Treatment method for arsenic-containing refractory gold concentrate

Abstract

The invention belongs to the field of resource recovery, and discloses a treatment method of arsenic-containing refractory gold concentrate, which comprises the following steps: carrying out first-stage roasting on the arsenic-containing refractory gold concentrate to obtain first-stage roasted arsenic-removed slag; first-stage gold leaching is conducted on the first-stage roasting arsenic removal residues, and first-stage leaching liquid and first-stage leaching residues are obtained; performing second-stage roasting on the first-stage leaching residues to obtain second-stage roasting residues; and second-stage gold leaching is conducted on the second-stage roasting slag, and second-stage leaching liquid and second-stage leaching slag are obtained. Through the staged leaching strategy of first-stage roasting arsenic removal, first-stage gold leaching, second-stage roasting desulfurization and second-stage gold leaching, the leaching property of different forms of gold can be fully released through staged leaching, and efficient leaching of the gold in the refractory gold ore is achieved; compared with a traditional process of single leaching after two-stage roasting, the method has the advantages that the gold leaching efficiency is greatly improved, and sufficient recovery of gold is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of resource recycling, and particularly relates to a treatment method of arsenic-containing refractory gold concentrate. BACKGROUND

[0002] With the continuous exploitation of gold resources, high-quality gold ore resources are gradually exhausted, and arsenic-containing refractory gold ore has become an important raw material source for gold smelting enterprises. At present, the pyrometallurgical treatment process of arsenic-containing refractory gold ore generally has the technical problem of low gold leaching rate.

[0003] In addition, the current cyanide leaching gold solution is usually replaced by zinc powder, which leads to the problem of large consumption of zinc powder. At the same time, in order to avoid the passivation of zinc powder in the reduction process, it is usually necessary to control the particle size of zinc powder below 75 microns, or / and add lead acetate, but this leads to the problem of lead pollution in the process. SUMMARY The technical problem to be solved by the present application is to overcome the deficiencies and defects mentioned in the above background art, and to provide a treatment method of arsenic-containing refractory gold concentrate to solve the problems of low gold extraction rate in existing refractory gold ore, high zinc powder consumption during zinc powder replacement of cyanide leaching gold solution, and lead pollution.

[0004] To solve the above technical problems, the technical solution provided by the present application is as follows: A treatment method of arsenic-containing refractory gold concentrate, the process flow chart thereof is as shown in Figure 1 The treatment method comprises the following steps: (1) one-stage roasting of the arsenic-containing refractory gold concentrate to obtain one-stage roasting arsenic removal residue; (2) one-stage gold leaching of the one-stage roasting arsenic removal residue to obtain one-stage leaching solution and one-stage leaching residue; (3) two-stage roasting of the one-stage leaching residue to obtain two-stage roasting residue; (4) two-stage gold leaching of the two-stage roasting residue to obtain two-stage leaching solution and two-stage leaching residue.

[0005] The treatment method of arsenic-containing refractory gold concentrate, preferably, in step (1), the temperature of the one-stage roasting is 400-580℃, the roasting time is 30-90min, and the one-stage roasting is carried out in an oxygen-containing atmosphere, and the amount of the oxygen-containing atmosphere introduced is 1.5-8 times the molar amount of arsenic in the arsenic-containing refractory gold concentrate.

[0006] The treatment method of the arsenic-containing refractory gold concentrate, preferably, in the step (2), the adding amount of the sodium cyanide in the first-stage leaching process is 5-6 kg / t, the pulp concentration in the leaching process is controlled to be 20%-50%, the pH value is controlled to be 10-11, the leaching time is 16-24 h, the leaching temperature is 20-35 ℃, and oxygen is continuously introduced into the pulp in the leaching process to ensure that the oxygen content in the pulp is not less than 5 g / m 3 .

[0007] The treatment method of the arsenic-containing refractory gold concentrate, preferably, in the step (3), the temperature of the second-stage roasting is 600-650 ℃, the roasting time is 60-90 min, and the second-stage roasting is carried out in an oxygen-containing atmosphere, and the oxygen-containing atmosphere is introduced in an atomic molar ratio of 2.5-15 times the number of moles of sulfur in the first-stage leaching residue.

