PURPOSE: To provide the method for economically postprocecssing residues produced by the distillation of chlorosilane and discharging only a fine amount of solid together with a gas stream exiting from a hydrolysis reactor.

CONSTITUTION: In the case of executing hydrolysis continuously, hydrolysis is stated at a temperature of ≤160°C and finished at a temperature of ≥170°C and when hydrolysis is performed on a batch basis, the dry residues are introduced into the hydrolysis reactor whose entrance temperature is at least 5°C lower than drying temperature and steam is supplied when heating up to the hydrolysis temperature.