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Resource treatment method of rare-earth oxalic acid precipitation wastewater

A technology for oxalic acid precipitation and recycling, which is applied in the field of rare earth oxalic acid precipitation wastewater recycling and can solve problems such as mutual pollution of organic phases.

Active Publication Date: 2019-04-05
CENT SOUTH UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the use of various extraction systems in the process, the organic phase is easily contaminated with each other during use.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Take the HCl concentration as 1.5mol / L H 2 C 2 o 4 Rare earth oxalic acid precipitation wastewater with a content of 10.5g / L 5m 3 , 65 ℃ stirring to add oxalic acid crystals, first H 2 C 2 o 4 The concentration of hydrochloric acid was increased to 65g / L, cooled and filtered, and the precipitated rare earth oxalate was separated, and then HCl gas was passed into the obtained filtrate to increase the concentration of hydrochloric acid to 10.5mol / L, cooled and crystallized at room temperature for 16 hours, and oxalic acid crystals and h 2 C 2 o 4 The hydrochloric acid content is 0.95g / L and the concentration of hydrochloric acid is 9.8mol / L after crystallization. The obtained oxalic acid crystals continue to be used for rare earth precipitation. After the crystallization liquid is added with an appropriate amount of oxidant to remove the residual oxalic acid, it is used for the decomposition of rare earth ores. Process The recovery rate of oxalic acid (oxalic acid...

Embodiment 2

[0023] Take the HCl concentration as 1.9mol / L H 2 C 2 o 4 Rare earth oxalic acid precipitation wastewater with a content of 14.1g / L 3m 3 , stir and add 10mol / L hydrochloric acid, increase the concentration of hydrochloric acid to 4.8mol / L, freeze and crystallize at -20°C for 8h, filter to obtain oxalic acid crystals and H 2 C 2 o 4 The post-crystallization solution with a content of 99.7%, and the recovery rate of hydrochloric acid is >99.5%.

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Abstract

The invention discloses a resource treatment method of rare-earth oxalic acid precipitation wastewater. The method comprises the following steps of firstly adding oxalic acid into the oxalic acid precipitation wastewater, by utilizing a common ion effect generated by the oxalic acid and an ion, impelling residual rare earth in an obtained mixture to precipitate and separate out, filtering to obtain a rare-earth oxalic acid precipitate and precipitated liquid of the obtained mixture, afterwards, adding hydrochloric acid or introducing a HCl gas into the precipitated liquid, improving the acidity of a solution, freezing to impel the oxalic acid in the solution to crystallize and separate out, and by utilizing the characteristic that the solubility of the oxalic acid is decreased as the acidity of the solution is increased and a temperature is lowered, realizing the separation of the oxalic acid and the hydrochloric acid. The method has the advantages of being clean, environment-friendly,economical and efficient, and the like, and is suitable for the industrial application of the treatment of the oxalic acid precipitation wastewater in a rare earth smelting technical process.

Description

technical field [0001] The invention belongs to the field of metallurgy and chemical industry, and in particular relates to a method for recycling rare earth oxalic acid precipitation wastewater. Background technique [0002] The rare earth smelting process generally uses hydrochloric acid to dissolve rare earth oxides, hydroxides and carbonate minerals, and then separates the rare earth chloride product solution through solvent extraction, and then the rare earth chloride product solution is precipitated by oxalic acid or sodium carbonate to obtain rare earth oxalate or carbonate. The oxalic acid precipitation process is widely used in the production of rare earth products because of its good removal effect of non-rare earth impurities. [0003] The rare earth oxalic acid precipitation process is to first mix the oxalic acid solution with the rare earth chloride product solution to generate hydrochloric acid and rare earth oxalic acid precipitation. Filter and wash to obt...

Claims

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Application Information

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IPC IPC(8): C02F1/66C02F101/34
CPCC02F1/66C02F2101/34
Inventor 王学文孟钰麒王懿王明玉杜艳苹
Owner CENT SOUTH UNIV
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