Method for flash roasting of supergravity slag gold fusion separation from neodymium iron boron waste

Abstract

The invention discloses a method for flash roasting of supergravity slag gold fusion separation from neodymium iron boron waste. The neodymium iron boron waste and a cosolvent are mixed and sprayed into a high-temperature vertical reaction tower space together with mixed gas, the material is in a highly dispersed floating state to fall from the upper end of the reaction tower to the lower end, bycontrolling the oxidizing atmosphere in the reaction tower, rare earth in the material is rapidly and fully oxidized, while iron is not oxidized as much as possible, and a small amount of oxidized iron is reduced into metal iron when passing through a hot coke layer arranged above a settling pond. Molten iron and rare earth slag high-temperature mixed melt is discharged and then enters a super-gravity slag gold fusion separator through a chute. Under the supergravity effect, the molten iron passes through a porous ceramic filter membrane, rare earth slag is trapped in a rotating drum, therefore, efficient enrichment and separation of rare earth and iron in the neodymium iron boron waste are achieved, the defects that in a traditional neodymium iron boron waste treating method, the processis long, energy consumption is high, rare earth and iron are oxidized at the same time and cannot be separated before acid dissolving, the acid leaching slag amount is large, the rear earth recyclingrate is low, and iron resources are difficult to recycle are overcome, and good economic and environmental benefits are obtained.

Description

technical field [0001] The invention relates to a method for flash roasting supergravity slag financial separation of NdFeB waste materials, 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 waste will be generated, most of which are NdFeB sludge waste. 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 oil sludge waste is often roasted in a two-stage rotary kiln, and then leached-extracted-precipitated-burned to recover the rare earths. The first stage of rotary kiln roasting...

AI Technical Summary

Problems solved by technology

The first stage of rotary kiln roasting is mainly to remove the oil in the NdFeB sludge and provide raw materials for the second stage of deep oxidation. However, due to the inherent defects of the rotary kiln, the temperature and atmosphere cannot be precisely controlled, and the deoiling process is often insufficiently burned, resulting in High energy consumption, and often black smoke, polluting the environment

The second stage of rotary kiln roasting often oxidizes rare earth and iron into RE as much as possible. 2 o 3 and Fe 2 o 3 , due to the slow oxidation reaction rate of the rotary kiln, it often takes 4-8 hours to achieve a high oxidation rate, and, due to the use of two-stage rotary kiln, the volume is large, the area is large, the external heat dissipation area is large, and there is heat-cold alternation link, high energy consumption

In addition, since the rare earth and iron are leached with hydrochloric acid after the simultaneous oxidation of rare earth and iron, a large amount of iron in the waste enters the acid leaching slag, the amount of slag is large, and the total amount of rare earth taken away by the slag is large, resulting in a decrease in the total recovery rate of rare earth, while the leaching slag It is difficult to get a good comprehensive utilization by itself, and it is often stockpiled, causing environmental pollution

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