Method for treating wastewater after ore leaching and ore closing of ionic rare earth ore

Abstract

The invention discloses a method for treating wastewater after ore leaching and ore closing of ionic rare earth ores. The method comprises the following steps: S1, taking ore leaching tail liquid, precipitation supernatant and product water washing liquid generated in an ore leaching process of ionic rare earth ores as raw materials, and determining the concentrations of rare earth ions, chlorineions, calcium ions and aluminum ions and the concentrations of other non-rare earth ions and heavy metal ions in the wastewater; S2, adding lime and sodium metaaluminate into the wastewater until themass ratio of Ca<2+> to Al<3+> to Cl<-> in the wastewater is (9-12):(1.5-2):1, stirring for reaction, and filtering; and S3, filtering to obtain a Fremys salt precipitate, and decomposing with hydrochloric acid to obtain a solution containing calcium chloride and aluminum chloride. According to the method, calcium salt, aluminum salt and chlorine ions in closed ore waste water are converted into Fremys salts to achieve recycling of an ore leaching agent while the content of the chlorine ions and the content of heavy metal Zn, Cd, Pb, Cu, As, Cr and Mn in the wastewater are reduced to achieve the harmless discharge of the wastewater, and the mining area environment influence after ore closing is small, so that efficient and environment-friendly extraction of ionic rare earth can be achieved.

Description

technical field [0001] The invention relates to the technical field of rare earth hydrometallurgy, in particular to a method for treating ionic rare earth ore leaching wastewater after mine closure. Background technique [0002] The rare earth in the ionic rare earth ore is adsorbed on the surface of the clay mineral in an ionic state, and the rare earth ions can be exchanged with a strong electrolyte. Therefore, according to the characteristics of the ionic rare earth ore, my country has invented an ionic rare earth extraction process. The extraction process has successively gone through the stages of sodium chloride pool leaching process, ammonium sulfate pool leaching process, ammonium sulfate heap leaching process, ammonium sulfate in-situ leaching process and magnesium sulfate leaching process, laying a solid foundation for the construction of an ionic rare earth industrial system in my country. foundation. The in-situ leaching technology of ammonium sulfate leaching-am...

AI Technical Summary

Problems solved by technology

However, this kind of leaching aid is quite different from the leaching agent used, and the influence on the pH and salinity of the ore body is not clear, which brings new pollution risks to the surrounding environment of the ore body and the groundwater system.

[0005] After the mine is closed, the amount of wastewater remaining in the mine is large, mainly from the recovered ore leaching tailings, impurity removal and sedimentation wastewater, etc. The content of valuable elements is low, and the cost of treatment and recovery is high. It is often discharged directly into the surrounding environment without treatment. middle

The high content of salt in the wastewater causes acidification and compaction of the soil in the rare earth mining area and the surrounding soil, and the cost of ecological restoration is high

Wastewater also contains low concentrations of calcium salts, aluminum salts, etc., direct discharge causes waste of resources, and the waste water contains a small amount of heavy metals such as lead, zinc, copper, etc., which is difficult to treat. If the discharge is not treated, it will also cause heavy metal elements in the surrounding environment. exceed the standard

Images