High silver copper-bearing gold concentrate cyanidation technology

Suichang gold mining sulfide-depleted quartz vein gold, the gold content of the ore 9.7g / t, silver content of up to 242.96g / t, the mineral composition is more complex, but still are easy dressing stone, fine particles of gold to the majority . Mainly in the gold and silver mines and silver and gold mines, fine grinding is required to dissociate the gold and silver mineral monomers. Since the completion of the 300t/d mining scale in 1986, the gold concentrate was sold to the Fuchunjiang smelter in the past by a single flotation process. In order to realize the real estate gold, reduce the loss of concentrate transportation, accelerate the turnover of funds, and improve the efficiency of enterprises, in 1989, the cyanide workshop was built and put into production. The chemical composition of the gold concentrate is shown in Table 1.

Table 1 Chemical composition of gold ore deposits in Suichang Gold Mine, Zhejiang Province

The mine was specially tested before the plant was built, but the results were unexpected. It is well known that the recovery rate of silver by cyanidation is generally not high, and the recovery rate of silver in this test is as high as 95.15%. Secondly, the size of concentrate concentrate reaches -320 mesh, accounting for 77.60%, the highest gold leaching rate, and the over-grinding decreases. Dissolved in the cyanide solution to form a silver cyanide complex, which must be maintained at a high concentration, the cyanide concentration is maintained at about 0.08%, and the cyanide consumption is as high as 8.1 kg/t.

Based on the research completed two tests on two wash dip, zinc powder replacement, wastewater treatment acidification, gold mud pyrometallurgical process, after years of production practice their gold and silver cyanide recoveries of 97.15% and 90.26% respectively. Get great results. Its main features are: (1) high concentration cyanide leaching plus moderate grinding, that is, a 320 mesh accounted for about 75%, a cyanide concentration in a dip operation is controlled between 0.08% and 0.10%, and a dip operation is controlled at 0.06%. -0.08% up and down; (2) using an automatic vertical filter press to filter the dross, the cyanide tailings are sulfur concentrates, 30% to 35% of sulfur is sold to the chemical plant near the acid; (3) the mine Located in Jiangnan Water Town, the population is dense and the water system is developed. If ordinary cylindrical filter is used, the water content of the filter cake will be as high as 20%, and the sulfur concentrate needs to pass through several villages. If the car is not tightly sealed, it will be scattered, which will cause serious pollution to the environment. However, the water content of the filter cake will be reduced to 8% to 10% after using the automatic vertical filter press. It is in the state of dry cake and meets environmental protection requirements.

Generally considered. When the take-containing fine gold grade of greater than 1% copper cyanide process is uneconomical, mainly copper minerals will consume a lot of cyanide. Thereby affecting the leaching rate of gold; at the same time, copper is not effectively recovered due to the large amount of cyanide dissolved during the leaching process. The solubility of copper minerals in sodium cyanide solution is shown in Table 2. however. Guangdong Gaoyao Hetai Gold Mine has solved this problem well in Jinjing. The ore deposits gold-altered mylonite deposits. The solubility of copper minerals in the 0.099% NaCN solution is 0.2% to 0.3% in the ore. Gold ore was obtained after ore flotation, and was sold to the smelter before 1998. Due to smelter pressure, pressure grade and delay in returning goods and long-distance transportation and loss. The business situation of the company has been passive. In order to change this aspect and realize the technical transformation of the gold concentrate cyanide project in 1998, the multi-element analysis of copper-bearing concentrates is shown in Table 3. The relative content of copper oxide is only 9.01%, and the rest is sulfide. It is pretreated with alkali in the conventional cyanide leaching test. The cyanide consumption is still l2kg/t. The gold leaching rate is 96%, which is ideal. In order to reduce the consumption of cyanide. The engineering and technical personnel of the mine made in-depth exploration and research. After years of efforts, a special method was adopted to reduce the consumption of sodium cyanide to 8kg/t.

Table 2 Solubility of copper minerals in 0.099% NaCN solution

Table 3 Multi-element analysis results of gold concentrate in Hetai Gold Mine