文档介绍：: .
Transa 100088, China;
2. GRIREM Advanced Materials Co., Ltd., Beijing 100088, China;
3. General Research Institute for Nonferrous Metals, Beijing 100088, China.
Abstract:
To realize the recycling of magnesium sulfate wastewater in the hydrometallurgy and
separation process of Baotou mixed rare earth (RE) concentrate, this paper researches on
preparation of magnesium bicarbonate (Mg(HCO3)2) solution from magnesium sulfate solution by
CO2 carbonation, extraction separation and transformation of RE sulfate solution by saponified
HDEHP. The key influencing factors and carbonation mechanism in the preparation of Mg(HCO3)2,
and the distribution of RE, calcium and magnesium elements in the saponification extraction are
systematically studied. The results show that the conversion of Mg(HCO3)2 during carbonation is
inhibited by calcium sulfate, but promoted by increasing the concentration of magnesium sulfate
and decreasing the carbonation temperature. Under the optimized conditions, Mg(HCO3)2 solution
with impurities (such as Fe, Al and Si) of less than 15 ppm is prepared stably and efficiently, and
the conversion rate of Mg(HCO3)2 is more than 95%. After multi-stage cascade extraction of RE
sulfate solution, the RE extraction recovery is greater than %. Calcium sulfate crystals do not
precipitate during the process, and the raffinate phase is magnesium sulfate solution that is used for
the preparation of Mg(HCO3)2 solution.
Key words: Carbonation; Magnesium bicarbonate; Rare earth sulfate solution; Saponification
Foundatio