The effect of isothermal-rolling process on the morphology, size and distribution of type II MnS was studied based on Gleeble-1500 simulator. The experimental results show that the relative plasticity of type II MnS increases with deformation temperature decreasing, but, it increases first and then decreases with deformation amount increasing; Heavy compression deformation is beneficial to improve the distribution of type II MnS; The changing trends of the size of type II MnS for varying deformation amount are basically same with deformation temperature changing, i.e. the average length of sulfides is shorter, and the average width is wider at high temperature rolling process; Under the same deformation temperature, the average size of type II MnS shows cyclical change with deformation amount increasing.
The reduction rates of manganese oxide by carbon and SiC was examined by heating MnO2-carbon and MnO2-SiC mixtures in a 7-kW industrial microwave oven. The results show that the rate of the reduction increased with the amount of carbon in MnO2-carbon mixture and with SiC in MnO2-SiC mixture. The rate of the MnO2 reduction by carbon was proportional to the reaction time, and that by SiC was proportional to 2/3 power of the reaction time. The reduction was found to be controlled by chemical reaction. The reaction rate constant of the reduction of MnO2kC increased with increasing the amount of carbon in the mixtures but kSiC decreased with increasing the amount of SiC in the mixtures.
CaF2 is used in large quantity during refining of steel, which is harmful to environment to be found. There is more and more study on use of B2O3 in metallurgical progress. This paper studied the effects of MgO on melting performance of CaO-SiO2-Al2O3 ternary system and B2O3 on that of CaO-SiO2-Al2O3-MgO quaternary system by calculation of phase diagram. The result shows that MgO can expand the range of liquid phase of CaO-SiO2-Al2O3 ternary system while the effect on melting performance is little. B2O3 can also reduce the melting point of CaO-SiO2-Al2O3-MgO quaternary system in high CaO zone and in high Al2O3 zone. So the proper composition of MgO in refining slag are 5~8% and B2O3 below 8%.
Caustic calcined dolomite based compound desulfurizer by the silicon thermal reduction method was taken as study object. Effect of fluxing agent and heating agent on caustic calcined dolomite based compound desulfurizer melting point was studied. The result showed that heating agent was the major influential factor for the melting point of compound desulfurizer, melting point of the compound desulfurizer gradually reduced with the increase of heating agent. Fluxing agents of CaF2 and SiO2 were the minor influential factors for the melting point of compound desulfurizer. The lowest melting point condition for the compound desulfurizer was:7% CaF2+11% Al2O3+17% SiO2 + 56% heating agent.
Health risk assessment (HRA) methodologies of three stages of Municipal Solid Waste Landfill (MSWL), including operation period, maintenance and management period after closure, and usage period without any restricted limits were built in this paper. The major exposure pathways to environmental contaminants were considered: inhalation of gas and dust during operation period, and ingestion of four food pathways categories (plant foods, meat, milk, and fish), groundwater and dust during usage period without any limits. The endpoints of HRA of MSWL are individual lifetime carcinogenic risk for all the carcinogenic chemical contaminants, and hazard index (HI) for all the non-carcinogenic chemical contaminants to the landfill worker (only at the operation period), and to the public near to the landfill (at all the three stages) respectively. The parameter values of calculation model are conservatively chosen. This is the first time in China that an integrated risk assessment methodology for landfill gas and leachate is attempted to develop. HRA methodologies will facilitate rapid estimation of the risk level of MSWL.
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