RU2448777C2 - Method and device for extraction of fine gold - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to extraction of minerals by dredging and may be used in placer mining. Proposed method comprises grading initial material to fineness and density, precipitating suspended particles and accumulating them on troughs. Initial material is hydraulically graded to fineness of -2 and +2 mm. Note here that +2 mm-material is directed to processing and extraction of gold while -2 mm-material is subjected to grading to -2 mm- and +2 mm-flows. Flows are accelerated to 0.5-1.0 m/s and gold particles are settled in troughs while rock particles are discharged. Proposed device comprises channel for pulp flow with initial material. It comprises also self-cleaning screen with 2 mm slit to divide the flow into two channels with particle size of +2 mm and -2 mm. Self-cleaning screen with 0.2 mm-slit is arranged in channel for particles of -2 mm, for dividing the flow into channels with 0.2 mm-particles and into channel woth -0.2+2 mm-particles. Said channels incorporate device for grading particles to density and are made up of set of arrow-shaped plates with angle of 60-65° and top edge inclination of 70-75° toward the flow, troughs for gold particles arranged under apparatuses. Note also that plate widths depends upon flow rate and terminal rate of rock and gold particle deposition in compliance with the formula

at 0.5 m/s≤U≤1.0 m/s, where L is plate width, m; V_m is pulp flow rate, m/s; g is gravity acceleration, m/s²; 9.8 m/s², k is constant, π=3.14; U_RD rock deposition terminal rate, m/s; U_GD is gold deposition terminal rate, m/s.

EFFECT: higher yield of gold.

2 cl, 4 dwg, 1 tbl

Description

The invention relates to the extraction of minerals by dragee method and enrichment and can be used in the development of alluvial deposits.

A known method and device for flotation gold recovery during drainage development of placer deposits [1], which allows to increase the efficiency of extraction of a valuable component, taking into account all size classes. The device includes a storage tank for collecting ephels, installed at the end of the tail deck, from which the pulp under pressure is fed into the aerator unit. When transporting the pulp to the aerator unit, it is saturated with reagents and partially aerated, and from the aerator unit, the pulp is unloaded by gravity into a dredging pit where the flotation process is carried out. The foam product from the surface of the dragee pit is removed by a foam trough. From the foam trough, the foam concentrate is forcibly pumped to the flotation concentrate tank. Depending on the quality of the foam product, the flotation concentrate is brought directly to the dredge to the required condition or sent to a metallurgical plant for subsequent enrichment.

The disadvantage of this method is the use of chemicals that pollute the environment.

There is a method of processing sands of placer gold deposits [2], which consists in the fact that the sands are mined by bulldozers, excavators, dredgers or dredges and fed to concentrators mounted at the place of extraction of sands, where enrichment takes place to obtain collective concentrate, and then collective concentrate processed on finishing equipment to the state of crude metal, characterized in that the collective concentrate from the place of extraction of sand is transported to a gold recovery enterprise And fine-tuning to the state of collective concentrate crude metal lead using the methods of enrichment hydrometallurgy, pyrometallurgy, and other technologies ore processing waste and finishing of bulk concentrate is placed in metal containers in spetshranilischah.

The disadvantage of this method is the need to use special storage.

A known method of developing oil and gold [3], which provides for the extraction of gold from sand reservoirs after the process of oil production. The inventive method according to the method of sand reservoirs containing oil and gold, pumping oil through production wells. Chlorine water is pumped into injection wells to maintain reservoir pressure at pH no higher than 4. When chlorine water moves from injection to production wells, it is saturated with gold as a result of its dissolution in chlorine water. Gold-containing solution is pumped out. In the case of conditioned concentrations of gold in the solution, it is sent to the processing stage for the extraction of gold. The solution is again chlorinated and fed into injection wells.

The disadvantage of this method is the use of chlorine, forming compounds of a high hazard class and harmful to the environment and humans.

There is a method of ore preparation of industrial waste for heap leaching of gold [4], which can be used in the stage of ore preparation of tailings of an extraction plant and off-balance ore of underground mining before heap leaching of gold. The technical result of the invention is to increase the efficiency of extraction of gold from industrial waste with a low gold content. It is achieved due to the fact that they perform ore preparation by joint pelletizing off-balance ore with a gold content of at least 0.5 g / t (50%) and stale tailings (50%) with the addition of cement 2-2.2 kg / t.

The disadvantage of this method is the difficult preparation of the source material.

