Inorganic, fibre-reinforced, heat-insulating refractory mouldings - for use on hot-tops of ingot moulds and other feeder heads

摘要

Refractory mouldings are prepd. by mixing together a granular or powdery refractory; inorganic fibres, chosen at least in part from refractory oxides, carbon fibre and metal fibre; a foaming agent; and a binder; followed by the moulding and the natural or artificial hardening and drying of the prod. Pref. conditions include the use of silicate fibre; a binder of alkali-silicate, natural rubber or resin, starch, a hardenable synthetic resin or its pre-stage used with an accelerator; the addn. of a small amt. of water to help foaming; the refractory is sand, quartz powder, olivine, chamotte, Al2O3 or refractory silicates; the fibres are SiO2, Al2O3, ZnO2, carbon or their mixt.; Fe2O3 may be added; the mixt. contains (all %) 0-20 inorganic fibres, 0.5-20 binder, 0.1-2 foaming agent, rest refractory; and the press. used in moulding is 0.035-0.7 kg/cm2. The mouldings are for use on hot-tops of ingot moulds and other feeder heads. As compared with prods. contg. organic fibres, this compsn. has higher hot-strength, less dust formation, clean stripping. Mouldings are cheaper to make because a wet process using an aq. suspension requiring much heat for evapn. of water is unnecessary.