Environment-friendly gold leaching agent and application method thereof

Abstract

The invention discloses an environment-friendly gold leaching agent and an application method thereof. The environment-friendly gold leaching agent is formed by mixing halate, thiosulfate and an enhancer. The application method of the environment-friendly gold leaching agent comprises the following steps that gold ore is crushed and ground, the concentration of ore pulp is adjusted to be 30%-50%, then 0.2 wt%-5 wt% of the gold leaching agent is added, the pH of the ore pulp is adjusted to be 6-12, and stirring leaching is conducted for 8-36 hours at the normal temperature and the normal pressure. The environment-friendly gold leaching agent is formed by mixing common chemical reagents, the method is simple, the gold leaching rate is high, the reagent stability is high, gold leaching can be achieved under the neutral to alkaline condition, and the method is an environment-friendly gold leaching method.

Description

Technical Field

[0001] The invention relates to the technical field of precious metal hydrometallurgy, and in particular to an environmentally friendly gold leaching agent and an application method thereof. Background Art

[0002] Gold is one of the most important precious metals in the world and an important strategic material. At present, more than 90% of the world's gold is leached using the traditional cyanidation method; the cyanidation method has the advantages of simple and mature technology and low investment cost, and has long dominated the gold industrial production. However, cyanide is highly toxic and poses a potential threat to the safety of the ecological environment and the health of operators in industrial production; in addition, the treatment and disposal of the cyanide-containing wastewater and cyanidation tailings are costly. With the increasingly stringent requirements for ecological environmental protection and human life safety around the world, there is an urgent need to develop efficient, non-toxic and pollution-free gold leaching agents to replace cyanide. This is an inevitable trend in implementing the national green ecological development strategy.

[0003] At present, the non-cyanide gold leaching methods that are studied more include thiosulfate method, polysulfide method, thiourea method, halogen method, thiocyanate method, lime sulfur method, etc. These traditional non-cyanide gold leaching agents have bottleneck problems such as high reagent prices and poor stability, which seriously limit their industrial application. Summary of the invention

[0004] In order to solve the technical problems in the above-mentioned background technology, the present invention provides an environmentally friendly gold leaching agent and an application method thereof. The method is simple, has a high gold leaching rate, strong reagent stability and low consumption.

[0005] The invention provides an environmentally friendly gold leaching agent, which is prepared by mixing a halogen acid salt, a thiosulfate and a strengthening agent.

[0006] In a preferred embodiment of the environmentally friendly gold leaching agent provided by the present invention, the mass ratio of the thiosulfate, the halogen acid salt and the enhancer is 100:(1-20):(1-10).

[0007] In a preferred embodiment of the environmentally friendly gold leaching agent provided by the present invention, the pH value of gold leaching by the environmentally friendly gold leaching agent is 6-12.

[0008] In a preferred embodiment of the environmentally friendly gold leaching agent provided by the present invention, the thiosulfate is sodium thiosulfate or potassium thiosulfate.

[0009] In a preferred embodiment of the environmentally friendly gold leaching agent provided by the present invention, the halogenate is one of chlorate, bromate and iodate.

[0010] In a preferred embodiment of the environmentally friendly gold leaching agent provided by the present invention, the halide salt is sodium halide or potassium halide.

[0011] In a preferred embodiment of the environmentally friendly gold leaching agent provided by the present invention, the enhancer is one of the gold ligands such as glycine, thiocyanate, thiourea, etc.

[0012] In a preferred embodiment of the environmentally friendly gold leaching agent provided by the present invention, the thiocyanate is sodium thiocyanate or potassium thiocyanate.

[0013] The present invention also provides an application method of an environmentally friendly gold leaching agent, comprising the following steps: crushing and grinding the gold ore, adjusting the slurry concentration to 30%-50%, then adding 0.2wt%-5wt% of the gold leaching agent, adjusting the slurry pH to 6-12, and stirring and leaching for 8-36 hours at normal temperature and pressure.

[0014] In the present invention, the environmentally friendly gold leaching agent is composed of thiosulfate and a reinforcing agent to form a gold mixed complex ion with gold to achieve synergistic enhanced gold leaching. The reinforcing agent can strengthen the anode process of gold oxidation and dissolution, which is conducive to gold losing electrons to form gold complex ions; the halide salt has a certain oxidizing property under neutral and alkaline conditions, and can catalyze the cathode process of gold oxidation and dissolution, thereby achieving efficient leaching of gold. In addition, both halide and thiosulfate are negatively charged anions, and there is electrostatic repulsion between the two. The halide is not easy to react with thiosulfate, so the consumption of thiosulfate is low.

[0015] Compared with the prior art, the environmentally friendly gold leaching agent and its application method provided by the present invention have the following beneficial effects:

[0016] 1. The environmentally friendly gold leaching agent of the present invention is prepared by mixing common chemical reagents, and its raw materials are non-toxic, environmentally friendly, easily available, simple to prepare, and low in cost.

[0017] 2. The environmentally friendly gold leaching agent of the present invention can be used under neutral to alkaline conditions, has low equipment requirements and is easy to operate.

[0018] 3. The environmentally friendly gold leaching agent of the present invention has a high gold leaching rate, strong reagent stability and low consumption. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In the present invention, the gold ore raw material is a typical quartz-type gold ore with a gold grade of 4.49 g / t. The main gangue components are SiO2, which accounts for 74.6% of the gold ore composition, and Al2O3 accounts for 6.32%.

