A comprehensive method for recovering resources from high-copper and high-silver cyanide gold cyanide wastewater

Abstract

The present invention relates to a comprehensive recovery method for gold cyanide wastewater resources containing high copper and high silver, comprising the following steps: (1) desludging and copper and silver adsorption; (2) activated carbon desorption electrolysis; (3) gold mud purification and refining; (4) first-stage copper precipitation in wastewater; (5) second-stage copper and silver precipitation in wastewater; (6) dense precipitation of silver and copper products; (7) copper mud dehydration; (8) pH adjustment of overflow liquid; (9) gypsum slurry thickening and dehydration. The present invention not only realizes the reuse of valuable wastewater resources, but also effectively purifies the gold cyanide leaching circulating liquid. Moreover, after the high free cyanide purified return water is reused in the cyanide gold extraction process, the recovery rates of gold, silver and copper in the cyanide leaching process are significantly improved, and the silver content of the tail liquid is also effectively controlled. More importantly, no toxic hydrogen cyanide gas escapes during the recovery process, providing a green, economical and safe disposal method for the comprehensive recovery of valuable elements in cyanide wastewater in polymetallic gold mines, which has broad application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical wastewater resource recovery, and specifically relates to a comprehensive recovery method for gold cyanide wastewater resources containing high copper and high silver content. Background Art

[0002] In recent years, with the decreasing number of easy-to-select and easy-to-leach gold ores, complex gold ores with high copper and silver content have been continuously mined and used. The cyanide gold extraction process is currently the main process for gold smelting in the world, and the cyanide carbon slurry method is one of the main processes, which mainly adopts the technical route of "ore-grinding-cyanide leaching and activated carbon adsorption-gold-loaded carbon desorption electrolysis-gold mud purification and refining-compound gold". Due to differences in mineralization, in addition to the lower-grade Au, the ore is also accompanied by silver minerals, copper minerals, iron minerals, arsenic minerals, etc., and the silver and copper content in gold ores from different deposits varies greatly.

[0003] When treating high-copper and high-silver gold mines, the wastewater from the cyanide carbon slurry process is used in a closed-loop cycle throughout the entire process. At the same time, the silver and copper grades in the ore are relatively high, and the copper and silver content in the cyanide wastewater continues to accumulate, resulting in the occupation of the gold and silver cyanide leaching space, and the competition between silver and copper in the adsorption process, resulting in low silver and copper recovery rates, and the silver in the tail liquid is greater than 1mg / L. The silver and copper in the liquid phase are seriously entrained and lost with the tailings. Therefore, providing a safe and efficient comprehensive method for recycling and utilizing cyanide wastewater resources is one of the main issues facing gold mines.

[0004] Traditional cyanide wastewater treatment methods, such as "acid stripping method" and "SART method". From 2018 to 2022, a mine successively used "acid stripping method" and "SART method" to study the treatment of high-copper and silver cyanide wastewater. The recovery effect was not ideal, resulting in waste of resources, and the safety issues of hydrogen cyanide were not effectively controlled. Among them, the "acid stripping method" has a high safety risk of hydrogen cyanide gas overflow, a low silver and copper recovery rate, and requires the addition of a sodium hydroxide solution absorption link, a long process, and high safety operation requirements. "SART method", during the acidification and precipitation process, the copper mud product has poor thickening and sedimentation effect, the copper and silver mud has high moisture content, the recovery rates of copper, silver and cyanide are unstable, and hydrogen cyanide gas is easily generated during copper mud dehydration and diffuses into the working environment, which is prone to hydrogen cyanide gas poisoning; the operating pH is low, the production control requirements are high, and a large amount of SCN- harmful ions are easily generated. At the same time, it is difficult to treat turbid cyanide-containing wastewater (a large amount of cyanide-containing wastewater will be produced when treating broken deposit-type oxide ores and other muddy and difficult to settle ores); a large amount of calcium sulfate scaling is easily generated in the wall of the neutralization reaction tank, the water pump impeller and the conveying pipeline in the purified wastewater, and the workload of descaling is large. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for comprehensive recovery of resources from high-copper and high-silver cyanide gold cyanide wastewater.

