Suspended oxidizing roasting-cyanidation leaching gold extraction method for carbonaceous silicate wrapped gold ore

Abstract

The invention relates to a suspension oxidizing roasting-cyaniding leaching gold extraction method for carbonaceous silicate wrapped type gold ore, and solves the technical problems that silicate inclusion is not thoroughly cracked, and carbonaceous'robbery 'gold and the like. Comprising the following steps: crushing the carbon-containing silicate coated gold ore until the particle size is less than 1mm; under an oxygen-enriched condition, carrying out suspension oxidizing roasting; grinding the suspension oxidation roasting product; and cyanidation leaching is carried out by adopting a golden cicada leaching agent. According to the method, the carbonaceous silicate wrapped gold ore is subjected to suspension oxidizing roasting under the oxygen-enriched condition, the roasted product is subjected to ore grinding, and then gold is recycled through the cyanidation leaching process. The method is short in roasting time, low in energy consumption and good in removal effect of sulfur, carbon and silicate, and the leaching rate of gold can reach 90% or above. The method is suitable for development and utilization of carbon-containing silicate wrapped gold ore difficult to treat, and has important industrial application value.

Description

Technical Field

[0001] The present invention belongs to the field of metallurgical technology, and particularly relates to a method for extracting gold by suspension oxidative roasting - cyanidation leaching of carbon - containing silicate - encapsulated gold ore, and is particularly suitable for the industrial development of refractory carbon - containing silicate - encapsulated gold ore. Background Art

[0002] With the gradual depletion of easily - treatable gold ore resources, the development of refractory gold ore has become an important direction for gold extraction. Carbon - containing silicate - encapsulated gold ore is a typical refractory gold ore, and its main feature is that gold particles are encapsulated by silicate minerals and organic carbon. The leaching rate of gold by traditional cyanidation leaching process is less than 20%. Existing pretreatment technologies such as roasting method have problems such as high energy consumption, easy sintering, and incomplete decarbonization, while processes such as biological oxidation and high - pressure leaching are costly and difficult to be applied industrially.

[0003] Suspension oxidative roasting is a new pretreatment technology, which has advantages such as fast reaction rate, low energy consumption, and high gold leaching rate. However, the process parameters for carbon - containing silicate - encapsulated gold ore have not been clarified. For example, insufficient oxygen concentration during roasting will lead to carbon residue, while excessive oxygen will cause mineral sintering; in the cyanidation leaching stage, insufficient grinding fineness cannot fully expose gold particles, and over - fineness will increase energy consumption. Existing roasting - leaching processes are only for sulfur - arsenic - containing gold ore and do not involve the cracking of silicate inclusions. Direct application results in a gold leaching rate lower than 50%. Therefore, developing an efficient and low - cost suspension oxidative roasting - cyanidation leaching method is of great significance for the development and utilization of carbon - containing silicate - encapsulated gold ore. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for extracting gold from carbon - containing silicate - encapsulated gold ore with high efficiency and low cost, and solve technical problems such as incomplete cracking of silicate inclusions and "gold robbing" by carbonaceous substances through suspension oxidative roasting combined with cyanidation leaching process.

[0005] To achieve the above - mentioned purpose, the present invention provides a method for extracting gold by suspension oxidative roasting - cyanidation leaching of carbon - containing silicate - encapsulated gold ore, which includes the following steps:

[0006] Crush the carbon - containing silicate - encapsulated gold ore to a particle size less than 1 mm;

[0007] Under oxygen - rich conditions, carry out suspension oxidative roasting;

[0008] Grind the product of suspension oxidative roasting;

[0009] Carry out cyanidation leaching using a gold - cicada leaching agent.

[0010] The present invention includes the following preferred schemes:

[0011] In the preferred embodiment, the oxygen concentration for the suspension oxidation roasting is 21% - 30%, the roasting temperature is 650°C - 700°C, and the roasting time is 0.5 h.

[0012] In the preferred embodiment, the grinding fineness of the suspension oxidation roasting product is -0.038 mm, with a content of 75%.

