Method for preparing pure sulfuric acid rare earth solution

Abstract

The invention relates to a method for preparing a pure sulfuric acid rare earth solution from sulfating roasting rare earth ore. Rare earth is recovered step by step through two phases, so that the rare earth recovery rate is improved. According to the dynamic characteristics of rare earth dissolution in the rare earth sulfuric acid roasted ore leaching process and the law of the influence of temperature on the solubility of sulfuric acid rare earth, and through low-liquid-solid-ratio rapid leaching and then heating recrystallization, 50% or above of rare earth is separated out in a high-purity sulfuric acid rare earth recrystallization phase, and preliminary separation of the rare earth and impurities is achieved; and the remaining rare earth can be separated from the impurities again by means of neutralization and impurity removal, specifically, (1) one-step impurity removal of magnesium oxide in a traditional process can be replaced by a magnesium bicarbonate solution, so that the total consumption of solid magnesium oxide is reduced by 90%, magnesium recycling is realized, and the impurities introduced by magnesium oxide and the amount of slag generated by incomplete reaction are also reduced; and (2) magnesium oxide two-step impurity removal is adopted, and the total consumption of solid magnesium oxide is reduced by about 10% compared with a traditional process. According to the preparation method, the total recovery rate of the rare earth is increased by 1-3%.

Description

technical field [0001] The invention relates to the field of extraction and separation of rare earth hydrometallurgy, in particular to a method for preparing pure sulfuric acid rare earth solution from sulfated roasted rare earth ore. Background technique [0002] Rare earth elements refer to 17 metal elements including 15 lanthanides and yttrium and scandium. Because rare earth resources play an important role in the development of clean energy economy and high-tech industries, they are the country's strategic resources. Typical rare earth mineral resources in my country include mixed rare earth mines in Baotou, Inner Mongolia (hereinafter referred to as "Baotou mines"), bastnaesite in Sichuan and Shandong, and ion-adsorption rare earth mines in seven southern provinces. The most important light rare earth resources. [0003] At present, about 90% of Baotou mines in my country's industry are smelted and separated by the "third-generation acid method": high-temperature inte...

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Problems solved by technology

Among them, the sulfuric acid rare earth leaching solution obtained in the water immersion process is 30-40g / L in terms of rare earth oxides. When solid magnesium oxide is used for one-time neutralization and removal of impurities, because solid magnesium oxide contains a large amount of impurities and the solid-liquid reaction efficiency is relatively low, A large amount of ferrophosphorus slag with high moisture content is produced, resulting in relatively high entrainment and adsorption loss of rare earths. The neutralized slag needs to be further washed with acid, which increases the consumption of acid and alkali

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