Method and system for recovering gold from low-grade gold-containing carbon mud

Abstract

The invention relates to a method and a system for recovering gold from low-grade gold-containing carbon mud. The method comprises the following steps: I-stage conventional cyanidation leaching; iI section ultrasonic enhancement-ozone / oxygen enrichment synergistic leaching; carrying out circulating adsorption on the leaching solution in the section II; and gold-loaded activated carbon is used for desorption and electrodeposition for gold extraction. The system comprises a first-section leaching tank, a discharge port of the first-section leaching tank is connected with a feed port of a second-section leaching tank through a delivery pump and a pipeline, a filter screen is vertically arranged in the second-section leaching tank, and one side of the second-section leaching tank is divided into filtrate tanks by the filter screen; a stirring device and at least two ultrasonic devices are arranged in the section II leaching tank, the ultrasonic devices are electrically connected with an ultrasonic controller, and the ultrasonic devices are connected with an air compressor and an ozone storage tank through air pipes; a discharge port of the filtrate tank is connected with a feed port of the multi-stage serial adsorption tower through a delivery pump and a pipeline, and a liquid outlet of the multi-stage serial adsorption tower is communicated with a feed port of the filtrate tank. According to the method, the gold and the silver in the low-grade gold-containing carbon mud can be efficiently recycled, and the leaching rates of the gold and the silver respectively reach 80%-92% and 70%-85%.

Description

Technical Field

[0001] The invention belongs to the technical field of resource hydrometallurgy, and in particular relates to a method and a system for recovering gold from low-grade gold-containing carbon mud. Background Art

[0002] In recent years, with the continuous development of gold resources, the surface easy-to-process oxide ore gold resources have gradually decreased. The medium-deep difficult-to-process oxygen-sulfur mixed ore and laterite ore have gradually become the main ore resources. These difficult-to-process gold resources contain more mud and are often accompanied by silver, iron, copper, lead, zinc, calcium, sulfur and other elements.

[0003] During the gold extraction process of cyanide carbon slurry, these impurity elements will react with cyanide to generate related cyanide complexes, which will be adsorbed by activated carbon to form complex and difficult-to-handle gold-loaded carbon with high impurity elements and heavy mud. During the hydraulic transportation of this complex and difficult-to-handle gold-loaded carbon to the desorption workshop and the re-cleaning of the gold-loaded carbon before desorption, most of the mud will settle into the return water pool of the desorption workshop. In addition, these gold-loaded carbons will also produce powdered carbon due to friction during the hydraulic transportation of various processes in the desorption workshop; when the desorption is completed and the pressure is released, the de-gold carbon is cooled with return water, which will also produce powdered carbon due to thermal expansion and contraction; these powdered carbons are deposited in the return water pool with the return water, and settle together with the mud, eventually forming low-grade gold-containing carbon mud.

[0004] At present, there are two main ways to treat this type of low-grade gold-containing carbon mud: one is to filter through a small filter press to obtain filter residue, and sell it after the filter residue reaches a certain amount. However, the carbon mud obtained by this simple filtration contains cyanide, which is a hazardous waste and needs to be sold to companies with qualifications for hazardous waste treatment. In addition, there are problems such as poor sampling representativeness and low discount coefficient during the sales process, which cannot maximize benefits. The second is to use a slurry pump to pump the carbon mud in the return pool back to the cyanide system for leaching and recovery. However, this treatment method has a low recovery rate, and most of the powdered carbon is lost with the cyanide tail liquid, and the purpose of recovery cannot be achieved.

[0005] Therefore, it is necessary to find more effective low-grade gold-containing carbon mud recovery methods and systems to increase the recovery rate of gold and silver while reducing safety and environmental protection pressures. Summary of the invention

[0006] In view of the above problems, the present invention provides a method and system for recovering gold from low-grade gold-containing carbon mud.

