A two-stage leaching cyanide gold extraction system and control method

Abstract

The present invention provides a two-stage leaching cyanide gold extraction system and a control method, the system includes a subsystem A for one-stage leaching and carbon adsorption, a subsystem B for two-stage leaching and washing, a stirring barrel for supplying slurry to the A subsystem, and a filter press for filtering and washing the slurry discharged from the B subsystem. The three-way valve on the U-shaped pipe of the A subsystem is connected to the B subsystem through a slurry pipe. A submersible pump is arranged in the cylindrical barrel of the B subsystem, and the submersible pump is connected to the A subsystem through a liquid replenishment pipe. The U-shaped pipe of the B subsystem is connected to the filter press through a slurry pump. Compared with conventional technology, the system of the present invention reduces investment costs by 89%, reduces floor space by 60%, reduces energy consumption of leaching and carbon adsorption operations by 60%, reduces labor costs by 53%, increases cyanide leaching rate by 1.2%, increases cyanide washing rate by 1.8%, and increases carbon cyanide adsorption rate by 4.4%.

Description

Technical Field

[0001] The invention belongs to the technical field of precious metal refining and relates to a cyanidation gold extraction system. Background Art

[0002] Cyanide gold extraction mainly includes ore pretreatment, leaching, washing, carbon adsorption, cyanide residue dehydration and other steps. Among them, leaching is the process of dissolving gold in oxygen-containing cyanide solution; washing is the process of reducing the gold ion concentration of the gold-containing solution after leaching; carbon adsorption is the process of recovering gold ions from the gold-containing solution after cyanide leaching by adsorption of activated carbon. Cyanide gold extraction involves factors such as gold particle state, ore pulp concentration, cyanide (or environmentally friendly gold extraction agent) concentration, oxygen concentration, pH value and leaching time.

[0003] The traditional cyanide leaching device is a mechanically stirred leaching tank, the tank body of which is made of rolled and welded steel plates, with a hollow shaft and a stirring impeller in the middle. The hollow shaft plays an aerating role, and the impeller plays a stirring role in the slurry. The traditional cyanide washing device is a single-layer or multi-layer thickener, which reduces the gold ion concentration of the gold-containing solution in the slurry through the countercurrent washing principle to form a precious solution and a lean solution. The cyanide gold extraction system composed of the above-mentioned devices generally has the disadvantages of large footprint, high engineering cost, long construction period, many operators, high operating cost, and high energy consumption, which greatly limits the construction or expansion of the cyanide gold extraction system.

[0004] On the other hand, most of the existing cyanide gold extraction systems perform leaching at a relatively low pulp concentration of 30-40%. The concentration of cyanide (or environmentally friendly gold extraction agent) in the pulp is limited, and the gold particles dissolve slowly. At the same time, conventional mechanical stirring has weak force and cannot achieve sufficient dispersion and mixing of gold particles, cyanide (or environmentally friendly gold extraction agent), and oxygen. The collision probability is not high, which limits the intensity of the leaching chemical reaction. Therefore, the existing cyanide gold extraction system generally has the problem of low leaching efficiency.

[0005] Thirdly, the existing cyanide gold extraction system uses lean liquid for countercurrent washing in a single-layer or multi-layer thickener. In production, due to construction cost considerations, the volume of the thickener is limited, the washing effect is poor, and lean liquid is mostly used for cyanide residue filter pressing and backwashing. There is a general problem of low washing efficiency and a high loss rate of valuable metals. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a two-stage leaching cyanide gold extraction system and a control method, which firstly reduces the system investment cost, floor space and operation cost; secondly, further improves the washing efficiency and minimizes the loss of valuable metals; and thirdly, further shortens the leaching time and improves the leaching efficiency.

[0007] The technical scheme of the present invention is as follows: a two-stage leaching cyanide gold extraction system, comprising an A subsystem for one-stage leaching and carbon adsorption, a B subsystem for two-stage leaching and washing, a stirring barrel for supplying slurry to the A subsystem, and a filter press for filtering and washing the slurry discharged from the B subsystem, the B subsystem comprising a collecting cone, the upper end of which is connected to a cylindrical barrel; the B subsystem also comprises a U-shaped tube and a water supply pipe, the feed end of the U-shaped tube is connected to the collecting cone, and the discharge end is inserted into the collecting cone; the straight pipe section of the U-shaped tube is connected in series with a gas-liquid mixer; the gas-liquid mixer comprises an outer shell connected to the U-shaped tube, the outer shell is connected to the lower end of the water supply pipe through a liquid inlet pipe with a water inlet valve, and the upper end of the water supply pipe is connected to the cylindrical barrel; the liquid inlet pipe is also connected to a drug inlet pipe; the outer shell is also connected to an air inlet pipe; and a gas supply pipe connected to the air inlet is installed inside the outer shell. A bubbler connected with a pipe and used to diffuse air into bubbles; subsystem A further includes a carbon adsorption tank installed above the cylindrical barrel on the basis of subsystem B; the carbon adsorption tanks are multiple and connected in series, the water inlet pipe of the first-stage carbon adsorption tank is connected with a second submersible pump located in the cylindrical barrel of subsystem A, and the water outlet pipe of the last-stage carbon adsorption tank is connected with the cylindrical barrel of subsystem A; subsystem A also includes a three-way valve connected to the U-tube of subsystem A, and the three-way valve is connected with the collecting cone or cylindrical barrel of subsystem B through the second slurry pipe; a third submersible pump is arranged in the cylindrical barrel of subsystem B, and the third submersible pump is connected with the cylindrical barrel of subsystem A or the collecting cone of subsystem A through the second liquid replenishment pipe; the U-tube of subsystem B is connected with a second slurry pump, and the second slurry pump is connected with the filter press through the third slurry pipe.

