2002 Volume 42 Issue 7 Pages 785-793
The minerals containing fluorine in hot metal pretreatment, BOF and secondary refining slags are identified by using X-ray diffraction method and electron microprobe analysis. From the area fractions of these minerals on a polished cross-section estimated by using an image processor, it was found that a main mineral in hot metal pretreatment and BOF slags is 2CaO · SiO2 containing fluorine and that in secondary refining slag is 11CaO · 7Al2 O3 · CaF2 or 12CaO · 7Al2 O3 containing fluorine. The CaF2 phase is observed in hot metal pretreatment and BOF slags with the fluorine content above 2.3 mass%. The dissolution behavior of synthetic F-containing minerals such as CaF2, Ca5 F(PO4)3, 3CaO · 2SiO2 · CaF2, 11CaO · 7Al2 O3 · CaF2 and 2CaO· SiO2-1 (or 2) mass%CaF2 solid solution, has been investigated in shaking test and the solubilities ofthese minerals are studied as a function of pH value of aqueous solution.