Lightweight, water resistant mouldings withstanding high temp. - made from vermiculite, mono:aluminium phosphate soln. and hydrogen peroxide

摘要

Mouldings of a density 400 g/l, high compression strength, and high dimensional stability, are made from non-expanded vermiculite or expandable three-layer minerals, mixed with an H2O2 soln. contg. over 5 wt. % H2O2, and mono-aluminium phosphate soln. or H3PO4 dissolving some Al out of the minerals. The mixt. is allowed to pre-expand for 1/2 hr. at room temp. or 5 mins. at =50 degrees c, then cast in moulds, followed by heating to 80-300 degrees C for complete expansion and hardening. The vermiculite or expandable minerals pref. have a size below 2 mm, and/or expandability below 18 times. Used e.g. for moulding used at is approx. 900 degrees C, where stable properties are obtd.