Effects Of Alkali Metal On Solution Loss And Degradation Of Coke

It is assumed that the alkali metal in the blast furnace aggravates the coke deterioration.Four industrial cokes absorbed K,Na and the molar ratios of K:Na = 1:1 vapor which were prepared by a high-temperature carbon thermal-reduction method were studied.Results showed that coke has the best adsorption effect on K:Na = 1:1,the worst adsorption effect on K vapor.The SEM and EDS analysis of the alkali-rich coke core area showed that Na content is higher than K content,which indicated that Na vapor penetrates the coke more than K vapor.The microstructure results of the original coke showed that a high alkali-rich coke results because of a high porosity,a large average pore size,a low anisotropic texture and in particular,a large specific surface area.The coke strength test and the CRI,CSR indices of alkali-rich coke indicated that the coke strength is reduced,CRI is increased,and CSR is decreased.The results obtained by a continuous thermogravimetric test showed that the K-rich coke has a fast reaction rate during the early stages of the solution-loss reaction,the Na-rich coke has a fast reaction rate during the later stages of the solution-loss reaction,and the CSR₂₅ of K-rich coke is higher than that of the original coke because the solution reaction is closer to the surface reaction.Na has a strong catalytic effect on the coke core,so the CSR₂₅ of the Na-rich coke is lower than that of the K-rich coke.The alkali-rich coke for the thermal properties test was tested at 1100 ? and at the variable temperature which was simulate blast furnace temperature regime in the mixed gas of N₂,CO,CO₂ atmosphere.Results showed that the degradation of alkali-rich coke tends to the shrinkage pattern,K-Na-rich coke is degraded most.The CSR₂₅ of alkali-rich coke tested at variable temperature is higher than that of alkali-rich coke tested at 1100 ?.The analysis of coke pore structure with different alkali rich schemes and different reaction conditions indicated that K-Na-rich coke tested at variable temperature showed most severe degredation at coke surface.so the variable temperature and the alkali metal are the important factors to promote coke surface reaction.Figure 18;Table 19;Reference 72...