[0007] The specific technical solution is: a method for recovering gold from low-grade gold-containing carbon mud, comprising the following steps: (1) Stage I conventional cyanide leaching: The carbon mud in the desorption workshop return water pool is mixed with the production return water in proportion, and the pH value is adjusted to >12 by adding lime milk solution, followed by adding sodium cyanide solution and stirring for cyanide leaching to obtain stage I leaching residue and stage I leaching liquid; (2) Stage II ultrasonic enhanced-ozone / oxygen-enriched synergistic leaching: The stage I leaching residue and the leaching liquid obtained in step (1) are mixed and transferred into a leaching tank, sodium cyanide solution is added for cyanide leaching, and a stirring device and an ultrasonic device are started at the same time, and ozone and oxygen supply equipment are turned on for aeration. Leaching is enhanced under the synergistic effect of the ultrasonic device and ozone and oxygen to obtain stage II leaching residue and stage II leaching liquid, and the stage II leaching liquid passes through the filter in the leaching tank and enters the filtrate tank; (3) Circulation adsorption of stage II leachate: After 1 hour of ultrasonic enhanced leaching-ozone / oxygen-enriched leaching in stage II, the stage II leachate is transferred to a multi-stage adsorption tower in series for circulation adsorption. The lean liquid adsorbed by activated carbon in the adsorption tower is returned to the filtrate tank. This cycle is repeated until the gold concentration of the stage II leachate in the filtrate tank is lower than 0.02 g / m 3 , silver concentration is less than 1.40g / m 3 The circulation is stopped at this time, and the gold and silver in the leaching solution are adsorbed by activated carbon to obtain gold-loaded activated carbon and barren solution. At this time, the leaching residue of stage II is filtered and stored in the tailings pond, and the filtrate and barren solution filtered from the leaching residue of stage II are returned to the recovery system. (4) Desorption and electrolysis of gold loaded activated carbon for gold extraction: The gold loaded activated carbon in the adsorption tower is transferred to the desorption column for desorption and electrolysis to recover and extract gold and silver. The specific desorption and electrolysis process is a conventional process and will not be described in detail here.

[0008] Furthermore, in step (1), the solid-to-liquid ratio of carbon sludge to production return water is 1:2-4.

[0009] Furthermore, in step (1), the concentration of the sodium cyanide solution is 0.03% to 0.05%, the cyanide leaching temperature is 45 to 65° C., and the leaching time is 1 to 1.5 h.

[0010] Furthermore, in step (2), the pH value of cyanide leaching is greater than 12, the concentration of sodium cyanide is 0.03% to 0.05%, the leaching temperature is 60 to 80° C., and the leaching time is 2 to 3 hours.

[0011] Furthermore, in step (2), the rotation speed of the stirring device is 50 to 90 rpm; the frequency of the ultrasonic device is 10 to 30 kHz; the delivery pressure of oxygen is 0.7 to 0.9 MPa and the flow rate is 70 to 100 L / min; and the delivery flow rate of ozone is 5 to 15 L / min.

[0012] The present invention also provides a system used in the above-mentioned method for recovering gold from low-grade gold-containing carbon mud, comprising a stage I leaching tank, wherein the discharge port of the stage I leaching tank is connected to the feed port of the stage II leaching tank through a delivery pump and a pipeline, and a filter screen is vertically arranged in the stage II leaching tank, and the filter screen separates one side of the stage II leaching tank into a filtrate tank; a stirring device and at least two ultrasonic devices are also arranged in the stage II leaching tank, and the ultrasonic device is electrically connected to an ultrasonic controller, and the ultrasonic device is also connected to an air compressor and an ozone storage tank through an air pipe; the discharge port of the filtrate tank is connected to the feed port of a multi-stage series adsorption tower through a delivery pump and a pipeline, and the liquid outlet of the multi-stage series adsorption tower is connected to the feed port of the filtrate tank through a pipeline.

[0013] Furthermore, the ultrasonic device includes a shell and a primary amplitude transformer and a secondary amplitude transformer connected thereto in sequence, an ultrasonic tool head is connected below the secondary amplitude transformer, a amplitude transformer shell is sleeved on the outside of the ultrasonic tool head, the top of the amplitude transformer shell is connected to the secondary amplitude transformer, two air inlets are provided on the side wall of the secondary amplitude transformer, the air inlets lead from the side wall of the secondary amplitude transformer to the inner cavity of the amplitude transformer shell, one of the air inlets is connected to the air compressor through an air pipe, and the other air inlet is connected to the ozone storage tank through an air pipe, and a plurality of air outlet holes are provided on the circumferential wall of the amplitude transformer shell.

