Refractory material produced from red mud

A process for producing a refractory material which is resistant to corrosion by alkaline materials and fluorides at high temperature, which process comprises:

• calcining red mud containing Bayer sodalite at a temperature in the range of about 900.degree. to 1400.degree. C. for a time sufficient to remove combined water and to produce nepheline from said Bayer sodalite in said red mud;
• grinding the product following calcination to the -4 Tyler mesh range;
• mixing the ground product with a binder selected from the group consisting of silica-containing particulate materials, alumina-containing materials and mixtures thereof, in an amount sufficient to bind the ground product upon firing, and sufficient water to produce a formable mixture;
• forming the mixture into a shaped product;
• and
• firing the shaped product at a temperature in the range of about 900.degree. to 1400.degree. C. to produce a refractory material;
• and
• wherein said binder is a silica-containing material or precursor thereof and said mixture prior to firing has a value of R in the range of 0.05<R<1, wherein ##EQU2## and wherein:
• Na.sub.2 O=the molar fraction of Na.sub.2 O in the product originating from the decomposition of soluble salts in the red mud during calcination and from the binder and from any additives added to said ground product;
• SiO.sub.2 =the molar fraction of SiO.sub.2 in the product originating from the binder;
• S=the ratio of specific surface area (SSA) of the calcined red mud particles to the maximum SSA value which is obtained from -65 Tyler mesh material.

A refractory material which is resistant to corrosion by alkaline materials and fluorides at high temperature, prepared by

• calcining red mud containing Bayer sodalite at a temperature in the range of about 900.degree. to 1400.degree. C. for a time sufficient to remove combined water and to produce nepheline from said Bayer sodalite in said red mud;
• grinding the product following calcination to the -4 Tyler mesh range;
• mixing the ground product with a binder selected from the group consisting of silica-containing particulate materials, alumina-containing particulate materials and mixtures thereof, in an amount sufficient to bind the ground product upon firing, and sufficient water to produce a formable mixture, wherein the amount of ground product and binder is such that the ratio of red mud to other ingredients is sufficient to provide a fired refractory material product which comprises at least 90% by weight of red mud, and wherein the alumina content of the ground product and binder is increased by addition so that it amounts to at least 10% more than that which becomes combined in nepheline formed in the refractory material when the alumina content of the ground product and binder is less than said 10%:
• forming the mixture into a shaped product;
• and
• firing the shaped product at a temperature in the range of about 900.degree. to 1400.degree. C. to produce said refractory material.

A refractory material of low porosity which is resistant to corrosion by alkaline materials at high temperature, prepared by

• calcining red mud containing Bayer sodalite at a temperature in the range of about 900.degree. to 1400.degree. C. for a time sufficient to remove combined water and to produce nepheline from said Bayer sodalite in said red mud;
• grinding the product following calcination to the -4 Tyler mesh range;
• mixing the ground product with a binder selected from the group consisting of silica-containing particulate materials, alumina-containing materials and mixtures thereof, in an amount sufficient to bind the ground product upon firing, and sufficient water to product a formable mixture;
• forming the mixture into a shaped product;
• firing the shaped product at a temperature in the range of about 900.degree. to 1400.degree. C. to produce a refractory material;
• and
• exposing the fired shaped product to a sodium compound at a temperature of about 850.degree. C. or higher;
• wherein said binder is a silica-containing material or precursor thereof and said mixture prior to firing has a value of R in the range of 0.05<R<1, wherein ##EQU3## and wherein:
• Na.sub.2 O=the molar fraction of Na.sub.2 O in the product originating from the decomposition of soluble salts in the red mud during calcination and from the binder and from any additives added to said ground product;
• SiO.sub.2 =the molar fraction of SiO.sub.2 in the product originating from the binder;
• S=the ratio of specific surface area (SSA) of the calcined red mud particles to the maximum SSA value which is obtained from -65 Tyler mesh material.