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Neodymium iron boron waste acid-leaching slag flashing-reduction super-gravity metal-slag melting and separating comprehensive recycling method

A technology of waste acid and NdFeB, applied in the direction of improving process efficiency, etc., can solve the problems of no comprehensive utilization method, high equipment requirements, lengthy process, etc., and achieve good promotion and application value, accurate atmosphere control, and large processing capacity Effect

Active Publication Date: 2019-03-01
JIANGXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] At present, there is no suitable comprehensive utilization method for the acid leaching residue of NdFeB waste. Most enterprises stockpile it, causing environmental pollution, and a few enterprises sell it as iron-making raw materials.
The patent (application number: 201610246932.3) announced "a method for comprehensive utilization of acid leaching slag from NdFeB waste". high equipment requirements

Method used

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  • Neodymium iron boron waste acid-leaching slag flashing-reduction super-gravity metal-slag melting and separating comprehensive recycling method
  • Neodymium iron boron waste acid-leaching slag flashing-reduction super-gravity metal-slag melting and separating comprehensive recycling method
  • Neodymium iron boron waste acid-leaching slag flashing-reduction super-gravity metal-slag melting and separating comprehensive recycling method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] After mixing the acid leaching slag of powdered NdFeB waste with a particle size of 100 mesh and CaO powder with a weight of 6% of the slag, spray it together with hydrogen into a reaction tower with a height of 3.5 meters and a temperature of 1200 °C through the nozzle (1) (2), the material is in a highly dispersed floating state and falls from the upper end of the reaction tower to the lower end. During this process, the reaction atmosphere is controlled so that the oxygen partial pressure is 10 -16 Atm, 63.5% of the iron oxides in the feed were reduced to metallic iron, while the rare earth oxides in the feed were not reduced. When the high-temperature melt obtained from reduction in the reaction tower falls to the sedimentation tank (3) below the reaction tower, it passes through the hot coke layer at 1350°C above the sedimentation tank, and the unreduced iron oxides are further reduced to metallic iron , At this time, the total reduction rate of iron reaches 99.5%....

Embodiment 2

[0030] The powdery NdFeB waste acid leaching slag with a particle size of 200 mesh and 5% SiO by slag weight 2 After the powder is mixed, it is sprayed together with hydrogen into a reaction tower (2) with a height of 5.5 meters and a temperature of 1300°C through a nozzle (1). In the reaction atmosphere, control the reaction atmosphere so that the oxygen partial pressure is 10 -18 Atm, 72.6% of the iron oxides in the feed were reduced to metallic iron, while the rare earth oxides in the feed were not reduced. When the high-temperature melt obtained by reduction in the reaction tower falls to the sedimentation tank (3) below the reaction tower, it passes through the hot coke layer at 1450°C above the sedimentation tank, and the unreduced iron oxides are further reduced to metallic iron , At this time, the total reduction rate of iron reaches 99.6%. The high-temperature mixed melt of molten iron and rare earth slag is discharged continuously or periodically from the outlet (5...

Embodiment 3

[0033] The powdery NdFeB waste acid leaching slag with a particle size of 300 mesh and 3% SiO by slag weight 2 Powder and 2% CaO powder are mixed, sprayed together with carbon monoxide gas from the nozzle (1) into a reaction tower (2) with a height of 8.5 meters and a temperature of 1300°C, and the materials are in a highly dispersed floating state from the upper end of the reaction tower Float to the lower end, during this process, control the reaction atmosphere, so that the oxygen partial pressure is 10 - 20 Atm, 85.3% of the iron oxides in the feed were reduced to metallic iron, while the rare earth oxides in the feed were not reduced. When the high-temperature melt obtained from the reduction in the reaction tower falls to the sedimentation tank (3) below the reaction tower, it passes through the hot coke layer at 1550°C above the sedimentation tank, and the unreduced iron oxide is further reduced to metallic iron , At this time, the total reduction rate of iron reaches...

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Abstract

The invention discloses a neodymium iron boron waste acid-leaching slag flashing-reduction super-gravity metal-slag melting and separating comprehensive recycling method. The method comprises the following steps: uniformly mixing neodymium iron boron waste acid-leaching slag and a fluxing agent, spraying the mixture together with reduction gas into a high-temperature vertical reaction tower spacevia a spray nozzle, wherein a majority of iron oxide in the material is reduced into metal iron, little iron which is not reduced is reduced into metal iron when passing by a hot coke layer arranged above a settling pond, and rare earth in the material is mixed with the slag in an oxide form; discharging the molten iron and rare-earth slag high-temperature mixed melt into a super-gravity metal-slag melting and separating device, under a super-gravity effect, enabling the molten iron to pass through a porous ceramic filter membrane, intercepting the rare-earth slag in a rotary drum, so that therare earth and the iron in the neodymium iron boron waste can be efficiently concentrated and separated, the defect that the traditional neodymium iron boron waste acid-leaching slag is difficult tocomprehensively recycle can be overcome, and the economic benefit and the environmental protection benefit are good.

Description

technical field [0001] The invention relates to a method for comprehensive recycling of NdFeB waste acid leaching slag by flash reduction and supergravity slag, and belongs to the technical field of rare earth metallurgy. Background technique [0002] NdFeB is a magnetic material. As the latest achievement in the development of rare earth permanent magnet materials, it is known as the "Magnetic King" because of its excellent magnetic properties and is widely used in various fields. In the production process of NdFeB magnetic materials, about 20-25% of the waste will be generated. These scraps contain about 60% iron and about 30% rare earth elements. The recycling of NdFeB waste not only rationally utilizes resources, but also reduces environmental pollution. [0003] At present, NdFeB waste is mainly treated by hydrochloric acid excellent solution method. First, the NdFeB is oxidized and roasted in a rotary kiln, and the rare earth and iron are oxidized into RE as much as...

Claims

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Application Information

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IPC IPC(8): C21B13/00C22B1/00C22B7/00C22B59/00
CPCC21B13/0066C21B13/0073C22B1/005C22B7/001C22B59/00Y02P10/20
Inventor 汪金良陈早明刘付朋
Owner JIANGXI UNIV OF SCI & TECH
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