RU-2861505-C1 - METHOD FOR LEACHING GOLD FROM MINERAL RAW MATERIALS WITH COPPER CONTENT OF 0.05-15%

RU2861505C1RU 2861505 C1RU2861505 C1RU 2861505C1RU-2861505-C1

Abstract

FIELD: metallurgy. SUBSTANCE: invention relates to the field of non-ferrous and precious metal metallurgy, in particular to the processing of mineral raw materials with a copper content ranging from 0.05 to 15%. Leaching is carried out in an alkaline solution in the presence of glycine and sodium cyanide while introducing an oxidising agent into the pulp. Glycine in an amount of 0.1-15 g/l and sodium cyanide in an amount ensuring a concentration of free sodium cyanide in the liquid phase of the pulp from 0.1 to 300 mg/l are simultaneously introduced into the leaching stage. Air or an air-oxygen mixture with an oxygen concentration of up to 95% is used as the oxidising agent. EFFECT: significant reduction in sodium cyanide consumption. 2 cl, 1 tbl, 1 ex

Inventors

Senchenko Arkadii Evgenevich
AKSENOV ALEKSANDR VLADIMIROVICH
Vasilev Andrei Anatolevich
Rybkin Sergei Georgievich
Seredkin Iurii Georgievich

Dates

Publication Date: 20260505
Application Date: 20250915

Claims (2)

1. A method for leaching gold from mineral raw materials with a copper content of 0.05-15%, including leaching in an alkaline solution in the presence of glycine and sodium cyanide with the introduction of an oxidizing agent into the pulp, characterized in that glycine in an amount of 0.1-15 g/l and sodium cyanide in an amount ensuring a concentration of free sodium cyanide in the liquid phase of the pulp from 0.1 to 300 mg/l are simultaneously introduced into the leaching stage.
2. The method according to paragraph 1, characterized in that atmospheric oxygen or an oxygen-air mixture with an oxygen concentration of up to 95% is used as the oxidizer.

Description

The invention relates to the field of metallurgy of non-ferrous and precious metals, in particular, the processing of gold-containing mineral raw materials with an increased copper content (0.05–15%). For many years, the primary method for extracting gold and silver from mineral raw materials has been cyanide leaching [1]. This process has become widely used in industry due to its high efficiency and relatively low setup costs. However, there are a number of ores, concentrates, and tailings, known as refractory, which are difficult to process using standard cyanide technology. One type of product that is resistant to cyanidation is mineral raw materials with high copper content [2]. Processing such ores and concentrates using conventional cyanide technology is associated with high reagent consumption and often low efficiency in precious metal extraction. A known method for extracting copper and/or precious metals from metal-containing materials involves leaching in an alkaline medium with an amino acid or its derivative in the presence of oxidizing agents (hydrogen peroxide, oxygen-containing gas, manganese dioxide, potassium permanganate, or calcium peroxide) [3]. Disadvantages of this method for gold extraction include the long duration of the process (from 5 to 30 days), the need to heat the pulp or solution, and the need to use strong oxidizing agents. A method for extracting silver from ores is known, which involves treating the source material with an aqueous solution of ammonium hydroxide and an oxidizing agent while heating, and the treatment is carried out in the presence of glycine and ammonium hydroxide [4]. The disadvantages of the method are the impossibility of using This method for extracting gold requires heating the pulp and using strong oxidizing agents - sodium peroxide or potassium persulfate. The closest to the claimed technical solution (prototype) is the method for leaching gold from gold-containing raw materials according to Russian Federation Patent No. 2832286, used in the method of hydrometallurgical processing of bacterial oxidation cake, according to which the cake is subjected to two-stage leaching. The first stage of leaching is carried out in an alkaline medium (pH=10.0÷10.5) with a solid content in the pulp of 50% in the presence of glycine (aminoacetic acid) with a concentration of 1 mol/l (75 g/l) at a reagent consumption of 3.3 kg/t with the addition of oxygen or potassium permanganate as an oxidizer at a consumption of 5 kg/t for 8 hours. At the second stage of the process, sorption cyanidation of the material is carried out for about 32 hours at a solid content in the pulp of 50%, a pH of 10.5, a sodium cyanide concentration in the liquid phase at the beginning of the process of about 2000 mg/l, in the middle of the process of about 1000 mg/l and about 300 mg/l at the end of the process, a dissolved oxygen concentration of about 10-15 mg/l, and an amount of carbon sorbent in the pulp of about 4% by volume [5]. The use of this method allows to reduce the consumption of sodium cyanide by 35% compared to the sorption cyanidation process. An analysis of the method for processing bacterial oxidation cake [5] showed that when processing mineral gold-bearing raw materials with an increased copper content (from 0.05% to 15%) using a two-stage technology, the process of dissolution of gold and copper in the first and second stages can be described by the reactions: A disadvantage of the prototype method is the high consumption of sodium cyanide during leaching of gold-bearing minerals with high copper content. The high sodium cyanide consumption in the prototype method is due to the fact that the second leaching stage is carried out with a high concentration of free sodium cyanide, which leads to the cyanide binding primarily to copper. The purpose of the claimed invention is to significantly reduce the consumption of sodium cyanide by combining the processes of glycinate and cyanide leaching, which allows the process of gold dissolution to be carried out with a minimum concentration of free cyanide in the solution. The said technical result is achieved by the fact that in the known method of leaching gold from gold-bearing raw materials with an increased copper content, which includes leaching in an alkaline solution in the presence of glycine and sodium cyanide with the introduction of an oxidizing agent into the pulp, glycine in an amount of 0.1÷15 g/l and sodium cyanide in an amount that ensures a concentration of free sodium cyanide in the liquid phase of the pulp from 0.1 to 300 mg/l are simultaneously introduced into the leaching stage. The differences between the proposed technical solution and the prototype are the implementation of the gold leaching operation in one stage and a lower concentration of glycine and free sodium cyanide in the liquid phase of the pulp. By combining glycinate and cyanide leaching, the mechanism of the physicochemical processes occurring duri