Method for recovery of rare earth products by in-situ carbothermal catalytic chlorination of NdFeB sludge waste

Abstract

The invention discloses a method for in-situ carbon thermal catalysis and chlorination of an NdFeB oil sludge waste material to recycle a rare earth product. The method includes the following steps that the NdFeB oil sludge waste material is reacted for 30-180min under the oxygen-free condition at the temperature of 350-550 DEG C for pyrolysis deoiling treatment at first, so that a remaining solid product and a gaseous product are obtained, and the remaining solid product is a mixture of NdFeB powder and coke; and then the remaining solid product is used as a raw material for direct in-situ carbon thermal catalysis-chlorination and then extraction separation to produce the rare earth product. By the adoption of the method, cutting oil in the waste material can be effectively removed and fully reused; moreover, the cutting waste material can be converted into a pure rare earth product, and the recovery rate and purity of rare earth are made high; and in addition, pollution to the environment is avoided in the airtight treatment process, harmless resource recycling of oil sludge can be guaranteed, and therefore the technological process has good economic benefits, environmental benefits and social benefits.

Description

technical field [0001] The invention relates to the treatment of NdFeB oil sludge waste, in particular to a treatment method for the oil sludge waste produced after NdFeB permanent magnet chips are cut. Background technique [0002] NdFeB magnetic materials, known as the "Magnetic King" due to their excellent magnetic properties, are widely used in many fields. In the production process of NdFeB magnets, about 30% of the raw material weight NdFeB waste will be generated, including turning blocks and oil-immersed waste. NdFeB waste contains about 30% of rare earth elements (including about 90% of neodymium, and the rest are terbium, dysprosium, etc.). China is a major producer of NdFeB materials, accounting for 80% of the world's total output. It is estimated that by 2016, the output of NdFeB in my country will exceed 300,000 tons, and will maintain a growth rate of 20%. In 2016, about 90,000 tons of NdFeB waste will be produced. In order to save resources, reduce industri...

AI Technical Summary

Problems solved by technology

[0003] At present, the recycling methods of NdFeB oil sludge waste mainly include: sulfuric acid-double salt precipitation method, fluoride precipitation method, total dissolution method using hydrochloric acid as solvent, oxidation roasting-hydrochloric acid dissolution method, and the production process mostly adopts the following production process: Incineration → Grinding → Oxidation Roasting → Acid Dissolution → Impurity Removal → Extraction Separation → Precipitation → Ignition, in which from incineration to oxidation roasting is the pretreatment process. Although this technology is relatively thorough in the treatment of NdFeB waste, the actual recycling production process The operating cost is high and the control is difficult. Moreover, in the production process of these recycling methods, there are problems of large consumption of chemical raw materials, high cost, many solid and liquid wastes, and secondary pollution to the environment.