| 摘要 |
<p>Process for mfg. a porous body based on plaster, with high mechanical strength, by foaming or expanding a plaster-water mixt. contg. an alkali H2O2, and a decompsn. catalyst. The novelty is that the mixt. includes a cpd. with an acid reaction but insufficient active hydrogen atoms for complete neutralisation of the alkali. The cpd. is pref. a water-soluble monohydrogen- or dihydrogen-phosphate or a metal of groups (I), (II), (III) of the periodic system, esp. KH2PO4 or K2HPO4; alternatively, a hydrogensulphate may be used. The final pH of the mixt. is pref. 10-13 and the alkali is pref. at least one cpd. being added to neutralize 2-60% of the alkali and bring the pH to 12-12.5. Light expanded blocks, bricks or panels for constructional use, esp. as fire-proof materials and/or for thermal- or sound- insulation. Precise control of the expansion and setting due to precise control of the ph. A compression strength of 3-50 kg. p/cm2 can be obtd. at densities of 200-800 kg/m3 with uniform distribution of porosity, the pores being 0.1-4 mm. pref. 0.2-2 mm dia.</p> |
