6. The highest reactivity obtained was for Taftan, which has the minimum LOI and highest soluble calcium content and was shown to be an important factor in the original mineral according to Xu and Van Deventer (2000) (Tables 1, 2, and 4). The overall molar ratio of soluble SiO2 Al2O3 is equal to 4.65 and, asdiscoveredbyRahieretal.(1996)andHosetal.(2002),isin the range where it is highly unlikely that all of the silica and alumina actually take part in the synthesis reaction.