Thiosulfate gold leaching method and application

Abstract

The invention provides a thiosulfate gold leaching method and its application, and relates to the technical field of hydrometallurgy. The thiosulfate gold leaching method includes adding metal salts, polycarboxylate additives, and thiosulfate into gold-containing pulp for leaching, wherein a large number of acid groups distributed on the hydrocarbon chain of the polycarboxylate additive can be combined with The cations produced by the hydrolysis of metal salts in the solution undergo multidentate chelation to generate complex ions, thereby replacing Cu(NH in the traditional thiosulfate gold leaching process 3 ) 4 2+ , can improve the Cu(NH 3 ) 4 2+ It has the defect of excessive consumption of thiosulfate caused by oxidation, which significantly reduces the S in the leachate 2 o 3 2‑ Decomposition products such as polythionate and other harmful ion concentrations are beneficial to the recycling of the leachate and the recovery of gold in the solution; at the same time, the thiosulfate gold leaching method also avoids the safety and environmental impact problems faced by the use of ammonia water.

Description

technical field [0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a thiosulfate gold leaching method and its application. Background technique [0002] Gold is an extremely important strategic metal resource, and is known as the "King of Metals" because of its irreplaceable role in industrial production, economic operation, and national economic security. At present, the global gold production process is mainly the cyanidation method, which is in a dominant position. However, there are still some shortcomings in the cyanide method: on the one hand, the toxicity of cyanide and its impact on the environment and human beings are being closely watched by the public, and some countries and regions have legislated to strictly prohibit the use of cyanide as a leaching agent; On the one hand, with the development and utilization of gold mineral resources, the easy-to-handle gold ore resources are decreasing day by day, and the recy...

AI Technical Summary

Problems solved by technology

However, there are still some shortcomings in the cyanide method: on the one hand, the toxicity of cyanide and its impact on the environment and human beings are being closely watched by the public, and some countries and regions have legislated to strictly prohibit the use of cyanide as a leaching agent; On the one hand, with the development and utilization of gold mineral resources, the easy-to-handle gold ore resources are decreasing day by day, and the recycling of difficult-to-handle gold ore is becoming more and more urgent

[0007] 2Cu(NH 3 ) 4 2+ +8S 2 o 3 2- =2Cu(S 2 o 3 ) 3 5- +S 4 o 6 2- +8NH 3 The above-mentioned side reactions occur, prompting S 2 o 3 2- Oxidative decomposition to generate S 4 o 6 2- , and finally form a series of decomposition products such as trithionate, tetrathionate, sulfate and elemental sulfur, which causes a large consumption of thiosulfate leaching agent, thereby increasing the production cost, and some of the decomposition products are also Will cover the surface of gold, forming a passivation layer, hindering the leaching of gold

At the same time, a large number of polythionate ions in the leaching solution will cause great interference to the subsequent gold extraction process

In addition, the storage and use of ammonia water in production requires a high level of safety. Once a leak occurs, it will cause serious pollution to the natural environment.

In addition, the leaching pH value of the traditional copper ammonia thiosulfate gold leaching process is limited to 9.0-10.0

The severe restriction of pH value further hinders the large-scale industrial application of thiosulfate gold leaching process

[0008] Although researchers have made many improvements to the traditional thiosulfate gold leaching process in recent years, such as adding new additives, such as alkyl trimethyl quaternary ammonium salt, triethylene tetramine, etc., there are still relatively high prices of additives. , or has strong toxicity, or the pH value of the leaching process is strict, or the consumption of thiosulfate is still high, etc.

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