Method for recovering gold and copper from gold-bearing waste

Abstract

A method for recycling gold and copper from gold-bearing waste specifically comprises the steps that after the gold-bearing waste of a gold smelting plant is finely ground, the gold-bearing waste and flotation sulfur gold tailings or cyanidation tailings are mixed according to the proportion of 1: (20-600) for ore blending, and a mixed ingredient is obtained; the mixed ingredients are mixed into ore pulp, the gold grade and the S content are controlled, hot-pressing pre-oxidation is conducted under the conditions of certain temperature, oxygen partial pressure, time and stirring linear speed, and oxidized ore pulp is obtained; the oxidized ore pulp is subjected to dense washing, and gold-rich underflow oxidizing slag and copper-rich overflow acid liquor are obtained; in one path, the underflow oxidizing slag is subjected to subsequent conventional cyanidation leaching, activated carbon adsorption, desorption electrodeposition and gold mud purification, and a gold ingot is obtained; in the other path, after the pH value of overflow acid liquor rich in copper is adjusted, the overflow acid liquor is thickened after being subjected to sulfuration and copper deposition under the conditions of certain reaction time, pH and oxidation-reduction potential, overflow liquid and underflow are obtained, the underflow is subjected to filter pressing and packaging to obtain copper concentrate, and the overflow liquid and flotation tailings are neutralized and then stacked to a tailings pond. And the method has the advantages of low cost, high efficiency and the like, and is particularly suitable for gold smelting plants.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrometallurgical treatment, and particularly to a method for recovering gold and copper from gold-containing waste materials, which is particularly suitable for application in gold smelting plants. Background Art

[0002] During the production process of gold mining enterprises, a large amount of gold-containing waste materials will be generated. These waste materials often contain some valuable metals such as gold and copper, and have high comprehensive recovery value. However, for a long time, due to technical and production cost reasons, gold-containing waste materials have not been effectively utilized and are piled up in large quantities, which not only pollutes the environment but also causes a large amount of resource waste. Although gold-containing waste materials can be supplied to large copper smelting companies for mixing and blending with copper concentrates, due to the existing processes having long recovery process flows, low direct recovery rates, and a large amount of system backlogs, there are problems that tailings generated by mines, especially gold-containing waste materials from gold smelting plants, and flotation sulfur gold tailings waste or cyanide tailings have not been effectively utilized, resulting in environmental pollution and waste of precious resources.

[0003] To solve the above problems, people have successively carried out research and development: "A method for comprehensively recovering valuable metals in gold smelting slag" disclosed in Chinese Patent CN105112677A uses a chlorinating agent mixed roasting process to treat cyanide tailings, and recovers precious metals by collecting flue gas. There is an environmental risk of overflow of flue gas in this process, and the roasted slag also needs to recover iron through a grinding and flotation process. However, the entire process flow is complex, parameter control is not easy, and the recovery rate is low; "A process for comprehensively recovering precious metals such as gold, silver, platinum, and palladium from gold-containing waste materials" disclosed in Chinese Patent CN104762479A is to roast the gold-containing waste materials in a rotary kiln, leach copper, bismuth, etc. with sulfuric acid, industrial salt, and sodium chlorate, and then perform secondary leaching with chemical reagents such as sulfuric acid and hydrochloric acid heated to 85 - 95 °C. However, the amount of chemical reagents used in the whole process is more than the amount of gold-containing waste materials, the production cost is high, and a large amount of industrial wastewater is easily generated; "A method for co-processing gold-containing waste slag with copper smelting slag" disclosed in Chinese Patent CN113355525A is to mix copper converting slag / copper refining slag, gold-containing waste slag, and a sulfiding agent and melt them at 1200 - 1350 °C to obtain matte rich in gold, silver, and copper, flue gas, and sulfide slag. The matte rich in gold, silver, and copper is refined to recover gold, silver, and copper, and the flue gas and sulfide slag adopt a flotation process to recover valuable metals such as copper and lead. However, a large amount of acid will be generated during the treatment process, and additional neutralizing agents need to be newly added.

[0004] After retrieval by this research group, no prior literature reports on methods for recovering gold and copper from gold-containing waste materials were found.

[0005] Therefore, it is of great significance to develop a method for recovering gold and copper from gold-containing waste materials with low cost and high efficiency. Summary of the Invention

[0006] The task of the present invention is to overcome the shortcomings of the prior art and propose a method for recovering gold and copper from gold-containing waste materials, which can not only turn waste slag from gold smelting plants into treasure, but also make use of flotation or cyanidation tailings, and has the characteristics of low cost and high efficiency.