[0014] Furthermore, the primary horn and the secondary horn are connected via a flange.

[0015] Furthermore, the feed port of the first adsorption tower of the multi-stage series adsorption tower is connected to the discharge port of the filtrate tank, the outlet port of the last adsorption tower is connected to the feed port of the filtrate tank, the outlet port of the previous adsorption tower is connected to the feed port of the next adsorption tower, and so on until the last adsorption tower.

[0016] Beneficial effects of the present invention: The present invention can efficiently recover gold and silver from low-grade gold-containing carbon mud, and the gold and silver leaching rate can reach 80% to 92% for gold and 70% to 85% for silver. The specific technical benefits are reflected in the following aspects: (1) According to the actual situation of carbon mud produced in the desorption workshop, the present invention adopts two-stage leaching (stage I conventional cyanide leaching and stage II ultrasonic enhanced-ozone / oxygen-enriched synergistic leaching), and arranges a stirring device, an ultrasonic device and an ozone / oxygen-enriched aeration supply device in the stage II leaching tank. Through the synergistic effect of multiple means, the deep leaching of gold and silver in the carbon mud is achieved under low energy consumption conditions. Compared with the traditional treatment method, the resource recovery and utilization effect is remarkable.

[0017] (2) The ultrasonic device added to the leaching of stage II of the present invention will produce mechanical vibration and cavitation effect, strengthen the turning and stirring of the material, and peel off the coating layer of the material, so as to achieve deep leaching of the unreacted core inside the material, and greatly improve the leaching rate of gold and silver. Moreover, when the ultrasonic device is working, it is supplemented by the gas introduced by the ozone / oxygen-enriched aeration supply device, and based on the design of several air outlet holes on the shell of the horn, a venturi effect will be generated to form a strong jet airflow, which can not only play a stirring role, but also further strengthen the cavitation effect, impact the outer layer of the product, expose the unreacted core of the material, and further leaching.

[0018] (3) The oxygen introduced in the second stage of leaching of the present invention can also increase the dissolved oxygen content, accelerate the leaching speed, and improve the leaching rate and processing capacity of gold; low-concentration ozone can not only accelerate the dissolution of gold, but also prevent the formation of an oxide film on the surface of gold that affects leaching. Under the action of ozone / enriched oxygen, the leaching of gold continues to rapidly advance towards the positive reaction, and the leaching effect and efficiency of gold and silver are improved.

[0019] (4) The integrated design of the stage II leaching tank and the filtrate tank of the present invention realizes the production mode of "immersing and absorbing at the same time", accelerates the forward reaction, and greatly improves the leaching efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a device association diagram of Example 4; Figure 2 yes Figure 1 A schematic diagram of the structure of the ultrasonic device; In the figure: 1-stage I leaching tank; 2-stage II leaching tank; 3-filtrate tank; 4-filter; 5-ultrasonic device, 501-housing, 502-first-stage amplitude transformer, 503-flange, 504-air inlet, 505-second-stage amplitude transformer, 506-ultrasonic tool head, 507-amplitude transformer housing, 508-air outlet; 6-stirring device; 7-ultrasonic controller; 8-air compressor; 9-ozone storage tank; 10-multi-stage series adsorption tower. DETAILED DESCRIPTION

[0021] In order to make the technical problems and technical solutions solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Example 1

[0022] The carbon sludge to be treated in the return pool of a desorption workshop contained gold grade of 126.05g / t and silver grade of 1407.58g / t.

[0023] The method of the present invention is used to recover gold and silver, and the specific process and effects are as follows: (1) Conventional cyanide leaching in stage I: the carbon mud in the desorption workshop return water pool was mixed with the production return water at a solid-liquid ratio of 1:2, and the pH value was adjusted to 12 by adding lime milk solution. Subsequently, 0.05% sodium cyanide solution was added and stirred for cyanide leaching. During the leaching process, the leaching temperature was controlled at about 45 °C. After leaching for 1 h, stage I leaching residue and stage I leaching liquid were obtained. The gold and silver grades in the stage I leaching residue were sampled and tested to be 58.90 g / t and 850.32 g / t, respectively, and the leaching rates of gold and silver were 53.27% and 39.59%, respectively.