[0008] Preferably, the mixing barrel is connected to the cylindrical barrel of subsystem A or the collecting cone of subsystem A through a first slurry pipe; a first submersible pump is arranged in the cylindrical barrel of subsystem A, and the first submersible pump is connected to the mixing barrel through a first liquid replenishing pipe.

[0009] Preferably, the liquid discharge end of the filter press is connected to the cylindrical barrel of subsystem B or the material receiving cone of subsystem B through a third liquid replenishment pipe; the filter press is also connected to a clean water pipe with a control valve.

[0010] Preferably, the connection point between the drug inlet pipe and the liquid inlet pipe is located between the water inlet valve and the shell; the drug inlet pipe is provided with a drug inlet check valve and a drug inlet valve; the air inlet pipe is provided with an air inlet check valve and an air inlet valve.

[0011] Preferably, the collecting cone and the cylindrical barrel are both made of galvanized canvas.

[0012] Preferably, the installation position of the gas-liquid mixer is determined by calculation according to Formula 1;

[0013] Formula 1: h=0.0981P+H;

[0014] Where h is the vertical distance between the lower end of the gas-liquid mixer and the system liquid level, m;

[0015] P—discharge pressure at the discharge end of the U-type tube, kPa;

[0016] P=200+( φ -10) × 5;

[0017] φ —Diameter of the cylinder, m;

[0018] H—vertical distance between the highest point of the U-tube and the system liquid level, m;

[0019] The air consumption is determined by calculation according to Formula 2;

[0020] Formula 2: ;

[0021] Where V 0 —Air consumption per unit volume of slurry, m 3 / m 3 ;

[0022] h—vertical distance between the lower end of the gas-liquid mixer and the system liquid level, m;

[0023] ρ n —Density of slurry mixed with air, t / m 3 ;

[0024] ρ n =ρ m / 2;

[0025] ρ m —Density of slurry before mixing with air, t / m 3 ;

[0026] The air pressure fed through the air intake pipe 21 is calculated and determined according to formula 3;

[0027] Formula 3: P 1 =1.2×(9.81hρ m +100);

[0028] Where P 1 —Minimum working pressure of compressed air, kPa;

[0029] h—vertical distance between the lower end of the gas-liquid mixer and the system liquid level, m;

[0030] ρ m —Density of slurry before mixing with air, t / m 3 .

[0031] The control method based on the two-stage leaching cyanide gold extraction system is characterized in that: the slurry is first leached and carbon adsorbed in the A subsystem; after the predetermined leaching and carbon adsorption time of the A subsystem is reached, the water supply pipe of the A subsystem is closed, and the slurry in the U-shaped tube of the A subsystem is lifted and discharged into the collecting cone or cylindrical barrel of the B subsystem with the help of the compressed air of the A subsystem; after the predetermined self-circulation leaching and washing time of the B subsystem is reached, the water supply pipe of the B subsystem is closed, and the second slurry pump is started to discharge the slurry in the B subsystem to the filter press for solid-liquid separation.

[0032] Preferably, before transferring materials from subsystem A to subsystem B, it is necessary to store supernatant in subsystem B, and during the process of transferring materials from subsystem A to subsystem B, the supernatant of subsystem B is introduced into subsystem A to ensure that subsystem A has a stable liquid level during the material transfer process and realize normal operation of air lifting.

[0033] Preferably, during the process of transferring material from subsystem A to subsystem B, the second submersible pump is turned off and the carbon adsorption operation is suspended.

[0034] Preferably, during the solid-liquid separation process, the liquid phase produced by the filter pressing is returned to the B subsystem; after the cyanide residue is formed in the filter chamber of the filter press, clean water with a certain pressure is first fed into the filter chamber, and then the material is discharged.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] During the operation of the system, the high-concentration self-circulation of the slurry in the system is achieved through the gas-liquid lifting device and the siphon effect, and the gold particles, oxygen, and cyanide (or environmentally friendly gold extraction agent) are fully dispersed and mixed by continuously feeding air and sodium cyanide (or environmentally friendly gold extraction agent) solution into the lifter, which promotes the chemical reaction and obtains a higher leaching efficiency. At the same time, the system has a large volume, and can also play a washing role when feeding a lean solution with a low gold ion concentration. Combined with the clean water washing of the filter cake during the filter press dehydration process, a high washing efficiency is guaranteed, which can minimize the loss of valuable metals and achieve water balance. In addition, compared with traditional technologies and equipment, the entire system has a simpler equipment configuration, a larger processing capacity, a smaller footprint, lower operating energy consumption, fewer post personnel, and the main body is made of galvanized canvas, which has a lower production cost, realizing low-cost and efficient operation of cyanide gold extraction operations. Experiments have shown that compared with conventional technologies, the system of the present invention reduces investment costs by 89%, reduces floor space by 60%, reduces energy consumption in leaching and carbon adsorption operations by 60%, and reduces labor costs by 53%; in terms of production indicators, the cyanide leaching rate reaches 95.2%, which is 1.2% higher than conventional technologies; the cyanide washing rate reaches 91.8%, which is 1.8% higher than conventional technologies; and the cyanide carbon adsorption rate is 86.4%, which is 4.4% higher than conventional technologies.