[0013] In the preferred embodiment, the dosage of the Jinchan leaching agent is 2.5 kg / t.

[0014] In the preferred embodiment, the cyanidation leaching pulp concentration is 40%, the pH value is adjusted to 11.5 with CaO, the leaching time is 24 h, and the leaching temperature is 25°C.

[0015] Advantages of the present invention:

[0016] Through oxygen-enriched suspension roasting, carbonaceous oxidation and silicate lattice destruction are achieved simultaneously, avoiding the complexity of multi-stage roasting;

[0017] Optimize the synergistic effect of the dosage of the Jinchan leaching agent and the cyanidation leaching pulp concentration to achieve a high leaching rate with low reagent consumption.

[0018] By optimizing the process parameters of suspension oxidation roasting and cyanidation leaching in the present invention, the gold leaching rate can reach over 90%, significantly improving the gold leaching rate. It is more than 30% higher than the traditional two-stage roasting process (leaching rate ≤ 70%), the roasting time is shortened to 0.5 h, the energy consumption is reduced by 40%, and the operation is simple, with significant economic and environmental benefits. Specific embodiments

[0019] The present invention will be further described below in conjunction with embodiments, but the present invention is not limited to the following embodiments.

[0020] Raw material conditions: The multi-element analysis of a carbonaceous silicate-wrapped gold concentrate is shown in Table 1 as follows:

[0021] Table 1 Chemical element analysis of gold concentrate / %

[0022] Au* <![CDATA[SiO2]]> C <![CDATA[Al2O3]]> MgO CaO S As TFe K 1.93 58.85 1.30 14.36 3.46 4.85 1.77 0.21 5.51 1.35

[0023] Note: * Unit is g / t;

[0024] Control Example 1: The feed particle size for suspension oxidation roasting is -1 mm, the roasting temperature is 500 - 800°C, the oxygen concentration is 10%, the roasting time is 2 h, and the total gas volume is 2 L / min; the grinding fineness of the suspension oxidation roasting product is -0.038 mm with a content of 95%, the cyanidation leaching pulp concentration is 30%, the dosage of the Jinchan leaching agent is 2.5 kg / t, the pH value is adjusted to 11.5 with CaO, the leaching time is 24 h, and the leaching temperature is 25°C. The test results of the suspension oxidation roasting temperature conditions are shown in Table 2 as follows:

[0025] Table 2 Test Results of Suspended Oxidative Roasting Temperature Conditions

[0026]

[0027] Control Example 2: The feed size for suspended oxidative roasting is -1 mm, the roasting temperature is 650 °C, the oxygen concentration is 10%, the roasting time is 0.25 - 4 h, and the total gas volume is 2 L / min; the grinding fineness of the suspended oxidative roasting product is 95% with a particle size of -0.038 mm, the cyanidation leaching pulp concentration is 30%, the dosage of Jinchan leaching agent is 2.5 kg / t, the pH value is adjusted to 11.5 with CaO, the leaching time is 24 h, and the leaching temperature is 25 °C. The test results of the suspended oxidative roasting time conditions are shown in Table 3:

[0028] Table 3 Test Results of Suspended Oxidative Roasting Time Conditions

[0029]

[0030] Control Example 3: The feed size for suspended oxidative roasting is -1 mm, the roasting temperature is 650 °C, the oxygen concentration is 5% - 40%, the roasting time is 0.5 h, and the total gas volume is 2 L / min; the grinding fineness of the suspended oxidative roasting product is 95% with a particle size of -0.038 mm, the cyanidation leaching pulp concentration is 30%, the dosage of Jinchan leaching agent is 2.5 kg / t, the pH value is adjusted to 11.5 with CaO, the leaching time is 24 h, and the leaching temperature is 25 °C. The test results of the suspended oxidative roasting oxygen concentration conditions are shown in Table 4:

[0031] Table 4 Test Results of Suspended Oxidative Roasting Oxygen Concentration Conditions

[0032]

