The metabolism of copper and arsenic in a copper pyrometallurgy process was studied through substance flow analysis method.The mass balance accounts and substance flow charts of copper and arsenic were established,ind...The metabolism of copper and arsenic in a copper pyrometallurgy process was studied through substance flow analysis method.The mass balance accounts and substance flow charts of copper and arsenic were established,indicators including direct recovery,waste recycle ratio,and resource efficiency were used to evaluate the metabolism efficiency of the system.The results showed that,the resource efficiency of copper was 97.58%,the direct recovery of copper in smelting,converting,and refining processes was 91.96%,97.13%and 99.47%,respectively.Meanwhile,for producing 1 t of copper,10 kg of arsenic was carried into the system,with the generation of 1.07 kg of arsenic in flotation tailing,8.50 kg of arsenic in arsenic waste residue,and 0.05 kg of arsenic in waste water.The distribution and transformation behaviors of arsenic in the smelting,converting,and refining processes were also analyzed,and some recommendations for improving copper resource efficiency and pollution control were proposed based on substance flow analysis.展开更多
Physicochemical and mineralogical characteristics of an alkali leaching residue of wolframite were studied by XRD,SEM−EDS,chemical phase analysis,mineral liberation analyzer(MLA),and TG−DSC methods.Batch leaching test...Physicochemical and mineralogical characteristics of an alkali leaching residue of wolframite were studied by XRD,SEM−EDS,chemical phase analysis,mineral liberation analyzer(MLA),and TG−DSC methods.Batch leaching tests,toxicity characteristic leaching procedure(TCLP)tests and Chinese standard leaching tests(CSLT)were conducted to determine the environmental mobility of toxic elements.The results show that,due to the high contents of W,Fe,Mn,Sn,and Nb,the residue is with high resource value,but the content of a toxic element,As,is also high.The existing minerals of the investigated elements mainly occur as monomer particles,but it is difficult to extract these valuable metals by conventional acid leaching due to their mineral properties.The release of As increases over time in acidic environment.The leaching concentration of all investigated harmful elements through TCLP is within the limiting value,while the leaching concentration of As through CSLT exceeds the limiting value by more than 4 times,so the residue is classified as hazardous solid waste based on the Chinese standard.A process for valuable metals recovery from this residue was proposed.Preliminary experimental results indicated that the main valuable metals could be extracted effectively.展开更多
Objective This study aimed to systematically evaluate the application of the Cavitron Ultrasonic Surgical Aspirator(CUSA)system in epilepsy surgery and summarize associated surgical experiences.Methods In this retrosp...Objective This study aimed to systematically evaluate the application of the Cavitron Ultrasonic Surgical Aspirator(CUSA)system in epilepsy surgery and summarize associated surgical experiences.Methods In this retrospective analysis,70 patients with refractory epilepsy underwent CUSA-assisted resection,while 20 controls underwent conventional surgical resection.Patients were categorized according to surgical scenarios for CUSA application,including lesion-related epilepsy resections,mesial temporal lobe procedures,neocortical resections within eloquent areas,and cases requiring preservation of critical vascular structures.Detailed operative metrics were analyzed for each category.Comparative assessments between the CUSA and conventional groups included surgical efficiency,complication rates,and postoperative seizure outcomes on the basis of the modified Engel classification.Results CUSA was used for the following procedures:resection of epileptic lesions(n=26),mesial temporal structures(n=32),the epileptogenic neocortex(n=28),and the rolandic cortex(n=17).Additionally,it was utilized in 6 cases requiring vascular protection during insular resection and in 18 cases involving preservation of cortical dangerous veins.Although the overall surgical efficiency was comparable between the CUSA and conventional groups(68.0±18.2 vs.61.1±14.7 min,P=0.180),the CUSA group demonstrated superior efficiency in resecting low-grade tumors(58.6±14.9 vs.68.1±11.2 min,P=0.034).Furthermore,the CUSA group presented significantly fewer permanent complications(5.7%vs.10%,P<0.0001)and a higher rate of Engel Class I outcomes(82.9%vs.70.0%,P=0.278).Conclusions The CUSA system represents a suitable and promising surgical tool for resective epilepsy surgery,potentially serving as a valuable option for epilepsy surgeons.Further studies are warranted to validate these findings.展开更多
In this study,the metabolism of a hydrometallurgical process for tungsten extracting from wolframite was studied through substance flow analysis.The mass balance accounts,substance flow charts of tungsten and arsenic ...In this study,the metabolism of a hydrometallurgical process for tungsten extracting from wolframite was studied through substance flow analysis.The mass balance accounts,substance flow charts of tungsten and arsenic were established to evaluate the metabolism efficiency of the investigated system.The results showed that,the total tungsten resource efficiency of the system was 97.56%,and the tungsten recovery of unit process autoclaved alkali leaching,ion exchange,Mo removing,concentration and crystallization was 98.16%,98.94%,99.71%,99.89%,respectively.Meanwhile,for extracting 1 ton of tungsten into the qualified ammonium paratungstate,10.0414 kg of arsenic was carried into the system,with the generation of 7.2801 kg of arsenic in alkali leaching residue,1.5067 kg of tungsten in arsenic waste residue,and 1.2312 kg of tungsten in Mo residue.Besides,7.9 g of arsenic was discharged into nature environment with waste water,15.5 g of arsenic was entrained into the final APT.The distribution and transformation behaviors of arsenic during production were analyzed through phases change analysis,and some recommendations for improving the resource efficiency of tungsten and pollution control during production were also proposed based on the substance flow analysis in this study.展开更多
基金financial supports from the National Key R&D Program of China(No.2019YFC1907400)the National Natural Science Foundation of China(Nos.51904351,51620105013)。
文摘The metabolism of copper and arsenic in a copper pyrometallurgy process was studied through substance flow analysis method.The mass balance accounts and substance flow charts of copper and arsenic were established,indicators including direct recovery,waste recycle ratio,and resource efficiency were used to evaluate the metabolism efficiency of the system.The results showed that,the resource efficiency of copper was 97.58%,the direct recovery of copper in smelting,converting,and refining processes was 91.96%,97.13%and 99.47%,respectively.Meanwhile,for producing 1 t of copper,10 kg of arsenic was carried into the system,with the generation of 1.07 kg of arsenic in flotation tailing,8.50 kg of arsenic in arsenic waste residue,and 0.05 kg of arsenic in waste water.The distribution and transformation behaviors of arsenic in the smelting,converting,and refining processes were also analyzed,and some recommendations for improving copper resource efficiency and pollution control were proposed based on substance flow analysis.
