Modification of Method for Rapid Determination of Modulus of Water Glass

Modifications of the conventional method for the determination of modulus of water glass were described in this paper. The main points are as follows: ① A supersaturated solution of sodium fluoride was used to ensure its complete reaction with SiO2;② Definite amount of sample was taken to avoid error arisen from variations of sample mass;③ A blank test was taken through the whole process of determination to compensate the alkalinity of sodium fluoride;and ④ End-point of titration was recognized by checking with precise pH-paper or determined by pH-meter. More rapid and precise determinations were achieved by these modifications.