Energy-saving and high-efficiency rare earth ore concentrate sulfuric acid stepped roasting method

Abstract

The invention relates to an energy-saving and high-efficiency rare earth ore concentrate sulfuric acid stepped roasting method, and belongs to the technical field of wet metallurgy and thermometallurgy. The energy-saving and high-efficiency rare earth ore concentrate sulfuric acid stepped roasting method comprises the following steps: mixing rare earth ore concentrate with sulfuric acid with the mass concentration of more than or equal to 92.5% according to weight ratio of 1 : (1.0-1.3); pelletizing, and charging particles into a first-section roasting kiln to roast, so that fluorine ions and water in the rare earth ore concentrate are completely volatilized; condensing the gasified fluorine ions and water, recovering hydrofluoric acid, roasting defluorinated dry ore particles, and charging the roasted particles into a second-section roasting kiln to separate; washing and absorbing separated sulfuric acid gas during roasting, recovering sulfuric acid, and directly leaching roasted ores to obtain a sulfuric acid rare earth solution. According to the energy-saving and high-efficiency rare earth ore concentrate sulfuric acid stepped roasting method, after the stepped roasting process is utilized, waste gas generated in pelletizing step is water vapor and can be directly discharged; compared with the prior art, the stepped roasting method has the advantages that a waste gas washing and absorbing system is reduced to more than 70% and the environmental protection input is reduced to more than 80%.

Description

technical field [0001] The invention relates to an energy-saving and high-efficiency rare earth concentrate sulfuric acid step-by-step roasting method, belonging to the technical fields of hydrometallurgy and pyrometallurgy. Background technique [0002] At present, the sulfuric acid roasting of rare earth concentrate adopts the traditional "three-generation acid method" rare earth concentrate treatment process, that is, the rare earth concentrate is mixed with excess sulfuric acid and then roasted and decomposed in the converter, which has the following defects: ① High consumption of sulfuric acid. In order to ensure the fluidity of the mixed slurry during the operation of the process, sulfuric acid is seriously excessive during the mixing process, and the highest unit consumption of sulfuric acid can reach 1.8 times. ② During the production and operation process, the converter is easy to be blocked by rings, and the production operation is not smooth. ③ Due to the large d...

AI Technical Summary

Problems solved by technology

[0002] At present, the sulfuric acid roasting of rare earth concentrate adopts the traditional "three-generation acid method" rare earth concentrate treatment process, that is, the rare earth concentrate is mixed with excess sulfuric acid and then roasted and decomposed in the converter, which has the following defects: ① High consumption of sulfuric acid

② During the production and operation process, the converter is easy to be blocked by rings, and the production operation is not smooth

③ Due to the large difference in the shape of the material, the roasting is uneven, the decomposition of the concentrate is also uneven, and the yield is low

④Because the waste gas generated during the decomposition of concentrate, the waste gas generated after sulfuric acid decomposition, combustion waste gas and air are all mixed and then enter the tail gas washing system, the waste gas treatment capacity is very large, and the system is also very complicated. At the same time, the waste water after washing needs to be evaporated Separation, very high operating and investment costs

⑤ Due to many uncertain and uncontrollable factors, the production operation is very unstable and the product quality fluctuates greatly