[0037] The beneficial effects of the present invention are described in detail below:

[0038] (1) The system can replace the leaching tank, washing and thickening machine, carbon adsorption equipment, and auxiliary facilities such as the precious liquid tank and the lean liquid tank in the existing technology. The cylindrical tube and the collecting cone are made of galvanized canvas. Under the same processing capacity, the investment can be reduced by 80% compared with the traditional technology, the floor space can be reduced by 50-60%, and the number of positions can be reduced by 50-60%.

[0039] (2) The slurry is self-circulated in the system through the siphon effect of the gas-liquid lifting device and the end of the discharge pipe, which better meets the leaching requirements. Through the concentration effect of the cylindrical barrel and the collecting cone, the leaching operation is carried out at a high slurry concentration and a high reagent concentration. In addition, air and liquid medicine are fed through the lifter to achieve a more complete dispersion and mixing of gold particles with cyanide (or environmentally friendly gold extraction agent) and oxygen. The above factors ensure the efficient occurrence of leaching chemical reactions, make it easy to obtain a higher leaching rate index, and significantly reduce the leaching time.

[0040] (3) The slurry is discharged at a certain initial velocity at the end of the discharge pipe, which continuously flushes the mineral particles deposited at the bottom of the pool, plays a role in forced discharge, solves the problem of reduced leaching volume caused by mineral accumulation, and greatly improves the system processing capacity.

[0041] (4) The leaching device uses the difference in specific gravity of the slurry at both ends of the U-shaped tube and the siphon effect to achieve self-circulation of ore and water. The water entering the lifting device is pressed in by its own weight. The entire system only requires an air compressor to provide an air source. With the same processing capacity, the power operating cost is only 30-40% of that of a conventional cyanide leaching system.

[0042] (5) Since the volume of the second-stage leaching device is large and the solution is a lean solution with a low gold ion concentration, it can also play a washing role during the leaching process. Combined with the clean water washing of the cyanide residue filter cake during the filter press dehydration process, a high washing efficiency is guaranteed, minimizing the loss of valuable metals.

[0043] (6) The whole system has a simple configuration, few process connections, low probability of leakage, and achieves water balance without sewage discharge, thus achieving inherent safety and environmental protection.

[0044] In general, the present invention can greatly simplify the equipment and facilities of the cyanidation gold extraction process, save infrastructure investment, reduce floor space, reduce operating personnel, reduce operation and maintenance costs, and easily obtain higher process indicators, thus having extremely high application value and promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 The figure is a schematic diagram of the overall structure and working principle of an embodiment of a two-stage leaching cyanide gold extraction system of the present invention.

[0046] Figure 2 The figure is a schematic diagram of the structure and working principle of subsystem A in the embodiment of the two-stage leaching cyanide gold extraction system of the present invention.

[0047] Figure 3 It is a schematic diagram of the top view of the structure of subsystem A in the embodiment of the two-stage leaching cyanide gold extraction system of the present invention.

[0048] Figure 4 The diagram is a schematic diagram of the structure and working principle of subsystem B in an embodiment of a two-stage leaching cyanide gold extraction system of the present invention.

[0049] Figure 5 The invention discloses a schematic diagram of the structure and working principle of a gas-liquid mixer in a two-stage leaching cyanide gold extraction system.

[0050] Figure 6 It is a structural schematic diagram of a carbon adsorption tank in subsystem A of a two-stage leaching cyanide gold extraction system according to the present invention.

[0051] Figure 7 The figure is a schematic diagram of the arrangement and working principle of the carbon adsorption tank in the subsystem A of the two-stage leaching cyanide gold extraction system of the present invention.

[0052] Description of reference numerals:

[0053] 1. Mixing barrel; 2. First slurry pump; 3. First slurry pipe; 4. First liquid replenishing pipe; 5. First submersible pump; 6. Second submersible pump; 7. Second liquid replenishing pipe; 8. Second slurry pipe; 9. Third submersible pump; 10. Second slurry pump; 11. Third slurry pipe; 12. Filter press; 13. Third liquid replenishing pipe; 14. Clean water pipe; 15. Collecting cone; 16. Cylinder; 17. U-shaped pipe; 18. Gas-liquid mixer; 181. Shell; 182. Foamer; 183, water inlet valve; 19, water supply pipe; 20, carbon adsorption tank; 201, water inlet pipe; 202, water outlet pipe; 203, carbon adsorption chamber; 204, bottom plate; 205, top plate; 206, water inlet channel; 207, water outlet channel; 208, lower sieve plate; 209, upper sieve plate; 21, air inlet pipe; 211, air inlet check valve; 212, air inlet valve; 22, drug inlet pipe; 221, drug inlet check valve; 222, drug inlet valve. DETAILED DESCRIPTION

[0054] In order to make the technical personnel in this field better understand, the present invention is clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should belong to the scope of protection of the present invention.

[0055] Embodiment 1: System composition embodiment

[0056] like Figure 1 The embodiment of the two-stage leaching cyanide gold extraction system of the present invention includes a subsystem A for primary leaching and carbon adsorption, a subsystem B for secondary leaching and washing, a stirring barrel 1 for supplying slurry to the A subsystem, and a filter press 12 for filtering and washing the slurry discharged from the B subsystem.

