| 摘要 |
<p>A process for the production of shaped articles from silicate material by extrusion and/or pelleting and subsequent annealing is described. In this process, pulverulent layered silicic acids of the general formula H2SiyO2y+1, in which y is a number from 1.7 to 24, or salts thereof, in which all or some of the H is replaced by at least one cation from the group comprising Li+, Na+, K+, NH4+, Ca2+, Cu2+, Co2+, Ni2+ and Mg2+, are mixed with water or an organic solvent, the mixture is extruded and/or pelleted to give roll-shaped or tube-shaped pieces and these are then dried and annealed under conditions such that the starting material is chiefly converted into cristobalite and/or tridymite. The same material can also be pressed in a molding tool under pressure. Under these conditions, shaped articles which predominantly consist of cristobalite or tridymite and have a Shore hardness of at least 70 can be obtained.</p> |
