Ye Shufeng

Preparation and Properties of Anti-oxidation Inorganic Nano-coating for Low Carbon Steel at an Elevated Temperature

A new kind of anti-oxidation inorganic nano-coating for the common low carbon steel was prepared. It included magnesite mineral, metallurgic dust and silicate adhesive as the main raw materials. The nano-coating could be sprayed directly onto the low carbon steel slab even though with hot surface as far as under 1000°C. And at the same time, a compact thin nano-film was formed, and the film would inhibit the oxygen into the interface of the steel body and decrease the loss of weight because of oxidation. The loss was decreased by about 60% or more. The properties and mechanism of oxidation resistance of the coating were discussed through XRD, TG-DTA and SEM. The experimental results show that many reactions woulld happen among the components of the coating and then many microspheres with the size of 80–100 nm generated in the system. By using the heat of the steel body, the silicate adhesive would interact with the microspheres, and the other components of the coating would be soft and sintered so that when the coating was sprayed onto the surface of the steel slab, the intact and compact film could be formed and adhesive with the steel body. Besides the special properties of anti-oxidation, the coating could prevent the volatilization of microelement in the steel such as silicate and carbon at a high temperature. So it can improve the quality and output of steel with this new kind of nano-coating.

Characteristics and reactivities of solid wastes sorbent for medium-temperature flue gas desulfurization

Abstract In this study, sorbent for flue gas desulfurization is prepared using metallurgical dusts (MD) abundant in iron oxides as the main active component, lime as promoter, and amylum as special additive. The reactivity of the sorbent is conducted in a quartz fixed-bed reactor within the medium temperature range of 300°C–750°C under heating and isothermal conditions, while the physical and chemical properties of the sorbent are measured using ICP-AAS, SEM, XRD, and so on. The experimental results indicate that with temperature increasing from 300°C to 750°C, breakthrough sulfur capacity of the sorbent increases from 0.0257 gS/gSorbent at 300°C to 0.1391 gS/gSorbent at 650°C, then decreases to 0.0836 gS/gSorbent at 750°C, and that the removal efficiency of SO2 and breakthrough sulfur capacity of the sorbent depend on the chemical kinetics of Fe2O3 and CaO in the temperature range of lower than 600°C, but on the thermodynamic equilibrium of sulfuration of Fe2O3, the thermal stability of the Fe2(SO4)3 and content of CaO in the range of higher than 650°C. Physical and chemical analyses of the fresh and reacted sorents further verify that the effective and dominating component of the sorbent is Fe2O3 within the temperature range of lower than 650°C, while is CaO in higher than 650°C.