[0021] Example 1

[0022] Preparation of environmentally friendly gold leaching agent: Sodium thiosulfate, sodium chlorate and thiourea are mixed in a mass ratio of 100:5:5 to prepare the environmentally friendly gold leaching agent.

[0023] The gold ore raw material was finely ground to a particle size of -74μm accounting for more than 90wt.%, the slurry concentration was 30wt.%, the mass concentration of the environmentally friendly gold leaching agent was 0.5wt.%, the slurry pH was adjusted to 7, the stirring speed was 300r / min, the leaching time was 12 hours, and the leaching was carried out under normal temperature and pressure. The leaching results were: the leaching rate of gold was 94.28%, and the consumption of sodium thiosulfate was 2.13kg / t-ore.

[0024] Example 2

[0025] Preparation of environmentally friendly gold leaching agent: Sodium thiosulfate, sodium bromate and thiourea are mixed in a mass ratio of 100:5:5 to prepare the environmentally friendly gold leaching agent.

[0026] The gold ore raw material was finely ground to a particle size of -74μm accounting for more than 90wt.%, the slurry concentration was 30wt.%, the mass concentration of the environmentally friendly gold leaching agent was 0.5wt.%, the slurry pH was adjusted to 8, the stirring speed was 300r / min, the leaching time was 12 hours, and the leaching was carried out under normal temperature and pressure. The leaching results were: the leaching rate of gold was 82.74%, and the consumption of sodium thiosulfate was 2.73kg / t-ore.

[0027] Example 3

[0028] Preparation of environmentally friendly gold leaching agent: Sodium thiosulfate, sodium chlorate and thiourea are mixed in a mass ratio of 100:5:10 to prepare the environmentally friendly gold leaching agent.

[0029] The gold ore raw material is finely ground to a particle size of -74μm accounting for more than 90wt.%, the slurry concentration is 30wt.%, the mass concentration of the environmentally friendly gold leaching agent is 0.5wt.%, the slurry pH is adjusted to 7, the stirring speed is 300r / min, the leaching time is 12 hours, and the leaching is carried out at room temperature and pressure. The leaching results are: the leaching rate of gold is 95.15%, and the consumption of sodium thiosulfate is 2.35kg / t-ore.

[0030] Example 4

[0031] Preparation of environmentally friendly gold leaching agent: Sodium thiosulfate, sodium chlorate and thiourea are mixed in a mass ratio of 100:10:5 to prepare the environmentally friendly gold leaching agent.

[0032] The gold ore raw material was finely ground to a particle size of -74μm accounting for more than 90wt.%, the slurry concentration was 30wt.%, the mass concentration of the environmentally friendly gold leaching agent was 0.5wt.%, the slurry pH was adjusted to 7, the stirring speed was 300r / min, the leaching time was 12 hours, and the leaching was carried out under normal temperature and pressure. The leaching results were: the leaching rate of gold was 88.26%, and the consumption of sodium thiosulfate was 4.47kg / t-ore.

[0033] Example 5

[0034] Preparation of environmentally friendly gold leaching agent: Sodium thiosulfate, sodium chlorate and glycine are mixed in a mass ratio of 100:5:5 to prepare the environmentally friendly gold leaching agent.

[0035] The gold ore raw material is finely ground to a particle size of -74μm accounting for more than 90wt.%, the slurry concentration is 30wt.%, the mass concentration of the environmentally friendly gold leaching agent is 0.5wt.%, the slurry pH is adjusted to 10, the stirring speed is 300r / min, the leaching time is 12 hours, and the leaching is carried out under normal temperature and pressure. The leaching results are: the leaching rate of gold is 92.51%, and the consumption of sodium thiosulfate is 2.73kg / t-ore.

[0036] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An environmentally friendly gold leaching agent, characterized in that: The environmentally friendly gold leaching agent is prepared by mixing halogen acid salt, thiosulfate and a strengthening agent.

2. The environmentally friendly gold leaching agent according to claim 1, characterized in that: The mass ratio of the thiosulfate, the halogen acid salt and the enhancer is 100:(1-20):(1-10).

3. The environmentally friendly gold leaching agent according to claim 1 or 2, characterized in that: The pH value of gold leaching by the environmentally friendly gold leaching agent is 6-12.

4. The environmentally friendly gold leaching agent according to claim 1 or 2, characterized in that: The thiosulfate is sodium thiosulfate or potassium thiosulfate.

5. The environmentally friendly gold leaching agent according to claim 1 or 2, characterized in that: The halogen acid salt is one of chlorate, bromate and iodate.

6. The environmentally friendly gold leaching agent according to claim 5, characterized in that: The halogen acid salt is sodium halogen acid salt or potassium halogen acid salt.

7. The environmentally friendly gold leaching agent according to claim 1 or 2, characterized in that: The enhancer is one of the gold ligands such as glycine, thiocyanate, thiourea, etc.

8. The environmentally friendly gold leaching agent according to claim 7, characterized in that: The thiocyanate is sodium thiocyanate or potassium thiocyanate.

9. An application method of the environmentally friendly gold leaching agent according to claim 1, characterized in that: The following steps are involved: The gold ore is crushed and ground, the pulp concentration is adjusted to 30%-50%, and then 0.2wt%-5wt% of the environmentally friendly gold leaching agent is added, the pulp pH is adjusted to 6-12, and the leaching is carried out under stirring at normal temperature and pressure for 8-36 hours.