[0007] A method for recovering gold and copper from gold-containing waste materials is provided to solve the problem that a large amount of waste materials containing some valuable metals such as gold and copper are stored in the production process of gold mining enterprises, which not only pollutes the environment but also causes a large amount of resource waste. The method specifically includes the following process steps and conditions:

[0008] (1) finely grinding the gold-containing waste from the gold smelter and mixing it with the flotation sulfur gold tailings or cyanide tailings in a ratio of 1:20 to 600 to obtain a mixed batch;

[0009] (2) slurrying the mixed ingredients to a slurry concentration of 15-36%, controlling the gold grade to 20-50 g / t and the S content to 8-16%, and hot pressing pre-oxidizing at a temperature of 180-225° C., an oxygen partial pressure of 0.5-1.2 MPa, a time of 0.5-4 h, and a stirring line speed of 1.0-3.0 m / s to obtain an oxidized slurry;

[0010] (3) densely washing the oxide slurry to obtain an underflow oxide slag rich in gold and an overflow acid solution rich in copper;

[0011] (4.1) The underflow slag is subjected to subsequent conventional cyanide leaching, activated carbon adsorption, analytical electrowinning, and gold mud purification to obtain gold ingots;

[0012] (4.2) The copper-rich overflow acid solution is adjusted to a pH value and then concentrated under the conditions of a reaction time of 0.5 to 1 h, a pH of 2 to 4, and a redox potential of 300 to 500 mv to obtain an overflow solution and an underflow. The underflow is filtered and packaged to obtain the copper concentrate. The overflow solution is neutralized with the flotation tailings and then piled into a tailings pond.

[0013] The innovation of the present invention is:

[0014] 1. Coordinated treatment of various gold-containing wastes, using pressurized oxidation pretreatment to fully dissociate the gold wrapped in sulfide and carbonate substances in cyanide tailings or flotation tailings. At the same time, the acid produced can leach copper and other metals in gold smelting slag. The oxidized slag can be directly cyanide leached after washing, with a high gold leaching rate and low sodium cyanide consumption. The copper-containing iron acid leaching liquid is directly used with sodium sulfide or sodium hydrosulfide to recover copper, and then neutralized with the mixed flotation tailings and piled into the flotation tailings pond, realizing the comprehensive utilization of resources and facilitating the sustainable and healthy development of mining and smelting enterprises.

[0015] 2. The wet method of gold extraction has the advantages of low cost, short process, simple technology, large processing scale, small footprint, and comprehensive recovery of multiple metals.

[0016] Compared with the prior art, the present invention has the following advantages or effects:

[0017] Since various gold-containing wastes are co-processed and pressure oxidation pretreatment is adopted to fully dissociate the gold wrapped in sulfide and carbonate substances in cyanide tailings or flotation tailings, waste can be turned into treasure; at the same time, since the generated acid is used to leach metals such as copper in gold smelting slag, and the oxidized slag can be directly subjected to cyanidation leaching after washing, metals such as copper can also be extracted; in addition, since the excellent wet gold extraction process is not changed and the oxidized slag is directly subjected to cyanidation leaching after washing, the gold leaching rate is high and the consumption of sodium cyanide is low. In short, the present invention realizes comprehensive utilization of resources, is beneficial to the sustainable and healthy development of mining enterprises and smelting enterprises, still adopts the wet gold extraction process, can also reduce costs, shorten the process, has a simple process, a large treatment scale, a small floor area and can comprehensively recover various metals. Therefore, this method can not only revitalize funds for enterprises, but also reduce environmental problems caused by the stacking of gold-containing wastes. At the same time, under the new situation of increasingly strict environmental protection, it realizes the resource utilization and efficient and clean utilization level of gold-containing upgrading wastes, and actively develops a green circular economy.

[0018] The percentages involved in the application documents are mass percentages. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic process flow diagram of a method for recovering gold and copper from gold-containing wastes proposed according to the present invention.

[0020] The present invention will be further described in detail below with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE INVENTION

[0021] As Figure 1 shown, a method for recovering gold and copper from gold-containing wastes aims at the problem that a large amount of waste containing valuable metals such as part of gold and copper generated in the production process of gold mining enterprises is stacked in large quantities, which not only pollutes the environment but also causes a large amount of resource waste. The specific process steps and conditions are as follows:

[0022] (1) After finely grinding the gold-containing waste from the gold smelter, it is mixed and proportioned with flotation sulfur gold tailings or cyanide tailings in a ratio of 1:20 to 600 to obtain a mixed mixture;

[0023] (2) The mixed mixture is adjusted to a pulp concentration of 15 to 36%, the gold grade is controlled at 20 to 50 g / t, the S content is 8 to 16%, and it is thermally pressed and pre-oxidized under the conditions of a temperature of 180 to 225 °C, an oxygen partial pressure of 0.5 to 1.2 MPa, a time of 0.5 to 4 h, and a stirring linear velocity of 1.0 to 3.0 m / s to obtain an oxidized pulp;

[0024] (3) The oxidized pulp is thickened and washed to obtain an underflow oxidized slag rich in gold and an overflow acid solution rich in copper;

[0025] (4.1) Subject the underflow oxidized slag to subsequent conventional cyanidation leaching, activated carbon adsorption, desorption electrowinning, and gold mud purification to obtain gold ingots.

