Zinc leaching residues are solid wastes produced in the process of zinc hydrometallurgy, but they contained valuable silver and the flotation method is an important way to recover silver. The flotation recovery of silver in zinc leaching residues is faced with the combined effects of various and dispersed silver-containing minerals, fine mineral particle size, strong acidity, high unavoidable ions content. Some zinc leaching residues can be recovered by the direct flotation method, but for zinc leaching residues with extremely complex silver occurrence state, it is often difficult to achieve high-efficiency separation and recovery of silver by the direct method, while the indirect flotation method is mostly used after certain pretreatment. The commonly used pretreatment technologies mainly include slurry washing, grinding, external-carrier, roasting and hot acid leaching. Pretreatments can adjust and control the pulp properties, change the occurrence state of silver and surface properties of minerals to improve selectivity and collection capacity. Each pretreatment has its unique advantages and disadvantages. An appropriate pretreatment technology combined with zinc hydrometallurgy process or organic combined the application of pretreatment technology will be more effective for flotation recovery silver in zinc leaching residues. |