[0006] The specific technical solution is: a comprehensive method for recovering resources from high-copper and high-silver cyanide gold cyanide wastewater, comprising the following steps:

[0007] (1) Desludging and copper-silver adsorption: After the cyanide leaching tailings are densely settled, the overflow liquid obtained is the high-copper and high-silver gold cyanide wastewater. The wastewater is first pumped through a pipeline filter to intercept floating objects and sludge, especially some difficult-to-precipitate objects, and then transported to multiple static activated carbon adsorption devices connected in series, so that some of the gold cyanide, silver cyanide, and copper cyanide complex ions in the wastewater are adsorbed and recovered by activated carbon to obtain gold, silver, and copper-loaded activated carbon.

[0008] (2) Activated carbon desorption electrolysis: The gold, silver and copper loaded activated carbon obtained in step (1) is regularly transferred to the desorption electrolysis system to extract silver and copper, thereby obtaining a gold mud intermediate product and desorbed lean carbon. The lean carbon is returned to the activated carbon adsorption device for repeated use, and the gold mud containing gold, silver, copper, iron and calcium enters purification and refining.

[0009] (3) Gold mud purification and refining: The gold mud obtained in step (2) is transferred into a trolley furnace for high-temperature roasting, and after roasting, it is transferred into a medium-frequency smelting furnace for slag smelting, and the molten liquid is quenched with water to obtain alloy sheets; the alloy sheets are placed in a nitric acid gold separation reactor to separate gold from silver, copper and iron, and gold powder is obtained through multiple separations and hot water washing. The gold powder is smelted at high temperature and cast into gold ingots; copper nitrate, silver nitrate and ferric nitrate are subjected to double decomposition reaction and iron powder replacement reaction using hydrochloric acid, and copper is separated from silver and iron in a silver separation reactor to obtain silver powder and ferric nitrate-copper nitrate solution; the ferric nitrate-copper nitrate solution is placed in a copper replacement reaction device for copper precipitation, and after the reaction is completed, HNO is obtained through dehydration. 3 -Fe(NO 3 ) 2 -Fe(NO 3 ) 3 Wastewater and sponge copper products.

[0010] Among them, the separation of gold and silver adopts the nitric acid method, which makes silver and other base metals react with nitric acid to generate soluble nitrates, while gold does not react with nitric acid and is deposited at the bottom of the reaction container, thus achieving the purpose of gold and silver separation. The main chemical reaction formula is:

[0011] 3Ag+4HNO 3 (dilute) = 3AgNO 3 +NO↑+2H 2 O

[0012] 3Cu+8HNO 3 (dilute) = 3Cu(NO 3 ) 2 +2NO↑+4H 2 O

[0013] 3Fe+8HNO 3(dilute)=3Fe(NO 3 ) 2 +2NO↑+4H 2 O

[0014] The nitrate solution containing Cu, Ag, and Fe is separated according to the double decomposition reaction of hydrochloric acid and silver to form silver chloride. The silver chloride is replaced by iron powder, and copper nitrate is also replaced by iron powder. The main chemical reaction formula is:

[0015] AgNO 3 + HCl = AgCl ↓ + HNO 3

[0016] AgCl+Fe+Cl-=Ag↓+FeCl 2

[0017] Cu(NO 3 ) 2 +Fe=Fe(NO 3 ) 2 +Cu↓

[0018] (4) First-stage copper precipitation of wastewater: The high-copper silver cyanide wastewater remaining in the activated carbon adsorption device in step (1) is transported to a first-stage copper precipitation reactor (the reactor is a stirring, sealed, and acid-resistant device, and the upper end of the reactor is provided with a micro-negative pressure exhaust pipe for emergency use), and the HNO obtained in step (3) is added to the reactor. 3 -Fe(NO 3 ) 2 -Fe(NO 3 ) 3 Wastewater and Na 2 S solution, the reaction produces Teng's blue, Prussian blue dark blue precipitate, iron hydroxide and copper sulfide precipitate.