[0057] like Figure 4 , wherein the B subsystem includes a material collecting cone 15, the upper end of which is connected to a cylindrical barrel 16 with both upper and lower ends open. It also includes a U-shaped tube 17 and a water supply tube 19, the feed end of the U-shaped tube 17 is connected to the material collecting cone 15, for example, connected to the cone bottom of the material collecting cone 15, and the discharge end is inserted into the material collecting cone 15 from the top of the cylindrical barrel 16 and is as close to the inner wall of the material collecting cone 15 as possible, preferably 0.5-1.0m away from the inner wall of the material collecting cone 15. The straight pipe section (i.e., the longitudinal section) of the U-shaped tube 17 is connected in series with a gas-liquid mixer 18.

[0058] like Figure 5 The gas-liquid mixer 18 includes a shell 181, the lower end slurry inlet and the upper end slurry outlet of the shell 181 are respectively connected to the straight pipe section of the U-shaped tube 17, and the slurry flowing through the U-shaped tube 17 from bottom to top passes through the inner cavity of the shell 181. The shell 181 is connected to the lower end of the water replenishment pipe 19 through a liquid inlet pipe with a water inlet valve 183, and the upper end of the water replenishment pipe 19 is connected and communicated with the cylindrical barrel 16, generally 200-300mm below the liquid level of the cylindrical barrel 16. The liquid inlet pipe is also connected to a drug inlet pipe 22, and a drug inlet check valve 221 and a drug inlet valve 222 are provided on the drug inlet pipe 22. The connection point between the drug inlet pipe 22 and the liquid inlet pipe is located between the water inlet valve 183 and the shell 181. The shell 181 is also connected to an air inlet pipe 21, and an air inlet check valve 211 and an air inlet valve 212 are provided on the air inlet pipe 21.

[0059] A foamer 182 for dispersing air into bubbles is installed inside the housing 181. The foamer 182 is generally in a polyhedral shape, made of polyurethane foam material, and has a plurality of air outlet holes evenly distributed on the side. The foamer 182 is installed inside the housing 181 and connected to the air inlet pipe 21, and the air outlet end of the air inlet pipe 21 is connected to the air outlet hole.

[0060] like Figure 2 and Figure 3 The A subsystem further includes a carbon adsorption tank 20 on the basis of the B subsystem. The carbon adsorption tank 20 is installed just above the cylindrical barrel 16.

[0061] like Figure 6As shown, the carbon adsorption tank 20 includes a tank body with a top plate 205 at the upper end and a bottom plate 204 at the lower end, wherein an upper sieve plate 209 and a lower sieve plate 208 are arranged in the tank body, and the space between the upper sieve plate 209 and the lower sieve plate 208 is a carbon adsorption chamber 203, and the carbon adsorption chamber 203 is filled with activated carbon particles. A water outlet channel 207 is provided between the top plate 205 and the upper sieve plate 209, and the water outlet channel 207 is connected to a water outlet pipe 202, and a water inlet channel 206 is provided between the bottom plate 204 and the lower sieve plate 208, and the water inlet channel 206 is connected to a water inlet pipe 201.

[0062] Furthermore, one or two layers of cotton sail filter cloth are laid on the upper side of the bottom plate 204 and the lower side of the top plate 205 respectively to prevent carbon particles from passing through the sieve holes and discharge, and also play a role in filtering and purifying water quality, further improving the carbon adsorption effect.

[0063] like Figure 7 The carbon adsorption tanks 20 of this embodiment are multiple ones connected in series. The outlet pipe 202 of the previous carbon adsorption tank is connected to the inlet pipe 201 of the adjacent next carbon adsorption tank. The inlet pipe 201 of the first carbon adsorption tank is connected to the second submersible pump 6 through a pipeline. The second submersible pump 6 is located below the liquid level of the cylindrical barrel 16. The outlet pipe 202 of the last carbon adsorption tank is connected to the cylindrical barrel 16. The gold-containing precious liquid is supplied to the carbon adsorption tank 20 through the second submersible pump 6, and the lean liquid is discharged into the cylindrical barrel 16 through the outlet pipe 202 of the last carbon adsorption tank, and the carbon adsorption cycle is carried out.

[0064] Furthermore, the carbon adsorption tank 20 is made of steel plate rolled and welded, and is cylindrical. The bottom plate 204 is welded to the tank body, and the top plate 205 is connected and fastened to the tank body by flanges, bolts, and rubber gaskets. The diameter of the carbon adsorption tank 20 is 1.5-2.0m, and the height is 2.0-2.5m. The number of series connections depends on the gold grade of the precious liquid. In this embodiment, there are six. The carbon adsorption tank 20 is located in the central area directly above the cylindrical barrel 16. During the production process, a second submersible pump 6 is used to pump the supernatant of the cylindrical barrel 16 to the water inlet of the first-stage carbon adsorption tank. The gold-containing precious liquid flows through each tank body from bottom to top in turn to complete carbon adsorption, and finally returns to the cylindrical barrel 16. According to the gold grade of the activated carbon in each carbon adsorption tank, the old carbon is regularly recovered and new carbon is loaded.

[0065] The A subsystem further includes a three-way valve connected to the U-shaped tube 17 on the basis of the B subsystem, two passages of the three-way valve are connected to the U-shaped tube 17, and the third passage is connected to the second slurry tube 8, and the other end of the second slurry tube 8 is connected to the collecting cone 15 or the cylindrical tube 16 of the B subsystem, such as Figure 1 shown.

[0066] One of the U-shaped tubes 17 of the subsystem A is connected to a ore discharge valve for detecting the concentration of the ore pulp.

