| It is the exploration direction of fluorine-free mold flux to search for substitutes for cuspidine at home and abroad in recent years.There were few studies to use borax instead of fluorite.Therefore,the performance of fluorine-free mold flux was measured,the effects of basicity and borax on the properties of mold flux were studied,the relationship between borax and phase structure of slag film was explored,and the microstructure and crystallization behavior of fluorine-free mold flux were analyzed by molecular dynamics and thermodynamics simulation.Fluorine-free mold fluxes and slag film were prepared from mineral materials with different basicity and borax content.The performance and phase structure of slag film were studied.The results show that when the borax content is 10%,with the increase of alkalinity(1.1?1.5),the melting temperature and crystallization temperature increase,the viscosity and heat flux decrease,the content and particle size of calcium borosilicate and wollastonite increased,and the crystallization rate increased from 15% to 90%;When the basicity is 1.3,with the increase of borax content(4%?16%),the melting temperature and viscosity decrease,the crystallization temperature and heat flux increase,the content and particle size of calcium borosilicate and wollastonite decreased,and the crystallization rate decreased from 95% to 5%.The melting and crystallization mechanism of boron containing fluorine-free mold flux was studied by using Scigress molecular dynamics and Factsage thermodynamics software.As the alkalinity and borax content increase,the complex Si-O tetrahedrons in the slag microstructure decrease,the degree of polymerization of the slag decreases,and the viscosity decreases.The precipitation temperature of calcium silicoborate in the slag film decreases with the increase of alkalinity,and its crystallizing amount also increases greatly;the effect of borax on calcium silicoborate is not insignificant.Figure 46;Table 27;Reference 71... |
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