[0019] Many small-scale and pilot studies have shown that the metal cyanide complex decomposition process can achieve relatively stable dissolution of hydrogen cyanide and cyanide in the solution or reactor by effectively controlling the acid concentration (pH control), the dosage and the speed of adding the agent, based on the principle of hydrocyanic acid decomposition kinetics (solubility, stability constant). The main chemical reaction formula is:

[0020] 2CN - +HNO 3 =HCN+NO 3 2-

[0021] CN - +Na + =NaCN

[0022] Add HNO containing divalent and trivalent iron ions to the cyanide wastewater 3-Fe(NO 3 ) 2 -Fe(NO 3 ) 3 Solution can generate dark blue precipitate (Teng's blue) and dark blue precipitate (Prussian blue). The main chemical reaction formula is:

[0023] Teng's blue precipitation: 3Fe 2+ +2[Fe(CN) 6 ] 3- =Fe 3 [Fe(CN) 6 ] 2

[0024] Prussian blue precipitation: 4Fe 3+ +3[Fe(CN) 6 ] 4- =Fe 4 [Fe(CN) 6 ] 2

[0025] After acidification and decomposition, the copper ions undergo sulfide precipitation reaction. The sulfide precipitation method uses heavy metal ions and S 2- The reaction generates M 2 S X Precipitate, according to the difference in solubility product of different metal sulfides, KspAg 2 S(1.6x10 -49 )<KspCuS(8.5x10 -45 )<KspPbS(83.4x10 -28 )<KspZnS(1.2x10 -23 )<KspFeS(3.7x10 -19) To achieve the purpose of removing or recovering heavy metals. The main chemical reaction formula is:

[0026] M X+ +S 2- →M 2 S X ↓

[0027] Multiple tests and studies have shown that the dark blue precipitate (Teng's blue) and dark blue precipitate (Prussian blue) in the solution can have a good "coagulation and aggregation" effect with copper sulfide, which is beneficial to the second stage copper precipitation and subsequent sedimentation separation and product moisture control. At the same time, due to the low pH control in the first stage, some of the hydrogen cyanide and cyanide after acidification decomposition can be stably dissolved in the liquid phase or stabilized in the closed space inside the reactor.

[0028] (5) Second stage copper and silver precipitation of wastewater: The first stage copper precipitation solution of step (5) is transferred to the middle area of ​​the second stage copper and silver precipitation reactor. The second stage copper and silver precipitation reactor consists of two reactors connected in series, and both are stirring, sealed, and acid-resistant reaction devices. The upper ends of the two reactors are equipped with micro-negative pressure exhaust pipes for emergency use.

[0029] Add H to the copper-silver precipitation reactor 2 SO 4 and Na 2 S solution to half the height of the reactor, the reaction produces copper sulfide precipitate, silver sulfide precipitate, Teng's blue precipitate, iron hydroxide and Prussian blue precipitate.

[0030] After the first stage of copper precipitation, the silver-copper-cyanide complex ions continue to undergo the second stage of "acidification + sulfide copper precipitation". The principle is: according to the principle of hydrocyanic acid decomposition kinetics (solubility, stability constant), the amount of sulfuric acid, the addition rate (most critical) and sodium sulfide can be effectively controlled to make the decomposed hydrogen cyanide and cyanide relatively stably dissolved in the solution or in the reactor (many experimental studies have fully demonstrated), and the copper and silver ions undergo sulfide precipitation reaction. The main chemical reaction formula is:

[0031] 2CN - +H 2 SO 4 =HCN+SO 4 2-

[0032] Cu 2+ +S 2- =CuS↓

[0033] Ag + +S 2- =Ag2S↓

[0034] (6) Dense precipitation of silver-copper products: The second-stage copper-silver solution of step (5) flows through a pipeline provided with a Venturi mixing section, and is fully mixed with the flocculant added in the Venturi mixing section, and then enters a thickener (the thickener is acid-resistant and fully enclosed, and an emergency micro-negative pressure exhaust device is provided at the top) for concentrated precipitation. In this way, the "Venturi flocculation + high-density precipitation" technology is used to utilize the gravity of the relatively high-density precipitate (Teng's blue precipitate + Prussian blue precipitate + copper sulfide + flocculant) and the "adsorption" and "agglomeration" effects of the carrier to accelerate the growth and precipitation of flocs.

