The present invention relates to a refractory composition characterized by containing as a carbonaceous binder for refractories a modified phenolic resin obtained by condensing phenol with lignin and/or molasses and/or an aldehyde in the presence of an acid catalyst or a basic catalyst. Tars and/or pitches have mainly been used as carbonaceous binders for refractories. However, these binders have some demerits. For example, hardening of the binder is extremely slow and development of strength during the temperature elevation stage is poor. A strength as high as possible at high temperature is required of refractories, so refractory products having even a slightly higher quality than quality conventional ones are always being sought after demanded. Recently, since carbonaceous binders containing carcinogenic substances have posed a health problem, investigations of applying resins of high carbonization rate such as phenolic resins and furan resins have been made. However, they have not as yet been successful. In addition, the application of general phenolic resins, furan resins, lignins or molasses independently as binders have also been studied, but an additive giving a product with satisfactory refractory property has not been found.
USPTO Backgrounds
USPTO Backgrounds