A low-cost method for preparing high-performance anisotropic NdFeB magnetic powder using NdFeB oil-based slice sludge

An anisotropic, NdFeB technology, which is applied in the field of reclaiming NdFeB oil-based slicing sludge to prepare recycled magnetic powder, can solve the problems of large amount of reducing agent Ca, reduce recycling costs, increase sludge oxygen content, etc., and achieve environmental friendliness Recycling of resources, realization of recycling of resources, and the effect of reducing the amount of calcium used

Active Publication Date: 2020-11-03
BEIJING UNIV OF TECH
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  • Application Information

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Problems solved by technology

Chinese patent (Application No. 201410101544.7) discloses a method for recovering valuable elements in NdFeB oil sludge by co-precipitation and diffusion reduction technology to obtain NdFeB magnetic powder. The performance is poor, and a large amount of metallic calcium is used in the reduction diffusion process, and the cost is high
Chinese patent (Application No. 201510101336.1) also successfully recovered NdFeB magnetic powder from sludge waste by using the reduction diffusion method, but it added additional raw materials such as NdO and FeB during the reduction diffusion process, resulting in an increase in the amount of reducing agent used. Helps reduce recycling costs
Chinese patent (application number 201811437315.7) discloses a method for recovering NdFeB casing sludge waste using Ca-chloride reduction and diffusion technology. In this method, it first uses blast drying to purify the sludge, although this method is effective The sludge is purified, but the oxygen content in the sludge is increased, which increases the amount of calcium added in the subsequent reduction and diffusion, which is not conducive to the reduction of recovery costs
In short, the current high-efficiency recovery methods for NdFeB oil sludge generally have the following problems: 1) The amount of reducing agent Ca used is too large, resulting in high recovery costs
For this kind of oil sludge, there is no corresponding short-process and low-cost recovery technology

Method used

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  • A low-cost method for preparing high-performance anisotropic NdFeB magnetic powder using NdFeB oil-based slice sludge
  • A low-cost method for preparing high-performance anisotropic NdFeB magnetic powder using NdFeB oil-based slice sludge

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Experimental program
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Effect test

Embodiment 1

[0021] Take 30g of NdFeB oil-based slice sludge, through sedimentation, centrifugation, and remove cutting fluid, first use OP-NH 4Cl aqueous solution was ultrasonically cleaned twice, distilled water was washed twice, dilute acetic acid solution was used to wash once, distilled water was washed twice, and acetone was finally used to wash once, and dried in a vacuum environment to obtain pretreated sludge. Take 5g of pretreated oil sludge, mix with 0.8g metallic calcium and 2.62g anhydrous calcium chloride, place it in a cemented carbide mold, and press it into a block on a cold press to obtain a reaction block; place the reaction block on a stainless steel Put the crucible in a tube furnace, raise the temperature to 1050°C in an argon atmosphere, and keep it warm for 120 minutes to obtain a reduced block; grind the reduced block into powder, and carry out the process in a container with an external magnet and a mixture of ice and water Remove calcium, soak for 10 minutes, rem...

Embodiment 2

[0023] Take 30g of NdFeB oil-based slice sludge, through sedimentation, centrifugation, and remove cutting fluid, first use OP-NaHCO 3 The aqueous solution is ultrasonically cleaned twice, distilled water is washed twice, then dilute nitric acid solution is used for washing, distilled water is washed twice, and finally acetone is used for washing once, and the pretreated sludge is obtained by drying in a vacuum environment. Take 5g of pretreated oil sludge, mix with 1g of calcium metal, and 2.62g of anhydrous calcium chloride, place it in a cemented carbide mold, and press it into a block on a cold press to obtain a reaction block; put the reaction block in a stainless steel crucible In the process, put the crucible in a tube furnace, raise the temperature to 1050°C in an argon atmosphere, and keep it warm for 120 minutes to obtain a reduced block; grind the reduced block into powder, and remove it in a container with an external magnet and equipped with an ice-water mixture. ...

Embodiment 3

[0025] Take 30g of NdFeB oil-based slice sludge, through sedimentation, centrifugation, and remove cutting fluid, first use OP-Na 2 CO 3 The aqueous solution is ultrasonically cleaned twice, distilled water is washed twice, then dilute sulfuric acid solution is used for washing, distilled water is washed twice, and finally acetone is used for washing once, and the pretreated oil sludge is obtained by drying in a vacuum environment. Take 5g of pretreated oil sludge, mix with 1.1g metallic calcium and 2.62g anhydrous calcium chloride, place it in a cemented carbide mold, and press it into a block on a cold press to obtain a reaction block; place the reaction block on a stainless steel Put the crucible in a tube furnace, raise the temperature to 1050°C in an argon atmosphere, and keep it warm for 120 minutes to obtain a reduced block; grind the reduced block into powder, and carry out the process in a container with an external magnet and a mixture of ice and water Remove calciu...

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Abstract

The invention relates to a low-cost method for preparing high-performance anisotropy neodymium-iron-boron magnetic powder by using neodymium iron boron oil-based slice oil sludge, and belongs to the technical field of recycling of rare-earth permanent magnet wastes. Firstly, cutting fluid and impurities of oil sludge are removed in a physical and chemical separation mode, so that the content of carbon, hydrogen, oxygen and other impurities in the oil sludge can be reduced, and the purification purpose is achieved. The metal calcium (Ca) is taken as a reducing agent to be added and one or morebuffering agents are assisted, namely potassium chloride and calcium chloride are used as the reducing agents, so that a stable reaction system is constructed. According to the reaction system, on thebasis of substantially reducing the use amount of the metal calcium, the reaction can be fully carried out, the grain size and distribution of recycled magnetic powder are greatly improved, and the single crystal proportion and the orientation degree of the recycled magnetic powder are improved; in addition, reactants are pressed into blocks during reaction, so that sufficient and uniform reaction of the reactants is facilitated; a reduction product is ground into powder, the mixture of ice water and the like is used for removing calcium, the oxidation degree of the recovered magnetic powderis reduced, and the speed and the efficiency of calcium removal are improved. The method has the characteristics of economy, high efficiency, environmental protection and the like.

Description

technical field [0001] The invention relates to reclaiming NdFeB oil-based slice oil sludge to prepare regenerated magnetic powder, and belongs to the technical field of rare earth permanent magnet waste recycling and reuse. [0002] technical background [0003] Sintered NdFeB permanent magnet materials have been widely used in various industries. my country is a major producer of NdFeB, supplying more than 90% of the world's NdFeB. In the production process of sintered NdFeB, about 40wt.% of the total weight of raw materials will produce NdFeB waste, and about 30wt.% of the waste is produced in the machining stage in the form of sludge waste, which contains high-rich rare earth elements and other valuable elements. In recent years, due to the increasing shortage of rare earth resources and the rising price of rare earth and metals, the production cost of sintered NdFeB magnets has increased significantly. In order to save resources and achieve sustainable development, it ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/00C22B59/00B22F8/00
CPCB22F8/00C22B7/001C22B59/00Y02P10/20Y02W30/50
Inventor 路清梅王峰岳明刘卫强邱玉冰尹小文徐海波
Owner BEIJING UNIV OF TECH
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