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Method for strengthening leaching reaction of neodymium-iron-boron magnet by combining electrochemical anodic oxidation with ionic flocculant

An anodizing, NdFeB technology, applied in anodizing, electrolysis process, electrolysis components, etc., can solve the problem of high cost, and achieve the effect of low cost, cost reduction and less pollution

Active Publication Date: 2021-06-11
QUZHOU RES INST OF ZHEJIANG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method can realize the separation and recovery of rare earth elements and iron elements, but requires a large amount of additional iron salts or rare earth salts as electrolyte, and the cost is high

Method used

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  • Method for strengthening leaching reaction of neodymium-iron-boron magnet by combining electrochemical anodic oxidation with ionic flocculant
  • Method for strengthening leaching reaction of neodymium-iron-boron magnet by combining electrochemical anodic oxidation with ionic flocculant

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032](1) A piece of NdFeB magnet waste was washed three times with absolute ethanol and deionized water, and dried in an oven at 60°C. ICP-OES is used to determine its main metal components (multiple measurement range values): neodymium 19.42% to 19.86%, iron 56.89% to 58.98%; take appropriate amount of NdFeB magnet block waste, weigh and record. The NdFeB magnet block waste is used as an anode, and the graphite rod is used as a cathode;

[0033] (2) Prepare 0.2mol L with anhydrous potassium sulfate -1 The solution of the electrolyte is used as the electrolyte, and the pH of the electrolyte is 7;

[0034] (3) Add flocculant polyacrylamide to the electrolyte, the amount added is 10g L -1 ;

[0035] (4) Build an electrolysis device. Pour the prepared electrolyte into the washed and dried electrolytic cell, and insert the electrodes.

[0036] (5) Regulate the temperature of the water bath, and control the electrolysis temperature to be 25°C;

[0037] (6) Turn on the consta...

Embodiment 2

[0042] (1) A certain NdFeB flake waste produced by the collapse of the magnet in the machining process was washed three times with absolute ethanol and deionized water, and dried in an oven at 60 °C. The main metal components determined by ICP-OES are: 22.23% neodymium, 64.07% iron; take appropriate amount of NdFeB magnet flake waste, weigh and record. Using the NdFeB flake waste as the anode and the graphite rod as the cathode;

[0043] (2) Prepare 0.4mol L with anhydrous sodium sulfate -1 The solution of the electrolyte is used as the electrolyte, and the pH of the electrolyte is 3;

[0044] (3) The flocculant polydimethyldipropylene ammonium chloride is added to the electrolyte, and the addition amount is 30g L -1 ;

[0045] (4) Build an electrolysis device. Pour the prepared electrolyte into the washed and dried electrolytic cell, and insert the electrodes.

[0046] (5) Regulate the temperature of the water bath, and control the electrolysis temperature to be 25°C;

...

Embodiment 3

[0051] (1) A spent NdFeB magnet was washed three times with absolute ethanol and deionized water, and dried in an oven at 60°C. The mass was 0.2699g. The main metal components of the waste magnet are: neodymium 19.57%, iron 57.84%; take a piece of NdFeB waste magnet, use the NdFeB magnet block waste as the anode, and use the graphite rod as the cathode;

[0052] (2) Prepare 0.2mol L with anhydrous sodium sulfate -1 The solution of the electrolyte is used as the electrolyte, and the pH of the electrolyte is 7;

[0053] (3) Build an electrolysis device. Pour the prepared electrolyte into the washed and dried electrolytic cell, and insert the electrodes.

[0054] (4) Regulate the temperature of the water bath, and control the electrolysis temperature to be 25°C;

[0055] (5) Turn on the electrochemical workstation, keep the voltage at 2.5V, perform electrolysis for 20 minutes, and the current density fluctuation range during the electrolysis process is 30-200mA·cm -2 , record...

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Abstract

The invention discloses a method for strengthening a leaching reaction of a neodymium-iron-boron magnet by combining electrochemical anodic oxidation with an ionic flocculant. According to the method for strengthening the leaching reaction of the neodymium-iron-boron magnet by combining the electrochemical anodic oxidation with the ionic flocculant, electrolysis is carried out at room temperature by taking a neodymium-iron-boron waste magnet as an anode of an electrolysis system and an inert conductive material as a cathode, so that rare earth and iron elements in the neodymium-iron-boron waste magnet enter a solution, and the ionic flocculant rapidly moves under an electric field to promote precipitation of metal elements and strengthen the leaching reaction; and after the electrolysis is finished, a recycled product is obtained after filtering, and an electrolyte is recycled to the electrolysis process. According to the method for strengthening the leaching reaction of the neodymium-iron-boron magnet by combining the electrochemical anodic oxidation with the ionic flocculant, metal ions in the neodymium-iron-boron magnet are directly leached through an electrochemical anodic oxidation method and can be precipitated by being combined with the floccuant, and a large amount of tail gas generated by high-temperature roasting is avoided; the electrolyte uses cheap and easily available reagents to replace hydrochloric acid, oxalic acid and other substances, so that the discharge amount of acidic wastewater is reduced, and the cost is reduced; and the recovered product is loose mixed hydroxide, and subsequent acid dissolution and separation of neodymium and iron elements are convenient.

Description

technical field [0001] The invention belongs to the technical field of industrial waste recycling and relates to a method for enhancing the leaching reaction of neodymium-iron-boron magnets in combination with electrochemical anodic oxidation and ion flocculant. Background technique [0002] NdFeB permanent magnet materials have extremely high magnetic energy product and coercive force, and have been widely used in many fields such as automobiles, energy, medical equipment and electronic products. In recent years, the output of NdFeB has increased year by year. In 2019, the export volume of NdFeB products in my country reached 40,700 tons, a year-on-year increase of 3.71%. Due to the problems of technology and equipment, about 25% of waste materials will be generated in the production process of NdFeB, among which rare earth elements account for about 33%, causing serious pollution and waste. Therefore, the recycling of rare earth elements in NdFeB waste can not only improv...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/00C22B59/00C25D11/34C25D21/18
CPCC22B7/006C22B59/00C25D11/34C25D21/18Y02P10/20
Inventor 张兴旺周利娜苏志伟雷乐成
Owner QUZHOU RES INST OF ZHEJIANG UNIV