Research On Effect Of Cooling Process On Crystallization Of Minerals In Molten Slags

The phase composition of the slag is very important for the operation of gasifiers. In this investigation, the focus of the research was to study the effect of cooling process on the generation of crystals in coal slags with the Shenfu coal slag after gasification. The main contents and conclusions were summarized as follows:1) The phase compositions of the Shenfu coal slags in different temperatures were calculated by the computer software FactSage, and it was found that the phase composition of the slags were complicated, differed with the temperature.2) In the experimental research about cooling process of the molten slag, the effect of cooling rate, residence temperature and residence time were systematically studied. The results showed that slow cooling process benefited the generation of crystals, while slower cooling rate and longer residence time at lower temperature were beneficial to the crystallization of minerals within a certain range. The crystals on the surface of the slag performed similar rectangular shape, elemental composition and content, and they were detected to be Gehlenite. By comparing the results it was found that there were some differences between the results of the thermodynamic equilibrium calculation and that of the experiments, for the crystallization of the minerals during the cooling process of the molten slag was not only controlled by thermodynamic equilibrium, but also affected by the rules of crystallization dynamics. Cooling process closely correlated with the crystallization of minerals in molten slags.