Neodymium iron boron waste double-flash supergravity slag metal melting comprehensive recovery method

Abstract

The invention discloses a neodymium iron boron waste double-flash supergravity slag metal melting comprehensive recovery method. According to the method, neodymium iron boron waste and oxygen-rich airare sprayed into a reaction tower through a spray nozzle, the materials float down to the lower end from the upper end of the reaction tower in a highly dispersed floating state, and rare earth and iron in the materials are fast and fully oxidized; oxidation products and reducing gas are sprayed into another reaction tower through a spray nozzle, most of ferric oxide is reduced into metal iron, and the small amount of iron not reduced is reduced into metal iron when passing through a molten coke layer; and molten iron and rare earth slag high-temperature mixed melt enters a supergravity slagmetal melting device, under the effect of supergravity, molten iron permeates porous ceramic filter film, rare earth slag is retained in a drum, accordingly, efficient enriching and separation of therare earth and iron in the neodymium iron boron waste is achieved, the defects that a traditional neodymium iron boron waste treatment method is long in process, high in energy consumption, large in acid dissolution iron slag amount, low in rare earth recovery rate, difficult in iron resource recovery are overcome, and the economic and environment friendliness benefits are good.

Description

technical field [0001] The invention relates to a method for comprehensively recycling NdFeB waste double-flash 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 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 is mainly ...

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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