[Nature and hygienic importance of industrial dust from the high-temperature processing of quartz]

The study aims at assessing, according to the physiochemical indices for silicosogenicity of the dusts, the risk of industrial aerosols of condensed SiO2, entailing the production of quartz glass in plant "Lenin" - Sliven and of ferrosilicon in plant "Kremikovci". The evaluation is done according to the present norms for quartz in this country (State Gazette No. 61/1977), accepted temporary on the basis of foreign experiment and as norms for condensed SiO2. The quantitative determination of free SiO2 in dusts is performed after infrared spectrophotometric method. In most of the studied processes on both working places pollution above the norm is registered with total and fine dust and condensed SiO2. In order to specify the silicogenicity of the respective dusts a study is to be carried out according to biological indices.