Papers by Author: Xian Zheng Gong

Abstract: As an important tool for water resource environmental impact assessment, the application of water footprint assessment method in copper production process is conducive to more accurate assessment of water resource environmental impact in copper production process. The water footprint assessment method released by the Water Footprint Network was used to study the water footprint of the production process of cathode copper products produced by pyrometallurgy. It was found that the water footprint of 1 ton of copper produced by pyrometallurgy was 242m³, of which the blue water footprint accounted for 60%, the grey water footprint accounted for 40%. The direct water footprint accounted for 67% and the indirect water footprint accounted for 33%. The characteristics of water footprint contribution at each process were compared, which provided data support and reference for enterprises to better understand the water resource environmental impact of copper by pyrometallurgy and to choose the water resource utilization mode with their own production characteristics.

Abstract: Based on the analysis of the development situation of China’s cement industry and the BCG Matrix method, this paper classifies and screens 31 energy-saving technologies in China's cement production, and puts forward guiding suggestions for the application of energy-saving technologies for cement enterprises. The screening results show that the “Energy-efficient powder separation technology” and “New low-calcium cement clinker and production technology” are “double-high” technologies with excellent on both screening indicators. The investment energy saving rates are 17.5 tce/10,000 yuan (tons of standard coal equivalent per 10,000 yuan) and 10 tce/10,000 yuan. The promotion ratio increments are 35% and 25%. “Cement clinker energy-saving nitrogen reduction firing technology”, “Fan drive mode adopts high voltage frequency conversion speed control technology”, “Pure low temperature waste heat power generation technology for cement kiln” are “single-high” technologies with excellent on one of screening indicators. The investment energy saving rates are 0.3tce/10,000 yuan, 4.1tce/10,000 yuan, 3.9tce/10,000 yuan respectively. The promotion ratio increments are 19%, 35%, 31.5% respectively.

Abstract: The rapid development of China’s automobile industry has led to increased demand for automobile glass. Combined with the present situation of China’s automobile glass industry, life cycle assessment(LCA) method was adopted for this study, through investigating the energy consumption and emissions during the raw and auxiliary materials acquisition stage and product production stage for auto laminated glass. Then a life cycle inventory was worked out and the data was characterized and normalized by CML analysis method. The results showed that the most serious environmental impacts were Marine Aquatic Ecotoxicity Potential, abiotic depletion potential-fossil and global warming potential, whose proportion of total environmental impact was 92.2%, 2.41%, 1.75%, respectively. Further analysis showed that the influence of float glass was 36%,42% and 33.9% respectively.

Abstract: The ISO14046 water footprint evaluation method was used in this study to calculate the water shortage footprint and water degradation footprint in plate glass production, in order to improve the water efficiency and management level in the production process of plate glass in China. A certain enterprise in Hebei province was selected for investigation in 2018. The results show that the water shortage footprint generated by the production of flat glass was 0.435 m³H₂Oeq/weight box. The proportion at raw material production stage was the largest, being 86%, so the water consumption control in raw material mining and the circulating water system should be strengthened and improved to reduce the fresh water consumption. Water degradation footprint in flat glass industry mainly consisted of eutrophication and acidification footprints. The eutrophication footprint was calculated as 0.027 kgNO₃^-eq/weight box, and water acidification footprint was 0.271 kgSO₂eq/weight box. The largest proportion occurred at flat glass production stage. It should be paid attention at this stage, to update the relatively clean production equipments and add the waste gas processing steps to reduce pollution discharge.

Abstract: The shortage of water has become a serious problem in the development of the steel industry in China. Therefore,it is important for research to be done in environment management, estimating the potential improvement of steel industry. This study propose an improved water footprint model of steel production based on the water footprint network methodology and the life cycle assessment framework. The result shows that the water footprint of steel production is 41.09m³/t, which requires larger amounts of direct blue water. The case of China highlights the relevance of clean production, energy efficiency measures, and grading utilization on reducing the water footprint of steel production.

Abstract: The scarcity of water resource has become one of major issues that constrain economic development and urbanization process in China. The water footprint is a comprehensive indicator used to measure water consumption and pollution that is widely used in global or regional studies. The previous practices showed that water footprint analysis was an effective tool to achieve sustainable utilization of water resources by guiding the development of water-saving technology and product. This paper reviewed the progress of water footprint research in materials industry including related theory, method and application. Firstly, the basic concept of water footprint was introduced. Secondly, the current accounting and assessment methods of water footprint and their applicable fields were summarized. Thirdly, the case studies on the water footprint of metallic materials, nonmetallic materials and chemical materials were reviewed to analyze its guidance significance on the sustainable development of water resources. At last, some suggestions for future research on the water footprint of materials were proposed.