[0067] Still Figure 1 The discharge end of the mixing barrel 1 is connected to a first slurry pump 2, and the discharge end of the first slurry pump 2 is connected to the cylindrical barrel 16 of the A subsystem or the collecting cone 15 of the A subsystem through a first slurry pipe 3. A first submersible pump 5 is also arranged in the cylindrical barrel 16 of the A subsystem, and the first submersible pump 5 is connected to the mixing barrel 1 through a first liquid replenishing pipe 4.

[0068] A third submersible pump 9 is arranged in the cylindrical barrel 16 of the B subsystem, and the third submersible pump 9 is connected to the cylindrical barrel 16 of the A subsystem or the material collecting cone 15 of the A subsystem through the second liquid replenishing pipe 7.

[0069] Any U-shaped tube 17 of the B subsystem is connected to the second slurry pump 10, and the second slurry pump 10 is connected to the feed end of the filter press 12 through the third slurry pipe 11. The discharge end of the filter press 12 is connected to the cylindrical barrel 16 of the B subsystem or the material collection cone 15 of the B subsystem through the third liquid replenishment pipe 13. The filter press 12 is also connected to a clean water pipe 14 with a control valve.

[0070] The filter press is a commonly used solid-liquid separation equipment, which is generally composed of a frame, a filter plate and a filter cloth. During the production process, the slurry is fed into the filter chamber of the filter press through a slurry pump, the slurry passes through the filter cloth, the solids stay on the filter cloth, and gradually accumulate on the filter cloth to form a filter cake. The filtrate permeates the filter cloth and is discharged as a liquid phase. The working process of the filter press usually includes the following steps: head pressing, feeding, filter cake forming, head loosening and pulling the filter plate to unload the car, and the filter cake is discharged intermittently. The filter press 12 used in the present invention is a cyanide filter press with a backwashing function.

[0071] In the A subsystem and the B subsystem, the cylinder 16 is made of galvanized canvas and is cylindrical. Its diameter determines the system processing capacity and is generally greater than 10m; the height is generally 2-3m, and can be placed on the surface or half underground depending on the situation. During the production process, the upper part of the cylinder 16 is clarified liquid, and the height of the clarified liquid is preferably controlled at 1.0-1.5m, and the lower part is slurry suspension.

[0072] In the A subsystem and the B subsystem, the collecting cone 15 is made of galvanized canvas, in the shape of an inverted cone, and is generally installed below the ground. It is built into a cone recessed in the ground surface, supported by the ground, and connected to the cylindrical tube 16 at the top. During the production process, under the action of gas-liquid lifting and siphoning, the slurry will be discharged at a certain initial velocity at the end of the U-shaped tube 17, continuously flushing the mineral particles deposited on the inner wall of the collecting cone 15, playing a role of forced collection and discharge.

[0073] In the subsystem A and subsystem B, the U-shaped tube 17 is made of seamless steel pipes. During the production process, the difference in specific gravity of the slurry on both sides of the U-shaped tube 17 is used to realize automatic lifting of the slurry. The slurry discharge from the U-shaped tube 17 has a siphon effect. Under the dual effects of specific gravity pressure difference and siphon, the slurry is self-circulated in the system. According to the size of the cylindrical tube 16, multiple U-shaped tubes 17 can be set and evenly distributed. In this embodiment, the number of U-shaped tubes in the A subsystem and the B subsystem is eight respectively.

[0074] In the subsystem A and subsystem B, the gas-liquid mixer 18 is made of seamless steel pipe and iron plate and is a cylindrical sealing structure. The diameter of the gas-liquid mixer 18 is 2.0-2.5 times the diameter of the U-shaped tube 17, and the height of the gas-liquid mixer 18 is 1.2-1.5 times the diameter.

[0075] During the production process, in subsystem A and subsystem B, compressed air, supernatant, sodium cyanide (or environmentally friendly gold extracting agent) solution are continuously fed into the gas-liquid mixer 18 through the air inlet pipe 21, water supply pipe 19 and drug inlet pipe 22. While changing the specific gravity of the slurry on both sides of the U-shaped tube 17, the necessary conditions for the leaching reaction are met, and efficient leaching is achieved.

[0076] The installation position of the gas-liquid mixer 18 is determined by calculation according to Formula 1.

[0077] Formula 1: h=0.0981P+H

[0078] Where h is the vertical distance between the lower end of the gas-liquid mixer and the system liquid level (i.e. the liquid level of the cylindrical tube 16), m;

[0079] P—discharge pressure at the discharge end of the U-type tube, kPa;

[0080] P=200+( φ -10) × 5;

[0081] φ —Diameter of the cylindrical barrel 16, m.

[0082] H—Vertical distance between the highest point of the U-tube and the system liquid level (i.e., the liquid level of the cylindrical tube 16), m.

[0083] The air consumption is calculated according to formula 2.

[0084] Formula 2: .

[0085] Where V 0 —Air consumption per unit volume of slurry, m 3 / m 3 ;

[0086] h—vertical distance between the lower end of the gas-liquid mixer and the system liquid level, m;

[0087] ρ n —Density of slurry mixed with air, t / m 3 ;

[0088] ρ n =ρ m / 2;

[0089] ρ m —Density of slurry before mixing with air, t / m 3 .

[0090] The air pressure supplied through the intake pipe 21 is determined by calculation according to formula three.

[0091] Formula 3: P 1 =1.2×(9.81hρ m +100).

[0092] Where P 1 —Minimum working pressure of compressed air, kPa;

[0093] h—vertical distance between the lower end of the gas-liquid mixer and the system liquid level, m;

[0094] ρ m —Density of slurry before mixing with air, t / m 3 .

