Cyanide-free environment-friendly leaching process for gold in micro-fine particle gold-containing material

Abstract

The invention discloses a cyanide-free green environment-friendly leaching process for gold in a material containing micro-fine-particle gold, which comprises the following steps: step 1, grinding the material containing micro-fine-particle gold to obtain a fine-fraction mineral, then adding water for size mixing to obtain ore pulp A, then adding sodium sulfite, ferric sulfate and sodium hydroxide, stirring and mixing, then adding a pypocholoride solution, mixing and size mixing, and uniformly stirring to obtain ore pulp B; pre-treated ore pulp B is obtained; 2, the concentration of the ore pulp B obtained in the step 1 is adjusted, then sodium bicarbonate and calcium oxide or calcium hydroxide are added, the pH value is adjusted, stirring is conducted, and ore pulp C is obtained; and 3, ammonium sulfate, ammonium chloride, ammonium bicarbonate and thiosulfate are added into the ore pulp C obtained in the step 2, a solution D is obtained, stirring and leaching are conducted, and gold leaching liquid and leaching residues are obtained. The process provided by the invention is used for cyanide-free green environment-friendly leaching of the micro-fine gold, can realize efficient leaching of the micro-fine gold at normal temperature, normal pressure and normal state, and improves the utilization rate of the gold material.

Description

Technical Field

[0001] The invention relates to a green and environmentally friendly leaching method for gold in gold-containing materials, and in particular to a cyanide-free green and environmentally friendly leaching process for gold in fine-grained gold-containing materials. Background Art

[0002] At present, the gold extraction methods commonly used at home and abroad are cyanide leaching and cyanide-containing agent leaching. However, the above methods will cause serious pollution and harm to the environment and humans.

[0003] With the continuous advancement of gold leaching technology and the continuous improvement of human environmental protection requirements, environmentally friendly gold extraction agents that aim to replace the cyanide method are also constantly innovating and developing. At present, there are mainly environmentally friendly gold extraction agents such as lime sulfur mixture, chlorination method, halogen series, and ammonium polysulfide. However, the efficiency and stability of gold extraction need to be further improved, especially now that easy-to-select resources are increasingly exhausted, and difficult-to-select gold mines have gradually become one of the main development targets. The fine particles of difficult-to-select gold ores are generally wrapped in silicates, carbonates, sulfides, and paragenetic minerals. It is difficult to dissociate gold monomers by finely grinding the ore, which makes it difficult for the gold particles to contact the leaching solution and cannot effectively leach gold.

[0004] Therefore, it is necessary to design a cyanide-free green and environmentally friendly leaching process method that can leach gold from materials containing fine gold particles. Summary of the invention

[0005] The purpose of the present invention is to provide a cyanide-free green and environmentally friendly leaching process method for leaching gold from a material containing fine gold particles, which can solve the problems existing in the prior art and improve the utilization rate of the gold material.

[0006] In order to achieve the above-mentioned object, the present invention provides a cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles, wherein the process comprises: step 1, grinding the material containing fine gold particles to obtain fine-grained minerals, then adding water to slurry to obtain slurry A, then adding sodium sulfite, ferric sulfate, and sodium hydroxide, stirring and mixing, adding hypochlorite solution, mixing and slurrying and stirring evenly to obtain pretreated slurry B; step 2, adjusting the concentration of the slurry B obtained in step 1, then adding sodium bicarbonate, and calcium oxide or calcium hydroxide, adjusting the pH value, and stirring to obtain slurry C; step 3, adding ammonium sulfate, ammonium chloride, ammonium bicarbonate, and thiosulfate to the slurry C obtained in step 2 to obtain solution D, stirring, leaching to obtain gold leaching solution and leaching residue, and then obtaining gold by replacement.

[0007] The above-mentioned cyanide-free green and environmentally friendly leaching process for gold in fine-grained gold-containing materials, wherein, in the step 1, the fine-grained gold-containing material is ground to a particle size of 200 meshes accounting for more than 90%, to obtain fine-grained minerals, and then water is added to the slurry to obtain a slurry A with a solid-liquid ratio of 1:1.

[0008] The above-mentioned cyanide-free green and environmentally friendly leaching process for gold in fine-grained gold-containing materials, wherein in the step 1, the amount of sodium sulfite added is 0.1-0.2kg / t, the amount of ferric sulfate added is 0.1-0.3kg / t, and the amount of sodium hydroxide added is 0.1-0.2kg / t.