[0008] The treatment method of the arsenic-containing refractory gold concentrate, preferably, in the step (4), the adding amount of the sodium cyanide in the second-stage leaching process is 3-5 kg / t, the pulp concentration in the leaching process is controlled to be 20%-50%, the pH value is controlled to be 10-11, the leaching time is 24-48 h, the leaching temperature is 20-35 ℃, and oxygen is continuously introduced into the pulp in the leaching process to ensure that the oxygen content in the pulp is not less than 5 g / m 3 .

[0009] The treatment method of the arsenic-containing refractory gold concentrate, preferably, the composition of the arsenic-containing refractory gold concentrate comprises S 15-48%, As 5-15%, and Au 5-80 g / t.

[0010] The treatment method of the arsenic-containing refractory gold concentrate, preferably, further comprising a step (5) of mixing the first-stage leaching solution and the second-stage leaching solution and then replacing the mixed solution with zinc-iron alloy powder to obtain a gold-containing mud product.

[0011] The treatment method of the arsenic-containing refractory gold concentrate, preferably, the zinc-iron alloy powder has a particle size of 200-500 μm, and the adding amount of the zinc-iron alloy powder is 0.8-1 times the theoretical amount of zinc powder for replacing gold.

[0012] The treatment method of the arsenic-containing refractory gold concentrate, preferably, the zinc-iron alloy powder is obtained by mixing metal zinc powder and metal iron powder in a mass ratio of 10:2-10:1, sintering at a temperature of 800-1200 ℃ for 2-4 h, and then ball milling.

[0013] The treatment method of the arsenic-containing refractory gold concentrate, preferably, in the process of replacing with the zinc-iron alloy powder, the pH value of the mixed solution is controlled to be 10-12, the reaction time is 3-8 min, and the reaction temperature is 20-35 ℃.

[0014] Preferably, the two-stage leaching residue can be sold as iron concentrate.

[0015] Compared with the prior art, the present application has the following beneficial effects: (1) The present application realizes efficient leaching of gold in refractory gold ore by adopting the strategy of "one-stage roasting and arsenic removal → one-stage gold leaching → two-stage roasting and sulfur removal → two-stage gold leaching", which can fully release the leachability of different forms of gold in different stages, and realize efficient leaching of gold in refractory gold ore.

[0016] (2) The present application uses zinc-iron alloy powder instead of pure zinc powder for displacement of gold cyanide leaching solution, and the zinc-iron alloy powder forms a micro-battery effect inside, which constitutes a pile of oxidation-reduction potentials, enhances the reduction potential, and greatly improves the displacement efficiency; at the same time, the theoretical consumption of zinc-iron alloy powder is optimized to 0.8-1 times of the theoretical dosage, which is significantly lower than the traditional zinc powder displacement process, thereby reducing the raw material cost.

[0017] (3) The present application uses zinc-iron alloy powder instead of traditional pure zinc powder, and does not need to add lead acetate to prevent passivation, thereby avoiding the risk of lead pollution from the source; the particle size requirement of zinc-iron alloy powder is relaxed to 200-500 μm, thereby reducing the preparation energy consumption and process complexity of traditional zinc powder. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0019] Figure 1 It is a process flow diagram of the refractory gold concentrate containing arsenic in the present application. DETAILED DESCRIPTION

[0020] In order to facilitate the understanding of the present application, the following will make a more comprehensive and detailed description of the present application in combination with the drawings of the specification and the preferred embodiments, but the protection scope of the present application is not limited to the following specific embodiments.

[0021] Unless otherwise defined, all the professional terms used in the following have the same meaning as generally understood by those skilled in the art. The professional terms used in this paper are only for the purpose of describing the specific embodiments, and are not intended to limit the protection scope of the present application.

[0022] Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by the existing method.

[0023] The chemical composition of the arsenic-containing refractory gold ore treated in the following examples and comparative examples is shown in Table 1.

