Method for Improving Decomposition Efficiency of Rare Earth Minerals and Sulfuric Acid

Abstract

The invention relates to a method for improving the decomposition efficiency of rare earth minerals and sulfuric acid, belonging to the field of hydrometallurgy. Including mixing rare earth concentrate with concentrated sulfuric acid and iron powder for segmental roasting, adding a certain amount of water to the solidified minerals during the low-temperature roasting process, optimizing the solid-liquid-gas reaction system, and improving the diffusion of sulfuric acid in the reaction process Speed, reduce sulfuric acid consumption, increase rare earth decomposition rate. During the high-temperature roasting process, the high-efficiency decomposition of excess sulfuric acid and the formation of iron phosphate and thorium pyrophosphate mainly fix radioactivity and phosphorus resources into the slag. The two-stage roasting simplifies the components of the tail gas, which facilitates the subsequent tail gas treatment, reduces the cost of tail gas treatment, and reduces environmental pollution.

Description

technical field [0001] The invention belongs to the field of hydrometallurgy, and in particular relates to a method for improving the decomposition efficiency of rare earth minerals and sulfuric acid. Background technique [0002] Ore-type rare earth minerals are mainly bastnaesite, monazite and mixed rare earth ores. Due to differences in mineral composition, smelting techniques are also different. Bastnaesite mainly adopts oxidation roasting-hydrochloric acid leaching process, and minerals are decomposed into Rare earth fluoride and rare earth oxide are preferentially dissolved in hydrochloric acid for roasting ore, and the concentration and addition process of hydrochloric acid are controlled to realize the extraction of trivalent rare earth and preliminary separation from tetravalent cerium, leaving cerium fluoride, cerium dioxide and other components in the residue. This process can recover valuable rare earths at a simple and low cost, but the fluorine resources are no...

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Problems solved by technology

The two-stage roasting method is still designed from the perspective of tail gas treatment, the consumption of sulfuric acid is large, and the subsequent treatment process is cumbersome

[0004] Patent name "A method for roasting and decomposing high-grade mixed rare earth concentrate with iron and low-temperature concentrated sulfuric acid" (application number: 201910424015.3). This method is still based on the principle of low-temperature roasting, so that thorium and phosphorus enter the solution, and the iron thorium slag is obtained through neutralization, but the water leaching slag is still radioactive, and the thorium content in the iron thorium slag is too high, so there is no better treatment method at present. And it is easy to cause the loss of rare earth during the neutralization process, which affects the yield of rare earth

[0005] None of the above patent documents refers to any means to improve the reaction efficiency of sulfuric acid decomposition of minerals in the low-temperature roasting process (150-250°C), thereby effectively reducing the consumption of sulfuric acid

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