TECHNOLOGY FOCUS - BIOLOGY - Preferred Components: The siliceous plant matter is derived from members of Equisetum. The biological agent comprises a culture of anaerobic thermophilic bacteria, co-mixture of enzymes and yeast or enzymes effective to break down cellulose into constituent sugars.    TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Process: The pretreatment process of siliceous plant material comprises chopping, crushing, shredding, pureeing, grinding, water soaking with or without surfactants, heat treatment in the presence or absence of chemicals below, at or above atmospheric pressure, microwave exposure, ultrasound and/or treatment with biological agent such as mold and fungi. The separation process of useful organic chemical reaction product comprises distillation below, at or above atmospheric pressure and/or removal by continuous flow of inert gas over reaction solution. The separation process of silica-containing co-product comprises precipitation, filtration, centrifugation, flocculation and/or belt-pressing. The refining process of silica-containing co-product involves rinsing the silica-containing co-product with water, acid or solvent, heating the silica-containing co-product under an inert atmosphere containing anhydrous hydrochloric acid at 400-1600 degrees C for converting any residual organic materials to elemental carbon and removing any unwanted inorganic elements, to obtain high purity silica mixed with elemental carbon. Then, the carbon-containing silicate is treated with aqueous oxidants including hydrogen peroxide and ozone and heating at oxidizing atmosphere to remove organics at 300-1600 degrees C, to produce a high purity silica. The refining process of silica-containing co-product comprises dissolving silica in silica-containing co-product in strong base leaving carbon component of silica-containing siliceous product undissolved, filtering supernatant liquid, precipitating silica from supernatant liquid by adding acid, isolating silica, heating the silica product under an inert atmosphere containing anhydrous hydrochloric acid at 400-1600 degrees C, treating the silica with aqueous oxidants including hydrogen peroxide and ozone, and heating silica in presence of oxidizing atmosphere to remove organics at 300-1600 degrees C, to produce high purity silica. The high purity silica is blended with carbon source, converting the carbon source to elemental carbon at a precise ratio by heating the silica under a controlled atmosphere, then processing the carbon-containing silica, to obtain industrially useful silicon-containing products. Preferred Composition: The industrially useful silicon-containing products include elemental silicon, silicon tetrachloride and silicon carbide. The feedstock has exposed cellulose and hemicellulose. Preferred Apparatus: The reactor is a chemicobiological reactor containing biological agent.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The industrially useful silicon-containing products include elemental silicon, silicon tetrachloride and silicon carbide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The feedstock has exposed cellulose and hemicellulose.