[0024] Table 1: Chemical composition of the arsenic-containing refractory gold ore (wt %)

[0025] Example 1: A method for treating an arsenic-containing refractory gold concentrate according to the present application comprises the following steps: (1) 100 g of the arsenic-containing refractory gold concentrate is subjected to a first roasting, the temperature of the first roasting is controlled at 550°C, the roasting time is 60 min, oxygen is introduced during the roasting, and the amount of oxygen introduced is 2 times the amount of arsenic in the arsenic-containing refractory gold concentrate in terms of atomic molar ratio, to obtain a first roasting arsenic removal residue, and the removal rate of arsenic in this process is 91.7%.

[0026] (2) The first roasting arsenic removal residue is subjected to a first gold leaching, 5.5 kg of sodium cyanide is added per ton of the first roasting arsenic removal residue for leaching, the pulp concentration is controlled at 35% during the leaching, the pH value is 11, the leaching temperature is 25°C, the leaching time is 18 h, and the oxygen content in the pulp is ensured to be not less than 7 g / m3 during the leaching; after the leaching is completed, filtration is performed to obtain a first leaching residue and a first leaching solution, and the leaching rate of gold in this step is 68.3%.

[0027] (3) The first leaching residue is subjected to a second roasting, the temperature of the second roasting is controlled at 630°C, the roasting time is 70 min, oxygen is introduced during the roasting, and the amount of oxygen introduced is 5 times the amount of sulfur in the first leaching residue in terms of atomic molar ratio, to obtain a second roasting residue; the removal rate of sulfur in this stage is 97.4%.

[0028] (4) The second roasting residue is subjected to a second gold leaching, 4 kg of sodium cyanide is added per ton of the second roasting residue for leaching, the pulp concentration is controlled at 35% during the leaching, the pH value is 11, the leaching temperature is 25°C, the leaching time is 40 h, and the oxygen content in the pulp is ensured to be not less than 5 g / m 3 After the leaching is completed, filtration is performed to obtain a second leaching residue and a second leaching solution, and the leaching rate of gold in this step is 93.8%. The total recovery rate of gold in the entire process reaches 98.0%.

[0029] Example 2: A method for treating an arsenic-containing refractory gold concentrate according to the present application comprises the following steps: (1) Take 100 g of arsenic-containing refractory gold concentrate for one-stage roasting, control the one-stage roasting temperature to be 500 DEG C, the roasting time to be 80 min, and oxygen is introduced during the roasting process, and the oxygen is introduced in an amount of 7 times the number of moles of arsenic in the arsenic-containing refractory gold concentrate, to obtain a one-stage roasting arsenic removal residue, and in this process, the removal rate of arsenic is 93.7%.

[0030] (2) The one-stage roasting arsenic removal residue is subjected to one-stage gold leaching, and 5 kg of sodium cyanide is added per ton of one-stage roasting arsenic removal residue for leaching, and in the leaching process, the pulp concentration is controlled to be 35%, the pH value is 11, the leaching temperature is 25 DEG C, the leaching time is 24 h, and the oxygen content in the pulp is ensured to be not less than 7 g / m3 during the leaching process; after leaching, the one-stage leaching residue and the one-stage leaching solution are obtained by filtration, and in this step, the leaching rate of gold is 71.4%.

[0031] (3) The one-stage leaching residue is subjected to two-stage roasting, and the two-stage roasting temperature is controlled to be 610 DEG C, the roasting time is 60 min, and oxygen is introduced during the roasting process, and the oxygen is introduced in an amount of 10 times the number of moles of sulfur in the one-stage leaching residue, to obtain a two-stage roasting residue; the removal rate of sulfur in this stage is 96.9%.

[0032] (4) The two-stage roasting residue is subjected to two-stage gold leaching, and 4.5 kg of sodium cyanide is added per ton of two-stage roasting residue for leaching, and in the leaching process, the pulp concentration is controlled to be 35%, the pH value is 11, the leaching temperature is 25 DEG C, the leaching time is 48 h, and the oxygen content in the pulp is ensured to be not less than 5 g / m 3 After leaching, the two-stage leaching residue and the two-stage leaching solution are obtained by filtration, and in this step, the leaching rate of gold is 95.1%. The total recovery rate of gold in the whole process reaches 98.6%.

