Determination of free lime in dicalcium silicate-alkaline earth metal systems

Abstract

The determination of residual free lime after the reaction of calcium oxide and silica containing alkaline earth metal dopants was examined. The method involves extraction with hot ethylene glycol. It was found that strontium and barium oxides present in silicate samples are extracted together with free lime. The extraction of both barium and strontium oxides is quantitative and these oxides are co-titrated with calcium oxide. However, magnesium oxide is not extracted and hence does not interfere. Hence the presence of barium and strontium oxides leads to a higher apparent value for free lime using a solvent extraction and titration procedure. A method is proposed for the determination of free lime in the presence of MgO, SrO and BaO and the accuracy is discussed.