Red mud, the waste generated during alumina production, contains iron and other valuable metals. To recover the iron efficiently from red mud, a three-factor five-level central composite design in response surface met...Red mud, the waste generated during alumina production, contains iron and other valuable metals. To recover the iron efficiently from red mud, a three-factor five-level central composite design in response surface methodology was used to study the effects of process parameters, such as FC/O （the molar ratio of fixed carbon in coal to reducible oxygen of iron oxide in red mud）, reduction temperature, reduction time, and their interaction on the iron recovery rate and total iron content in magnetic product obtained from the process of direct reduction-magnetic separation. The relevant assessment model was established. The model could predict the changing rules of iron recovery rate and total iron content in the magnetic product affected by the process parameters. The results show that the iron recovery rate is significantly influenced by three factors and reduction temperature plays the most important role. The iron recovery rate and total iron content in magnetic product could be up to 98.37 and 82.52%, respectively, under the numerically optimal process parameters condition of reduction temperature of 1400 ℃, FC/O of 0.80 and reduction time of 100 min obtained by the assessment model. The predicted values are in good agreement with the experimental values.展开更多
Manganese-rich slag is a raw material for smelting silicon–manganese alloys using an electric furnace.The blast furnace method is the main method for smelting manganese-rich slag.This method has the problems of a lon...Manganese-rich slag is a raw material for smelting silicon–manganese alloys using an electric furnace.The blast furnace method is the main method for smelting manganese-rich slag.This method has the problems of a long process,large coke consumption,and easy volatilization of metals such as lead and zinc,which affects smelting safety.A new technology for smelting manganese-rich slag with low-manganese high-iron ore by smelting reduction optimization was proposed.This technology has the advantages of a short process,low energy consumption,low carbon emissions,and comprehensive recycling of lead,zinc,and other metals.According to the chemical composition,X-ray diffraction analysis,and particle size analysis of Cote d’Ivoire low-manganese ore,an experiment was carried out on manganese-rich slag by reduction–smelting separation.Combined with the design scheme of the Box–Behnken principle,three experimental factors(temperature,basicity,and carbon content)were selected as the influences to study.The influence that each factor has on the recovery rate of manganese was studied by response surface methodology,and the experimental factors were optimized.The results show that under the conditions of a reduction-smelting temperature of 1402℃,basicity of R=0.10,and carbon content of 10 mass%,the recovery rate of manganese is 97%.A verification experiment was carried out under the optimal conditions,and the error was only 1.24%;this proves that the response surface method prediction model is reliable and accurate.This is of great significance for the comprehensive utilization of lean-manganese ore resources.展开更多
针对规模化养殖场沼液难以农田消纳的问题,探索化学方法回收沼液中氮磷的工艺条件和优化参数。本研究选择猪场沼液为研究对象,采用鸟粪石沉淀法,进行单因素影响试验,选取p H、镁氮比、磷氮比为自变量,以氮磷回收率为响应值,通过BoxBehn...针对规模化养殖场沼液难以农田消纳的问题,探索化学方法回收沼液中氮磷的工艺条件和优化参数。本研究选择猪场沼液为研究对象,采用鸟粪石沉淀法,进行单因素影响试验,选取p H、镁氮比、磷氮比为自变量,以氮磷回收率为响应值,通过BoxBehnken响应面试验设计对工艺参数进行优化。结果显示:猪场沼液氮磷回收的最佳工艺为:p H 10,镁氮比为1.1,磷氮比为0.6,氨氮回收率为65.21%,磷酸盐回收率为89.47%,实际值氨氮回收率为65.01%,磷酸盐回收率为90.81%,差值分别为0.20%、1.34%,回归模型拟合较好。展开更多
基金The authors are especially thankful to the National Natural Science Foundation of China （51374058 and 51704061 ）, China Postdoctoral Science Foundation （2016M601321 ） and Fundamental Research Funds of the Central Universities of China （N162503003）.
文摘Red mud, the waste generated during alumina production, contains iron and other valuable metals. To recover the iron efficiently from red mud, a three-factor five-level central composite design in response surface methodology was used to study the effects of process parameters, such as FC/O （the molar ratio of fixed carbon in coal to reducible oxygen of iron oxide in red mud）, reduction temperature, reduction time, and their interaction on the iron recovery rate and total iron content in magnetic product obtained from the process of direct reduction-magnetic separation. The relevant assessment model was established. The model could predict the changing rules of iron recovery rate and total iron content in the magnetic product affected by the process parameters. The results show that the iron recovery rate is significantly influenced by three factors and reduction temperature plays the most important role. The iron recovery rate and total iron content in magnetic product could be up to 98.37 and 82.52%, respectively, under the numerically optimal process parameters condition of reduction temperature of 1400 ℃, FC/O of 0.80 and reduction time of 100 min obtained by the assessment model. The predicted values are in good agreement with the experimental values.
文摘Manganese-rich slag is a raw material for smelting silicon–manganese alloys using an electric furnace.The blast furnace method is the main method for smelting manganese-rich slag.This method has the problems of a long process,large coke consumption,and easy volatilization of metals such as lead and zinc,which affects smelting safety.A new technology for smelting manganese-rich slag with low-manganese high-iron ore by smelting reduction optimization was proposed.This technology has the advantages of a short process,low energy consumption,low carbon emissions,and comprehensive recycling of lead,zinc,and other metals.According to the chemical composition,X-ray diffraction analysis,and particle size analysis of Cote d’Ivoire low-manganese ore,an experiment was carried out on manganese-rich slag by reduction–smelting separation.Combined with the design scheme of the Box–Behnken principle,three experimental factors(temperature,basicity,and carbon content)were selected as the influences to study.The influence that each factor has on the recovery rate of manganese was studied by response surface methodology,and the experimental factors were optimized.The results show that under the conditions of a reduction-smelting temperature of 1402℃,basicity of R=0.10,and carbon content of 10 mass%,the recovery rate of manganese is 97%.A verification experiment was carried out under the optimal conditions,and the error was only 1.24%;this proves that the response surface method prediction model is reliable and accurate.This is of great significance for the comprehensive utilization of lean-manganese ore resources.
文摘针对规模化养殖场沼液难以农田消纳的问题,探索化学方法回收沼液中氮磷的工艺条件和优化参数。本研究选择猪场沼液为研究对象,采用鸟粪石沉淀法,进行单因素影响试验,选取p H、镁氮比、磷氮比为自变量,以氮磷回收率为响应值,通过BoxBehnken响应面试验设计对工艺参数进行优化。结果显示:猪场沼液氮磷回收的最佳工艺为:p H 10,镁氮比为1.1,磷氮比为0.6,氨氮回收率为65.21%,磷酸盐回收率为89.47%,实际值氨氮回收率为65.01%,磷酸盐回收率为90.81%,差值分别为0.20%、1.34%,回归模型拟合较好。