[0009] The above-mentioned cyanide-free green and environmentally friendly leaching process for gold in fine-grained gold-containing materials, wherein, in the step 1, the hypochlorite solution is any one of sodium hypochlorite, potassium hypochlorite, and calcium hypochlorite aqueous solutions; the amount of the hypochlorite solution added is 1-2 times the mass of the gold-containing material; and the mass concentration of the hypochlorite solution is 0.1-0.3% by mass percentage.

[0010] In the above-mentioned cyanide-free green and environmentally friendly leaching process for gold in fine-grained gold-containing materials, in the step 1, the mixing and slurry stirring is carried out at a speed of 200-350r / min for 20-30min to obtain a slurry B solution.

[0011] The above-mentioned cyanide-free green and environmentally friendly leaching process for gold in fine-grained gold-containing materials, wherein, in the step 2, water is added to adjust the concentration of slurry B to a solid-liquid ratio of 1:3, and then sodium bicarbonate and calcium oxide or calcium hydroxide are added to adjust the pH value of the mixed solution to 9-10, and then stirred for 20-30 minutes to obtain a slurry C solution.

[0012] In the above-mentioned cyanide-free green and environmentally friendly leaching process for gold in fine-grained gold-containing materials, the amount of sodium bicarbonate added is 0.5-1kg / t; the amount of any one of calcium oxide and calcium hydroxide added is 0.2-4kg / t.

[0013] The above-mentioned cyanide-free green and environmentally friendly leaching process for gold in fine-grained gold-containing materials, wherein in the step 3, the amount of ammonium sulfate added is 0.3-1kg / t, the amount of ammonium chloride added is 0.1-0.5kg / t, and the amount of ammonium bicarbonate added is 0.1-0.3kg / t.

[0014] In the above-mentioned cyanide-free green and environmentally friendly leaching process for gold in fine-grained gold-containing materials, in step 3, the thiosulfate is ammonium thiosulfate or sodium thiosulfate; and in terms of mass percentage, the mass concentration of the thiosulfate in the mixed solution D is 0.01-0.05%.

[0015] The above-mentioned cyanide-free green and environmentally friendly leaching process for gold in fine-grained gold-containing materials, wherein, in the step 3, the solution D is stirred at room temperature for 4-6 hours for leaching, and the solid-liquid separation is carried out by a filter press to obtain a gold leaching solution and a leaching residue, and then the gold is obtained by a replacement method.

[0016] The cyanide-free green and environmentally friendly leaching process for gold in fine gold-containing materials provided by the present invention has the following advantages:

[0017] The cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles of the present invention uses sodium sulfite, ferric sulfate, hypochlorite, sodium hydroxide, etc. to pretreat the gold material together to dissolve impurities wrapped on the surface of the gold, expose the gold, and facilitate the subsequent leaching of the gold. Then, ammonium sulfate, ammonium chloride, ammonium bicarbonate, and thiosulfate are added. The thiosulfate uses the effect of ammonium ions to cooperate with gold ions to generate ammonia complex ions, which enter the solution and are replaced by thiosulfate ions to form more stable gold thiosulfate complex ions. In this way, efficient leaching of fine gold particles under normal temperature and normal conditions can be achieved, and the utilization rate of the gold material can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a schematic diagram of the process of cyanide-free green and environmentally friendly leaching of gold from fine gold-containing materials. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is described in detail below through specific implementation cases and in conjunction with the accompanying drawings. For specific experimental conditions and methods not specified, the technical means used are generally conventional means known to those skilled in the art.

[0020] like Figure 1 As shown, the present invention provides a cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles, which comprises: step 1, grinding the material containing fine gold particles to obtain fine-grained minerals, then adding water to prepare pulp to obtain pulp A, then adding sodium sulfite, ferric sulfate, and sodium hydroxide, stirring and mixing, adding hypochlorite solution, mixing and preparing the pulp and stirring evenly to obtain pretreated pulp B; step 2, adjusting the concentration of the pulp B obtained in step 1, then adding sodium bicarbonate, and calcium oxide or calcium hydroxide, adjusting the pH value, and then stirring to obtain pulp C; step 3, adding ammonium sulfate, ammonium chloride, ammonium bicarbonate, and thiosulfate to the pulp C obtained in step 2 to obtain solution D, stirring, leaching to obtain gold leaching solution and leaching residue, and then obtaining gold by replacement.

[0021] Preferably, in step 1, the fine gold-containing material is ground until particles with a particle size of 200 mesh account for more than 90%, thereby obtaining fine-grained minerals, and then water is added to the slurry to obtain slurry A with a solid-liquid ratio of 1:1.

[0022] The amount of sodium sulfite added is 0.1-0.2 kg (kilogram) / t (ton), the amount of iron sulfate added is 0.1-0.3 kg / t, and the amount of sodium hydroxide added is 0.1-0.2 kg / t.