[0024] (2) Stage II ultrasonic enhanced-ozone / oxygen-enriched synergistic leaching: The stage I leaching residue and the leaching liquid obtained in step (1) are mixed and transferred into a leaching tank, lime milk solution is added to adjust the pH value to 12, and then 0.05% sodium cyanide solution is added for cyanide leaching. At the same time, the stirring device and the ultrasonic device are started, and the ozone and oxygen supply equipment are turned on for aeration. The leaching is enhanced under the synergistic action of the ultrasonic device and ozone and oxygen. The temperature is controlled at about 60°C during the leaching process. After leaching for 2 hours, stage II leaching residue and stage II leaching liquid are obtained. The stage II leaching liquid enters the filtrate tank through the filter in the leaching tank; sampling and testing of the gold and silver grades in the stage II leaching residue are 24.90 g / t and 427.37 g / t, respectively, and the leaching rates of gold and silver are 80.25% and 69.64%, respectively.

[0025] In addition, during the leaching process, the rotation speed of the stirring device was 90 rpm, the frequency of the ultrasonic device was 30 kHz, the ozone flow rate was 15 L / min, and the pressure of the compressed air was 0.90 MPa and the flow rate was 100 L / min.

[0026] (3) Circulation adsorption of stage II leachate: After 1 hour of ultrasonic enhanced leaching-ozone / oxygen-enriched leaching in stage II, the stage II leachate is transferred to a multi-stage adsorption tower in series for circulation adsorption. The lean liquid adsorbed by activated carbon in the adsorption tower is returned to the filtrate tank. This cycle is repeated until the gold concentration of the stage II leachate in the filtrate tank is lower than 0.02 g / m 3 , silver concentration is less than 1.40g / m 3 The circulation is stopped at this time, and the gold and silver in the leaching solution are adsorbed by activated carbon to obtain gold-loaded activated carbon and barren solution. At this time, the leaching residue of stage II is filtered and stored in the tailings pond, and the filtrate and barren solution filtered from the leaching residue of stage II are returned to the recovery system. (4) Desorption and electrowinning of gold-loaded activated carbon: Finally, the gold-loaded activated carbon in the adsorption tower is transferred to the desorption column for desorption and electrowinning to recover gold and silver. The specific desorption and electrowinning process is a conventional process and will not be described in detail here. Example 2

[0027] The carbon mud to be treated is the carbon mud of Example 1, and the method of the present invention is used to recover gold and silver. The specific process and effect are as follows: (1) Conventional cyanide leaching in stage I: the carbon mud in the desorption workshop return water pool was mixed with the production return water at a solid-liquid ratio of 1:3, and the pH value was adjusted to 12 by adding lime milk solution. Subsequently, 0.05% sodium cyanide solution was added and stirred for cyanide leaching. During the leaching process, the leaching temperature was controlled at about 55°C. After leaching for 1 hour, stage I leaching residue and stage I leaching liquid were obtained. The gold and silver grades in the stage I leaching residue were sampled and tested to be 37.40 g / t and 748.17 g / t, respectively, and the leaching rates of gold and silver were 70.33% and 46.85%, respectively.

[0028] (2) Stage II ultrasonic enhanced-ozone / oxygen-enriched synergistic leaching: The stage I leaching residue and the leaching liquid obtained in step (1) are mixed and transferred into a leaching tank, lime milk solution is added to adjust the pH value to 12, and then 0.05% sodium cyanide solution is added for cyanide leaching. At the same time, the stirring device and the ultrasonic device are started, and the ozone and oxygen supply equipment are turned on for aeration. The leaching is enhanced under the synergistic action of the ultrasonic device and ozone and oxygen. The temperature is controlled at about 70°C during the leaching process. After leaching for 2.5 hours, the stage II leaching residue and the stage II leaching liquid are obtained. The stage II leaching liquid enters the filtrate tank through the filter in the leaching tank; sampling and testing of the gold and silver grades in the stage II leaching residue are 16.10 g / t and 359.25 g / t, respectively, and the leaching rates of gold and silver are 87.23% and 74.48%, respectively.

