which the axis of rotation of each stationary vortex is oriented to the direction of the stream feed, is substantially equal to the angle of the stream transverse deflection. 55

4. A method according to Claim 1, CHARACTERIZED in that as the stream advances over the processing zone it is additionally deflected crosswise while alternating the orientation of the deflection.

5. A method according to Claim 2, CHARACTERIZED in that as the stream advances over the processing zone it is subjected to additional local acceleration.

6. A method according to Claim 2 or 3, CHARACTERI- ZED in that as the stream advances over the processing zone, the flow resistance offered to its longitudinal motion is either decreased or increased locally, or else the stream be deflected vertically by curving its lower boundary.

7. A method according to Claim 2 or 3, CHARACTERI- ZED in that as the stream advances over the processing zone it is deflected vertically by curving its lower boundary.

8. A device for dressing useful minerals, predomi- nantly gold-bearing rook, comprising an inlet section and at least one additional section consecutive- ly butt-joined together and arranged at an angle to the horizontal plane in the direction of the pulp stream feed, each of the sections having side walls 4) and a.bottom 6) which carries detachable riffles 8) having baffles 10, 10') positioned with a slope (W1, W2, 3s) towards the respective bottom 5) in the direction of the stream feed, the baffles of the I i u 56 inlet section making right angles with the side walls thereof and being parallel to one another, CHARACTERIZED in that the additional section is so turned transversely either side with respect to the inlet section that an acute angle between the longitudinal axes (a and bj) of' both sections is within and 450, and the baffles (10, 10 of thea riffles (8) of the additional section are turned to the side opposite to the direction of turn of said section (2) relative to the inlet section and are arranged at an acute angle (oj) to the side walls of the additional section so as to make up an acute angle (y)with the baffles of the inlet section

9. A device according to Claim 8, CHARACTERIZED in that the acute angle (yj) between the baffles of the inlet and additional sections 2) is substantially equal to the acute angle (oai) between the longitudinal axes (a and bl) of said sections. A device according to Claim 9, CHARACTERIZED in that when making use of at least two additional sections 11), a second additional section (11) is positioned with respect to the preceding additional section (2) with a transverse turn to either side so that an angle (c2) between the longitudinal axes b2) of' the res- pective inlet section and the second additional section (1i) is within 0.5 and 450, and baffles (12) of riffles (13) of the second additional section are 57 turned in a direction opposite to the direction of turn of said section (11) relative to the preceding additio- nal section and are arranged at an acute angle (02) to side walls (14) of its section (1i) so as to make up an acute angle (r2) with the baffles of the inlet section

11. A device according to Claim 10, CHARACTERIZED in that the acute angle (T2) between the baffles 12) of the inlet section and of the second additional section (11) is substantially equal to the acute angle between the longitudinal axes b 2 of said sections.

12. A device according to Claim 9, CHARACTERIZED in that when at least three additional sections 11, 16) are made use of, each of the next additional sections (11, 15, 16) is butt-joined with the preceding additio- nal section 11, 15) and is turned transversely with respect to the inlet section in a direction opposite to the direction of turn of the preceding additional section 113 16) relative to the inlet section (1. 13 A device according to Claim 8, or 10, or 12, CHARACTERIZED in that at least one baffle (10 or 10') in at least one additional section has a height (hi or h2) which is either greater or lesser than a height (H) of the baffles in the inlet section (M.

14. A device according to Claim 8, or 10, or 12, CHARACTERIZED in that a bottom (18) of at least one I I 58 additional section (15) is at least partially convex or concave, A device according to Claim 8, or 10, or 12, CHARACTERIZED in that a bottom (19) of at least one ad- ditional section (15) is sinusoidal.

16. A device according to Claim 8, or 10, or 12, CHARACTERIZED in that at least one of the next additional sections 11, 15, 16) is butt-joined with the preceding additional section 2, 11, 15) in such a manner that its slope (p2, ys, p4. 5 to the horizon- tal plane is either greater or lesser than the slope (91, 92, T3, 94) of the preceding section (1, 2, 11,

17. A device according to Claim 8, or 10, or 12, CHARACTERIZED in that at least one baffle (10 or 10') in at least one additional section be so positioned that its slope g or ws) towards the respective bottom is either greater or lesser than the slope (wi) of each baffle of the inlet section towards the respective bottom

18. A device according to Claim 8, or 10, or 12, CHARACTERIZED in that in at least one additional section (11) the riffles (24) with the baffles (12) are provided on a part of the bottom (25) thereof.

19. A device according to Claim 8, OHARAOTERIZED in that at least one additional section (21) has side walls curved and parallel to each other, and that each 59 baffle (22) of riffles (23) in said additional section (21) runs along a line the tangent to which passes at each point at an acute angle (r3) to the baffles of the inlet section and said acute angle (r3) is substantially equal to an angle (d3) between the longitudinal axis of the inlet section and the longitudinal axis (b 3 of said additional section (21) passing through said given point A device according to Claim 8, or 10, or 12, CHARACTERIZED in that at least the outlet portion of the bottom of the last section is perforated and the perforations can be shut up periodically. i 1111 60 METHOD AND DEVICE FOR DRESSING USEFUL MINERALS Abstract of the Disclosure The herein-proposed method for dressing useful minerals, predominantly gold-bearing rook, consists in that fed to the proooessing zone is the stream of the pulp under processing, containing valu-'le-component grains and barren-rook particles, a trapping coating is established in the processing zone to be filled with the valuable-component grains. The process of filling the trapping coating with the valuable-component grains proceeds concurrently with restoration of the trapping capacity of the coating, for which purpose a flow resistance nonuniform as for the stream length and width is created, offered to the stream longitudinal motion, stationary vortices are established in the lower stream portion, the axis of rotation of each of the vortices being oriented at an angle to the direction of the pulp stream flow, which vortices acting upon the barren-rook particles with an orbital velocity exceeding the fall velocity of the barren-rook particles and being lower than the fall velocity of the valuable-component grains; while advancing over the processing zone the pulp stream is deflected transversely and a spiral flow is developed whose axis aligns with the direction of flow of the deflected stream. The herein-proposed device for dressing useful pl -B I 61 minerals comprises an inlet section and at least one additional section consecutively butt-joined together, the additional section being so turned transversely either side with respect to the inlet section that an angle ol) between the longitudinal axes (a and bl) of both sections is within 0.5 and 450, and the baffles (10) of the riffles of the additio- nal section are turned to the side opposite to the direction of turn of said section relative to the inlet section and are arranged at an angle (Bi) to the side walls of the additional section so as to make up an acute angle (yi) with the baffles of the inlet section I