Method for recovering rare earth in neodymium-iron-boron waste by high-temperature and high-pressure leaching

A technology for recycling NdFeB, high temperature and high pressure, applied in the direction of improving process efficiency, etc., can solve the problems of high waste particle size requirements, low hydrochloric acid utilization rate, long leaching time, etc., to achieve increased hydrochloric acid utilization rate, low hydrochloric acid consumption, and improved The effect of recovery value

Active Publication Date: 2019-04-02
INNER MONGOLIA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The invention proposes for the first time to use hydrochloric acid as the leaching agent in the reaction kettle for high temperature and high pressure leaching, which effectively solves the problems of energy saving and environmental protection such as high waste parti

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] This embodiment provides a method for high temperature and high pressure leaching and recovery of rare earths in NdFeB waste, comprising the following steps:

[0050] S1: Take 300g of NdFeB waste powder, particle size -100 mesh, chemical composition (mass percentage): TRE-29.14, Fe-66.34, Co-0.74, Al-0.38, B-0.96. The above-mentioned NdFeB waste is oxidized and roasted so that the content of low-valent iron oxide FeO in it is less than 1%, and then crushed and ground to below -100 mesh.

[0051] S2: Get 30.00 g of waste powder after roasting, 23.19 g of 37% concentrated hydrochloric acid is diluted with water to 90 g (the amount of HCl is 1.15 times of the theoretical amount), and the mixed material liquid composed of the two is added into the autoclave, and the autoclave is sealed. The pressure in the autoclave is 0.6MPa, the leaching temperature is 110°C, the stirring speed is 300r / min, and the leaching time is 30min. After the leaching is completed, take out the auto...

Embodiment 2

[0055] This embodiment provides a method for high temperature and high pressure leaching and recovery of rare earths in NdFeB waste, comprising the following steps:

[0056] S1: Select the NdFeB waste powder obtained by roasting in Example 1, further crush and grind to a particle size of -200 mesh.

[0057] S2: Take 30.00g of roasted NdFeB waste powder, add 23.19g of 37% concentrated hydrochloric acid and dilute it to 90g with water (the amount of HCl is 1.15 times the theoretical amount), add the mixed material liquid formed by the two into the autoclave, seal Autoclave, the pressure inside the autoclave is 0.6MPa, the leaching temperature is 110°C, the stirring speed is 300r / min, and the leaching time is 30min. After the leaching is completed, the reactor is taken out, and the solid and liquid are separated to obtain the leachate.

[0058] S3: Slowly add oxidant H to the leaching solution under stirring 2 o 2 15mL, so that the Fe 2+ fully oxidized.

[0059] S4: neutrali...

Embodiment 3

[0061] This embodiment provides a method for high temperature and high pressure leaching and recovery of rare earths in NdFeB waste, comprising the following steps:

[0062] S1: select the NdFeB waste powder obtained by roasting in Example 1.

[0063] S2: Get 30.00g of NdFeB waste powder after roasting, add 25.61g of 37% concentrated hydrochloric acid and dilute to 90g with water (the amount of HCl is 1.27 times of the theoretical amount), add the mixed material liquid formed by the two into the autoclave, Seal the autoclave so that the pressure inside the autoclave is 1.0MPa, the leaching temperature is 110°C, the stirring speed is 300r / min, and the leaching time is 30min. After the leaching is completed, take out the autoclave, separate the solid and liquid, and obtain the leachate.

[0064] S3: Leave the leaching solution open for 24 hours, using air as the oxidant to oxidize the Fe in it 2+ , and slowly add the oxidant H to the leaching solution under stirring 2 o 2 5m...

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Abstract

The invention relates to a method for recovering rare earth in neodymium-iron-boron waste by high-temperature and high-pressure leaching. The neodymium-iron-boron waste is subjected to oxidation roasting, hydrochloric acid high-temperature and high-pressure leaching, and oxidation and impurity removal purification on Fe2+ in a leachate so as to obtain a rare-earth chloride leachate; and the rare-earth chloride leachate can be used as a subsequent process and a product raw material, rare earth is obtained through extraction and separation, rare earth carbonate is prepared through precipitation,or rare earth oxide is prepared through precipitation-roasting. According to the method, a closed high-pressure reaction kettle is adopted as leaching equipment, so that the dynamic condition of theleaching process is excellent, the requirement for the particle size of the leached raw materials is low, a large amount of dust generated by the fine grinding process of the raw materials is avoided,the leaching rate of rare earth in the leaching process is high, the utilization rate of hydrochloric acid is high, no acid gas is discharged, energy is saved, and the environment is protected; and in addition, the method has the advantages of being short in process flow, simple in process conditions and low in recovery cost, and the method has considerable economic, social and environmental protection benefits for large-scale recovery of the neodymium-iron-boron waste.

Description

technical field [0001] The invention relates to the technical field of rare earth metallurgy, in particular to a method for leaching and recovering rare earths in NdFeB waste materials under high temperature and high pressure. Background technique [0002] As the third-generation rare earth permanent magnet material, NdFeB has the advantages of light weight, small size, strong magnetism, and high magnetic energy product, so it is widely used. However, the waste (about 30-40%) produced in the preparation process and the waste produced by long-term use failure become secondary resources for the extraction of rare earths and other valuable metal elements, which are generally recovered by wet methods, such as Sulfuric acid double salt precipitation method, hydrochloric acid excellent solution method, hydrochloric acid total solution method, etc. The wet recovery method has the advantage of a high recovery rate of rare earths, but the leaching process of the above-mentioned reco...

Claims

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Application Information

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IPC IPC(8): C22B7/00C22B1/02C22B59/00
CPCC22B1/02C22B7/007C22B59/00Y02P10/20
Inventor 邓永春姜银举张婧辛文彬郭超
Owner INNER MONGOLIA UNIV OF SCI & TECH
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