[0029] In addition, during the leaching process, the rotation speed of the stirring device was 75 rpm, the frequency of the ultrasonic device was 20 kHz, the ozone flow rate was 10 L / min, and the pressure of the compressed air was 0.80 MPa and the flow rate was 85 L / min.

[0030] (3) Circulation adsorption of stage II leachate: After 1 hour of ultrasonic enhanced leaching-ozone / oxygen-enriched leaching in stage II, the stage II leachate is transferred to a multi-stage adsorption tower in series for circulation adsorption. The lean liquid adsorbed by activated carbon in the adsorption tower is returned to the filtrate tank. This cycle is repeated until the gold concentration of the stage II leachate in the filtrate tank is lower than 0.02 g / m 3 , silver concentration is less than 1.40g / m 3 The circulation is stopped at this time, and the gold and silver in the leaching solution are adsorbed by activated carbon to obtain gold-loaded activated carbon and barren solution. At this time, the leaching residue of stage II is filtered and stored in the tailings pond, and the filtrate and barren solution filtered from the leaching residue of stage II are returned to the recovery system. (4) Desorption and electrowinning of gold-loaded activated carbon: Finally, the gold-loaded activated carbon in the adsorption tower is transferred to the desorption column for desorption and electrowinning to recover gold and silver. The specific desorption and electrowinning process is a conventional process and will not be described in detail here. Example 3

[0031] The carbon mud to be treated is the carbon mud of Example 1, and the method of the present invention is used to recover gold and silver. The specific process and effect are as follows: (1) Conventional cyanide leaching in stage I: the carbon mud in the desorption workshop return water pool was mixed with the production return water at a solid-liquid ratio of 1:4, and the pH value was adjusted to 12 by adding lime milk solution. Subsequently, 0.05% sodium cyanide solution was added and stirred for cyanide leaching. During the leaching process, the leaching temperature was controlled at about 65°C. After leaching for 1.5 hours, stage I leaching residue and stage I leaching liquid were obtained. The gold and silver grades in the stage I leaching residue were sampled and tested to be 20.50 g / t and 426.85 g / t, respectively, and the leaching rates of gold and silver were 83.74% and 69.67%, respectively.

[0032] (2) Stage II ultrasonic enhanced-ozone / oxygen-enriched synergistic leaching: The stage I leaching residue and the leaching liquid obtained in step (1) are mixed and uniformly transferred into a leaching tank, lime milk solution is added to adjust the pH value to 12, and then 0.05% sodium cyanide solution is added for cyanide leaching. At the same time, the stirring device and the ultrasonic device are started, and the ozone and oxygen supply equipment are turned on for aeration. The leaching is enhanced under the synergistic action of the ultrasonic device and ozone and oxygen. The temperature is controlled at about 80°C during the leaching process. After leaching for 2.5 hours, the stage II leaching residue and the stage II leaching liquid are obtained. The stage II leaching liquid enters the filtrate tank through the filter in the leaching tank; sampling and testing of the gold and silver grades in the stage II leaching residue are 9.80 g / t and 212.11 g / t, respectively, and the leaching rates of gold and silver are 92.23% and 84.93%, respectively.

[0033] In addition, during the leaching process, the rotation speed of the stirring device was 50 rpm, the frequency of the ultrasonic device was 10 kHz, the ozone flow rate was 5 L / min, and the pressure of the compressed air was 0.70 MPa and the flow rate was 70 L / min.

