Assessing and accounting for material consumption and environmental impact are necessary to measure environmental externalities of the aluminum industry and to construct an ecological civilization.In this research,lif...Assessing and accounting for material consumption and environmental impact are necessary to measure environmental externalities of the aluminum industry and to construct an ecological civilization.In this research,life cycle assessment(LCA)theory was used to assess the environmental impact of primary aluminum based on the lime soda Bayer process and different power generation modes,and the sources and distributions of the four selected impact categories were analyzed.The results show that,(1)Negative environmental impact of aluminum industry generally occurs from alumina extraction,carbon anode fabrication and electrolysis,particularly electrolysis and alumina extraction.Primary energy demand(PED),water use(WU),global warming potential(GWP)and freshwater eutrophication potential(FEP)are main environmental impact categories.(2)The environmental load with thermal power is higher than that with hydropower,e.g.,for the former,the greenhouse gas emission coefficient of 21800 kg CO2 eq/t(Al)will be generated,while for the latter,4910 kg CO2 eq/t(Al)will be generated.(3)Both power mode methods reflect the energy structure,whereas direct emissions reflect the technical level,indicating the potential for large energy savings and emission reductions,and some policies,related to clean power,energy efficiency and technological progress,should be made for emission reduction.展开更多
Aluminum production by carbothermo-chlorination reduction of alumina in vacuum was investigated by XRD, SEM, EDS and thermodynamic analysis. Thermodynamic calculations indicate that AlCl（g） generated by carbothermo-...Aluminum production by carbothermo-chlorination reduction of alumina in vacuum was investigated by XRD, SEM, EDS and thermodynamic analysis. Thermodynamic calculations indicate that AlCl（g） generated by carbothermo-chlorination process among Al2O3-C-AlCl3 system should be at 1377-1 900K （100 Pa） and AlCl（g） will disproportionate into aluminum and AlCl3（g） below 950-1 050 K at 10-102 Pa. Experimental results demonstrate that Al4O4C and Al4C3 begin to be formed by Al2O3-C system over 1698 K （40-150Pa）. It is Al4O4C and Al4C3 but not Al2O3-C that participate in the carbothermic-chlorination reaction. Temperature for AlCl（g） generated by Al4O4C-AlCl3-C, Al4C3-Al2O3-AlCl3 and Al4OC-Al4C3-Al2O3-AlCl3-C system is 1 703-1853 K （40-150 Pa）. Aluminum metal is produced by AlCl（g） disproportionation process below 933 K. The average purity of aluminum metal reaches 95.32%, which has perfect crystallization and uniform grain size.展开更多
基金Projects(71633006,71403298) supported by the National Natural Science Foundation of ChinaProjects(14YJCZH045,15YJCZH019) supported by the Ministry of Education of Humanities and Social Science,China
文摘Assessing and accounting for material consumption and environmental impact are necessary to measure environmental externalities of the aluminum industry and to construct an ecological civilization.In this research,life cycle assessment(LCA)theory was used to assess the environmental impact of primary aluminum based on the lime soda Bayer process and different power generation modes,and the sources and distributions of the four selected impact categories were analyzed.The results show that,(1)Negative environmental impact of aluminum industry generally occurs from alumina extraction,carbon anode fabrication and electrolysis,particularly electrolysis and alumina extraction.Primary energy demand(PED),water use(WU),global warming potential(GWP)and freshwater eutrophication potential(FEP)are main environmental impact categories.(2)The environmental load with thermal power is higher than that with hydropower,e.g.,for the former,the greenhouse gas emission coefficient of 21800 kg CO2 eq/t(Al)will be generated,while for the latter,4910 kg CO2 eq/t(Al)will be generated.(3)Both power mode methods reflect the energy structure,whereas direct emissions reflect the technical level,indicating the potential for large energy savings and emission reductions,and some policies,related to clean power,energy efficiency and technological progress,should be made for emission reduction.
基金Project(u0837604) supported by the Joint Funds of the National Natural Science Foundation of China and Yunnan ProvinceProject(20095314110003) supported by the special Research Funds of the Docter Subject of Higher School,China
文摘Aluminum production by carbothermo-chlorination reduction of alumina in vacuum was investigated by XRD, SEM, EDS and thermodynamic analysis. Thermodynamic calculations indicate that AlCl（g） generated by carbothermo-chlorination process among Al2O3-C-AlCl3 system should be at 1377-1 900K （100 Pa） and AlCl（g） will disproportionate into aluminum and AlCl3（g） below 950-1 050 K at 10-102 Pa. Experimental results demonstrate that Al4O4C and Al4C3 begin to be formed by Al2O3-C system over 1698 K （40-150Pa）. It is Al4O4C and Al4C3 but not Al2O3-C that participate in the carbothermic-chlorination reaction. Temperature for AlCl（g） generated by Al4O4C-AlCl3-C, Al4C3-Al2O3-AlCl3 and Al4OC-Al4C3-Al2O3-AlCl3-C system is 1 703-1853 K （40-150 Pa）. Aluminum metal is produced by AlCl（g） disproportionation process below 933 K. The average purity of aluminum metal reaches 95.32%, which has perfect crystallization and uniform grain size.
