Unlock instant, AI-driven research and patent intelligence for your innovation.

Method for recovering hydrochloric acid and rare earth from oxalate rare earth precipitation waste water

A technology for recovering hydrochloric acid and rare earth, which is applied to the improvement of process efficiency, instruments, optics, etc., and can solve the problems of incomplete extraction of oxalic acid, high energy consumption, strong corrosion of hydrochloric acid, etc.

Active Publication Date: 2013-07-17
INST OF RESOURCES UTILIZATION & RARE EARTH DEV GUANGDONG ACAD OF SCI
View PDF8 Cites 7 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The evaporation method uses the characteristics of oxalic acid and the principle of azeotroping of hydrogen chloride and water in hydrochloric acid to evaporate rare earth oxalic acid precipitation wastewater, evaporate hydrochloric acid and water, and crystallize and precipitate oxalic acid in the evaporated mother liquor with evaporation. Very corrosive at higher temperatures
Extraction methods include oxalic acid extraction method and hydrochloric acid extraction method. The oxalic acid extraction method extracts the oxalic acid in the wastewater, and the wastewater is reused. The extraction agent extracts the oxalic acid and then back-extracts the oxalic acid. However, the extraction of oxalic acid is not complete, and the volume of waste water increases; the extraction of hydrochloric acid also has the same problem

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] The rectangular diaphragm electrolyzer consists of an anode chamber and a cathode chamber, which are separated by a Nafion cation exchange membrane. The anode uses a titanium-based metal plate coated with ruthenium and iridium, the cathode uses a metal titanium plate, and the anolyte is europium oxalate precipitation wastewater. The europium ion concentration of the solution is 45mg / L, the H + Concentration is 0.89mol / L, C 2 o 4 2- The concentration is 3g / L; catholyte is dilute hydrochloric acid solution, in which H + The concentration is 0.9mol / L, and the current density is 25A / m 2 , the anolyte and catholyte are circulated separately, and the concentration of europium ions in the anode chamber is 42 mg / L after electrolysis for 15 hours, and the H + Concentration is 0.59mol / L, C 2 o 4 2- The concentration is 0.03g / L, the decomposition rate of oxalate is 99%, the recovery rate of acid is 66%, and the recovery rate of europium ion is 93%.

Embodiment 2

[0016] Simultaneously embodiment 1, wherein anolyte is terbium oxalate precipitation wastewater, the terbium ion concentration of this solution is 75mg / L, H + Concentration is 0.95mol / L, C 2 o 4 2- The concentration is 15g / L, and the catholyte is dilute hydrochloric acid solution, in which H + The concentration is 0.0015mol / L, and the current density is 125A / m 2 , the anolyte and catholyte are circulated separately, and the terbium ion concentration in the anode chamber is 72 mg / L after electrolysis for 8 hours, and the H + Concentration is 0.62mol / L, C 2 o 4 2- The concentration of 0.01g / L, the decomposition rate of oxalate is higher than 99%, the recovery rate of acid is 65%, and the recovery rate of terbium ion is 96%.

Embodiment 3

[0018] The rectangular diaphragm electrolyzer is composed of two anode chambers and a cathode chamber. The anode chamber and the cathode chamber are separated by a model Nafion cation exchange membrane. The anode is made of titanium-based metal mesh coated with ruthenium and iridium, and the cathode is made of metal titanium mesh. The anolyte is Terbium oxalate precipitation waste water, the terbium ion concentration of this solution is 75mg / L, H + Concentration is 0.51mol / L, C 2 o 4 2- The concentration is 0.6g / L; catholyte is dilute hydrochloric acid solution, in which H + The concentration is 5.0mol / L, and the current density is 21A / m 2 ; The anolyte and catholyte are circulated separately, and the terbium ion concentration in the anode chamber is 74 mg / L after electrolysis for 8 hours, and the H + Concentration is 0.40mol / L, C 2 o 4 2- The concentration of 0.009g / L, the decomposition rate of oxalate is higher than 99%, the recovery rate of acid is 78%, and the recov...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

A method for recovering hydrochloric acid and rare earth from oxalate rare earth precipitation waste water. The method is characterized in that: a titanium-based metal plate or net coated with ruthenium and iridium is used as an anode, and a metal titanium plate or net is used as a cathode; an anode chamber and a cathode chamber are separated by an ion exchange membrane; a cathode solution is an acidic solution, and the anode solution is oxalate rare earth precipitation wastewater; the current density is 20-600A / m<2>; and an oxidation reaction is taken place in the anode chamber to precipitate chlorine and to oxidize and decompose oxalate ions in the waste water, so as to recycle acid and rare earth in the waste water. The method provided by the invention can recycle water and acid resources in wastewater, and recover rare earth, and generates no new wastewater or waste emission.

Description

technical field [0001] The invention relates to a method for recovering hydrochloric acid and rare earth from oxalic acid rare earth precipitation wastewater. Background technique [0002] Since the mid-1980s, my country's rare earth industry has developed rapidly and made great achievements. However, rare earth smelting belongs to wet smelting, and the amount of wastewater is relatively large, and the wastewater has the characteristics of serious pollution and difficult treatment. Rare earth smelting will bring about major environmental problems. [0003] Rare earth oxalate precipitation wastewater is produced in the process of converting rare earth chloride to rare earth oxalate, and the chemical reaction formula is as follows: 2RECl 3 + 3 H 2 C 2 o 4 = RE 2 (C 2 o 4 ) 3 + 6HCl, the precipitation wastewater produced is mainly a mixed solution of hydrochloric acid and oxalic acid and traces of rare earth oxalic acid and impurities. At present, the lime neutraliza...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): C22B7/00C25C1/22
CPCY02P10/20
Inventor 刘志强邱显扬朱薇郭秋松
Owner INST OF RESOURCES UTILIZATION & RARE EARTH DEV GUANGDONG ACAD OF SCI