Toshihiko Sakai

Thermodynamics of sulfur in BaO-CaO-CO2 system

The sulfide and carbonate capacity were measured for the CaO-BaO-CO2 system in the temperature range from 1000 °C to 1350 °C by equilibrating a BaO-based mixture, silver, and a CO-CO2-Ar gas mixture. The BaO-CO2 mixture melted completely in the temperature range from 480 °C to 700 °C in an Ar-CO2 atmosphere, while the CaO-BaO-CO2 mixture was solid at experimental temperature under the conditions used. TheCs2− concept was extended for solid-state mixture, and the sulfide capacity was measured as a function of composition. The maximum value of this system, logCs2− = −0.3 at 1200 °C, was the highest of all of the fluxes reported to date. Experimental results for mol pct BaCO3 againstPCO2 at 1200 °C indicated that the dissolution of carbon dioxide loweredCs2− markedly when the ratio (BaO + BaCO3 + BaS)/ BaCO3 exceeded unity. TheCs2− of this system increased with increasing temperature from 1050 °C to 1200 °C, and a value of above zero was predicted at hot metal pretreatment temperature, which is roughly 1300 °C. A linear relation between logCs2− and logCCO32− with a unit slope was observed.