chemical products for commercial and scientific purposes, siliceous powder and granulate, especially for use as a filler, additive, as an auxiliary flow agent, as a pigment, as a basic material for the manufacture of quartz glass products, and as a carrier and packing material in catalysis; pressed products of quartz glass powder or quartz glass granulate, especially for use as a basic material for the manufacture of quartz glass products and as a carrier and packing material in catalysis; qu...