基金the financial supports from the National Natural Science Foundation of China(Nos.51904351,U20A20273)the National Key R&D Program of China(No.2019YFC1907400)+1 种基金the Science and Technology Innovation Program of Hunan Province,China(No.2021RC3005)the Innovation Driven Project of Central South University,China(No.2020CX028)。
基金the financial supports from the National Key R&D Program of China(No.2019YFC1907400)the National Natural Science Foundation of China(Nos.51904351,51620105013)。
文摘Physicochemical and mineralogical characteristics of an alkali leaching residue of wolframite were studied by XRD,SEM−EDS,chemical phase analysis,mineral liberation analyzer(MLA),and TG−DSC methods.Batch leaching tests,toxicity characteristic leaching procedure(TCLP)tests and Chinese standard leaching tests(CSLT)were conducted to determine the environmental mobility of toxic elements.The results show that,due to the high contents of W,Fe,Mn,Sn,and Nb,the residue is with high resource value,but the content of a toxic element,As,is also high.The existing minerals of the investigated elements mainly occur as monomer particles,but it is difficult to extract these valuable metals by conventional acid leaching due to their mineral properties.The release of As increases over time in acidic environment.The leaching concentration of all investigated harmful elements through TCLP is within the limiting value,while the leaching concentration of As through CSLT exceeds the limiting value by more than 4 times,so the residue is classified as hazardous solid waste based on the Chinese standard.A process for valuable metals recovery from this residue was proposed.Preliminary experimental results indicated that the main valuable metals could be extracted effectively.
基金supported by the Featured Clinical Technique of Guangzhou(2023P-TS09).
文摘Objective This study aimed to systematically evaluate the application of the Cavitron Ultrasonic Surgical Aspirator(CUSA)system in epilepsy surgery and summarize associated surgical experiences.Methods In this retrospective analysis,70 patients with refractory epilepsy underwent CUSA-assisted resection,while 20 controls underwent conventional surgical resection.Patients were categorized according to surgical scenarios for CUSA application,including lesion-related epilepsy resections,mesial temporal lobe procedures,neocortical resections within eloquent areas,and cases requiring preservation of critical vascular structures.Detailed operative metrics were analyzed for each category.Comparative assessments between the CUSA and conventional groups included surgical efficiency,complication rates,and postoperative seizure outcomes on the basis of the modified Engel classification.Results CUSA was used for the following procedures:resection of epileptic lesions(n=26),mesial temporal structures(n=32),the epileptogenic neocortex(n=28),and the rolandic cortex(n=17).Additionally,it was utilized in 6 cases requiring vascular protection during insular resection and in 18 cases involving preservation of cortical dangerous veins.Although the overall surgical efficiency was comparable between the CUSA and conventional groups(68.0±18.2 vs.61.1±14.7 min,P=0.180),the CUSA group demonstrated superior efficiency in resecting low-grade tumors(58.6±14.9 vs.68.1±11.2 min,P=0.034).Furthermore,the CUSA group presented significantly fewer permanent complications(5.7%vs.10%,P<0.0001)and a higher rate of Engel Class I outcomes(82.9%vs.70.0%,P=0.278).Conclusions The CUSA system represents a suitable and promising surgical tool for resective epilepsy surgery,potentially serving as a valuable option for epilepsy surgeons.Further studies are warranted to validate these findings.
基金financially supported by the National Key R&D Program of China(Grant No.2019YFC1907400)the National Natural Science Foundation of China(Grant Nos.51904351 and 51620105013)
文摘In this study,the metabolism of a hydrometallurgical process for tungsten extracting from wolframite was studied through substance flow analysis.The mass balance accounts,substance flow charts of tungsten and arsenic were established to evaluate the metabolism efficiency of the investigated system.The results showed that,the total tungsten resource efficiency of the system was 97.56%,and the tungsten recovery of unit process autoclaved alkali leaching,ion exchange,Mo removing,concentration and crystallization was 98.16%,98.94%,99.71%,99.89%,respectively.Meanwhile,for extracting 1 ton of tungsten into the qualified ammonium paratungstate,10.0414 kg of arsenic was carried into the system,with the generation of 7.2801 kg of arsenic in alkali leaching residue,1.5067 kg of tungsten in arsenic waste residue,and 1.2312 kg of tungsten in Mo residue.Besides,7.9 g of arsenic was discharged into nature environment with waste water,15.5 g of arsenic was entrained into the final APT.The distribution and transformation behaviors of arsenic during production were analyzed through phases change analysis,and some recommendations for improving the resource efficiency of tungsten and pollution control during production were also proposed based on the substance flow analysis in this study.