[0035] The concentrated overflow liquid enters the pH adjustment tank, the concentrated liquid at the upper 1 / 4 of the thickener underflow is returned to the first copper precipitation reactor, and the remaining lower 3 / 4 of the concentrated slurry underflow enters the underflow buffer tank; a mixture of sodium hydroxide and lime milk is added to the buffer tank to adjust the pH to prevent hydrogen cyanide gas poisoning accidents during copper mud dehydration (experimental studies have shown that at pH = 7-8, the decomposition ability of hydrogen cyanide is relatively weak and relatively safe and controllable), and a slurry containing Teng's blue, Prussian blue dark blue precipitates, iron hydroxide and copper sulfide is obtained.

[0036] (7) Dehydration of copper mud: The slurry obtained in step (6) containing dark blue precipitates of Tengger's blue and Prussian blue, iron hydroxide and copper sulfide is deeply dehydrated by plate and frame pressing and air-drying filter press, and the filtrate is returned to the first copper precipitation reactor. The filter cake is dark blue copper mud, which enters the copper smelting system for smelting to obtain copper products and silver ingots.

[0037] (8) pH adjustment of overflow liquid: The pH of the overflow liquid obtained in step (6) is adjusted by adding lime milk to the pH adjustment tank to adjust the pH to 10.5-11, and then starting the ultrasonic device to react to obtain gypsum slurry.

[0038] The main purpose of this process is to stabilize the free cyanide ions in the liquid phase so that hydrogen cyanide gas is not generated. Lime milk is used to adjust the pH. The main chemical reaction formula is:

[0039] H 2 SO 4 +Ca(OH) 2 =CaSO 4 +H 2 O

[0040] The reaction process needs to focus on the problem of calcium sulfate scaling to prevent pipe blockage and other problems. Therefore, mechanical stirring + ultrasound is used to adjust pH and remove scale. The principle is to use the cavitation effect, chemical effect, shear effect, and inhibition effect of ultrasound to treat the fluid with an ultrasonic field, so that the scaling substances in the pipelines and reactors undergo a series of changes in their physical and chemical forms under the action of the ultrasonic field, so that they are dispersed, crushed, loosened and fall off, and are not easy to adhere to the inner wall of the reactor and the pipeline to form scale.

[0041] (9) Thickening and dehydration of gypsum slurry: The gypsum slurry obtained in step (8) is transported to a thickener, and a flocculant is added to the thickener for flocculation and precipitation. The overflow liquid of the thickener is returned to the cyanide gold extraction process such as grinding and cyanide leaching to achieve efficient recycling of cyanide; the sedimentation underflow slurry enters the plate and frame press and air-drying filter press for dehydration, and the filtrate is returned to the cyanide gold extraction process such as grinding and cyanide leaching to achieve efficient recycling of cyanide in wastewater. The calcium sulfate filter cake is transported to the grinding system such as the semi-autogenous mill before cyanide leaching.

[0042] Furthermore, in step (1), the inlet and outlet liquid pipes of the activated carbon adsorption device are both provided with 18-mesh sieve tubes; and the residence time of the wastewater in the activated carbon adsorption device is controlled to be 2-4 hours.

[0043] Furthermore, in step (2), the activated carbon desorption electrolysis time is 13-16 hours, the electrolysis voltage is 3-5V, and the concentration of sodium cyanide added during the desorption process is 0.2%-0.5%.

[0044] Furthermore, in step (3), the roasting temperature of the trolley furnace is controlled at 550-700°C, and the melting temperature of the medium frequency melting furnace is controlled at 1200-1300°C.

[0045] Further, in step (4), the reaction pH is 4-5, the reaction time is 10-20 min, and Na 2 The amount of S used is 0.2 times the copper metal content in the solution.

[0046] Furthermore, in step (5), the reaction pH is 3-4 and the reaction time is 5-10 min.

