Method for recycling oxalic acid and hydrochloric acid from rare earth oxalate precipitation wastewater

Abstract

The invention relates to the field of treatment of industrial rare earth wastewater and resource recycling, in particular to a method for recycling oxalic acid and hydrochloric acid from rare earth oxalate precipitation wastewater. The method comprises the following steps: extracting the oxalic acid and the hydrochloric acid from the rare earth oxalate precipitation wastewater through an extraction method, thus obtaining an oxalic acid and hydrochloric acid mixing solution, and recycling the wastewater; and separating the oxalic acid from the hydrochloric acid through the extraction method, thus respectively obtaining an oxalic acid solution and a hydrochloric acid solution. By the use of the method, no rare earth oxalate precipitation wastewater is discharged, and the oxalic acid and the hydrochloric acid are recycled. Valuable resources in the rare earth oxalate precipitation wastewater are recycled, so that the production cost is reduced, and the environmental pollution is relieved.

Description

technical field [0001] The invention relates to the field of rare earth industrial wastewater treatment and resource recycling, in particular to a method for recovering oxalic acid and hydrochloric acid from rare earth oxalic acid precipitation wastewater. Background technique [0002] With the development of science and technology, rare earth oxides, which are the basic materials of high-tech materials, are more and more widely used. Many single oxides are the matrix components of many emerging rare earth functional materials, so they have high purity requirements. Most of the rare earth solutions obtained through extraction, separation and purification are in the form of rare earth chlorides, rare earth sulfates or rare earth nitrates. In order to produce rare earth oxides with higher purity in industry, oxalic acid precipitation is often used to convert them into rare earth oxalate in neutral or weakly acidic solution. In the current rare earth extraction and separation...

AI Technical Summary

Problems solved by technology

However, using a metal salt solution to precipitate and strip oxalic acid will deposit a large amount of precipitate in the extraction tank, which is not conducive to the stripping process, and also increases the difficulty of cleaning the precipitate, thereby increasing the production cost.

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