[0095] In the A subsystem and the B subsystem, the pipe diameter of the water supply pipe 19 is generally 1 / 5 of the diameter of the U-shaped pipe 17. During the production process, the supernatant in the cylindrical barrel 16 is fed into the gas-liquid mixer 18 by gravity pressure difference, and the sodium cyanide (or environmentally friendly gold extraction agent) solution is continuously and stably fed through the drug feed pipe 22, while further increasing the specific gravity difference of the slurry on both sides of the U-shaped pipe 17, optimizing the gas-liquid lifting effect.

[0096] Embodiment 2: Control method embodiment

[0097] The embodiment of the two-stage leaching cyanide gold extraction system control method of the present invention is as follows:

[0098] The raw materials are first slurried in the mixing barrel 1 and lime is added. The slurry water can be extracted from the upper clear liquid of the cylindrical barrel 16 of the A subsystem through the first submersible pump 5 and the first liquid replenishment pipe 4. The slurry in the mixing barrel 1 is fed into the A subsystem through the first slurry pump 2 and the first slurry pipe 3 for self-circulating leaching operation. The supernatant in the cylindrical barrel 16 of the A subsystem enters the carbon adsorption tank 20 through the second submersible pump 6 for carbon adsorption and gold recovery.

[0099] After reaching the predetermined leaching and carbon adsorption time of subsystem A (the leaching and carbon adsorption time of subsystem A in this embodiment is 8 hours), the water supply pipe 19 of subsystem A is closed, and the three-way valve on the U-shaped tube 17 of subsystem A is operated to lift the slurry in the U-shaped tube 17 of subsystem A with the help of the compressed air of subsystem A, and discharge it into the collecting cone 15 or the cylindrical tube 16 of subsystem B through the second slurry pipe 8, and enter the second stage of washing and leaching.

[0100] Before transferring materials from subsystem A to subsystem B, a portion of the supernatant liquid (generally about half of the capacity of subsystem B) needs to be stored in subsystem B to ensure that subsystem A has a stable liquid level during the material transfer process and that the air lift can operate normally. Similarly, during the material transfer process from subsystem A to subsystem B, the supernatant liquid from subsystem B needs to be transferred to subsystem A through the third submersible pump 9 to ensure that subsystem A has a stable liquid level and that the air lift can operate normally.

[0101] The leaching, washing and carbon adsorption of the ore pulp are circulated between subsystem A and subsystem B. During the process, both subsystem A and subsystem B play a leaching and washing role. When subsystem A is basically clarified, the material guiding is completed. Specifically, the ore is discharged through the ore discharge valve connected to one of the U-shaped tubes of subsystem A, and the ore discharge concentration is detected. When the ore discharge concentration is lower than the set value, such as lower than 5%, it is considered that subsystem A is basically clarified and the material guiding is completed.

[0102] During the material introduction process, the second submersible pump 6 is turned off, the carbon adsorption operation is suspended, and a small amount of mineral particles brought in by the supernatant of the B subsystem gradually settles in the A subsystem.

[0103] After the material guiding is completed, the slurry passage with the B subsystem is closed by operating the three-way valve on the U-shaped pipe 17 of the A subsystem, and the third submersible pump 9 is turned off. The B subsystem performs self-circulating leaching and washing operations.

[0104] After reaching the predetermined leaching time of subsystem B (the leaching and washing time of subsystem B in this embodiment is 4 hours), the second stage leaching and washing is completed, the water supply pipe 19 of subsystem B is closed, and the second slurry pump 10 is started, and the slurry in subsystem B is discharged to the filter press 12 through the third slurry pipe 11 for solid-liquid separation. The liquid phase produced by the filter press returns to subsystem B through the third liquid supply pipe 13. After the cyanide slag is formed in the filter chamber of the filter press 12 (the feed pipeline of the filter press 12 is provided with a pressure gauge, which displays the feed pressure in real time. After the feed pressure reaches a certain value, it can be determined that the filter cake has been formed). At this time, the unloading is not carried out immediately, but clean water with a certain pressure is fed into the filter chamber through the clean water pipe 14. The clean water penetrates the filter cake under pressure, thereby replacing and diluting the residual gold-containing water in the filter cake, playing a secondary washing role, and reducing the valuable metal content in the cyanide slag. After completing the above operations, unloading is carried out.

[0105] The circulation time of the slurry in subsystem A and subsystem B is mainly determined by the leaching time. Under certain conditions such as sodium cyanide concentration, pH value, slurry concentration, etc., the leaching time is directly related to the properties of the ore, and the specific time is determined by conducting a small leaching test in the laboratory. In the present invention, the leaching time of the slurry in subsystem A is set to be about twice the leaching time in subsystem B.

[0106] In order to meet environmental protection requirements, most cyanide plants use a production process in which all cyanide-containing production water is reused and zero external discharge is used. In general, the amount of water brought into the gold-containing ore raw material is required to be consistent with the amount of water discharged with the cyanide slag, thereby ensuring the stability of the circulating water volume in the system and achieving zero discharge. The present invention uses clean water for backwashing in the cyanide slag filter press link, which requires that the gold-containing ore raw material does not contain water or contains a small amount of water. For example: if the water content of the gold-containing ore raw material entering the system of the present invention for cyanide gold extraction is 5%, and the water content of the discharged cyanide slag is 20%, then the cyanide slag filter press link can use 15% of the total amount of ore for backwashing to improve the washing effect. In production, a flow meter can be installed in the clean water pipe 14 to control the water consumption of each backwashing to ensure the stability of the total water volume in the system. For some ores with higher water content, the water content of the raw materials can be reduced to the greatest extent by pre-drying, creating conditions for backwashing with clean water. In extremely special circumstances, the water content of the raw materials cannot be reduced, and lean liquid backwashing can be temporarily used to ensure stable water volume.