[0023] The hypochlorite solution is any aqueous solution of sodium hypochlorite, potassium hypochlorite and calcium hypochlorite; the amount of the hypochlorite solution added is 1-2 times the mass of the gold-containing material; and the mass concentration of the hypochlorite solution is 0.1-0.3% by mass percentage.

[0024] The mixing and slurry stirring is carried out at a speed of 200-350r (revolution) / min (minute) for 20-30min to obtain a slurry B solution.

[0025] In step 2, water is added to adjust the concentration of slurry B to a solid-liquid ratio of 1:3, and then sodium bicarbonate and calcium oxide or calcium hydroxide are added to adjust the pH value of the mixed solution to 9-10, and then stirred for 20-30 minutes at a speed of 200-350 r / min to obtain a slurry C solution.

[0026] The amount of sodium bicarbonate added is 0.5-1 kg / t; the amount of calcium oxide or calcium hydroxide added is 0.2-4 kg / t. That is, the pH of the slurry solution is adjusted by sodium bicarbonate and either calcium oxide or calcium hydroxide.

[0027] In step 3, the amount of ammonium sulfate added is 0.3-1 kg / t, the amount of ammonium chloride added is 0.1-0.5 kg / t, and the amount of ammonium bicarbonate added is 0.1-0.3 kg / t.

[0028] The thiosulfate is ammonium thiosulfate or sodium thiosulfate; in terms of mass percentage, the mass concentration of the thiosulfate in the mixed solution D is 0.01-0.05%.

[0029] Solution D is stirred at room temperature for 4-6 hours at a rotation speed of 150-300 r / min for leaching, and the solid and liquid are separated by a filter press to obtain gold leaching solution and leaching residue, which are then passed through a replacement device to obtain gold by a replacement method.

[0030] The following is a further description of the cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles provided by the present invention in conjunction with the embodiments.

[0031] Example 1

[0032] The cyanide-free leaching process for fine-grained gold of the present invention was used to leach a raw ore containing fine-grained gold in Guizhou, China. The composition of the inclusions of the raw ore is shown in Table 1 below.

[0033] Table 1. Composition of inclusions in Guizhou ore.

[0034]

[0035] The leaching process of the raw ore specifically includes the following steps:

[0036] 1. Mineral pretreatment: grind the mineral to 95% of the particles with a size of 200 mesh, then add water with a volume of 1 times that of the gold-containing material to make a solid-liquid ratio of 1:1 to obtain slurry A, then add 0.2kg / t of sodium sulfite, 0.3kg / t of ferric sulfate, and 0.1kg / t of sodium hydroxide to the slurry A, stir and mix evenly, then add 0.1% sodium hypochlorite solution with a volume of 1.5 times that of the gold-containing particles, and treat for 30 minutes at a stirring speed of 200r / min to obtain a pretreated slurry solution B.

[0037] 2. Adjust the slurry: add water to the slurry solution B to adjust the slurry concentration to 33%, that is, the solid-liquid ratio is 1:3, then add 0.5kg / t of sodium bicarbonate and 0.5kg / t of calcium oxide to the slurry, adjust the pH value to 9, and then stir for 20 minutes to obtain slurry solution C.

[0038] 3. Gold leaching treatment: add 0.3kg / t ammonium sulfate, 0.1kg / t ammonium chloride, 0.2kg / t ammonium bicarbonate and 0.1kg / t ammonium thiosulfate to the slurry solution C, stir at room temperature for 6 hours, and after the leaching treatment is completed, perform solid-liquid separation to obtain leachate and leaching residue.

[0039] The gold grade in the leached residue was analyzed and the gold leaching rate was calculated to be 91.62%.

[0040] Example 2

[0041] The cyanide-free leaching process for fine-grained gold of the present invention was used to leach a raw ore containing fine-grained gold in Yunnan, China. The composition of the inclusions of the raw ore is shown in Table 2 below.

[0042] Table 2. Composition of inclusions in Yunnan ore.

[0043]

[0044] The leaching process of the raw ore specifically includes the following steps:

[0045] (1) Mineral pretreatment: Grind the fine gold-containing material until the particles with a size of 200 mesh account for 93% to obtain fine-grained minerals, then add water to adjust the slurry so that the solid-liquid ratio is 1:1 to obtain slurry A, then add a certain amount of sodium sulfite, ferric sulfate, and sodium hydroxide, stir and mix, then add a predetermined amount of hypochlorite solution, stir for a period of time to obtain a pretreated slurry solution B.