[0034] (3) Circulation adsorption of stage II leachate: After 1 hour of ultrasonic enhanced leaching-ozone / oxygen-enriched leaching in stage II, the stage II leachate is transferred to a multi-stage adsorption tower in series for circulation adsorption. The lean liquid adsorbed by activated carbon in the adsorption tower is returned to the filtrate tank. This cycle is repeated until the gold concentration of the stage II leachate in the filtrate tank is lower than 0.02 g / m 3 , silver concentration is less than 1.40g / m 3 The circulation is stopped at this time, and the gold and silver in the leaching solution are adsorbed by activated carbon to obtain gold-loaded activated carbon and barren solution. At this time, the leaching residue of stage II is filtered and stored in the tailings pond, and the filtrate and barren solution filtered from the leaching residue of stage II are returned to the recovery system. (4) Desorption and electrowinning of gold-loaded activated carbon: Finally, the gold-loaded activated carbon in the adsorption tower is transferred to the desorption column for desorption and electrowinning to recover gold and silver. The specific desorption and electrowinning process is a conventional process and will not be described in detail here. Example 4

[0035] The present embodiment provides a system for recovering gold from low-grade gold-containing carbon mud, including a leaching tank 1 of stage I, wherein the discharge port of the leaching tank 1 of stage I is connected to the feed port of the leaching tank 2 of stage II through a delivery pump and a pipeline, and a filter screen 4 is vertically arranged in the leaching tank 2 of stage II, and the filter screen 4 separates one side of the leaching tank 2 of stage II into a filtrate tank 3; a stirring device 6 and at least two ultrasonic devices 5 are also arranged in the leaching tank 2 of stage II, and the ultrasonic device 5 is electrically connected to the ultrasonic controller 7, and the ultrasonic device 5 is also connected to the air compressor 8 and the ozone gas storage tank 9 through an air pipe; the discharge port of the filtrate tank 3 is connected to the feed port of the multi-stage series adsorption tower 10 through a delivery pump and a pipeline, and the liquid outlet of the multi-stage series adsorption tower 10 is connected to the feed port of the filtrate tank 3 through a pipeline. In addition, valves are installed on the air pipes near the air outlets of the air compressor and the ozone gas storage tank, and valves are also installed on the discharge ports of the leaching tank 1 of stage I and the filtrate tank 3.

[0036] Preferably, the ultrasonic device 5 includes a shell 501 and a primary horn 502 and a secondary horn 505 connected thereto in sequence, the primary horn 502 and the secondary horn 505 being connected via a flange 503; an ultrasonic tool head 506 is connected below the secondary horn 505, a horn shell 507 is sleeved on the outside of the ultrasonic tool head 506, the top of the horn shell 507 is connected to the secondary horn 505, two air inlets 504 are provided on the side wall of the secondary horn 505, the air inlets 504 lead from the side wall of the secondary horn 505 to the inner cavity of the horn shell 507, one of the air inlets 504 is connected to the air compressor 8 via an air pipe, the other air inlet 504 is connected to the ozone storage tank 9 via an air pipe, and a plurality of air outlet holes 508 are provided on the circumferential wall of the horn shell 507.

[0037] When the ultrasonic device is working, the ultrasonic device 5 is started by the ultrasonic controller 7, and the first-stage horn 502 and the second-stage horn 505 begin to vibrate, thereby driving the ultrasonic tool head 506 to vibrate, generating mechanical vibration and cavitation effect. The mechanical vibration can drive the leaching residue of stage I and the leaching liquid of stage I in the leaching tank of stage II to turn and stir, and the cavitation effect can penetrate the leaching residue, peel off the coating layer of the material, and achieve deep leaching of the unreacted nucleus inside the material, greatly improving the leaching rate of gold and silver. At the same time, the air compressor 8, the ozone gas storage tank 9 and the valve on the air pipe are opened to introduce oxygen and ozone into the ultrasonic device. After the gas enters the inner cavity of the horn housing 507 through the air inlet 504, it is ejected from the air outlet 508 as the ultrasonic tool head 506 vibrates. The design of the air outlet 508 will produce a Venturi effect to form a strong jet airflow. This airflow can not only play a stirring role, but also further strengthen the cavitation effect, impact the outer layer of the product, expose the unreacted core of the material, and further leaching. In addition, the oxygen introduced can also increase the dissolved oxygen content, speed up the leaching speed, and improve the leaching rate and processing capacity of gold. Low-concentration ozone can not only accelerate the dissolution of gold, but also prevent the formation of an oxide film on the surface of gold that affects leaching. Under the action of ozone / enriched oxygen, the leaching of gold continues to rapidly advance towards the positive reaction (the reaction formula is 4Au+8CN - +O2+2H2O→4Au (CN)2 - +4OH - ), the gold and silver leaching effect and efficiency are improved.

