Journal of Northeastern University Natural Science ›› 2019, Vol. 40 ›› Issue (9): 1284-1290.DOI: 10.12068/j.issn.1005-3026.2019.09.013

• Materials & Metallurgy • Previous Articles     Next Articles

Study on Decomposition of Monazite Concentrate in NaOH-Ca(OH)2

ZHANG Bo1, XUE Xiang-xin1, YANG He1, RI Jong-chol1, 2   

  1. 1. School of Metallurgy, Northeastern University, Shenyang 110819, China; 2. Kim Chaek University of Technology, Pyongyang 999093, DPR of Korea.
  • Received:2018-09-10 Revised:2018-09-10 Online:2019-09-15 Published:2019-09-17
  • Contact: YANG He
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Abstract: In order to decrease alkali dosage and increase decomposition rate of monazite, decomposition experiment of monazite concentrate in system of NaOH-Ca(OH)2 was implemented by roasting. The roasted products were characterized by using X-ray diffraction. The decomposition effect of monazite was further judged through leaching rate of rare earth in hydrochloric acid. The influence factors for roasting process, such as roasting temperature, NaOH dosage, Ca(OH)2 dosage and roasting time were investigated. The optimum roasting decomposition parameters are proposed as the following: roasting temperature of 800℃, NaOH dosage of 25%, Ca(OH)2 dosage of 20%, and roasting time of 1.5h. With these optimum parameters, rare earth phase transformed from REPO4 into REO. Leaching experiments demonstrated that leaching rate of rare earth in concentrated hydrochloric acid reaches up to 98% in these optimum parameters. Comparing with index of industrial production process, alkali dosage in this process reduces about 55%. Additionally, decomposition rate of monazite increased about 2%.

Key words: monazite, NaOH-Ca(OH)2, roasting decomposition, phase analysis, rare earth leaching rate

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