[0047] Furthermore, in step (6), the amount of flocculant added to the mixing section is 3-5 g / m3, and the pH in the buffer tank is adjusted to 7-8.

[0048] Furthermore, the air-drying time of the air-drying filter press in step (7) is 15-20 minutes per time.

[0049] Furthermore, in step (8), the ultrasonic frequency of the ultrasonic device is controlled to be 10-25 KHz, and the reaction time is 10-30 minutes.

[0050] Furthermore, the method is applicable to a sample containing 700-3000 mg / L Cu, 1-4 mg / L Ag, 0.5-10 mg / L Fe, 0.02-0.04 mg / L Au, and total CN - 700-3200mg / L cyanide wastewater.

[0051] Beneficial effects of the present invention: The present invention provides a safe, efficient and green comprehensive recovery method for high-copper and high-silver gold cyanide wastewater. The recovery rate of silver, copper and cyanide in the wastewater is as high as 90% or more. It not only realizes the reuse of valuable wastewater resources, but also effectively purifies the gold cyanide leaching circulating liquid. After the high free cyanide purified return water is reused in the cyanide gold extraction process, the recovery rate of gold, silver and copper in the cyanide leaching process is significantly improved, and the silver content of the tail liquid is also effectively controlled. More importantly, no toxic hydrogen cyanide gas escapes during the recovery process, which provides a green, economical and safe disposal method for the comprehensive recovery of valuable elements in cyanide wastewater of polymetallic gold mines, and has broad application prospects.

[0052] The technical advantages of this method are specifically reflected as follows:

[0053] (1) The reaction conditions of this method are all carried out at room temperature and pressure, which is relatively mild and more conducive to implementation.

[0054] (2) Before acidification of cyanide-containing wastewater, a pretreatment of “pipeline filtration + activated carbon adsorption and desludging” is carried out to ensure the cleanliness of the wastewater and make the raw liquid more adaptable. It can also avoid the problem of unstable recovery rates of copper, silver and cyanide caused by the need to use a large amount of sulfuric acid due to the high mud content in the raw liquid.

[0055] (3) Using nitric acid to separate gold and silver, and hydrochloric acid and iron powder to reduce silver, we can obtain both gold and silver products and HNO2, which can be used as a first-stage copper precipitation. 3 -Fe(NO 3 ) 2 -Fe(NO 3 ) 3 Wastewater helps reduce costs and avoid new environmental problems.

[0056] (4) One-stage acidification and copper deposition using HNO 3 -Fe(NO 3 ) 2 -Fe(NO 3 ) 3 Wastewater and sodium sulfide, by controlling the pH and 5, the position and acceleration speed of the reagent solution addition, and using a closed reactor, the cyanide can be relatively stably dissolved in the reactor and the liquid solution, and a "Knee blue precipitate + Prussian blue precipitate + copper sulfide" precipitate with good agglomeration effect is obtained, and the safety risk of hydrogen cyanide is low.

[0057] (5) The second stage of copper and silver precipitation is achieved by precisely controlling the amount of sulfuric acid and the reaction pH. With the support of the previous steps, the acidification and copper precipitation effects are obvious. The recovery rates of silver, copper and cyanide are high and stable. The silver recovery rate is >98%, the copper recovery rate is >91%, and the cyanide recovery rate is >92%. SCN in the purifying return water is - It is low and can be stably controlled within 800mg / L.

[0058] (6) The "high-density sedimentation + Venturi flocculation" technology is used to utilize the gravity of higher-density sediments (Kenneberg blue sedimentation + Prussian blue sedimentation + copper sulfide + flocculant) and the "adsorption" and "agglomeration" effects of the carrier to accelerate the growth and precipitation of flocs and ensure the moisture content of the copper mud. The moisture content can be stably controlled within 40%.

[0059] (7) Ultrasonic technology is used to purify high-cyanide overflow return water and adjust the pH, which completely solves the serious problem of calcium sulfate scaling in the reactor, agitator impeller and pipeline.

[0060] (8) The gypsum slag obtained at the end is returned to the grinding system, and the high-cyanide purified return water is returned to the cyanide gold extraction process. The whole process has no waste slag, zero wastewater discharge, and no hydrogen cyanide gas overflow on site, ensuring safe and environmentally friendly operations.