[0107] Embodiment 3, application effect embodiment

[0108] A gold mine concentrator uses a cyanide gold extraction process with two leaching, two washings, and precious liquid carbon adsorption to select gold concentrate. The cyanide gold extraction system has a processing capacity of 100t / d and operates 330 days per year. The main leaching equipment is as follows: 10 4.0×4.5m aerated mechanical stirring leaching tanks; 2 12m three-layer thickeners; 2 2.4×4.5m vibrating screens; 8 slurry pumps; 2 blowers. The main process indicators are as follows: gold concentrate grade 30-40g / t; leaching time 48h; leaching concentration 35%; sodium cyanide concentration 3‰; pulp pH 11-12; cyanide leaching rate 94.0%; cyanide washing rate 90%; cyanide carbon adsorption rate 82%. The mine's cyanide leaching and carbon adsorption system covers an area of ​​about 1500m 2 The total investment is 50 million yuan, the energy consumption of immersion and adsorption operations is 99.72kwh / t, and there are 15 operators and maintenance personnel.

[0109] As the mine's production scale continues to increase and its industrial structure transforms, the cyanide plant not only processes the gold concentrate produced by the mine, but also processes some purchased gold concentrate. As a result, the cyanide gold extraction system has insufficient processing capacity, and the leaching operation needs to be expanded and renovated according to the additional processing capacity of 120t / d.

[0110] In view of the above situation, the mine adopts the two-stage leaching cyanide gold extraction system and control method of the present invention under confidentiality conditions. The specific parameters are as follows: the diameter of the cylindrical barrel 16 of subsystem A and subsystem B is 15m, and the height of the cylindrical barrel 16 is 2.5m; the angle of the collecting cone is 110°, and there are eight U-shaped tubes 17, each with a diameter of 130mm; the installation position of the gas-liquid mixer 18 is 23m vertically away from the system liquid surface. Air compressor selection: air supply volume 50m 3 / min, gas supply pressure 0.6Mpa.

[0111] Among them, the vertical distance between the lower end position of the gas-liquid mixer 18 and the system liquid surface is based on the formula h=0.0981P+H.

[0112] Where h is the vertical distance between the lower end of the gas-liquid mixer and the system liquid level, m; P is the discharge pressure at the end of the U-tube, kPa; H is the vertical distance between the highest point of the U-tube and the system liquid level, 1.0 m; where P = 200 + ( φ -10)×5, where φ —Diameter of the cylinder, 15m; calculated P=225kPa.

[0113] Calculation result: h=0.0981×225+1=23.07m.

[0114] According to the calculation results, it is determined that the vertical distance between the lower end of the gas-liquid mixer and the system liquid level is 23m.

[0115] When the mine constructs the cyanide gold extraction system of the present invention, the idle goaf of the mine is fully utilized, the cylindrical tube 16 is arranged on the ground surface, and the collecting cone 15 and the U-shaped tube 17 are arranged below the ground surface.

[0116] The underground space is effectively utilized, and the sunken ground after excavation forms a 15-degree support for the collecting cone, ensuring the installation requirements.

[0117] The comparison between the present invention and conventional technology after construction and commissioning is as follows: (1) The total investment of the system of the present invention is 6.5 million yuan, which reduces the investment cost by 89% compared with conventional technology; (2) The system of the present invention occupies an area of ​​700m 2 , compared with conventional technology, the floor space is reduced by 60%; (3) The energy consumption of leaching and carbon adsorption is 40.43kwh / t, which is 60% lower than that of conventional technology. (4) The number of personnel is reduced to 7, which reduces the labor cost by 53% compared with conventional technology; (5) In terms of production indicators, the cyanide leaching rate reaches 95.2%, which is 1.2% higher than that of conventional technology; the cyanide washing rate reaches 91.8%, which is 1.8% higher than that of conventional technology; the cyanide carbon adsorption rate is 86.4%, which is 4.4% higher than that of conventional technology. Only through the optimization of indicators, the economic benefits of the mine can be increased by more than 7 million yuan per year.

