Study on fluoride evaporation from casting powders

摘要: Casting powders are commonly used in continuous casting of steels. The chemical composition these is based on various oxides, carbonaceous materials and fluoride compounds. purpose fluorite (CaF2) addition to control viscosity, fluidity temperature cuspidine crystallization during casting. Unfortunately, compounds lost the vapour phase operations, due high pressure In view environmental problems associated with evaporation from powders, a kinetic study was carried out. Three commercial different contents (between 2.6 10.6 mass%) were selected this study. Powders characterization includes melting behaviour determined by hot stage microscopy, physical properties such as viscosity estimated Fact Sage 7.1 surface tension calculated base contact angle measurements. tendency samples microscopy observations quenched 1300 °C. emission thermal analysis (DTA–TG) tests. phases present system predicted through thermodynamic simulation. gaseous species were: NaF, KF, (NaF)2, NaAlF4, KAlF4 SiF4. It possible establish that gases emissions occur when liquid phases. type gas while percentage depends both liquids.