[0061] (9) Comprehensive recycling of high-copper and silver cyanidation wastewater resources solves the problems of "liquid swelling" and "copper enrichment" of cyanide-containing water and avoids waste of resources. The reuse of high-cyanide purified water is conducive to improving the recovery rate of copper and silver in the ore, stabilizing the control of Ag concentration in the tail liquid below 1 mg / L, and greatly reducing the loss of Ag and Cu in the tail liquid with tailings and water. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a flow chart of a method for comprehensive recovery of resources from high-copper and high-silver cyanide gold cyanide wastewater of the present invention; DETAILED DESCRIPTION

[0063] 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.

[0064] Example 1

[0065] High-silver and high-copper cyanide wastewater from a polymetallic gold mine in southern my country is the return water from cyanide leaching, adsorption, magnetic iron separation, and tailings filtration in a carbon pulp plant. It mainly contains Au0.024mg / L, Ag4.02mg / L, Cu1114mg / L, and total CN - 1399mg / L, SCN - 894mg / L, Fe0.22mg / L, pH is 11.

[0066] The method of the present invention is used to comprehensively recycle the high-silver and high-copper cyanide wastewater. The solution components at each stage of the treatment process are shown in the following table:

[0067]

[0068] According to the data in the above table, we can conclude that:

[0069] ① The copper mud produced in steps (1) to (6) has a copper recovery rate of 95.51% (1-50 / 1114×100%) and a silver recovery rate of 98.75% (1-0.05 / 4.02×100%); and after component detection of the copper mud, it is found that the copper mud contains Ag1800g / t, Cu56.5%, Fe0.1%, Ca2%, and the water content of the copper mud is 38%.

[0070] ② The cyanide overflow liquid produced in steps (4) to (9) has a total cyanide recovery rate of 90.06% (1260 / 1399×100%), and the thiocyanate is stabilized at 896 mg / L.

[0071] ③ No hydrogen cyanide gas was detected at the production site through the 24-hour hydrogen cyanide online detection equipment installed on site.

[0072] ④ The high-cyanide return water is reused in the cyanide gold extraction process. Compared with the original process, the Au leaching rate is increased by 0.58%, the silver leaching rate is increased by 0.4%, and the copper leaching rate is increased by 1.5%; the Ag in the tail liquid is stabilized below 0.6 mg / L.

[0073] Example 2

[0074] High-silver and high-copper cyanide wastewater from a polymetallic gold mine in southern my country is the return water from cyanide leaching, adsorption, magnetic iron separation, and tailings filtration in a carbon pulp plant. It mainly contains Au0.021mg / L, Ag1.30mg / L, Cu800mg / L, and total CN - 942mg / L, SCN - 700mg / L, Fe0.22mg / L, pH is 11.

[0075] The method of the present invention is used to comprehensively recycle the high-silver and high-copper cyanide wastewater. The solution components at each stage of the treatment process are shown in the following table:

[0076]

[0077] According to the data in the above table, we can conclude that:

[0078] ① The copper mud produced in steps (1) to (6) has a copper recovery rate of 95.00% (1-40 / 800×100%) and a silver recovery rate of 98.46% (1-0.02 / 1.3×100%); and after component detection of the copper mud, it is found that the copper mud contains Ag850g / t, Cu50%, Fe0.2%, Ca2.5%, and the water content of the copper mud is 40%.

[0079] ② The cyanide overflow liquid produced in steps (4) to (9) has a total cyanide recovery rate of 95.54% (900 / 942×100%), and the thiocyanate is stabilized at 705 mg / L.

[0080] ③ No hydrogen cyanide gas was detected at the production site through the 24-hour hydrogen cyanide online detection equipment installed on site.

[0081] ④ The high-cyanide return water is reused in the cyanide gold extraction process. Compared with the original process, the Au leaching rate is increased by 0.3%, the silver leaching rate is increased by 0.5%, and the copper leaching rate is increased by 2%; the Ag in the tail liquid is stabilized below 0.5 mg / L.