[0033] Example 3: In this embodiment, zinc-iron alloy powder is used to treat the mixed solution of the one-stage leaching solution and the two-stage leaching solution obtained by the method in Example 1, and the specific steps are as follows: (1) Mix the metal zinc powder and the metal iron powder in a mass ratio of 10:2, then sinter at a temperature of 900 DEG C for 4 h, ball mill, and sieve to obtain zinc-iron alloy powder with a particle size of about 250 microns.

[0034] (2) Mix the one-stage leaching solution and the two-stage leaching solution obtained by the method in Example 1, and add zinc-iron alloy powder for gold displacement, control the solution pH = 11, the zinc-iron alloy powder is added in an amount of 1 times the theoretical amount of zinc powder for gold displacement, the displacement reaction temperature is 25 DEG C, and the reaction time is 5 min, to obtain a gold-containing mud product. In this step, the displacement rate of gold reaches 99.9%.

[0035] Example 4: The embodiment utilizes zinc-iron alloy powder to treat the mixed solution of the first-stage leaching solution and the second-stage leaching solution obtained according to the method in Embodiment 1, and the specific steps are as follows: (1) The metallic zinc powder and the metallic iron powder are mixed in a mass ratio of 10:2, and then sintered at a temperature of 1000°C for 3h, ball-milled, and sieved to obtain zinc-iron alloy powder with a particle size of about 425 microns.

[0036] (2) The first-stage leaching solution and the second-stage leaching solution obtained according to the method in Embodiment 1 are mixed, and the zinc-iron alloy powder is added for gold displacement, the solution pH is controlled to be 11, the zinc-iron alloy powder is added in an amount of 1 times the theoretical amount of zinc powder for gold displacement, the displacement reaction temperature is 25°C, and the reaction is performed for 4min to obtain a gold-containing slurry product. In this step, the gold displacement rate reaches 99.9%.

[0037] Comparative Example 1 In this comparative example, the arsenic-containing refractory gold concentrate is leached by a one-stage leaching method, and the specific steps are as follows: (1) 100g of the arsenic-containing refractory gold concentrate is subjected to one-stage roasting, the one-stage roasting temperature is controlled to be 550°C, the roasting time is 60min, oxygen is introduced during the roasting process, and the amount of oxygen introduced is 2 times the amount of arsenic in the arsenic-containing refractory gold concentrate in terms of atomic molar ratio, to obtain a one-stage roasting arsenic removal residue.

[0038] (2) The one-stage roasting arsenic removal residue is subjected to two-stage roasting, the two-stage roasting temperature is controlled to be 630°C, the roasting time is 70min, oxygen is introduced during the roasting process, and the amount of oxygen introduced is 5 times the amount of sulfur in the one-stage leaching residue in terms of atomic molar ratio, to obtain a two-stage roasting residue.

[0039] (3) The two-stage roasting residue is subjected to gold leaching, 5kg of sodium cyanide is added per ton of the two-stage roasting residue for leaching, the pulp concentration is controlled to be 35% during the leaching process, the pH value is 11, the leaching temperature is 25°C, the leaching time is 40h, and the oxygen content in the pulp is ensured to be not less than 5g / m 3 After the leaching is completed, the two-stage leaching residue and the two-stage leaching solution are obtained by filtration. In this step, the gold leaching rate is only 85.7%. Comparative Example 2 In this comparative example, the arsenic-containing refractory gold concentrate is leached by a one-stage leaching method, and the specific steps are as follows: (1) 100g of the arsenic-containing refractory gold concentrate is subjected to one-stage roasting, the one-stage roasting temperature is controlled to be 550°C, the roasting time is 60min, oxygen is introduced during the roasting process, and the amount of oxygen introduced is 2 times the amount of arsenic in the arsenic-containing refractory gold concentrate in terms of atomic molar ratio, to obtain a one-stage roasting arsenic removal residue.

[0040] (2) The first roasting arsenic removal residue is subjected to second roasting, the second roasting temperature is controlled to be 630 ℃, the second roasting time is 70 min, oxygen is introduced during the roasting, the oxygen introduction amount is 5 times of the sulfur molar number in the first leaching residue, and the second roasting residue is obtained.

