| China is abundant in rare earth resources, with its reserves ranking first in the world. However, it has a low recovery of rare earth resources in ore processing stage, which cause the waste of resources. This mainly because the ore property is complex and mineral processing technology is less advanced. Aiming to solve this problem, this paper mainly studied flotation reagents. Collector and depressant, which of good selectivity, have been discovered through pure mineral flotation tests, and they are successfully used in the treatment of refractory rare earth ore from Hubei. At last, the action mechanism of reagents on minerals was studied by solution chemistry of flotation, determination of adsorption and IR spectrum analysis. The research contents and results are as follows:Individual mineral collector tests studied the collecting performance of731, H205and dodecylamine on bastnasite, fluorite and calcite. The results showed the collectivity of731on fluorite and calcite was stronger than that on bastnasite. H205exhibited better collectivity on bastnasite and fluorite, while it was weak in the collection of calcite, and the best pH value for H205to collect bastnasite was9. Dodecylamine showed strong collectivity on the three minerals, and the selectivity was bad. Consequently, in the condition of direct flotation, only H205exhibited a certain of selectivity on bastnasite, and the selectivity of731and dodecylamine on fluorite and calcite was better than that on bastnasite.Individual mineral depressant tests studied depressing performance of sodium citrate, sodium silicate, sodium fluosilicate, calgon and amylum on the minerals, during which the collector was H205and pH value was9. The results showed fluorite and calcite were completely depressed when the dosage of sodium citrate was140mg/L, while bastnasite was depressed as well. When the dosage of sodium silicate was40mg/L, fluorite and calcite were completely depressed, while bastnasite was weakly depressed, which showed sodium silicate, as a depressant, was of better selectivity. The floatability of the three minerals remained unchanged with the increase of the dosage of sodium fluosilicate, and fluorite and calcite could not be completely depressed. Both calgon and amylum exhibited strong depressing performance on the three minerals even though their dosage was very small. Consequently, sodium silicate was a depressant of better selectivity when H205was used as collector and pH value was9.Results of artificially mixed minerals flotation tests showed bastnasite could be separated from fluorite and calcite effectively when pH was9, the dosage of H205was100mg·L-1and the dosage of sodium silicate was50mg-L’1. Meanwhile, the grade and recovery of CeO2in concentrate was33.43%and68.63%respectively.Study on beneficiation process of low grade refractory rare earth ore from Hubei showed good flotation indexes could be obtained under the condition of sodium silicate as depressant, H205as collector and BY-10as auxiliary collector of H205. The ReO grade of raw ore could be concentrated from0.69%to43%in open circuit test, and the recovery was48%, while in closed circuit test, the grade of final concentrate was27%, and the recovery was80%. Beneficiation process of pre-decarbonization and single flotation was relatively simple, which solved the problem of local rare earth mine failing to develop for many years.Research of action mechanism between flotation reagents and minerals showed that the main effective components of sodium silicate to" depress gangue minerals were Si(OH)4and SiO(OH)3-when the pH was9. The collection of H205on bastnasite was mainly because H205chelated with metal ion on the surface of bastnasite mineral, and generated a stable five-ring chelate compound. The auxiliary collection of BY-10on bastnasite was mainly because BY-10combined with H205by hydrogen bond association, and both of them adsorbed on the surface of bastnasite, which enhanced the hydrophobicity of bastnasite surface to a large extend. |
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