Study of the Mechanochemical Calcification for Mixed Rare Earth Concentrate
The paper aimed to propose that mixed rare earth concentrate was decomposed by pressurized calcification where mechanical milling was applied simultaneously (also known as mechanochemical calcification). The bastnaesite and monazite were both decomposed by OH−, where released rare earth formed RE(OH)3, released fluorine and phosphorus formed CaF2 and Ca2P2O7. Then, the calcified slag was leached by diluted hydrochloric acid to extract rare earth and both recover fluorine and phosphorus. The phase transformation regularity, the behavioral trends of rare earth, fluorine and phosphorus were investigated. Results showed under the optimal conditions of ball to material weight 80:1, the calcification temperature 250 °C, the liquid-solid ratio 5:1, the leaching yield of rare earth reached to 92.16%, Ce was 86.47%, La was 97.58%, Nd was 99.99% and the mass fraction of F, P entering into calcified liquor were 8.27, 0.21% respectively. The micromorphology of the mineral has a transition from dense to fluffy, and then became dense again.
KeywordsMixed concentrate Calcification transformation Acid leaching Mechanical milling
The authors gratefully acknowledge the financial support received from the National Basic Research Program of China (973 program, No. 2012CBA01205) and the basic research universities special fund operations (N162505002).
- 1.Huang X, Li H, Xue X, Zhang G et al (2006) Development status and research progress in rare Earth hydrometallurgy in China. J Chin Rare Earth Soc 24(2):129–133Google Scholar
- 5.James SL, Adams CJ, Bolm C et al (2012) Mechanochemistry: opportunities for new and cleaner synthesis. Chem Soc Rev 41(1):413–447Google Scholar
- 9.Kumar R, Alex TC, Jha MK et al (2004) Mechanochemistry and the Bayer process of alumina production. In: Paper presented at the 133rd TMS annual meeting, Charlotte, NC, 14–18 March 2004Google Scholar
- 10.Sun P, Li H, Li Y et al (1998) New technology on decomposition of monazite by mechanical activation and caustic decomposition. J Central South Univ 29(1):36–38Google Scholar
- 11.Tang F (2014) Study on efficient extraction of the rare earth from bastnaesite concentrate by calcification transition process. Master’s thesis, Northeastern UniversityGoogle Scholar