A known method of dry beneficiation of placer gold ore [5] using a gravity-pneumatic system, which consists in the fact that dry placer gold ore is crushed in centrifugal impact mills to a size of 1.0 + 0.05 mm, dried to a relative humidity of 10- fifteen%. Ore is poured into the hopper, at the exit of which a slot with a width of 1.1 mm is placed, which passes into a conical flat tray, inside which a flat slotted nozzle is placed. Using a nozzle form a slotted injector. Compressed air is supplied to the nozzle using a compressor through a receiver and gearbox and the crushed ore is taken from the hopper and sprayed with a flat, film-shaped stream into the separator. With the expiration of a flat stream using the effect of sail and gravity split into two streams. The lower stream contains platinum metals and gold, and the upper stream contains particles with a windage an order of magnitude greater than the windage of particles of the lower stream. The separation is carried out using an adjustable protrusion, after which the platinum metal concentrate together with gold is collected in the separator hopper and conveyed to the final gold extraction operation with a conveyor. The remaining elements and compounds located in the ore are sent to the dump. They prevent the possibility of clogging the slit injector using sieves and installing a mechanical vibrator on the injector surface with a frequency of 150-250 Hz and an amplitude of up to 2g. Providing selective separation of ore into two fractions is carried out by an adjustable swivel protrusion with a control electric drive. EFFECT: increased gold recovery from poor alluvial gold ore, as well as ensuring all-season gold mining in the northern regions of the country.

The disadvantage of this method is the high-energy technology for the preparation of the source material: grinding and thermal drying.

Known [6] is an apparatus for centrifugal separation of mixed substances with different specific gravities, which contains a centrifuge basket having many ring elements on the peripheral surface. The outer basket has a casing from which water is injected through openings into the inner cavity of the basket into the recesses between the annular elements. The feed materials containing gold and mercury are separated so that gold and mercury are collected in recesses. Liquid mercury is discharged through openings in the inner basket to the inner surface of the outer basket, on which an annular receiver is provided and which is profiled to allow accumulation of mercury in the receiver axially spaced from the open neck of the basket. A plurality of outlet openings in the annular receiver allows the release of mercury into a second tray inside the outer tray for the main discharge of materials from the open neck. Liquid mercury therefore collects and accumulates separately from the heavy solids inside the basket and separately from the unloaded light materials.

The disadvantage of this method is the use of centrifuges, which require the cost of separation of substances by density.

The closest technical solution adopted for the prototype is a device for cleaning process water from suspended particles [7], including a housing, a partition made in the form of parallel plates installed with gaps to each other at an angle to the horizontal plane, and the plates are tilted the upper edge towards the flow, and the lower edge of each previous plate is overlapped by the upper edge of the subsequent plate, characterized in that the plates are installed at an angle of 40-55 ° to the horizontal plane, each eduyuschaya plate spaced from the previous one by a distance equal to 0.8-1.0 the plate width and the lower edge of each plate is covered previous upper edge of the plate followed by adjustment by an amount equal to 0.1-0.2 the plate width.

The objective of the invention is to reduce costs and increase recovery of finely divided gold from ore tailings.

The solution to this problem is achieved by the fact that the source material is hydraulically separated by size according to the classes of -2 and +2 mm, while the +2 mm material is sent for processing and gold recovery by known methods, for example, hydrometallurgy, pyrometallurgy, and the material with a particle size of -2 mm classifications of flows by classes of -0.2 mm and +0.2 mm, while flows are attached to 0.5 m / s and 1 m / s, respectively, and provide directional deposition of gold particles into pallets and removal of rock particles to discharge.

A device that implements a method of extracting finely dispersed gold contains a self-cleaning sieve with a 2 mm gap for separating the stream into two channels with particle sizes of 2 mm and +2 mm, a self-cleaning sieve with a 0.2 mm gap for separation is installed in the particle channel - 2 mm the flow into the channels with particles - 0.2 mm and into the channel with particles + 0.2 ÷ -2.0 mm, while in the channels there are devices for separating particles by density, made as a set of arrow-shaped plates with an angle of 60-65 ° and a slope of 70-75 ° to the upper edge towards the flow and spaced along the length of the channel, as well as includes trays for collecting gold particles under apparatuses installed in addition, the width of the plates is made of devices, depending on the flow velocity and the terminal velocity of sedimentation of waste and gold particles by the formula

,

,

where L is the width of the plate, m;

V _m - pulp flow rate, m / s; V _m = 0.5 m / s and V _m = 1.0 m / s, respectively;

g - gravitational acceleration, m / s ² ; g = 9.8 m / s ² ;

π is a constant, π = 3.14;

U _CP - the final sedimentation rate of the rock, m / s;

U _KZ - the final sedimentation rate of gold, m / s.

