Process for cleaning quartz sand

摘要

The cleaning (purification) of quartz sand from mineral contaminants, such as feldspar or granite, which are in the form of intergrowths with quartz particles, is carried out by heating quartz particles in a screen fraction having the narrowest possible particle spectrum to a temperature in the range from 1200 DEG C to 1400 DEG C to form melt agglomerates. The heating to the desired temperature is carried out for a period of from 10 to 120 minutes. After cooling, the melt agglomerates are separated from the quartz particles, for example by screening or air (pneumatic) classification. The heat treatment is carried out in a receptacle of which at least the surface in contact with the quartz particles during the heat treatment comprises SiO2.