[0041] (3) The second roasting residue is subjected to gold leaching, 4 kg of sodium cyanide is added per ton of the second roasting residue for leaching, the pulp concentration is controlled to be 35% during the leaching, the pH value is 11, the leaching temperature is 25 ℃, the leaching time is 40 h, and the oxygen content in the pulp is ensured to be not less than 5 g / m 3 After the leaching is completed, the second leaching residue and the second leaching solution are obtained by filtration, and the gold leaching rate in this step is only 80.4%.

[0042] Comparative Example 3: In this comparative example, the mixed solution of the first leaching solution and the second leaching solution obtained by the method in Example 1 is treated by using zinc powder with a particle size of 425 microns, and the specific steps are as follows: The first leaching solution and the second leaching solution obtained by the method in Example 1 are mixed, zinc powder with a particle size of 425 microns is added for gold displacement, the solution pH is controlled to be 11, the zinc powder addition amount is 1 times of the theoretical amount of zinc powder for gold displacement, the displacement reaction temperature is 25 ℃, and the reaction is performed for 4 min to obtain a gold-containing slurry product. In this step, the gold displacement rate is only 61.7%.

[0043] Comparative Example 4: In this comparative example, the mixed solution of the first leaching solution and the second leaching solution obtained by the method in Example 1 is treated by using zinc powder with a particle size of 425 microns and lead acetate, and the specific steps are as follows: The first leaching solution and the second leaching solution obtained by the method in Example 1 are mixed, zinc powder with a particle size of 425 microns is added for gold displacement, and 0.09% of lead acetate based on the mass of zinc powder is added, the solution pH is controlled to be 11, the zinc powder addition amount is 1 times of the theoretical amount of zinc powder for gold displacement, the displacement reaction temperature is 25 ℃, and the reaction is performed for 4 min to obtain a gold-containing slurry product. In this step, the gold displacement rate is only 79.2%.

[0044] Comparative Example 5: In this comparative example, the mixed solution of the first leaching solution and the second leaching solution obtained by the method in Example 1 is treated by using zinc powder with a particle size of 75 microns and lead acetate, and the specific steps are as follows: The first and second stage leachates obtained according to the method in Example 1 were mixed, and 75-micron metallic zinc powder was added to replace gold. Simultaneously, 0.09% lead acetate (by weight of the zinc powder) was added, and the solution pH was controlled at 11. The amount of metallic zinc powder added was twice the theoretical amount for gold replacement. The replacement reaction temperature was 25°C, and the reaction time was 4 minutes to obtain a gold-containing mud product. In this step, the gold replacement rate was 85.5%.

[0045] Comparative Example 6: This comparative example uses 75-micron metallic zinc powder and lead acetate to treat a mixture of first-stage and second-stage leachates obtained according to the method in Example 1. The specific steps are as follows: The first and second stage leachates obtained according to the method in Example 1 were mixed, and 75-micron metallic zinc powder was added to replace gold. Simultaneously, 0.09% lead acetate (by weight of the zinc powder) was added, and the solution pH was controlled at 11. The amount of metallic zinc powder added was twice the theoretical amount for gold replacement. The replacement reaction temperature was 25°C, and the reaction time was 4 minutes to obtain a gold-containing mud product. In this step, the gold replacement rate was 99.7%.

[0046] Comparative Example 7: This comparative example utilizes 425-micron metallic zinc powder and lead acetate to treat a mixture of first-stage and second-stage leachates obtained according to the method in Example 1. The specific steps are as follows: The first and second stage leachates obtained according to the method in Example 1 were mixed, and zinc powder with a particle size of 425 micrometers was added to replace gold. Simultaneously, 0.09% lead acetate (by weight of the zinc powder) was added, and the solution pH was controlled at 11. The amount of zinc powder added was twice the theoretical amount for gold replacement. The replacement reaction temperature was 25°C, and the reaction time was 4 minutes to obtain a gold-containing mud product. In this step, the gold replacement rate was 83.1%.