The method and device for the extraction of fine gold is illustrated by drawings:

figure 1 - diagram of the technological classification of suspended particles by size and density with a General view of the apparatus for the directional deposition of gold particles in pallets (top view);

figure 2 is a longitudinal section of the sleeve of the channel with the deposition apparatus;

figure 3 is a view of the apparatus along section aa;

figure 4 - dependence of the final deposition rates of suspended particles of gold and rock in still water and at a flow velocity of 0.5-1.0 m / s

The following conventions are adopted in the drawings: 1 - common channel; 2 - self-cleaning sieve with a slot size of 2 mm; 3 - output sleeve of a common channel for issuing particles for processing by known methods; 4 - technological sleeve of the common channel; 5 - self-cleaning sieve with a slot size of 0.2 mm; 6 - output sleeve of the channel for the pulp with the size of suspended particles + 0.2 ÷ -2.0 mm; 7 - output sleeve of the channel for the pulp with the size of suspended particles - 0.2 mm; 8 - apparatus for separating suspended particles by density; 9 - pallets; 10 - rock particles; 11 - gold particles; α is the hydraulic angle of the channel; β - swept angle of the plates; γ is the angle of inclination of the plates.

The method is implemented by double sequential classification of suspended particles in the pulp stream by size and sieving them at the bottom of the channel by density (Fig. 1) due to the deposition properties of gold and rock particles, resulting from the dependence of the final deposition rate of suspended particles in standing water on their size and density determined by the formula

where U _to - the final deposition rate of suspended particles in stagnant water;

g - gravitational acceleration, 9.8 m / s ² ;

With _l - drag coefficient (particle flow), 0.35;

ρ _m is the density of the solid particle, kg / m ³ ;

ρ _in - the density of water, kg / m ³ ;

R is the particle radius, m;

d is the thickness of the "boundary" layer of particles and their "parachute" effect, m

The sedimentation rate of suspended particles U _o in a stream of water moving at a speed of V, m / s, is determined by the formula

,

,

V _m is the pulp flow rate, m / s.

The ratio of the deposition rates of gold and rock particles in the size range of less than 2 mm remains almost constant and equal to

U _KZ / U _KP = 11.1,

where U _CP - the final sedimentation rate of rock particles, m / s;

U _KZ - the final sedimentation rate of gold particles, m / s.

The calculation results are presented in table 1 and figure 4.

A device for implementing the method of extracting fine gold works as follows.

The pulp of the source material with a concentration by volume of solid and liquid T: L = 1: 5 ÷ 1: 7 is fed into channel 1, providing a pulp speed of ≈ 1 m / s in it, the channel is inclined to the horizontal plane at an angle of α-4 ° ( slope 0.07) on a sieve with self-cleaning slits 2 mm wide, the flow is divided into two sleeves. A pulp with a suspended particle size of +2.0 mm leaves for the extraction of gold particles by known methods, and a pulp with a suspended particle size of -2 mm passes to a sieve with self-cleaning slots with a slit size of 0.2 mm, and the flow is divided into two sleeves.

A pulp with a particle size of + 0.2 ÷ -2.0 mm passes through the output sleeve 6 and a pulp with a particle size of 0.2 mm passes along the output sleeve 7. Pulp flows in sleeves 6 and 7 are directed to a density-based particle classification apparatus 8, in which gold particles 11 settle into pallets 9 installed on the bottom of the channel, and rock particles 10 slide along inclined plates and are carried out by water from inter-plate slots from the apparatus to discharge, which, after clarification, returns to form a pulp stream with the starting material.

Table 1 Final velocity calculation results for suspended gold and rock particles Particle radius R, m The thickness of the boundary layer d, m For rock particles p = 2650 kg / m ³ For gold particles = 19300 kg / m ³ Final speed U _k , m / s The deposition rate at a flow velocity of V = 0.5 m / s
U ₀ , m / s V = 1.0 m / s
U ₀ , m / s Final speed U _k , m / s The deposition rate at a flow velocity of V = 0.5 m / s
U ₀ , m / s The deposition rate at a flow rate of V = 1.0 v / s
U ₀ , m / s 5 · 10 ^-6 6.15 · 10 ^-4 2.73 · 10 ^-4 8.65 · 10 ^-6 2.17 · 10 ^-7 3.0310 ^-3 9.60 · 10 ^-5 2.41 · 10 ^-6 10 ^-5 5.8610 ^-4 8.01 · 10 ^-4 5.0510 ^-5 1.25 · 10 ^-6 8.88 · 10 ^-3 5.60 · 10 ^-4 1.39 · 10 ^-5 10 ^-4 3.17 · 10 ^-4 3.6310 ^-2 2.20 · 10 ^-3 5.7 · 10 ^-4 4.0310 ^-1 2.44 · 10 ^-2 6.32 · 10 ^-3 10 ^-3 8.70 · 10 ^-4 2.56 · 10 ^-1 1.37 · 10 ^-1 1.15 · 10 ^-1 2.8410 ⁰ 1.9210 ⁰ 1.28 · 10 ⁰

