Glass Industry Quartz Sand

Glass is essentially produced by melting quartz sand, soda ash and lime together at high temperature. Quartz sand is the component that builds the network structure of the glass; the other raw materials are added to lower the melting temperature and to make the glass chemically stable. The melting point of quartz at 1710 °C and its density of 2.65 g/cm³ are among the factors that determine the operating temperature and energy consumption of a glass furnace. The chemical purity and grain size distribution of the sand therefore affect the entire process, from batch preparation through to the drawing line.

Iron content is of critical importance in glass production. Iron oxide in the sand gives the glass melt a greenish-blue tint and reduces light transmission. For this reason low-iron quartz sand is required in flat glass, container glass and especially colorless glass production; other coloring impurities such as chromium and titanium are also monitored. In Seyman Maden's silica sand products the SiO₂ content is above 98% and the Fe₂O₃ content is below 0.1%; the exact purity and fraction range required by the application are defined together according to the type of production.

Grain size distribution determines how quickly and how homogeneously the batch melts in the furnace. Very fine grains lead to dusting, carry-over and agglomeration in the batch, while oversized grains remain unmelted and create stone and bubble defects in the glass. That is why narrowly graded, screened fractions are preferred in the glass industry rather than widely graded sand. Controlled moisture content is also important for accurate batch weighing and smooth material flow.