[0118] Although the present invention has been described in detail by reference to the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A two-stage leaching cyanide gold extraction system, comprising a subsystem A for primary leaching and carbon adsorption, a subsystem B for secondary leaching and washing, a stirring barrel (1) for supplying slurry to the subsystem A, and a filter press (12) for filtering and washing slurry discharged from the subsystem B, characterized in that: The B subsystem comprises a material receiving cone (15), the upper end of which is connected to a cylindrical tube (16); the B subsystem also comprises a U-shaped tube (17) and a water supply tube (19); the feed end of the U-shaped tube (17) is connected to the material receiving cone (15), and the discharge end is inserted into the material receiving cone (15); the straight tube section of the U-shaped tube (17) is connected in series to a gas-liquid mixer (18); the gas-liquid mixer (18) comprises a shell (181) in communication with the U-shaped tube (17), and an outer shell (181) is connected to the outer shell (182). The shell (181) is connected to the lower end of the water supply pipe (19) through a liquid inlet pipe with a water inlet valve (183), and the upper end of the water supply pipe (19) is connected to the cylindrical tube (16); the liquid inlet pipe is also connected to the drug inlet pipe (22); the shell (181) is also connected to the air inlet pipe (21); a foaming device (182) connected to the air inlet pipe (21) and used to diffuse air into bubbles is installed inside the shell (181); the subsystem A further includes, based on the subsystem B, The invention comprises a carbon adsorption tank (20) installed above the cylindrical barrel (16); the carbon adsorption tank (20) is a plurality of carbon adsorption tanks connected in series, the water inlet pipe of the first-stage carbon adsorption tank is connected to the second submersible pump (6) located in the cylindrical barrel (16) of the A subsystem, and the water outlet pipe of the last-stage carbon adsorption tank is connected to the cylindrical barrel (16) of the A subsystem; the A subsystem further comprises a three-way valve connected to the U-shaped pipe (17) of the A subsystem, the three-way valve is connected to the material collecting cone (15) or the cylindrical barrel (16) of the B subsystem through the second slurry pipe (8); a third submersible pump (9) is arranged in the cylindrical barrel (16) of the B subsystem, the third submersible pump (9) is connected to the cylindrical barrel (16) of the A subsystem or the material collecting cone (15) of the A subsystem through the second liquid replenishment pipe (7); the U-shaped pipe (17) of the B subsystem is connected to the second slurry pump (10), and the second slurry pump (10) is connected to the filter press (12) through the third slurry pipe (11); Wherein, the installation position of the gas-liquid mixer (18) is determined by calculation according to Formula 1; Formula 1: h=0.0981P+H; Where h is the vertical distance between the lower end of the gas-liquid mixer and the system liquid level, m; P—discharge pressure at the discharge end of the U-tube, kPa; P=200+（ -10）×5； — diameter of the cylindrical barrel (16), m; H—Vertical distance between the highest point of the U-tube and the system liquid level, m.

2. The two-stage leaching cyanide gold extraction system according to claim 1, characterized in that: The mixing barrel (1) is connected to the cylindrical barrel (16) of subsystem A or the material collecting cone (15) of subsystem A via a first slurry pipe (3); a first submersible pump (5) is arranged in the cylindrical barrel (16) of subsystem A, and the first submersible pump (5) is connected to the mixing barrel (1) via a first liquid replenishing pipe (4).

3. The two-stage leaching cyanide gold extraction system according to claim 1, characterized in that: The liquid discharge end of the filter press (12) is connected to the cylindrical barrel (16) of the B subsystem or the material collection cone (15) of the B subsystem via a third liquid replenishing pipe (13); the filter press (12) is also connected to a clean water pipe (14) with a control valve.

4. The two-stage leaching cyanide gold extraction system according to claim 1, characterized in that: The connection point between the drug inlet pipe (22) and the liquid inlet pipe is located between the water inlet valve (183) and the housing (181); the drug inlet pipe (22) is provided with a drug inlet check valve (221) and a drug inlet valve (222); and the air inlet pipe (21) is provided with an air inlet check valve (211) and an air inlet valve (212).

5. The two-stage leaching cyanide gold extraction system according to any one of claims 1 to 4, characterized in that: The collecting cone (15) and the cylindrical barrel (16) are both made of galvanized canvas.

6. The two-stage leaching cyanide gold extraction system according to any one of claims 1 to 4, characterized in that: The air consumption is determined by calculation according to Formula 2; Formula 2: ; Where V0 is the air consumption per unit volume of slurry, m 3 / m 3 ; h—vertical distance between the lower end of the gas-liquid mixer and the system liquid level, m; ρ n —Density of slurry mixed with air, t / m 3 ; r n =p m / 2; ρ m —Density of slurry before mixing with air, t / m 3 ; The air pressure fed through the air intake pipe (21) is determined by calculation according to Formula 3; Formula 3: P1=1.2×(9.81hρ m +100); Where P1 is the minimum working pressure of compressed air, kPa; h—vertical distance between the lower end of the gas-liquid mixer and the system liquid level, m; ρ m —Density of slurry before mixing with air, t / m 3 .

7. A control method for a two-stage leaching cyanide gold extraction system according to any one of claims 1 to 4, characterized in that: The slurry is first subjected to leaching and carbon adsorption in subsystem A; after reaching the predetermined leaching and carbon adsorption time of subsystem A, the water supply pipe (19) of subsystem A is closed, and the slurry in the U-shaped pipe (17) of subsystem A is lifted and discharged into the collecting cone (15) or cylindrical barrel (16) of subsystem B with the aid of compressed air from subsystem A; after reaching the predetermined self-circulating leaching and washing time of subsystem B, the water supply pipe (19) of subsystem B is closed, and the second slurry pump (10) is started to discharge the slurry in subsystem B to the filter press (12) for solid-liquid separation.

8. The control method according to claim 7, characterized in that: Before transferring materials from subsystem A to subsystem B, it is necessary to store supernatant in subsystem B, and during the process of transferring materials from subsystem A to subsystem B, the supernatant of subsystem B is introduced into subsystem A to ensure that subsystem A has a stable liquid level during the material transfer process and realize normal operation of air lifting.

9. The control method according to claim 7, characterized in that: During the process of transferring material from subsystem A to subsystem B, the second submersible pump (6) is turned off and the carbon adsorption operation is suspended.

10. The control method according to claim 7, characterized in that: During the solid-liquid separation process, the liquid phase produced by the filter pressing is returned to the B subsystem; after the cyanide residue is formed in the filter chamber of the filter press (12), clean water with a certain pressure is first fed into the filter chamber, and then the material is discharged.

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