Method for recovering rare earth elements from waste neodymium iron boron leftover material

Abstract

The invention discloses a method for recovering rare earth elements from a waste neodymium iron boron leftover material, comprising the following steps: cutting the waste neodymium iron boron leftover material into small pieces; then, introducing the small pieces into the first cylinder ring part of an internal-heating spontaneous-combustion rotary kiln with multiple cylinder rings through a continuous feeding mode; and controlling the internal temperature, the induced air amount, the material dwell time and the like of the first cylinder ring and the rest cylinder ring positions so as to fully oxidize and roast the waste neodymium iron boron material; and leaching the preprocessed material with hydrochloric acid, comprehensively decontaminating, carrying out extraction separation, precipitating and roasting to obtain rare earth oxide. According to the method, harm and pollution on on-site operation personnel and peripheral environment by raised dust and micro powder in the original preprocessing link can be avoided, inert gas consumption is avoided, coal and electricity power consumption can be drastically reduced, labor intensity is greatly lowered, an operation period is greatly shortened, and the requirement of continuous production can be satisfied.

Description

technical field [0001] The invention relates to the technical field of recovery and recycling of rare earth resources, in particular to a method for recovering rare earth elements from NdFeB scraps. Background technique [0002] NdFeB permanent magnet is a kind of permanent magnet material with superior performance. Since it came out in 1983, it has stood out from many permanent magnet materials and has been widely used in various high-tech fields. Because NdFeB permanent magnet materials have high remanence, high coercive force, and high energy product, they have become the best among permanent magnet materials and are recognized as the "magnet king". In recent years, the output of sintered NdFeB in China has grown at a rate of 35%. It is estimated that the output of NdFeB in my country in 2010 has exceeded 100,000 tons. [0003] In the process of producing NdFeB permanent magnet components, it must be machined and made into rectangular, square, round, inner and outer roun...

AI Technical Summary

Problems solved by technology

Its purpose is to solve the problems of large inert gas and energy consumption, high risk factor in operation and control process, long operation cycle, environmental pollution and inability to continue production in the previous NdFeB recycling pretreatment process.