Abstract: In recent years, the building materials industry in China has made great progress in the R&D of energy conservation, emission reduction and cleaner production technologies, in order to implement sustainable development policy. Life cycle assessment (LCA) is one of the mainstream method to analyze the environmental impact of product during its life cycle, which plays an important role on ecological design of building materials and development of green manufacture technology in recent year. This paper reviewed the LCA studies of building materials. Firstly, the development of China's building materials industry and technical framework of LCA standardized by ISO14040/14044 were introduced. Moreover, the typical LCA case studies of cement, glass, ceramics, wall materials, insulation materials and other building materials were reviewed. At last, some prospects for future research and development in this field were put forward.

Abstract: In this study, the LCA assessment model of CML was employed to analyze the environmental burden caused by the production of glass substrates, and the evaluation of the environmental performance of five stages of preparation of ingredients, including glass melting, precision clarification, overflow molding and post process, was also conducted. The results show that the global warming potential is the dominant impact category in the comprehensive environmental burden with a normalized value of 4.64×10^-14, followed by the acidification potential (2.57×10^-14), photochemical oxidation potential (2.82×10^-15). And the relative contribution of abiotic depletion potential and human toxicity to the comprehensive environmental burden is rather limited, with the normalized values of 8.31×10^-17 and 1.21×10^-16, respectively. The single score of environmental impact due to the whole production system is 2.37×10^-13, wherein the environmental impact values of the processes of preparation of ingredients, glass melting, precision clarification, overflow molding, and post are 1.07×10^-15, 9.10×10^-14 (highest), 2.26×10^-14, 7.36×10^-14, and process 4.90×10^-14, respectively. The preparation of the batch, the glass melting, the overflow molding and the post process mainly cause the environmental effects of global warming potential and acidification potential, the cumulative values of which are 1.13×10^-13 and 9.01×10^-14, respectively. The precision clarification stage mainly causes the environmental effect of acidification potential, the value of which is 2.02×10^-14 and much higher than those of other environmental impact categories.

Abstract: Tungsten is an important strategic metal, widely used in cemented carbide manufacturing, steel industry, and other economic fields. The amount of tungsten resource consumed in China each year accounts for more than 80% of the world’s annual total consumption. The purpose of this study is to quantify the environmental impact of tungsten production in China through the method of LCA. The result shows that, regarding the contributions of impact categories, the normalized value of HTP is the largest one among various impact categories, which accounts for 35.39% of the total environmental impact, followed by AP, PMFP, GWP, MDP, FDP, and POFP, respectively. The results also show that, regarding the contributions of production processes, smelting process is the largest contributor to the environmental burden of tungsten production due to the crystallization and calcination reduction occurred in the smelting process consumes a large amount of electricity, followed by mining, beneficiation, and transportation, respectively. The major academic contribution of this paper to the existing literatures is that we employed process-based analysis method, which could improve the accuracy of the study and provide practical advices for tungsten enterprises to reduce the environmental impact.

Abstract: The demand for rare earths in aluminum alloy industry has experienced substantial growth in recent years. The erbium and scandium are two effective rare earth additives, mainly due to its remarkable improvement to aluminum alloy performance. However, the production process of rare earth has caused significant environmental problems. Hence, the analysis of environmental impacts associated with erbium and scandium processing is gaining importance. In this study, a life cycle analysis on the environment impacts of erbium oxide (Er₂O₃) and scandium oxide (Sc₂O₃) was carried out based on life cycle assessment (LCA) method. The life cycle assessment results showed that the production of 1 kg of Er₂O₃ and Sc₂O₃ generated 21.7 kg CO₂ eq. and 743 kg CO₂ eq., respectively. The leaching and purification process accounting for 95% of the overall water usage of Er₂O₃ production. For Sc₂O₃, energy and chemical consumption played a key role in reducing environmental impacts. Furthermore, Er₂O₃ appeared to have less environmental impact than Sc₂O₃ on most environmental issues. A detailed review of contribution was conducted and recommendations for further research were given.