Pool officer, Centre for Rural Development and Appropriate Technology, Indian Institute of Technology, New Delhi,
Executive consultant, Feeders India Consultants, New Delhi,
Alkali contents of portland cement/clinker significantly affect the hydration reaction rate and the development of mechanical strength of cements. An accurate, rapid method has been developed for the quantitative determination of alkalies sodium oxide and potassium oxide by use of the flame photometric emission spectroscopic technique. The procedure is free from errors caused by the presence of calcium atoms and the mutual disturbance caused by the different ionization behavior of sodium and potassium salts in the flame. The determinations have been performed in a nitric acid medium with use of optimum amounts of aluminum sulfate and cesium sulfate as the controlling electrolytes. A combination of 2000 ppm of alumina +30 ppm of cesium is optimum for the analysis of ordinary portland cements and clinkers. In the procedure a wide range of alkali concentration is covered by the analysis of solutions for 1 to 10 ppm of sodium oxide and potassium oxide with the best reproducibility in the range of 4 to 8 ppm. The accuracy of the determinations is better than 0.01 ppm. The method is suitable for laboratory analysis as well as for on-line quality control determinations of alkali content.
Paper ID: CCA10237J