Diatomites of Karelia for glass production

Two samples of lacustrine diatomites of Karelia, differing in rock-forming species of diatoms, shape, size and degree of preservation of valves, were investigated. It was found that the size of the valves significantly affects the granulometric composition and physicochemical properties of diatomites. In the initial samples of diatomites, the content of SiO ₂ is 70%, and after heat treatment and leaching increases to 91%, the iron content sharply decreases to 0.075%. After removal of impurities, lacustrine diatomites are of interest for the production of sheet glass, crystal, glazes and enamels, silicic acid glasses, and ceramic products. Tab. 2, ill. 3, bibliography: 4 titles.