1991 Volume 77 Issue 2 Pages 209-216
The solubility of carbon dioxide has been measured by the thermogravimetric technique for CaO-CaF2-SiO2 molten fluxes at temperatures from 1 200 to 1 500°C. The values of carbonate capacity (CC=wt%CO32-/PCO2) were calculated by the solubilities and the partial pressure of carbon dioxide.
Carbonate capacities were compared with the sulfide capacities appearing in the literature. A linear relationship was obtained for CS2- and CC as log CS2-=1.1 log CC -3.3 at 1 200 °C.
With increasing CaF2 from 29.0 to 88.2wt% at constant XCaO/XSiO2 of three at 1 400°C, CC increased from 0.53 to 0.89.
The influence of the replacement of CaO by CaF2 on CC at various SiO2 content has been investigated. With increasing CaF2, CC decreased for fluxes of XCaO/XSiO2 smaller than three, while it increased for fluxes with a ratio larger than three.
Carbonate capacities of slags of XCaO/XCaF2=1.56 decreased with increasing SiO2 content from 8.3 to 25wt%. In fluxes of which the ratio was 0.68, CC decreased with an increase of SiO2 more than 5wt%. There was a maximum of CC at 0.8wt%SiO2 for the fluxes of a ratio of 0.14.
