Life Cycle Environmental Impact Assessment Of High Purity Magnesia

High purity magnesia was one of the most demanded and widely used magnesia refractories.However,high purity magnesia production industry also has brought serious problems of resource and energy waste and environmental pollution,which hindered the sustainable development of magnesia production industry.In this study,the traditional process,clean production process and flotation process were selected as the research objects,and the environmental impact assessment and comparative analysis of the whole life cycle of high-purity magnesia production were carried out,so as to provide reference for the improvement of high-purity magnesia production process.The main research contents and results were as follows(1)Based on the life cycle assessment method,the environmental impact of high-purity magnesia produced by traditional process was evaluated,and the environmental impact of each production stage was quantitatively analyzed from the perspective of life cycle.The results showed that the total environmental impact of traditional process was 4.23e-12.Among them,global warming potential(GWP)was the largest environmental impact type in the production process of high purity magnesia,and inhalable inorganic matter(RI),eutrophication potential(EP),acidification potential(AP)and solid waste(WS)also had greater environmental impact.From the perspective of production stage,the light burning stage was the stage with the largest environmental impact in the production process of high purity magnesia,and its environmental impact was 2.29e-12,in which GWP,EP,RI and AP made a greater contribution to the environmental impact in the light burning stage.The environmental impact of reburning stage was 1.74e-12,which was the second most polluted production stage,especially WS,RI,GWP and AP.However,the environmental pollution caused by the other four production stages was smaller than that caused by light burning and heavy burning.(2)Based on the results of traditional process life cycle assessment,two improved processes,cleaner production process and flotation process,were proposed.The environmental impact of the two improved processes on the production of high purity magnesia was evaluated by using life cycle assessment method,and compared with the traditional process.The results showed that the environmental impact of cleaner production process was 1.97e-12,and that of flotation process was 2.96e-12.Compared with the traditional process,the environmental impact of cleaner production process was reduced by53.43%,and that of flotation process was reduced by 30.02%.It could be seen that the cleaner production process was better than the flotation process.For cleaner production process,the environmental impact of light burning stage was the largest,followed by heavy burning stage,which was mainly due to the remarkable effect of dust removal,desulfurization and denitration process,and the environmental impact of fine grinding,ball pressing,mining and transportation stage was roughly equivalent to that of traditional process;for the flotation process,the reduction of its environmental impact is mainly to reduce the environmental benefits brought by the one-step calcination process.In addition,the environmental impact of two new links,ore crushing and flotation,can not be ignored.(3)On the basis of the research results of cleaner production process and flotation process,the cleaner production process of flotation based on flotation process and cleaner production technology was further proposed,and the environmental impact of the process was evaluated by life cycle assessment method.The results show that the environmental impact of clean production process of flotation is 1.86e-12,which is reduced by 56.03% compared with traditional process,37.16% compared with flotation process and 5.60% compared with clean production process.It is a cleaner production process for producing high purity magnesia.