[0046] Preferably, the slurry solution B is obtained by treating the mixture for 25 minutes under stirring at a speed of 300 r / min.

[0047] The hypochlorite solution is a potassium hypochlorite aqueous solution with a mass percentage concentration of 0.2%. The amount of the hypochlorite solution added is 1 times the mass of the material containing fine gold particles.

[0048] The amount of sodium sulfite added is 0.1kg / t, the amount of ferric sulfate added is 0.1kg / t, and the amount of sodium hydroxide added is 0.2kg / t.

[0049] (2) Adjusting the slurry: adding water to the pretreatment solution B, adjusting the slurry concentration of B in (1) to a solid-liquid ratio of 1:3, adding a certain amount of sodium bicarbonate and calcium hydroxide, adjusting the pH value, and then stirring for 25 minutes to obtain a slurry solution C.

[0050] Preferably, calcium hydroxide and sodium bicarbonate are added to adjust the pH concentration of the mixed solution until the pH is adjusted to 9.5.

[0051] The amount of sodium bicarbonate added is 1 kg / t. The amount of any one of calcium hydroxide added is 1 kg / t.

[0052] (3) Gold leaching treatment: Add a predetermined amount of ammonium sulfate, ammonium chloride, ammonium bicarbonate, and thiosulfate to the slurry C solution in (2) to obtain solution D, and then stir at room temperature for 4 hours to perform leaching treatment to obtain gold leaching solution and leaching residue, and then use the replacement method to obtain gold.

[0053] Preferably, the thiosulfate is sodium thiosulfate. The mass percentage concentration of the thiosulfate added to the mixed solution is 0.01%.

[0054] The amount of ammonium sulfate added is 0.5kg / t. The amount of ammonium chloride added is 0.4kg / t. The amount of ammonium bicarbonate added is 0.1kg / t.

[0055] The gold grade in the leached residue was analyzed and the gold leaching rate was calculated to be 89.12%.

[0056] Example 3

[0057] The cyanide-free leaching process for fine-grained gold of the present invention was used to leach a raw ore containing fine-grained gold in Guangxi, China. The composition of the inclusions of the raw ore is shown in Table 3 below.

[0058] Table 3. Composition of inclusions in Guangxi ore.

[0059]

[0060] The leaching process of the raw ore specifically includes the following steps:

[0061] Step 1: Grind the fine gold-containing material to obtain fine-grained minerals, then add water to prepare the slurry to obtain slurry A, then add sodium sulfite, ferric sulfate, and sodium hydroxide, stir and mix, then add hypochlorite solution, mix and prepare the slurry and stir evenly to obtain pretreated slurry B.

[0062] Preferably, the fine gold-containing material is ground to a particle size of 200 meshes accounting for 96% to obtain fine-grained minerals, and then water is added to the slurry to obtain slurry A with a solid-liquid ratio of 1:1.

[0063] The amount of sodium sulfite added is 0.15kg / t, the amount of ferric sulfate added is 0.2kg / t, and the amount of sodium hydroxide added is 0.15kg / t.

[0064] The hypochlorite solution is a calcium hypochlorite aqueous solution; the amount of the hypochlorite solution added is twice the mass of the gold-containing material; and the mass concentration of the hypochlorite solution is 0.3% by mass percentage.

[0065] The mixing and slurry stirring is carried out at a speed of 350 r / min for 20 minutes to obtain a slurry B solution.

[0066] Step 2: Adjust the concentration of the slurry B obtained in step 1, then add sodium bicarbonate and calcium oxide or calcium hydroxide, adjust the pH value, and stir to obtain slurry C.

[0067] Preferably, water is added to adjust the concentration of slurry B to a solid-liquid ratio of 1:3, and then sodium bicarbonate and calcium oxide are added to adjust the pH value of the mixed solution to 10, and then stirred for 30 minutes to obtain a slurry C solution.

[0068] The amount of sodium bicarbonate added is 0.8kg / t; the amount of calcium oxide added is 3kg / t.

[0069] Step 3: add ammonium sulfate, ammonium chloride, ammonium bicarbonate and thiosulfate to the slurry C obtained in step 2 to obtain solution D, stir and leach to obtain gold leaching solution and leaching residue, and then obtain gold by replacement.

[0070] Preferably, the amount of ammonium sulfate added is 1 kg / t, the amount of ammonium chloride added is 0.5 kg / t, and the amount of ammonium bicarbonate added is 0.3 kg / t.

[0071] The thiosulfate is ammonium thiosulfate or sodium thiosulfate; in terms of mass percentage, the mass concentration of the thiosulfate in the mixed solution D is 0.05%.

