| 摘要 |
Refractory prods. are made by mixing a granular refractory component with a binder comprising an aq. emulsion of a hard bitumen, and drying the mixt. to a moisture content of less than 0.3wt.% before further processing. Pref. the temp. of the mixt. during drying is lower than the ring and ball softening point of the binder. Pref. after the drying the mixt. contains 4-12%, esp. 5wt.% binder and 0-7%, esp. 2wt.% graphite. The granular refractory starting material is e.g. silica, chamotte, sillimanite, andalusite, mullite, bauxite, corundum, magnesite, magnesite-chromium oxide, silicon carbide, carbon or graphite. The prods. are made at moderate temps., which avoids the harmful evolution of vapours caused by using pitch tar binders, and give materials which can be formed under heat and pressure into refractory prods. for lining metallurgical furnaces, steel casting equipment, etc. The prods. have good mechanical properties and good high temp. |
