The feasibility and kinetics of lead recovery from the slag of traditional lead melting furnace using chloride leaching were investigated.The effects of operating parameters such as leaching time,NaCl concentration,Fe...The feasibility and kinetics of lead recovery from the slag of traditional lead melting furnace using chloride leaching were investigated.The effects of operating parameters such as leaching time,NaCl concentration,FeCl3concentration,liquid/solid ratio,stirring rate,temperature,and particle size on recovery of lead were studied and the optimization was done through the response surface methodology(RSM)based on central composite design(CCD)model.The optimum conditions were achieved as follows:leaching time60min,80°C,stirring rate800r/min,NaCl concentration200g/L,FeCl3concentration80g/L,liquid/solid ratio16,and particle size less than106μm.More than96%of lead was effectively recovered in optimum condition.Based on analysis of variance,the reaction temperature,liquid/solid ratio,and NaCl concentration were determined as the most effective parameters on leaching process,respectively.Kinetics study revealed that chloride leaching of galena is a first-order reaction and the diffusion through solid reaction product and chemical reaction control the mechanism.The activation energy of chloride leaching of galena was determined using Arrhenius model as27.9kJ/mol.展开更多
Laboratory-scale experiments were performed to investigate the deoxidation of H13 tool steel with CaF_(2)-MgO-Al_(2)O_(3)-CaO-SiO_(2) slags at 1873 K.The calculation of thermodynamics and kinetics was also verified th...Laboratory-scale experiments were performed to investigate the deoxidation of H13 tool steel with CaF_(2)-MgO-Al_(2)O_(3)-CaO-SiO_(2) slags at 1873 K.The calculation of thermodynamics and kinetics was also verified through the experimental results.The results show that[Si]-[O]reaction is the control reaction,and with the increase of basicity of slag,the limitation of deoxidation was decreased.The limitation of deoxidation is the lowest for the slag with basicity of 2.0.Under the conditions of the basicity of 2.0 and the content of CaF_(2) more than 50%,the limitation of deoxidation is less than 10×10^(−6),and it does not depend on the contents of Al_(2)O_(3) and CaF_(2) in slags.The mass transport of oxygen in the metal phase is the rate-controlling step,and the slag composition has no effect on the equilibrium time of deoxidation.Based on this finding,the optimized slag composition is designed and it contains the following components:51.5%CaF_(2),20.3%MgO,16.2%Al_(2)O_(3),8.2%CaO and 3.8%SiO_(2).In the case of the optimized deoxidizing slag,the total oxygen content in H13 steel can be reduced from 25×10^(−6) to 6×10^(−6).展开更多
文摘The feasibility and kinetics of lead recovery from the slag of traditional lead melting furnace using chloride leaching were investigated.The effects of operating parameters such as leaching time,NaCl concentration,FeCl3concentration,liquid/solid ratio,stirring rate,temperature,and particle size on recovery of lead were studied and the optimization was done through the response surface methodology(RSM)based on central composite design(CCD)model.The optimum conditions were achieved as follows:leaching time60min,80°C,stirring rate800r/min,NaCl concentration200g/L,FeCl3concentration80g/L,liquid/solid ratio16,and particle size less than106μm.More than96%of lead was effectively recovered in optimum condition.Based on analysis of variance,the reaction temperature,liquid/solid ratio,and NaCl concentration were determined as the most effective parameters on leaching process,respectively.Kinetics study revealed that chloride leaching of galena is a first-order reaction and the diffusion through solid reaction product and chemical reaction control the mechanism.The activation energy of chloride leaching of galena was determined using Arrhenius model as27.9kJ/mol.
基金Project(18SYXHZ0069)supported by the Science and Technology Program of Sichuan Province,ChinaProjects(51974139,51664021)supported by the National Natural Science Foundation of China。
文摘Laboratory-scale experiments were performed to investigate the deoxidation of H13 tool steel with CaF_(2)-MgO-Al_(2)O_(3)-CaO-SiO_(2) slags at 1873 K.The calculation of thermodynamics and kinetics was also verified through the experimental results.The results show that[Si]-[O]reaction is the control reaction,and with the increase of basicity of slag,the limitation of deoxidation was decreased.The limitation of deoxidation is the lowest for the slag with basicity of 2.0.Under the conditions of the basicity of 2.0 and the content of CaF_(2) more than 50%,the limitation of deoxidation is less than 10×10^(−6),and it does not depend on the contents of Al_(2)O_(3) and CaF_(2) in slags.The mass transport of oxygen in the metal phase is the rate-controlling step,and the slag composition has no effect on the equilibrium time of deoxidation.Based on this finding,the optimized slag composition is designed and it contains the following components:51.5%CaF_(2),20.3%MgO,16.2%Al_(2)O_(3),8.2%CaO and 3.8%SiO_(2).In the case of the optimized deoxidizing slag,the total oxygen content in H13 steel can be reduced from 25×10^(−6) to 6×10^(−6).