[0072] Solution D was stirred at room temperature for 6 hours for leaching, and the solid and liquid were separated by a filter press to obtain gold leaching solution and leaching residue, which were then passed through a replacement device to obtain gold by a replacement method.

[0073] The gold grade in the leached residue was analyzed and the gold leaching rate was calculated to be 93.67%.

[0074] It can be seen from the above embodiments that an excellent gold leaching rate can be obtained according to the process of the present invention.

[0075] The cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles provided by the present invention is a cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles that can improve the utilization rate of the gold material. The principle of the cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles is as follows: during the mineral pretreatment process, sodium sulfite, ferric sulfate, hypochlorite solution, sodium hydroxide, etc. are added to the gold material, and the treatment is carried out under stirring conditions. The silicates, sulfides, and carbonates in the solution part are conducive to the exposure of fine gold particles, which is convenient for subsequent leaching treatment of the gold. After pretreatment, under the catalytic action of pH value, redox potential, and ammonium ions, thiosulfate ions are complexed with gold ions to form more stable gold thiosulfate complex ions, so that efficient leaching of fine gold particles can be achieved at room temperature and pressure.

[0076] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles, characterized in that: The process comprises: Step 1, grinding the fine gold-containing material to obtain fine-grained minerals, then adding water to prepare the slurry to obtain slurry A, then adding sodium sulfite, ferric sulfate, and sodium hydroxide, stirring and mixing, adding hypochlorite solution, mixing and preparing the slurry and stirring evenly to obtain pretreated slurry B; Step 2: adjusting the concentration of the slurry B obtained in step 1, then adding sodium bicarbonate and calcium oxide or calcium hydroxide, adjusting the pH value, and stirring to obtain slurry C; Step 3: add ammonium sulfate, ammonium chloride, ammonium bicarbonate and thiosulfate to the slurry C obtained in step 2 to obtain solution D, stir and leach to obtain gold leaching solution and leaching residue, and then obtain gold by replacement.

2. The cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles as claimed in claim 1, characterized in that: In the step 1, the fine gold-containing material is ground until the particles with a particle size of 200 mesh account for more than 90%, thereby obtaining fine-grained minerals, and then water is added to the slurry to obtain a slurry A with a solid-liquid ratio of 1:

1.

3. The cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles as claimed in claim 2, characterized in that: In the step 1, the amount of sodium sulfite added is 0.1-0.2 kg / t, the amount of ferric sulfate added is 0.1-0.3 kg / t, and the amount of sodium hydroxide added is 0.1-0.2 kg / t.

4. The cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles as claimed in claim 3, characterized in that: In the step 1, the hypochlorite solution is any one of sodium hypochlorite, potassium hypochlorite and calcium hypochlorite aqueous solutions; the amount of the hypochlorite solution added is 1-2 times the mass of the gold-containing material; and the mass concentration of the hypochlorite solution is 0.1-0.3% by mass percentage.

5. The cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles as claimed in claim 4, characterized in that: In the step 1, the mixing and slurry stirring is carried out at a speed of 200-350 r / min for 20-30 min to obtain a slurry B solution.

6. The cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles as claimed in claim 1, characterized in that: In the step 2, water is added to adjust the concentration of slurry B to a solid-liquid ratio of 1:3, and then sodium bicarbonate and calcium oxide or calcium hydroxide are added to adjust the pH value of the mixed solution to 9-10, and then stirred for 20-30 minutes to obtain a slurry C solution.

7. The green and environmentally friendly cyanide-free leaching process for gold in a material containing fine gold particles as claimed in claim 6, characterized in that: The amount of sodium bicarbonate added is 0.5-1kg / t; the amount of any one of calcium oxide and calcium hydroxide added is 0.2-4kg / t.

8. The cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles as claimed in claim 1, characterized in that: In the step 3, the amount of ammonium sulfate added is 0.3-1 kg / t, the amount of ammonium chloride added is 0.1-0.5 kg / t, and the amount of ammonium bicarbonate added is 0.1-0.3 kg / t.

9. The cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles as claimed in claim 8, characterized in that: In step 3, the thiosulfate is ammonium thiosulfate or sodium thiosulfate; and the mass concentration of the thiosulfate in the mixed solution D is 0.01-0.05% by mass.

10. The cyanide-free green and environmentally friendly leaching process for gold in a material containing fine gold particles as claimed in claim 9, characterized in that: In the step 3, solution D is stirred at room temperature for 4-6 hours for leaching, and the solid and liquid are separated by a filter press to obtain a gold leaching solution and leaching residue, and then gold is obtained by a replacement method.

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