Some Valuable and Recoverable Elements of Lead-zinc Tailings

Large discharging of lead-zinc tailings not only occupies land area, but also pollutes the environment. Tailings will make a difference under the condition of stacking, such as oxidation, hydrolysis and weathering, which make pollution-free components transform into polluting components. For example, the sulfide of lead-zinc tailings composition can generate soluble substances after oxidation, then flow into surrounding environment with rivers. In addition, the residual chemicals, radioactive substances and raise dust caused by tailings grinding can bring serious pollution to the environment.

Sericite is the main part of lead-zinc tailings, which can be separated by flotation process. At the same time, there are complex compositions in lead-zinc tailings, such as a certain amount of gold, silver, sulfur, iron, tungsten and molybdenum, which are usually deposited in the tailings as sulphides. And the sulfides will be oxidized as soluble ions in nature, and cause serious damage to the surrounding ecology if they are not recycled. As the major sulfide in lead-zinc tailings, pyrite is the main raw materials of industrial sulfuric acid. Because its good native floatability, pyrite can be separated by the flotation process. The recovery of rare metals (gold, silver and molybdenum) should take their respective grade and recovery difficulty into account. After recycling the valuable compositions in tailings, the remaining slag still has utilization value, such as backfilling mines after thickening, producing cement clinker with iron powder discharge, manufacturing building materials.

With the depletion of mineral resources, it is necessary to recycle the useful parts of lead-zinc tailings reasonably, which not only improves economic efficiency, but also confirms to the demand of sustainable development.