Closed pore moulded refractory prod mfr - by mixing spherical particles of lower melting refractory with clay

摘要

Moulded refractory insulating prods. with a generally closed pore structure are made by mixing powdered refractory material(s) with a less refractory spherical material, moulding, drying and firing, using spheroids =1 mm dia. making up 25-50 wt. % of the mixt., and a mixt. of approx. equal amts of two clays of respective alumina contents 28-32 and 40-42% Al2O3, opt. together with chamotte which may comprise up to 25% of the total mixt. Prod. is used esp. for refractory insulating bricks for backing up furnace linings, and has improved refractoriness and mechanical properties.