[0026] (4.2) Adjust the pH value of the overflow acid solution rich in copper, then carry out copper sulfide precipitation under the conditions of a reaction time of 0.5 - 1 h, pH 2 - 4, and redox potential of 300 - 500 mV, followed by thickening to obtain overflow liquid and underflow. The underflow is pressure-filtered and packed into copper concentrate, and the overflow liquid is neutralized with flotation tailings and then stacked in the tailings pond.

[0027] The process of the present invention may further be:

[0028] In step (1), the gold smelting plant is the neutralization and precipitation slag of pyrometallurgical smelting slag, desorption liquid, and external discharge liquid of gold refining, with a gold grade of 200 - 3000 g / t and a copper grade of 5 - 15%.

[0029] The flotation sulfur gold tailings in step (1) contain a large amount of carbonate and silicate chemicals, with an Au grade of 0.5 - 3 g / t, a Cu content of 0.08%, and an S content of 10 - 18%; the copper grade of the underflow is 28% - 45%.

[0030] In step (1), the gold-containing waste materials in the gold smelting plant are finely ground to a proportion of -200 mesh accounting for 75%.

[0031] The main minerals of the flotation sulfur gold tailings in step (1) or the cyanidation tailings in step (4.1) are pyrite that encloses fine-grained gold, with a gold content of 0.5 - 3 g / t and an S content of 10 - 18%.

[0032] In step (4.2), add lime milk or other inorganic alkaline agents to the overflow acid solution rich in copper, control the reaction pH at 3 - 4, the reaction time at 1 h, and the redox potential at 300 - 380 mV, and then add sodium sulfide or sodium hydrosulfide according to 1.05 - 1.15 times the chemical equivalent of the copper content for copper sulfide precipitation to obtain copper concentrate.

[0033] Example 1

[0034] The gold-containing waste materials from a gold smelter are successively finely ground to a particle size of not less than 75% passing through a 200-mesh sieve and then mixed with flotation sulfur-gold tailings or cyanidation tailings in a weight ratio of 1:100 to obtain a mixed ore charge with Au 25 g / t, Cu 0.23%, and S 16%. The mixed ore charge is slurried to a pulp density of 20 - 30%, and subjected to hot pressure pre-oxidation at a temperature of 220 °C, an oxygen partial pressure of 0.8 MPa, a residence time of 3 h, and a stirring linear velocity of 2.5 m / s to obtain an oxidized pulp. The oxidized pulp is thickened and washed to obtain an underflow rich in gold oxide slag and an overflow acidic solution rich in copper. The above underflow oxide slag is washed and adjusted to alkaline cyanidation. The above washing solution is mixed with the copper-rich overflow solution and the pH is adjusted to 2.5 - 3 with lime, and the oxidation-reduction potential is 368 mV - 400 mV. Sodium sulfide is added to precipitate copper, and the copper grade in the tail solution is reduced to 0.5 mg / L, and the copper content in the copper precipitation slag is 36.52%. The copper precipitation underflow is filtered and packed and sold as copper concentrate. The copper precipitation tail solution is mixed with the mixed flotation tailings and pumped to the flotation tailings pond. The underflow gold-rich oxide slag is subjected to cyanidation leaching, and the gold leaching rate is 98.75%.

[0035] Example 2

[0036] The gold-containing waste materials from a gold smelter are successively finely ground to a particle size of not less than 75% passing through a 200-mesh sieve and then mixed with flotation sulfur-gold tailings or cyanidation tailings in a weight ratio of 1:80 to obtain a mixed ore charge with Au 35 g / t, Cu 0.31%, and S 13%. The mixed ore charge is slurried to a pulp density of 20 - 30%, and subjected to hot pressure pre-oxidation at a temperature of 210 - 220 °C, an oxygen partial pressure of 0.7 - 0.8 MPa, a residence time of 2 h, and a stirring linear velocity of 2.2 m / s to obtain an oxidized pulp. The oxidized pulp is thickened and washed to obtain an underflow rich in gold oxide slag and an overflow acidic solution rich in copper. The above underflow oxide slag is washed and adjusted to alkaline cyanidation. The washing solution is mixed with the copper-rich overflow solution and the pH is adjusted to 3 - 3.5 with lime, and the oxidation-reduction potential is 352 mV - 380 mV. Sodium sulfide is added to precipitate copper, and the copper grade in the tail solution is reduced to 0.5 mg / L, and the copper content in the copper precipitation slag is 32.62%. The copper precipitation underflow is filtered and packed and sold as copper concentrate. The copper precipitation tail solution is mixed with the mixed flotation tailings and pumped to the flotation tailings pond. The underflow gold-rich oxide slag is subjected to cyanidation leaching, and the gold leaching rate is 98.92%.