[0082] In summary, the Ag, Cu, and cyanide in the cyanide wastewater resources are efficiently recycled by this method, the water content of the product is greatly reduced, and the thiocyanate in the purified solution is low, without a significant increase. More importantly, there is no overflow of toxic hydrogen cyanide gas during the recovery process, and the safety problem is effectively solved. At the same time, the return water is reused in the cyanide gold extraction process. Compared with the original process, the leaching rates of gold, silver, and copper are all improved, and the silver content in the tail liquid is also effectively controlled, reducing resource losses. After multiple production applications, it is further shown that the use of this process has good and stable indicators and strong adaptability. It provides a green, economical and safe disposal method for the comprehensive recovery of valuable elements in cyanide wastewater in polymetallic gold mines, and has broad application prospects.

[0083] 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 comprehensive recovery of resources from high-copper and high-silver cyanide gold cyanide wastewater, characterized in that: The steps include: (1) Desludging and copper-silver adsorption: After the cyanide leaching tailings are densely settled, the overflow liquid obtained is the high-copper and high-silver gold cyanide wastewater. The wastewater is first pumped through a pipeline filter to intercept floating objects and sludge, and then transported to multiple static activated carbon adsorption devices connected in series, so that part of the gold cyanide, silver cyanide, and copper cyanide complex ions in the wastewater are adsorbed and recovered by activated carbon to obtain gold, silver, and copper loaded activated carbon; (2) Activated carbon desorption electrolysis: The gold, silver and copper loaded activated carbon obtained in step (1) is regularly transferred to the desorption electrolysis system to extract silver and copper, thereby obtaining a gold mud intermediate product and desorbed lean carbon. The lean carbon is returned to the activated carbon adsorption device for repeated use, and the gold mud containing gold, silver, copper, iron and calcium enters purification and refining; (3) Purification and refining of gold mud: the gold mud obtained in step (2) is transferred into a trolley furnace for high-temperature roasting, and after roasting, it is transferred into a medium-frequency smelting furnace for slag smelting, and the molten liquid is quenched with water to obtain alloy sheets; the alloy sheets are placed in a nitric acid gold separation reactor to separate gold from silver, copper and iron, and gold powder is obtained through multiple separations and hot water washing. The gold powder is smelted at high temperature and cast into gold ingots; copper nitrate, silver nitrate and ferric nitrate are subjected to double decomposition reaction and iron powder replacement reaction using hydrochloric acid, and copper is separated from silver and iron in a silver separation reactor to obtain silver powder and ferric nitrate-copper nitrate solution; the ferric nitrate-copper nitrate solution is placed in a copper replacement reaction device for copper precipitation, and after the reaction is completed, HNO3-Fe(NO3)2-Fe(NO3)3 wastewater and sponge copper products are obtained through dehydration; (4) First-stage copper precipitation of wastewater: The high-copper silver cyanide wastewater remaining in the activated carbon adsorption device of step (1) is transported to a first-stage copper precipitation reactor, and the HNO3-Fe(NO3)2-Fe(NO3)3 wastewater and Na2S solution obtained in step (3) are added to the reactor to react and obtain Teng's blue, Prussian blue dark blue precipitates, iron hydroxide and copper sulfide precipitates; (5) Second stage copper and silver precipitation of wastewater: the first stage copper precipitation solution of step (5) is transferred to the middle area of ​​the second stage copper and silver precipitation reactor, the second stage copper and silver precipitation reactor is two reactors connected in series, H2SO4 and Na2S solution are added to the copper and silver precipitation reactor to half the height of the reactor, and the reaction obtains copper sulfide precipitation, silver sulfide precipitation, Teng's blue precipitation, iron hydroxide and Prussian blue precipitation; (6) dense precipitation of silver-copper products: the second-stage copper precipitation silver solution of step (5) is passed through a pipeline provided with a venturi mixing section, and is fully mixed with the flocculant added in the venturi mixing section and then enters a thickener for concentrated precipitation. The concentrated overflow liquid enters a pH adjustment tank, and the concentrated liquid at the upper 1 / 4 of the thickener underflow is returned to the first-stage copper precipitation reactor, and the remaining lower 3 / 4 of the concentrated slurry underflow enters an underflow buffer tank; sodium hydroxide and lime milk mixed solution are added to the buffer tank to adjust the pH, and a slurry containing Teng's blue, Prussian blue dark blue precipitates, iron hydroxide and copper sulfide is obtained; (7) Dehydration of copper mud: The slurry containing Tengger's blue, Prussian blue dark blue precipitate, iron hydroxide and copper sulfide obtained in step (6) is deeply dehydrated by plate and frame pressing and air drying filter press, and the filtrate is returned to the first copper precipitation reactor. The filter cake is dark blue copper mud, which enters the copper smelting system for smelting to obtain copper products and silver ingots; (8) pH adjustment of the overflow liquid: adjusting the pH of the overflow liquid obtained in step (6), adding lime milk to the pH adjustment tank, adjusting the pH to 10.5-11, and starting the ultrasonic device to react to obtain gypsum slurry; (9) Gypsum slurry thickening and dehydration: The gypsum slurry obtained in step (8) is transported to a thickener, and a flocculant is added to the thickener for flocculation and precipitation. The overflow of the thickener is returned to the cyanide gold extraction process, and the precipitated underflow slurry enters the plate and frame press and air-dried filter press for dehydration. The filtrate is returned to the cyanide gold extraction process, and the calcium sulfate filter cake is transported to the grinding system before cyanide leaching.

