Selenium distillation slag(SDS)is a high-value-added secondary resource with a high recovery value.This paper aims to investigate the leaching behavior and kinetics of selenium,tellurium,and copper in the SDS acid oxi...Selenium distillation slag(SDS)is a high-value-added secondary resource with a high recovery value.This paper aims to investigate the leaching behavior and kinetics of selenium,tellurium,and copper in the SDS acid oxidation leaching process with H_(2)SO_(4) and H_(2)O_(2).The experimental results showed that under the optimum conditions,the contents of selenium,tellurium,and copper in the SDS were reduced from 22.13 wt%,3.58 wt%,and 6.42 wt%to 3.06 wt%,0.27 wt%,and 0.33 wt%,respectively.Correspondingly,the recovery rates are 87.08%,97.15%and 99.7%.The leaching processes of selenium and tellurium were controlled by diffusion and chemical reactions,and the leaching behavior of copper was controlled by chemical reactions.Below 45℃,the activation energies for selenium,tellurium,and copper were found to be 26.47,62.18 and 19.67 kJ/mol,respectively.In addition,the contents of lead,silver and gold in the leaching residue are increased to 46.8 wt%,8.35 wt%and 0.27 wt%,respectively.These substances can be utilized as raw materials for the recovery of these valuable metals.Importantly,the entire process does not generate toxic or harmful waste,making it a green and environmentally friendly method for resource recovery.展开更多
The kinetics of reductive leaching of manganese from a low-grade manganese oxide ore were studied using cellulose as reductant in dilute sulfuric acid medium.It was found that when the stirring speed was higher than 2...The kinetics of reductive leaching of manganese from a low-grade manganese oxide ore were studied using cellulose as reductant in dilute sulfuric acid medium.It was found that when the stirring speed was higher than 200 r/min,the effect of gas film diffusion on manganese extraction efficiency could be neglected,and the kinetic behavior was investigated under the condition of elimination of external diffusion influence on the leaching process.Effects of leaching temperature,mass ratio of cellulose and ore,and the sulfuric acid concentration on manganese extraction efficiency were discussed.The kinetic data were analyzed based on the shrinking core model,which indicated that the leaching process was dominated by both ash layer diffusion and chemical reaction at the initial stage,with the progress of leaching reaction,the rate-controlling step switched to the ash layer diffusion.It was also concluded that the sulfuric acid concentration had the most significant influence on the leaching rate,the reaction orders with respect to the sulfuric acid concentration were 2.102 in the first 60 min,and 3.642 in the later 90 min,while the reaction orders for mass ratio of cellulose and ore were 0.660 and 0.724,respectively.An Arrhenius relationship was used to relate the temperature to the rate of leaching,from which apparent activation energies were calculated to be 46.487 kJ/mol and 62.290 kJ/mol at the two stages,respectively.Finally,the overall leaching rate equations for the manganese dissolution reaction with cellulose in sulphuric acid solution were developed.The morphological changes and mineralogical forms of the ore before and after the chemical treatment were discussed with the support of SEM and XRD analyses.展开更多
The leaching kinetics of molybdenum from Ni-Mo ore in sulfuric acid solution with sodium peroxodisulfate was studied.The effects including leaching temperature, reaction time, particle size, stirring speed, and concen...The leaching kinetics of molybdenum from Ni-Mo ore in sulfuric acid solution with sodium peroxodisulfate was studied.The effects including leaching temperature, reaction time, particle size, stirring speed, and concentrations of sulfuric acid and sodium peroxodisulfate were investigated. The leaching process of molybdenum from Ni-Mo ore is controlled by the chemical reaction through the solid layer across the unreacted shrinking core. The apparent activation energy of the leaching of molybdenum is calculated to be 41.0 k J/mol and the leaching kinetics equation of molybdenum from Ni-Mo ore is expressed as1-(1-a)1/3=3405.7exp[-41030.0/(RT)]t.展开更多
基金Project(2022YFC2904900) supported by the National Key Research and Development Program of ChinaProject(U1902221) supported by the National Natural Science Foundation of China。
文摘Selenium distillation slag(SDS)is a high-value-added secondary resource with a high recovery value.This paper aims to investigate the leaching behavior and kinetics of selenium,tellurium,and copper in the SDS acid oxidation leaching process with H_(2)SO_(4) and H_(2)O_(2).The experimental results showed that under the optimum conditions,the contents of selenium,tellurium,and copper in the SDS were reduced from 22.13 wt%,3.58 wt%,and 6.42 wt%to 3.06 wt%,0.27 wt%,and 0.33 wt%,respectively.Correspondingly,the recovery rates are 87.08%,97.15%and 99.7%.The leaching processes of selenium and tellurium were controlled by diffusion and chemical reactions,and the leaching behavior of copper was controlled by chemical reactions.Below 45℃,the activation energies for selenium,tellurium,and copper were found to be 26.47,62.18 and 19.67 kJ/mol,respectively.In addition,the contents of lead,silver and gold in the leaching residue are increased to 46.8 wt%,8.35 wt%and 0.27 wt%,respectively.These substances can be utilized as raw materials for the recovery of these valuable metals.Importantly,the entire process does not generate toxic or harmful waste,making it a green and environmentally friendly method for resource recovery.
基金Project(2010FJ1011)supported by the Major Project of Science and Technology of Hunan Province,China
文摘The kinetics of reductive leaching of manganese from a low-grade manganese oxide ore were studied using cellulose as reductant in dilute sulfuric acid medium.It was found that when the stirring speed was higher than 200 r/min,the effect of gas film diffusion on manganese extraction efficiency could be neglected,and the kinetic behavior was investigated under the condition of elimination of external diffusion influence on the leaching process.Effects of leaching temperature,mass ratio of cellulose and ore,and the sulfuric acid concentration on manganese extraction efficiency were discussed.The kinetic data were analyzed based on the shrinking core model,which indicated that the leaching process was dominated by both ash layer diffusion and chemical reaction at the initial stage,with the progress of leaching reaction,the rate-controlling step switched to the ash layer diffusion.It was also concluded that the sulfuric acid concentration had the most significant influence on the leaching rate,the reaction orders with respect to the sulfuric acid concentration were 2.102 in the first 60 min,and 3.642 in the later 90 min,while the reaction orders for mass ratio of cellulose and ore were 0.660 and 0.724,respectively.An Arrhenius relationship was used to relate the temperature to the rate of leaching,from which apparent activation energies were calculated to be 46.487 kJ/mol and 62.290 kJ/mol at the two stages,respectively.Finally,the overall leaching rate equations for the manganese dissolution reaction with cellulose in sulphuric acid solution were developed.The morphological changes and mineralogical forms of the ore before and after the chemical treatment were discussed with the support of SEM and XRD analyses.
基金Project(51364009) supported by the National Natural Science Foundation of ChinaProject(JSU071302) supported by the Construct Program of the Key Discipline in Hunan Province,ChinaProject(2015JJ2115) supported by the Natural Science Foundation of Hunan Province,China
文摘The leaching kinetics of molybdenum from Ni-Mo ore in sulfuric acid solution with sodium peroxodisulfate was studied.The effects including leaching temperature, reaction time, particle size, stirring speed, and concentrations of sulfuric acid and sodium peroxodisulfate were investigated. The leaching process of molybdenum from Ni-Mo ore is controlled by the chemical reaction through the solid layer across the unreacted shrinking core. The apparent activation energy of the leaching of molybdenum is calculated to be 41.0 k J/mol and the leaching kinetics equation of molybdenum from Ni-Mo ore is expressed as1-(1-a)1/3=3405.7exp[-41030.0/(RT)]t.
