For increasing reaction rate and reducing decomposing temperature,TG-DTA,XRD,SEM and Chemical analysis were used to study the kinetics of mixed rar e earths minerals decomposed by CaO with NaCl-CaCl2. The results show...For increasing reaction rate and reducing decomposing temperature,TG-DTA,XRD,SEM and Chemical analysis were used to study the kinetics of mixed rar e earths minerals decomposed by CaO with NaCl-CaCl2. The results showed that the reaction rate increased with increasing of NaC-CaCl2 addition,CaO addition,an d decomposition temperature. The kinetics of mixed rare earths minerals decompos ed by CaO conformed to 1-2/3X-(1-X) 2/3=kdt mode. The decomposition reaction rate was controlled by two steps,and the activation energy was decreased with addin g of NaCl-CaCl2 melting salt. The micro-pattern of products was loosening and po rous with NaCl-CaCl2 in decomposition system.展开更多
The products of mixed rare earth minerals containing monazite and bastnaesite calcined by CaO-NaCl-CaCl2 contained calcium phosphate and phosphorite. In this paper, HCl-H3cit solution was used to wash the calcination ...The products of mixed rare earth minerals containing monazite and bastnaesite calcined by CaO-NaCl-CaCl2 contained calcium phosphate and phosphorite. In this paper, HCl-H3cit solution was used to wash the calcination products, and the kinetic character of dissolved phosphorus was studied. The results showed that the reaction rate control changed from chemical reaction control mode to mixed control mode and diffusion control mode with increasing temperature, and the activation energy were 7.36, 27.64 and 61.27 kJ·mol-1, respectively. The change of temperature, the reagent concentration and stirring speed were studied in order to increase the dissolution rate of phosphorus. Phosphorus and rare earth in the calcination products could be separated in this process applicable to the rare earth recovery in phosphorite containing the rare earth.展开更多
基金Project supported by the National Natural Science Foundation of China (50974042)Scientific Research Special Foundation of Doctor Subject of Chinese Universities (20090042120015)The Fundamental Research Funds for the Central Universities (N090302007)
文摘For increasing reaction rate and reducing decomposing temperature,TG-DTA,XRD,SEM and Chemical analysis were used to study the kinetics of mixed rar e earths minerals decomposed by CaO with NaCl-CaCl2. The results showed that the reaction rate increased with increasing of NaC-CaCl2 addition,CaO addition,an d decomposition temperature. The kinetics of mixed rare earths minerals decompos ed by CaO conformed to 1-2/3X-(1-X) 2/3=kdt mode. The decomposition reaction rate was controlled by two steps,and the activation energy was decreased with addin g of NaCl-CaCl2 melting salt. The micro-pattern of products was loosening and po rous with NaCl-CaCl2 in decomposition system.
基金the National Natural Science Foundation of China (50574031)
文摘The products of mixed rare earth minerals containing monazite and bastnaesite calcined by CaO-NaCl-CaCl2 contained calcium phosphate and phosphorite. In this paper, HCl-H3cit solution was used to wash the calcination products, and the kinetic character of dissolved phosphorus was studied. The results showed that the reaction rate control changed from chemical reaction control mode to mixed control mode and diffusion control mode with increasing temperature, and the activation energy were 7.36, 27.64 and 61.27 kJ·mol-1, respectively. The change of temperature, the reagent concentration and stirring speed were studied in order to increase the dissolution rate of phosphorus. Phosphorus and rare earth in the calcination products could be separated in this process applicable to the rare earth recovery in phosphorite containing the rare earth.