2. A method for comprehensive recovery of resources from high-copper and high-silver cyanide gold cyanide wastewater according to claim 1, characterized in that: In step (1), the inlet and outlet liquid pipes of the activated carbon adsorption device are both provided with 18-mesh sieve tubes; and the residence time of the wastewater in the activated carbon adsorption device is controlled to be 2-4 hours.

3. A method for comprehensive recovery of resources from high-copper and high-silver cyanide gold cyanide wastewater according to claim 1, characterized in that: In step (2), the activated carbon desorption electrolysis time is 13-16 hours, the electrolysis voltage is 3-5V, and the concentration of sodium cyanide added during the desorption process is 0.2%-0.5%.

4. A method for comprehensive recovery of resources from high-copper and high-silver cyanide gold cyanide wastewater according to claim 1, characterized in that: In step (3), the roasting temperature of the trolley furnace is controlled at 550-700°C, and the melting temperature of the medium frequency melting furnace is controlled at 1200-1300°C.

5. A method for comprehensive recovery of resources from high-copper and high-silver cyanide gold cyanide wastewater according to claim 1, characterized in that: In step (4), the reaction pH is 4-5, the reaction time is 10-20 min, and the amount of Na2S used is 0.2 times the copper metal content in the solution.

6. A method for comprehensive recovery of resources from high-copper and high-silver cyanide gold cyanide wastewater according to claim 1, characterized in that: In step (5), the reaction pH is 3-4 and the reaction time is 5-10 min.

7. A method for comprehensive recovery of resources from high-copper and high-silver cyanide gold cyanide wastewater according to claim 1, characterized in that: Step (6) The amount of flocculant added in the Chinese mixing section is 3-5 g / m 3 , the pH in the buffer tank is adjusted to 7-8.

8. The method for comprehensive recovery of resources from high-copper and high-silver cyanide gold cyanide wastewater according to claim 1, characterized in that: The air-drying time of the air-drying filter press in step (7) is 15-20 minutes per time.

9. A method for comprehensive recovery of resources from high-copper and high-silver cyanide gold cyanide wastewater according to claim 1, characterized in that: In step (8), the ultrasonic frequency of the ultrasonic device is controlled to be 10-25 KHz, and the reaction time is 10-30 minutes.

10. A method for comprehensive recovery of resources from high-copper and high-silver cyanide gold cyanide wastewater according to any one of claims 1 to 9, characterized in that: The method is suitable for samples containing 700-3000 mg / L Cu, 1-4 mg / L Ag, 0.5-10 mg / L Fe, 0.02-0.04 mg / L Au, and total CN - 700-3200mg / L cyanide wastewater.

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