LITERATURE

1. RF patent No. 2262987. Method and device for flotation gold recovery during drainage development of placer deposits. IPC B03D 1/00, B03B 7/00. Author (s) and patent holder (s): Usmanova N.F., Bragin V.I., Mikhailov A.G. Claim 02/11/2004. Publ. 10/27/2005.

2. Application for invention No. 98108071/03. A method of processing the sand of placer gold deposits. IPC C02F 1/46, B01D 35/05. Applicant: Amur Scientific Center of the Far Eastern Branch of the Russian Academy of Sciences, Author (s): Kuzminykh V.M., Moiseenko V.D. Claim 04.24.1998. Publ. 02/10/2000.

3. RF patent No. 2152512. A method of developing oil and gold. IPC Е21В 43/16, Е21В 43/28. Patent holders): OJSC Uralkali. Author (s): Belkin V.V., Nikolaev A.S. Claim 07/14/1998. Publ. 07/10/2000.

4. RF patent №2309804. The method of dry beneficiation of placer gold ore. IPC V07V 4/00. Patentee (s): Chita State University (ChitSU). Author (s): Shumilova L.V., Reznik Yu.N., Rubtsov Yu.I. Claim 03.03.2005. Publ. 09/20/2006.

5. RF patent No. 2152512. A method of developing oil and gold. IPC С22В 11/08. Patent holder (s) and author (s): Adamovich B.A., Dudov V.I., Derbichev Akhmed-Giri Bamatgireevich. Claim 03/02/2006. Publ. 11/10/2007.

6. Application for invention No. 94019326/02. apparatus for centrifugal separation of mixed substances with different specific gravities. IPC С22В 3/00, С22В 3/02. Patentee (s) and author (s): Benjamin Nelson [CA]. Claim 06/02/1994. Publ. 04/10/1996.

7. RF patent No. 2345815. A device for purifying process water from suspended particles. IPC B01D 21/02. Patent owners and authors: Senkus Vas.V., Fomichesv S.G., Senkus V.V., Stefanyuk B.M., Senkus Val.V. Claim 01/31/2006. Publ. 02/10/2009.

Claims (2)

1. The method of extraction of finely divided gold, including the classification of the source material by size and density, the deposition of suspended particles and their accumulation on trays, characterized in that the source material is hydraulically separated by size according to the classes -2 mm and +2 mm, while the material +2 mm is sent for processing and extraction of gold, and material with a grain size of -2 mm is re-classified into flows of classes -0.2 mm and +0.2 mm, while the flows are given a speed of 0.5-1.0 m / s and provide directional deposition of gold particles into a pan s and removal of rock particles to discharge. 2. A device that implements a method of extracting fine gold, including a channel for the flow of pulp with the source material, characterized in that it contains a self-cleaning sieve with a slit of 2 mm for separating the stream into two channels with particle sizes of +2 mm and -2 mm, in the channel for for particles of -2 mm, a self-cleaning sieve with a slit of 0.2 mm is installed to separate the flow into channels with particles of -0.2 mm and into the channel with particles -0.2 + 2 mm, while in the channels there are devices for separating particles by density, made as a set of arrow-shaped plates with an angle of 60-65 ° and inclined 70-75 ° with the upper edge facing the flow and spaced along the length of the channel, and also contains trays for collecting gold particles installed under the apparatus, in addition, the width of the apparatus plates is made depending on the flow velocity and the final deposition rates of the rock and gold particles according to the formula :

at 0.5 m / s≤V _m ≤1.0 m / s,
where L is the width of the plate, m;
V _m - pulp flow rate, m / s;
g - gravitational acceleration, m / s ² ; g = 9.8 m / s ² ;
π is a constant, π = 3.14;
U _CP - the final sedimentation rate of the rock, m / s;
U _KZ - the final sedimentation rate of gold, m / s.

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