Process for treating tail gas of rare earth mineral powder and concentrated sulphuric acid roasting process

Abstract

The present invention is a tail gas treatment process of rare earth mineral powder and concentrated sulfuric acid roasting process. In this process, the process tail gas at 300°C is introduced into the dust collector for mechanical dust removal; The acid liquid is condensed and recovered for reuse; the cooled flue gas enters the acid mist collector, and the acid mist and water mist in the flue gas are collected for recycling; the treated flue gas enters the first absorber after being boosted by the fan In the flue gas, the remaining sulfuric acid mist, hydrofluoric acid and fluosilicic acid in the flue gas are removed by washing with dilute acid solution or process water; then enter the second absorber, the flue gas is washed by an alkaline scrubber to remove the The remaining sulfuric acid mist, hydrofluoric acid and SO2 gas are discharged after demisting. The invention can not only save a lot of flue gas cooling water, reduce the amount of waste water produced, and reduce the cost of waste water treatment, but also can recover the by-product hydrofluoric acid produced by solid minerals, sulfuric acid, hydrofluoric acid and other substances in the tail gas as the raw material for fluorine recovery and utilization.

Description

technical field [0001] The invention belongs to the field of environmental engineering, and in particular relates to a tail gas treatment process of rare earth mineral powder and concentrated sulfuric acid roasting process. Background technique [0002] 1. General situation of rare earth industry [0003] my country's proven industrial reserves of rare earths are 52 million tons, accounting for about 50% of the world, and it is the country with the most abundant rare earth resources. There are more than 60 mining areas with proven rare earth reserves in the country, distributed in 22 provinces and regions, among which Inner Mongolia has the largest rare earth reserves, accounting for 83% of the country, and the rest are distributed in Sichuan, Shandong, Jiangxi, Guangdong, Guangxi, Fujian, Hunan and other provinces district. [0004] Baotou mixed rare earth mine is the world's largest light rare earth resource. The rare earth minerals are bastnaesite and monazite. The conc...

AI Technical Summary

Problems solved by technology

The disadvantage is that the investment scale is large, the requirements for equipment and materials are special, and it is not easy to operate

[0041] The purification efficiency of the acid recovery process is generally F>99.5%, SO2>80%, H2SO4>95%, but due to the influence of equipment and the constraints of process conditions, it is still difficult to meet the emission limits of sulfur dioxide and sulfuric acid mist in the sulfuric acid system.

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