If conventional flotation schemes such as high strength alkali, butylammonium, and xanthate are used for high sulfur copper silver ore, the flotation indicators will be poor.
Comparative experiments were conducted on rough selection under weak and strong alkaline conditions, and the use of weak alkaline combination pyrite inhibitor scheme can significantly improve the indicators of copper and silver concentrates.
The closed circuit test obtained production indicators of copper concentrate with a copper grade of 20.17%, a recovery rate of 92.39%, a silver recovery rate of 87.84%, a sulfur grade of 47.37%, and a recovery rate of 95.23%.
The experimental copper minerals are mainly chalcopyrite, followed by silver tetrahedrite, followed by chalcopyrite, bornite, and malachite; Pyrite is relatively high, with a small amount of magnetite; Most of the copper ore is large particle chalcopyrite, with a small amount of silver tetrahedrite embedded in pyrite and gangue as extremely fine particles; Gangue minerals are mainly silicates, followed by carbonaceous shale, with a small amount of pyrolusite and non-metallic minerals such as calcite and quartz.
(1)Rough selection test under strong alkaline conditions
The test samples were prepared in a 1:1 ratio for sample 3 and sample 4, which were roughly crushed by a jaw crusher, finely crushed by a double roll crusher, and then screened by a 2mm vibrating screen in a closed circuit. The screened products were used as test samples.
The experimental results showed poor indicators. Under high alkaline conditions, only chalcopyrite, chalcopyrite, and bornite were recovered, while silver tetrahedrite and malachite were strongly suppressed, resulting in low recovery rates of copper and silver.
(2)Rough selection test under weak alkaline conditions
The experiment on sulfur suppression and floating copper under weak alkaline conditions showed a significant improvement in the environmental indicators compared to strong alkaline conditions. Not only did the grades of copper and silver in the crude copper concentrate significantly increase, but the recovery rates of copper and silver also increased significantly.
(3)Comprehensive Closed Circuit Test
The raw ore is ground by a ball mill, and the particle size of the ground product is -0.074mm, accounting for 82%. Copper concentrate is obtained by 1 coarse and 1 fine process, and sulfur concentrate is obtained by 4 sweeps of tailings.
It is difficult to obtain ideal production indicators for copper, silver, and sulfur beneficiation using conventional high strength alkaline flotation schemes for high sulfur copper silver ores.
Through long-term experimental exploration and industrial production, it has been found that using weak alkaline combination inhibitors to suppress pyrite, and then using a comprehensive floating sulfur scheme under weak alkaline conditions, can achieve production indicators of copper concentrate with a copper grade of 20.17%, a recovery rate of 92.39%, a silver recovery rate of 87.84%, a sulfur grade of 47.37%, and a recovery rate of 95.23%, bringing huge economic benefits to enterprises.
