FIELD: chemical industry. SUBSTANCE: described are purified polyalkylsiloxane mixture and method of preparing said mixture which has boiling temperature of less than 250 C under atmospheric conditions and comprises polyalkylsiloxane and admixtures with boiling temperature of higher than 250 C. Total concentration of which admixtures being less than 14 ppm. Also described is method of preparing melted quartz glass by conversion of purified mixture of polyalkylsiloxanes. EFFECT: simplified technology of purifying polyakylsiloxane mixture and technology of preparing melted quartz glass. 22 cl, 8 dwg, 3 ex