[0038] Specifically, the feed port of the first adsorption tower of the multi-stage series adsorption tower 10 is connected to the discharge port of the filtrate tank 3, the liquid outlet of the last adsorption tower is connected to the feed port of the filtrate tank 3, the liquid outlet of the previous adsorption tower is connected to the feed port of the next adsorption tower, and so on until the last adsorption tower.

[0039] When the system is working: the carbon mud in the desorption workshop return water pool is transferred to the stage I leaching tank 1, and the production return water is added in proportion to mix, and then the lime milk solution is added for adjustment, and then the sodium cyanide solution is added, and the cyanide leaching is stirred to obtain the stage I leaching residue and the stage I leaching liquid; The leaching residue from stage I and the leaching liquid are mixed and transferred to the leaching tank 2 of stage II, and sodium cyanide solution is added for cyanide leaching. At the same time, the stirring device 6 and the ultrasonic device 5 are started, and the air compressor 8 and the ozone storage tank 9 are turned on to pass oxygen and ozone into the ultrasonic device 5 for aeration. Under the vibration and cavitation of the ultrasonic device 5 and the synergistic effect of the aeration of oxygen and ozone, the gold and silver in the leaching residue from stage I are leached intensified, greatly improving the leaching rate and leaching efficiency. At the same time, the leaching residue from stage II and the leaching liquid from stage II are separated by the filter 4, the leaching residue from stage II is stored in the leaching tank of stage II, and the leaching liquid from stage II is stored in the filtrate tank 3; After the ultrasonic device 5 has been working for 1 hour, the valve of the discharge port of the filtrate tank 3 is opened, and the delivery pump is started to pump the stage II leaching solution to the multi-stage series adsorption tower 10 for activated carbon adsorption. The lean solution after adsorption by activated carbon in the adsorption tower is returned to the filtrate tank 3, and the cycle is repeated until the gold concentration of the stage II leaching solution in the filtrate tank 3 is lower than 0.02g / m 3 , silver concentration is less than 1.40g / m 3 The circulation is stopped when the gold-loaded activated carbon and barren liquid are obtained; at this time, the leaching residue of stage II is filtered and stored in the tailings pond, the filtrate and barren liquid filtered out of the leaching residue of stage II are returned to the recovery system, and the gold-loaded activated carbon is transferred to the desorption column for desorption and electrowinning to recover gold and silver.

[0040] The present invention is described in detail above through specific and preferred embodiments, but those skilled in the art should understand that the present invention is not limited to the embodiments described above, and any modifications, equivalent substitutions, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for recovering gold from low-grade gold-containing carbon mud, characterized in that: The steps include: (1) Stage I conventional cyanide leaching: The carbon mud in the desorption workshop return water pool is mixed with the production return water in proportion, and the pH value is adjusted to >12 by adding lime milk solution, followed by adding sodium cyanide solution and stirring for cyanide leaching to obtain stage I leaching residue and stage I leaching liquid; (2) Stage II ultrasonic enhanced-ozone / oxygen-enriched synergistic leaching: The stage I leaching residue and the leaching liquid obtained in step (1) are mixed and transferred into a leaching tank, sodium cyanide solution is added for cyanide leaching, and a stirring device and an ultrasonic device are started at the same time, and ozone and oxygen supply equipment are turned on for aeration. Leaching is enhanced under the synergistic effect of the ultrasonic device and ozone and oxygen to obtain stage II leaching residue and stage II leaching liquid, and the stage II leaching liquid passes through the filter in the leaching tank and enters the filtrate tank; (3) Circulation adsorption of stage II leachate: After 1 hour of ultrasonic enhanced leaching-ozone / oxygen-enriched leaching in stage II, the stage II leachate is transferred to a multi-stage adsorption tower in series for circulation adsorption. The lean liquid adsorbed by activated carbon in the adsorption tower is returned to the filtrate tank. This cycle is repeated until the gold concentration of the stage II leachate in the filtrate tank is lower than 0.02 g / m 3 , silver concentration is less than 1.40g / m 3 The circulation is stopped at this time, and the gold and silver in the leaching solution are adsorbed by activated carbon to obtain gold-loaded activated carbon and barren solution. At this time, the leaching residue of stage II is filtered and stored in the tailings pond, and the filtrate and barren solution filtered from the leaching residue of stage II are returned to the recovery system. (4) Desorption and electrolysis of gold loaded activated carbon: The gold loaded activated carbon in the adsorption tower is transferred to the desorption column for desorption and electrolysis to recover gold and silver.