[0047] Comparative Example 8: This comparative example utilizes zinc powder with a particle size of 425 micrometers to treat a mixture of first-stage and second-stage leachates obtained according to the method in Example 1. The specific steps are as follows: The first and second stage leachates obtained according to the method in Example 1 were mixed, and zinc powder with a particle size of 425 micrometers was added to replace gold. The pH of the solution was controlled at 11, and the amount of zinc powder added was twice the theoretical amount for zinc powder to replace gold. The replacement reaction temperature was 25°C, and the reaction time was 4 minutes to obtain a gold-containing mud product. In this step, the gold replacement rate was 70.5%.

Claims

1. A process for the treatment of arsenic-bearing refractory gold concentrates, characterised in that, The method comprises the following steps: (1) roasting the arsenic-containing refractory gold concentrate to obtain a first roasting arsenic-removal residue; (2) leaching gold from the first roasting arsenic-removal residue to obtain a first leaching solution and a first leaching residue; (3) second roasting the first leaching residue to obtain a second roasting residue; (4) leaching gold from the second roasting residue to obtain a second leaching solution and a second leaching residue.

2. The method of treating arsenic-bearing refractory gold concentrates as claimed in claim 1, characterised in that, In step (1), the temperature of the first roasting is 400-580 ℃, the roasting time is 30-90 min, and the first roasting is carried out in an oxygen-containing atmosphere, wherein the amount of the oxygen-containing atmosphere introduced is 1.5-8 times the amount of arsenic in the arsenic-containing refractory gold concentrate in terms of atomic molar ratio.

3. The method of treating arsenic-bearing refractory gold concentrates of claim 1, wherein, In step (2), the amount of sodium cyanide added in the process of gold leaching is 5-6 kg / t, the pulp concentration is controlled at 20%-50%, the pH value is controlled at 10-11, the leaching time is 16-24 h, the leaching temperature is 20-35℃, and oxygen is continuously supplied to the pulp during the leaching process to ensure that the oxygen content in the pulp is not less than 5 g / m 3 .

4. The method of treating arsenic-bearing refractory gold concentrates of claim 1, wherein, In step (3), the temperature of the second roasting is 600-650 ℃, the roasting time is 60-90 min, and the second roasting is carried out in an oxygen-containing atmosphere, wherein the amount of the oxygen-containing atmosphere introduced is 2.5-15 times the amount of sulfur in the first leaching residue in terms of atomic molar ratio.

5. The method of treating arsenic-bearing refractory gold concentrates of claim 1, wherein, In step (4), the adding amount of sodium cyanide is 3-5 kg / t, the pulp concentration is controlled to be 20%-50%, the pH value is controlled to be 10-11, the leaching time is 24-48 h, the leaching temperature is 20-35℃, and oxygen is continuously fed into the pulp to ensure that the oxygen content in the pulp is not less than 5 g / m 3 .

6. The method of treating arsenic-bearing refractory gold concentrates of claim 1, wherein, The arsenic-containing refractory gold concentrate comprises S 15-48%, As 5-15%, and Au 5-80 g / t.

7. The process for treating arsenic-bearing refractory gold concentrates according to any one of claims 1 to 6, characterized in that, The method further comprises step (5), wherein the first leaching solution and the second leaching solution are mixed and then replaced by zinc-iron alloy powder to obtain a gold-containing mud product.

8. The method of treating arsenic-bearing refractory gold concentrates as claimed in claim 7, characterised in that, The zinc-iron alloy powder has a particle size of 200-500 μm, and the amount of the zinc-iron alloy powder added is 0.8-1 times the theoretical amount of zinc powder for replacing gold.

9. The method of treating arsenic-bearing refractory gold concentrates as claimed in claim 7, characterised in that, The zinc-iron alloy powder is obtained by mixing metal zinc powder and metal iron powder in a mass ratio of 10:2-10:1, sintering at a temperature of 800-1200 ℃ for 2-4 h, and then ball milling.

10. The method of treating arsenic-bearing refractory gold concentrates as claimed in claim 7, characterised in that, In the process of replacing gold by the zinc-iron alloy powder, the pH value of the mixed solution is controlled to be 10-12, the reaction time is 3-8 min, and the reaction temperature is 20-35 ℃.

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