Silica Sand

Silica Sand (SiO2) chemically stands for Silicon Dioxide. It may be produced from crushing sandstone or can directly be obtained from unconsolidated sands viz. natural occurring locations like river beds and beaches. The pure silica fuses at a temperature point of nearly 1,760 oC (3,200 oF), though the most commonly used silica sand may have a considerably lower melting point because of the impurities present in it. When taken from natural sources, it can exist in unstructured crystalline forms which can further be processed to make it more suitable for several applications. The unprocessed sand might have limited uses but it suitability for varied uses is enhanced by washing and sizing.

The grains of silica sand have different shapes and sizes. They can be available in several shapes viz. rounded, angular and sub-angular, and the sizes can be fine to coarse. The overall grain sizes and shapes of the silica sand affect the quality of finishes. A fine grain size can give finer finish but it offers poorer flow characteristics, whereas a coarse grain size gives rougher finish on the surface allowing the metal to penetrate well into the mould but it can have lower binder properties. As a result a combination of the both can be used respectively at the face and at the back of the mould to get a combination of both finish and binding capacities.