2. A method for recovering gold from low-grade gold-containing carbon mud according to claim 1, characterized in that: In step (1), the solid-liquid ratio of carbon sludge to production return water is 1:2-4.

3. A method for recovering gold from low-grade gold-containing carbon mud according to claim 1 or 2, characterized in that: In step (1), the concentration of the sodium cyanide solution is 0.03% to 0.05%, the cyanide leaching temperature is 45 to 65° C., and the leaching time is 1 to 1.5 h.

4. A method for recovering gold from low-grade gold-containing carbon mud according to claim 1, characterized in that: In step (2), the pH value of cyanide leaching is greater than 12, the concentration of sodium cyanide is 0.03% to 0.05%, the leaching temperature is 60 to 80° C., and the leaching time is 2 to 3 hours.

5. A method for recovering gold from low-grade gold-containing carbon mud according to claim 1 or 4, characterized in that: In step (2), the rotation speed of the stirring device is 50 to 90 rpm; the frequency of the ultrasonic device is 10 to 30 kHz; the delivery pressure of oxygen is 0.7 to 0.9 MPa and the flow rate is 70 to 100 L / min; and the delivery flow rate of ozone is 5 to 15 L / min.

6. A system for recovering gold from low-grade gold-bearing carbon mud, characterized in that: The invention comprises a first-stage leaching tank (1), wherein the discharge port of the first-stage leaching tank (1) is connected to the feed port of the second-stage leaching tank (2) through a delivery pump and a pipeline, and a filter screen (4) is vertically arranged in the second-stage leaching tank (2), and the filter screen (4) separates one side of the second-stage leaching tank (2) into a filtrate tank (3); a stirring device (6) and at least two ultrasonic devices (5) are also arranged in the second-stage leaching tank (2), and the ultrasonic devices (5) are electrically connected to an ultrasonic controller (7), and the ultrasonic devices (5) are also connected to an air compressor (8) and an ozone storage tank (9) through an air pipe; the discharge port of the filtrate tank (3) is connected to the feed port of a multi-stage series adsorption tower (10) through a delivery pump and a pipeline, and the liquid discharge port of the multi-stage series adsorption tower (10) is connected to the feed port of the filtrate tank (3) through a pipeline.

7. A system for recovering gold from low-grade gold-containing carbon mud according to claim 6, characterized in that: The ultrasonic device (5) comprises a housing (501) and a primary horn (502) and a secondary horn (505) connected thereto in sequence; an ultrasonic tool head (506) is connected below the secondary horn (505); a horn housing (507) is sleeved on the outside of the ultrasonic tool head (506); the top of the horn housing (507) is connected to the secondary horn (505); two air inlets (504) are provided on the side wall of the secondary horn (505); the air inlets (504) lead from the side wall of the secondary horn (505) to the inner cavity of the horn housing (507); one of the air inlets (504) is connected to an air compressor (8) via an air pipe, and the other air inlet (504) is connected to an ozone storage tank (9) via an air pipe; a plurality of air outlet holes (508) are provided on the circumferential wall of the horn housing (507).

8. A system for recovering gold from low-grade gold-containing carbon mud according to claim 7, characterized in that: The primary horn (502) and the secondary horn (505) are connected via a flange (503).

9. A system for recovering gold from low-grade gold-containing carbon mud according to claim 6, characterized in that: The feed inlet of the first adsorption tower of the multi-stage series adsorption tower (10) is connected to the discharge port of the filtrate tank (3), the discharge port of the last adsorption tower is connected to the feed inlet of the filtrate tank (3), the discharge port of the previous adsorption tower is connected to the feed inlet of the next adsorption tower, and so on until the last adsorption tower.

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