Papers by Author: Zhi Hong Wang

Abstract: The water consumption intensity of steel production through BF-BOF technology was decomposed by an innovative process-based water-accounting model, i.e., water-balance model. One ton of steel product was chosen to be the functional unit. The system boundary of the case study included the production processes of coking, sintering, iron making, steel making, continuous casting and rolling. The results showed that the water consumption intensity of steel production was 3.969t/t in this case. The water consumption of evaporation, solidification and wastewater were 2.373t, 0.013t and 1.583t, accounting for 59.79%, 0.33% and 39.88% of the total water consumption, respectively. Steel rolling is the largest contributor to water consumption, and the amount of water consumption is 1.523t, accounting for 38.37% of the total water consumption; followed by coking process and continuous casting process, the amounts of which are 0.814t (20.50%) and 0.634t (15.97%), respectively. This finding can push the utilization of advanced technologies to save water resource in steel industry.

Abstract: As a new type of unsaturated linear magnetoresistive materials, tungsten ditelluride series material has potential applications in the fields of strong magnetic detection, information recording and magnetic storage devices. The current development concepts of “green materials”, “green chemical technology” and “environmentally friendly technology” require us to pursue the non-toxic, low-emission and non-emission in material synthesis technology. At the same time, the prepared products show excellent performance and high versatility and efficiency. According to our previous work, the study attempts to use a low-volatile amine solvent as a pretreatment raw material to synthesize a tungsten germanium-based linear magnetoresistive material by hydrothermal/solvothermal method and self-fluxing method. The obtained materials were subjected to XRD, Raman, SEM and Magnetoresistance. Experimental results show that when the mass ratio of W and Te is 1:4, the prepared material is pure phase and the sample is the layered structure. The Magnetoresistance Property points out that the maximum value is about 190 %, which appears in the condition of 10 K and 7 T. Those test projects include phase, structure and morphology characteristics, and provide technical parameters and methods for the development of green synthesis and potential applications of tungsten ditelluride series linear magnetoresistive materials.

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.

Abstract: The development of eco-materials has become an important direction of materials science. Using appropriate methods to evaluate the environmental impacts caused by materials production is important for eco-materials research. For the purpose of obtaining more objective results to environment impacts, several exergy-based methods to indicate resource depletion have been established. However, no proper exergy-based evaluation methods for emissions in China have been reported. The objective of this study is to establish comprehensive exergy-based characterization model for life cycle assessment, and to apply this model to steel production.

Abstract: Transportation is an important part of industrial production systems, with serious energy consumption and environmental pollution. In this study, environment impact of road transportation, river freight in the Yangtze River, and railway transportation was established and analyzed by life cycle assessment method. The analysis results show that CO₂ is the largest emission of pollutants for freight transport in China. abiotic depletion potential (ADP) of electric locomotives significantly lower than the other five kinds of shipping methods, only 3.2% of diesel locomotive, 3.9% of the Yangtze barges fleet; 1.2% of the Yangtze Cargo vessel, 0.2% of heavy-duty trucks and 0.1% of light-duty trucks. The results show that accomplishing the same cargo turnover, light-duty truck has the largest environmental impact, while the Electric locomotive freight has the minimum environmental impact. Although the environmental impact of river freight transport is greater than rail transport, but it is far less than road transport.

Abstract: Aluminum is an essential material for the construction and development of national economy, however the GHG (greenhouse gas) emissions caused by its production have been noticed by China’s government gradually. In this study, the life cycle energy consumption and GHG emissions caused by the production of primary aluminum in different years in China were calculated, and the correlation between GHG emissions and some important factors i.e. resource consumption and procedure energy consumption was analyzed. The final results show that for GHG emissions, electricity is the major contributor that accounts for 68.5% of the total, followed by the emissions of anode effect and calcination of limestone, which accounts for 7.9% and 6.8% respectively, and the percentages other factors account for less than 6%. The results also show that the calcination of limestone, combustion of coal gas and consumption of electricity are the three main factors which have the largest correlation degree with GHG emissions, and their correlation degrees are 0.96, 0.94 and 0.90 respectively. Therefore, decreasing the consumption of coal gas and improving the efficiency of the calcination of limestone are effective ways to decrease the GHG emissions of primary aluminum production.

Abstract: Based on life cycle assessment, analysis of energy consumption and other environment load by steel production in Chinese typical iron and steel industry was carried out. The process accounted for the most environment load was found by studying the different processes in steel production route. The results indicate that the most important process is blast furnace (BF) which is the major factor of CO₂ and CO emissions, and contributes most to globe warming potential (GWP) and photochemical ozone creation potential (POCP).

Abstract: This study attempted to estimate the environmental performance of poly (propylene carbonate, PPC) in the whole life cycle. The life cycle is from raw materials, energy acquisition, manufacture, transportation, to the final disposal, sequentially. The environment impacts of these phases are assessed by the method of Life Cycle Assessment (LCA) to identify key aspects of environmental loads involving global warming, non-renewable resource consumption, and acidification effects and so on. Moreover, a comparative study due to manufacturing of PPC in its whole life cycle was taken to reveal which stage would make the most environmental load.

Abstract: With the development of economy, China has become one of the largest cement producers in the world. However, cement industry is a main contributor of global carbon emissions. Substituting calcium carbide sludge for limestone is an effective method for CO₂ emission reduction in cement industry and has developed rapidly in recent years in China. The purpose of this study is to determine the life cycle CO₂ emission of cement clinker produced with calcium carbide sludge as secondary raw material. The results show that compared with general cement clinker, the life cycle CO₂ emission intensity of cement clinker produced with calcium carbide sludge will be decreased by 39.1% when substitution rate is 80%. And the CO₂ emission results from the procedure of cement clinker production accounts for 85.7% of the total emission, in this stage, the CO₂ emission declined by 42.2%.

Abstract: Aerated concrete is a new type of wall material with beneficial features like light weight, heat insulation, fire prevention and low energy consumption. As a key milestone in wall materials innovation and energy-saving of building system, it has been proven to be an ideal wall material which can replace traditional clay brick through years of application and practice. This study calculated the CO₂ emissions in all the stages of life cycle of aerated concrete production. Compared with clay brick, the life cycle CO₂ intensity of aerated concrete block will be decreased by 67.4% with the same insulation effect. Study on the environmental loads of aerated concrete industry will provide theoretical base for the carry out of energy-saving and emission reduction, the formulation of clean production and the development of recycling economy.