[0033] Control Example 4: The feed size for suspended oxidative roasting is -1 mm, the roasting temperature is 650 °C, the oxygen concentration is 21%, the roasting time is 0.5 h, and the total gas volume is 2 L / min; the grinding fineness of the suspended oxidative roasting product is 55% - 95% with a particle size of -0.038 mm, the cyanidation leaching pulp concentration is 30%, the dosage of Jinchan leaching agent is 2.5 kg / t, the pH value is adjusted to 11.5 with CaO, the leaching time is 24 h, and the leaching temperature is 25 °C. The test results of the grinding fineness conditions of the suspended oxidative roasting product are shown in Table 5:

[0034] Table 5 Test Results of Grinding Fineness Conditions of Suspended Oxidative Roasting Product

[0035]

[0036] Control Example 5: The particle size of the feed for suspension oxidation roasting is -1 mm, the roasting temperature is 650 °C, the oxygen concentration is 21%, the roasting time is 0.5 h, and the total gas volume is 2 L / min; the grinding fineness of the suspension oxidation roasting product is 75% with a particle size of -0.038 mm, the concentration of the cyanidation leaching pulp is 30%, the dosage of Jinchan leaching agent is 0.5 - 10 kg / t, the pH value is adjusted to 11.5 with CaO, the leaching time is 24 h, and the leaching temperature is 25 °C. The test results of the dosage conditions of Jinchan leaching agent in cyanidation leaching are shown in Table 6:

[0037] Table 6 Test Results of Dosage Conditions of Jinchan Leaching Agent in Cyanidation Leaching

[0038]

[0039] Control Example 6: The particle size of the feed for suspension oxidation roasting is -1 mm, the roasting temperature is 650 °C, the oxygen concentration is 21%, the roasting time is 0.5 h, and the total gas volume is 2 L / min; the grinding fineness of the suspension oxidation roasting product is 75% with a particle size of -0.038 mm, the concentration of the cyanidation leaching pulp is 30%, the dosage of Jinchan leaching agent is 2.5 kg / t, the pH value range is adjusted to 9.5 - 11.5 with CaO, the leaching time is 24 h, and the leaching temperature is 25 °C. The test results of the pH conditions of the cyanidation leaching pulp are shown in Table 7:

[0040] Table 7 Test Results of pH Conditions of Cyanidation Leaching Pulp

[0041] Leaching pH 9.5 10.5 11.5 12.5 Au Leaching Rate / % 78.60 80.31 90.39 89.21

[0042] Control Example 7: The particle size of the feed for suspension oxidation roasting is -1 mm, the roasting temperature is 650 °C, the oxygen concentration is 21%, the roasting time is 0.5 h, and the total gas volume is 2 L / min; the grinding fineness of the suspension oxidation roasting product is 75% with a particle size of -0.038 mm, the concentration of the cyanidation leaching pulp is 30%, the dosage of Jinchan leaching agent is 2.5 kg / t, the pH value is adjusted to 11.5 with CaO, the leaching time is 8 - 32 h, and the leaching temperature is 25 °C. The test results of the leaching time conditions of cyanidation leaching are shown in Table 8:

[0043] Table 8 Test Results of Leaching Time Conditions of Cyanidation Leaching

[0044] Leaching Time / h 8 16 24 32 Au Leaching Rate / % 86.97 88.89 88.21 84.76

[0045] Control Example 8: The particle size of the feed for suspension oxidation roasting is -1 mm, the roasting temperature is 650 °C, the oxygen concentration is 21%, the roasting time is 0.5 h, and the total gas volume is 2 L / min; the grinding fineness of the suspension oxidation roasting product is 75% with a particle size of -0.038 mm, the concentration of the cyanidation leaching pulp is 20% - 50%, the dosage of Jinchan leaching agent is 2.5 kg / t, the pH value is adjusted to 11.5 with CaO, the leaching time is 24 h, and the leaching temperature is 25 °C. The test results of the cyanidation leaching pulp concentration conditions are shown in Table 9:

[0046] Table 9 Test Results of Concentration Conditions of Cyanidation Leaching Pulp

[0047] Slurry Concentration / % 20 30 40 50 Au Leaching Rate / % 89.64 88.74 90.39 87.60

