Melting Characteristics of Coal Slags

摘要

During the viscosity measurements of the coal slag samples obtained from the Canadian Combustion Research Laboratory (CCRL), it was observed that at high temperature and near the softening poing of the slag, the slag volume tended to expand. This expansion creates a problem in the viscosity measurements due to overflow and loss of material. The cause of the expansion of the slags at high temperature was examined using a Leitz heating microscope. The results showed that the as-recieved slag samples contained minor amounts of unoxidized carbon. Near the softening point, the residual carbon is oxidized carbon. Near the softening point, the residual carbon is oxidized and, as a result, both CO and CO sub 2 are released causing the melt to expand. In order to suppress this expansion, the slag samples were calcined at 800 exp 0 C in air. During the calcining the carbon residue was fully oxidized and hence no expansion of slag should occur during viscosity mearurements. 2 references, 1 figure, 2 tables. (ERA citation 10:017893)