Dangers of Lead-Zinc Tailings

Protecting water resources, preventing water pollution and improving water environment ecology are important parts of environmental protection and sustainable development. The heavy metal ions in lead-zinc tailings are toxic, and it is very difficult to be transformed in the environment. If it enters into the water, and enters into human body after biological concentration, it will cause huge harm to people's health.

Tailings water, especially heavy metal ions-contained tailings water, must be treated to the standards before discharge. Lead-zinc tailings often contain a variety of toxic heavy metal ions. If entering into the human body through the food chain, it will cause serious damage to plants, animals and people's health. What's more, these heavy metal ions will only be transformed in translation and not disappear, so the mineral processing plant must deal with the discharge of lead-zinc tailings well.

Most heavy metal elements in mineral wastewater exist as the solid form, and physical subsidence method can avoid the problem of heavy metal pollution. Due to different ore properties and flotation process demands, pH value of slurry is different too. The pH value of lead-zinc tailings generally shows alkaline. When the pH value of slurry is alkalescence, heavy metal ions in tailings will precipitate in the form of hydroxide, which won't exceed the standard generally. When the pyrite is much more in raw ore, adding a large amount of lime can increase the slurry pH value as high as 12, even higher. Because the heavy metal hydroxide is amphoteric hydroxide, solubility will increase again with the increase of pH value, which leads to the exceeding of heavy metal ions, sometimes even hundreds of time. These dissolved heavy metal ions will entec the surrounding ecological environment as the water flow, which causes huge damage.

The heavy metal ions in lead-zinc tailings are very harmful. Only controlling the discharge of water and slag strictly can the mineral processing plant achieve sustainable development.