A method for comprehensive recovery of NdFeB waste acid leaching slag flash reduction supergravity slag financial fraction

A waste acid, NdFeB technology, applied in the direction of improving process efficiency, can solve the problems of no comprehensive utilization method, high equipment requirements, environmental pollution, etc., and achieve good popularization and application value, accurate atmosphere control, and environmental friendly effects.

Active Publication Date: 2020-08-28
JIANGXI UNIV OF SCI & TECH
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  • 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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  • A method for comprehensive recovery of NdFeB waste acid leaching slag flash reduction supergravity slag financial fraction
  • A method for comprehensive recovery of NdFeB waste acid leaching slag flash reduction supergravity slag financial fraction
  • A method for comprehensive recovery of NdFeB waste acid leaching slag flash reduction supergravity slag financial fraction

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Experimental program
Comparison scheme
Effect test

Embodiment 1

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

Embodiment 2

[0030] The powdery NdFeB waste acid leaching residue with a particle size of 200 meshes and 5% SiO by weight of the residue 2 After the powder is mixed, it is sprayed together with hydrogen from the nozzle (1) into a reaction tower (2) with a height of 5.5 meters and a temperature of 1300°C. The materials are floating in a highly dispersed state from the upper end of the reaction tower to the lower end. During this process In, control the reaction atmosphere to make the oxygen partial pressure 10 -18 Atm, 72.6% of the iron oxide in the material is reduced to metallic iron, while the rare earth oxide in the material is 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 1450°C hot coke layer set above the sedimentation tank, and the unreduced iron oxide is further reduced to metallic iron At this time, the total iron reduction rate reached 99.6%. The molten iro...

Embodiment 3

[0033] The powdery NdFeB waste acid leaching slag with a particle size of 300 mesh and 3% SiO by weight of the slag 2 After mixing the powder and 2% CaO powder, they are sprayed together with carbon monoxide gas into a reaction tower (2) with a height of 8.5 meters and a temperature of 1300℃ from the nozzle (1). The materials are floating in a highly dispersed state from the upper end of the reaction tower Floating to the lower end, in the process, control the reaction atmosphere to make the oxygen partial pressure 10 -20 Atm, 85.3% of the iron oxide in the material is reduced to metallic iron, while the rare earth oxide in the material is 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 1550°C hot coke layer set above the sedimentation tank, and the unreduced iron oxide is further reduced to metallic iron At this time, the total iron reduction rate 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 recovery of the supergravity slag by flash reduction of NdFeB waste acid leaching slag, and belongs to the technical field of rare earth metallurgy. Background technique [0002] NdFeB is a kind of magnetic material. As the latest development of rare earth permanent magnet materials, it is called "magnet 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 waste will be generated. These scraps contain about 60% iron and about 30% rare earth elements. The recycling of NdFeB waste not only makes rational use of resources, but also reduces environmental pollution. [0003] Currently, NdFeB waste is mainly treated by the hydrochloric acid solution method. First, the NdFeB is oxidized and roasted in a rotary kiln, and the rare earth and iron are oxidized to RE as much as possible 2 O 3 And Fe 2 O 3 , Then...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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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