Abstract:
A process for making non-porous, dense, silica particles having a diameter of about 3 to 1000 microns, a nitrogen B.E.T. surface area less than about 1 m2/g, a total impurity content of less than about 50 ppm and a metal impurity content of less than about 15 ppm from an aqueous dispersion of fumed silica. The particles are converted into porous particles and sintered in an atmosphere having a water partial pressure of from about 0.2 to about 0.8 atmosphere for temperatures below about 1200 °C.
Abstract:
A process for manufacturing glass from silicon dioxide by vacuum melting, which comprises mixing silicon dioxide powder containing a phase conversion promoter in an excess amount with a substantially promoter-free silicon dioxide powder or adding a silicon dioxide powder to a solution containing the phase conversion promoter, adjusting the pH of the solution by adding an acid or alkali component thereto, stirring the mixture, dehydrating and drying it to obtain a silicon dioxide powder uniformly containing the promoter, filling the powder in a vessel, then heating it to obtain a sintered molding of cristobalite crystal phase having self-supportaing properties, proper strength, and high porosity, and heating it in vacuo to obtain high-quality glass with good efficiency.
Abstract:
유리온실에서 살균기능이 있는 자외선이 투과할 수 없는 일반유리를 사용하여 태양광으로 유리온실의 내부를 살균할 수 없었다. 유리온실의 유리를 살균기능이 있는 자외선의 투과율이 높은 석영유리 등으로 일부 또는 전부를 대체하거나 시공하여 유리온실이 태양광에 의해 살균이 가능하다.
Abstract:
Process for preparing a silicon dioxide granule having a specific surface area of less than 1 m/g and a proportion of impurities of less than 50 ppm, in which a) a silicon dioxide powder with a tamped density of 15 to 190 g/l, b) is compacted to slugs which are subsequently crushed, the slug fragments having a tamped density of 210 to 800 g/l, and c) the slug fragments are treated with one or more reactive compounds at 400 to 1100 °C.