[0037] Example 3

[0038] The gold-containing waste materials from the gold smelter are successively finely ground to not less than 75% - 200 mesh and then mixed with flotation sulfur gold tailings or cyanidation tailings in a weight ratio of 1:60 to obtain a mixed ore with Au 45 g / t, Cu 0.41%, and S 10%; the mixed ore is slurried to a pulp concentration of 20 - 30%, and subjected to hot pressure pre-oxidation at a temperature of 200 - 210 °C, an oxygen partial pressure of 0.6 - 0.8 MPa, a residence time of 2 h, and a stirring linear velocity of 2 m / s to obtain an oxidized pulp; the above oxidized pulp is thickened and washed to obtain an underflow rich in gold oxidized slag and an overflow acidic solution rich in copper; the above underflow oxidized slag is washed and adjusted for alkaline cyanidation; the above washing solution is mixed with the copper-containing overflow solution and the pH is adjusted to 3.5 - 4 with lime, the oxidation-reduction potential is 308 mv - 345 mv, sodium sulfide is added to precipitate copper, the copper grade in the tail solution is reduced to 0.5 mg / L, and the copper content in the copper precipitation slag is 28.62%; the copper precipitation underflow is pressure-filtered and packaged and sold as copper concentrate; the copper precipitation tail solution is mixed with the mixed flotation tailings and pumped to the flotation tailings pond; the underflow rich in gold oxidized slag is subjected to cyanidation leaching with a gold leaching rate of 98.83%.

[0039] As described above, the present invention can be preferably realized. The above embodiments are only the best implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall all be equivalent substitution methods and are included in the protection scope of the present invention.

Claims

1. A method for recovering gold and copper from gold-containing waste, which is aimed at the problem that a large amount of waste containing some gold, copper and other valuable metals is stored in the production process of gold mining enterprises, which not only pollutes the environment but also causes a large amount of resource waste. The specific process steps and conditions are as follows: (1) finely grinding the gold-containing waste from the gold smelter and mixing it with the flotation sulfur gold tailings or cyanide tailings in a ratio of 1:20 to 600 to obtain a mixed batch; (2) slurrying the mixed ingredients to a slurry concentration of 15-36%, controlling the gold grade to 20-50 g / t and the S content to 8-16%, and hot pressing pre-oxidizing at a temperature of 180-225° C., an oxygen partial pressure of 0.5-1.2 MPa, a time of 0.5-4 h, and a stirring line speed of 1.0-3.0 m / s to obtain an oxidized slurry; (3) densely washing the oxide slurry to obtain an underflow oxide slag rich in gold and an overflow acid solution rich in copper; (4.1) The underflow slag is subjected to subsequent conventional cyanide leaching, activated carbon adsorption, analytical electrowinning, and gold mud purification to obtain gold ingots; (4.2) The copper-rich overflow acid solution is adjusted to a pH value and then concentrated under the conditions of a reaction time of 0.5 to 1 h, a pH of 2 to 4, and a redox potential of 300 to 500 mv to obtain an overflow solution and an underflow. The underflow is filtered and packaged to obtain the copper concentrate. The overflow solution is neutralized with the flotation tailings and then piled into a tailings pond.

2. The method according to claim 1, characterized in that In the step (1), the gold smelter is composed of pyrometallurgical slag, analytical solution and gold refining effluent neutralized and precipitated slag, wherein the gold grade is 200-3000 g / t and the copper grade is 5-15%.

3. The method according to claim 1, characterized in that The flotation sulphur-gold tailings in step (1) contain a large amount of carbonate and silicate chemicals, wherein the Au grade is 0.5-3 g / t, the Cu content is 0.08%, and the S content is 10-18%; the underflow copper grade is 28%-45%.

4. The method according to claim 1 or 2, characterized in that In the step (1), the gold-containing waste from the gold smelter is finely ground to -200 mesh, accounting for 75%.

5. The method according to claim 1 or 3, characterized in that The main minerals of the flotation sulfide gold tailings in step (1) or the cyanide tailings in step (4.1) are pyrites encapsulating fine gold particles, with a gold content of 0.5 to 3 g / t and a sulfur content of 10 to 18%.

6. The method according to claim 1, characterized in that In the step (4.2), lime milk or other inorganic alkaline agents are added to the overflow acid solution rich in copper, the pH of the reaction is controlled to be 3-4, the reaction time is 1 hour, the redox potential is controlled to be 300-380 mv, and then sodium sulfide or sodium hydrosulfide is added at 1.05-1.15 times the chemical equivalent of the copper content to sulfide precipitate copper to obtain copper concentrate.

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