The bastnaesite used in hydrometallurgy usually contains 7%-11% fluorine,and the conversion of fluorine into high-value products is the key to achieving green production of rare earths and improving the comprehensive ...The bastnaesite used in hydrometallurgy usually contains 7%-11% fluorine,and the conversion of fluorine into high-value products is the key to achieving green production of rare earths and improving the comprehensive utilization of bastnaesite.In order to recover fluorine from bastnaesite in the form of KBF4,the mechanism of F^(-)conversion to BF^(4-)in sulphuric acid leaching solution of roasted bastnaesite was studied by using Eh-pH diagram and simulation experiment.It shows that the formation of BF^(4-)is affected by pH in the absence of rare earths.BF^(4-)is hydrolyzed to BF3 OH-and F-when the pH is greater than 3.9,and part of F-exists as HF^(2-)when pH is lower than 2.In the presence of La^(3+),the formation of BF^(4-)is mainly affected by LaF_(3) when pH is greater than 0,and in the case that the pH is lower than 2,it is mainly affected by HF^(2-).When Ce4+is present in solution,CeF_(2)^(2+) can exist stably in sulphuric acid solution.Bringing down the pH can reduce the stability of CeF_(2)^(2+) and increase the BF^(4-)conversion rate.Based on these results,KBF4 was prepared in the alkaline solution of bastnaesite,and the conversion of BF^(4-)is 84.31%.This provides a theoretical basis for the recovery of fluorine from bastnaesite in the form of KBF_(4).展开更多
介绍了废硫酸热分解的过程和热量计算,详细介绍了在硫铁矿沸腾焙烧炉中掺烧烷基化废酸制取硫酸的方法。利用硫铁矿沸腾焙烧释放的反应热使烷基化废酸裂解为SO_2。裂解气汇入硫铁矿沸腾焙烧炉气,进入制酸系统。掺烧1 t w(H_2SO_4)90.5%...介绍了废硫酸热分解的过程和热量计算,详细介绍了在硫铁矿沸腾焙烧炉中掺烧烷基化废酸制取硫酸的方法。利用硫铁矿沸腾焙烧释放的反应热使烷基化废酸裂解为SO_2。裂解气汇入硫铁矿沸腾焙烧炉气,进入制酸系统。掺烧1 t w(H_2SO_4)90.5%烷基化废酸费用为463.5元。当烷基化废酸处理费为250元/t时,硫铁矿制酸装置可考虑掺烧烷基化废酸。展开更多
基金the National Natural Science Foundation of China(51176122,41641010)the Science and Technology Support Project of Sichuan Province(2016SZ0071,20GJHZ0042)。
文摘The bastnaesite used in hydrometallurgy usually contains 7%-11% fluorine,and the conversion of fluorine into high-value products is the key to achieving green production of rare earths and improving the comprehensive utilization of bastnaesite.In order to recover fluorine from bastnaesite in the form of KBF4,the mechanism of F^(-)conversion to BF^(4-)in sulphuric acid leaching solution of roasted bastnaesite was studied by using Eh-pH diagram and simulation experiment.It shows that the formation of BF^(4-)is affected by pH in the absence of rare earths.BF^(4-)is hydrolyzed to BF3 OH-and F-when the pH is greater than 3.9,and part of F-exists as HF^(2-)when pH is lower than 2.In the presence of La^(3+),the formation of BF^(4-)is mainly affected by LaF_(3) when pH is greater than 0,and in the case that the pH is lower than 2,it is mainly affected by HF^(2-).When Ce4+is present in solution,CeF_(2)^(2+) can exist stably in sulphuric acid solution.Bringing down the pH can reduce the stability of CeF_(2)^(2+) and increase the BF^(4-)conversion rate.Based on these results,KBF4 was prepared in the alkaline solution of bastnaesite,and the conversion of BF^(4-)is 84.31%.This provides a theoretical basis for the recovery of fluorine from bastnaesite in the form of KBF_(4).
文摘介绍了废硫酸热分解的过程和热量计算,详细介绍了在硫铁矿沸腾焙烧炉中掺烧烷基化废酸制取硫酸的方法。利用硫铁矿沸腾焙烧释放的反应热使烷基化废酸裂解为SO_2。裂解气汇入硫铁矿沸腾焙烧炉气,进入制酸系统。掺烧1 t w(H_2SO_4)90.5%烷基化废酸费用为463.5元。当烷基化废酸处理费为250元/t时,硫铁矿制酸装置可考虑掺烧烷基化废酸。
