A cradle-to-gate life cycle assessment was conducted in this paper to calculate the greenhouse gas (GHG) emissions, such as CO2, CH4, CF4 and C2F6 emissions, based on statistic data of Chinese aluminum industry of the year 2003. The results showed that the GHG emissions for 1 t primary aluminum production was 21.6 t CO2 equivalent which is 70% higher than that of worldwide average level of the year 2000. The main contributors of emission were the alumina refining and aluminum smelting process accounting for 72% and 22% in accumulative emission, respectively. According to the development and application of new process technologies for primary aluminum production and the ‘target of energy-saving and emissions-reducing’ of Chinese government, the reduction potential of the GHG emissions for alumina and aluminum production were estimated. The results indicated that China aluminum industry would achieve the target of reducing about 25% GHG emissions by the end of 2010.
The availability of resources for economic activities differs between regions, and the importance of the resources is consequently observed to be different within regions compared to a global scale. With the current situation in Chinese mining industry and its statistic characteristics, the characterization procedures of abiotic resource in life cycle impact assessment (LCIA) have demonstrated certain limita-tions in the Chinese materials industry. The aim of this paper is to propose new characterization and normalization factors for abiotic resource depletion categories such as metals and non-renewable en- ergy resources in a Chinese context. The actual production of abiotic resources calculated by a modi- fied model is compared to the reserve base in line with the new national standard to determine char- acterization factors in equivalence units, with antimony as the reference mineral. The normalization factors are based on the total base reserves of the most important minerals in China. A case study on primary magnesium production using the Pidgeon process is used to compare LCIA results for abiotic resource categories that are between current LCIA factors and the new Chinese factors. These factors not only reflect the importance of abiotic resource with respect to region-specific resource depletion, but also can compare with the global factors.
Nanoparticles of cerium oxide were prepared by common precipitation method using cerium nitrate solution and ammonia reagent. Cerium oxide particles with different morphologies were synthesized through adjusting pH values of the solution. TEM and BET results showed that spherical crystal was gained in acid solution, with the specific surface of 148. 1944 m2·g^-1. The cerium oxide appeared in the form of spherical and rod-like grains under neutral condition, and the specific surface changed to 114.7975 m^2·g^-1. Moreover, in alkaline solution, cerium oxide powders were exhibited in rod-like form with the specific surface of 106.2465 m^2·g^-1. Precipitation formation mechanism of different morphologies was also discussed, which followed decomposition precipitation mechanism and topology reaction mechanism in acid and alkaline solution, respectively.
Based on the practice of magnesium production in China, a quantitative evaluation of the environment impact was carried out according to the theory and framework of life cycle assessment(LCA) study. The major gaseous pollutants including CO2, SO2, NOx, CH4, HF and particulates were calculated. The accumulative environmental performances of different energy use strategies and the characterization results, including abiotic depletion potential(ADP), global warming potential(GWP), acidification potential(AP) and human-toxicity potential(HTP) were compared. The results show that the direct emission of fuel combustion in the process is the major contributor to the pollutants emission of magnesium production. Global warming potential and acidification potential make the main contribution to the accumulative environmental impact. The different fuel use strategies in the practice of magnesium production cause much different impacts on the environmental performance. The accumulative environmental impact of coal burned directly is the highest, and that of producer-gas comes to the next, while that of coke-oven gas is the lowest.
The availability of resources for economic activities differs between regions, and the importance of the resources is consequently observed to be different within regions compared to a global scale. With the current situation in Chinese mining industry and its statistic characteristics, the characterization procedures of abiotic resource in life cycle impact assessment (LCIA) have demonstrated certain limita-tions in the Chinese materials industry. The aim of this paper is to propose new characterization and normalization factors for abiotic resource depletion categories such as metals and non-renewable en- ergy resources in a Chinese context. The actual production of abiotic resources calculated by a modi- fied model is compared to the reserve base in line with the new national standard to determine char- acterization factors in equivalence units, with antimony as the reference mineral. The normalization factors are based on the total base reserves of the most important minerals in China. A case study on primary magnesium production using the Pidgeon process is used to compare LCIA results for abiotic resource categories that are between current LCIA factors and the new Chinese factors. These factors not only reflect the importance of abiotic resource with respect to region-specific resource depletion, but also can compare with the global factors.
