| 摘要 |
An inorganic, phosphate-containing foam is produced from Portland cement, polyphosphoric acid and a blowing agent active in an acidic medium. Fused alumina cement, oxides of calcium, zinc, aluminium and iron, hydroxides of aluminium and iron, fillers and reinforcing agents can also be added. By intensive prior mixing of the starting products, a mixture is prepared whose equivalent ratio (Al + Mg + Ca + Fe) : phosphate is greater than 1 : 1, but at most 3 : 1. The mixture foams up, is filled into a mould, if necessary heated to a temperature of 80 DEG C and, after the exothermic reaction has subsided, hardened under the action of heat. The hardening can also take place in the presence of superheated steam.
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