[0048] Control Example 9: The feed size of suspension oxidation roasting is -1 mm, the roasting temperature is 650 °C, the oxygen concentration is 21%, the roasting time is 0.5 h, and the total gas volume is 2 L / min; the grinding fineness of the suspension oxidation roasting product is 75% with -0.038 mm content, the concentration of cyanidation leaching pulp is 30%, the dosage of Jinchan leaching agent is 2.5 kg / t, the pH value is adjusted to 11.5 with CaO, the leaching time is 24 h, and the leaching temperature is 25 - 40 °C. The test results of cyanidation leaching temperature conditions are shown in Table 10:

[0049] Table 10 Test Results of Cyanidation Leaching Temperature Conditions

[0050] Slurry Concentration / % 25 30 35 40 Au Leaching Rate / % 90.39 88.67 88.76 80.05

[0051] Example 1:

[0052] The feed size of suspension oxidation roasting is -1 mm, the roasting temperature is 650 °C, the oxygen concentration is 21%, the roasting time is 0.5 h, and the total gas volume is 2 L / min; the grinding fineness of the suspension oxidation roasting product is 75% with -0.038 mm content, the concentration of cyanidation leaching pulp is 40%, the dosage of Jinchan leaching agent is 2.5 kg / t, the pH value is adjusted to 11.5 with CaO, the leaching time is 24 h, the leaching temperature is 25 °C, and the gold leaching rate is 90.39%.

[0053] Example 2:

[0054] The feed size of suspension oxidation roasting is -1 mm, the roasting temperature is 700 °C, the oxygen concentration is 30%, the roasting time is 0.5 h, and the total gas volume is 2 L / min; the grinding fineness of the suspension oxidation roasting product is 75% with -0.038 mm content, the concentration of cyanidation leaching pulp is 40%, the dosage of Jinchan leaching agent is 2.5 kg / t, the pH value is adjusted to 11.5 with CaO, the leaching time is 24 h, the leaching temperature is 25 °C, and the gold leaching rate is 91.00%.

[0055] The method of the present invention conducts suspension oxidation roasting on carbonaceous silicate encapsulated gold ore under oxygen-rich conditions, and the roasted product is ground and then the cyanidation leaching process is used to recover gold. The roasting time of the present invention is short, the energy consumption is low, the removal effects of sulfur, carbon and silicate are good, and the gold leaching rate can reach more than 90%. This method is applicable to the development and utilization of refractory carbonaceous silicate encapsulated gold ore and has important industrial application value.

Claims

1. A method for extracting gold by suspended oxidation roasting - cyanidation leaching of carbon - containing silicate - encapsulated gold ore, characterized in that :Crush the carbonaceous silicate-wrapped gold ore to a particle size less than 1 mm; under oxygen-rich conditions, carry out suspended oxidation roasting; grind the product of suspended oxidation roasting; carry out cyanidation leaching with Jinchan leaching agent.

2. The method for extracting gold by suspended oxidation roasting - cyanidation leaching of carbon - containing silicate - coated gold ore according to claim 1, wherein: The oxygen concentration of the suspended oxidation roasting is 21% - 30%, the roasting temperature is 650 °C - 700 °C, and the roasting time is 0.5 h.

3. A method for extracting gold by suspended oxidation roasting - cyanidation leaching of carbon - containing silicate - encapsulated gold ore according to claim 1 or 2, characterized in that: The grinding fineness of the product of suspended oxidation roasting is -0.038 mm, with a content of 75%.

4. A method for extracting gold by suspended oxidation roasting - cyanidation leaching of carbon - containing silicate - encapsulated gold ore according to claim 3, characterized in that: The dosage of the Jinchan leaching agent is 2.5 kg / t.

5. A method for extracting gold by suspension oxidation roasting - cyanidation leaching of carbon - containing silicate - coated gold ore according to claim 4, characterized in that: The concentration of the cyanidation leaching pulp is 40%, the pH value is adjusted to 11.5 with CaO, the leaching time is 24 h, and the leaching temperature is 25 °C.

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