The present invention relates to a light-transmitting ceramic sintered body which contains air voids having pore diameters of 1 m or more but less than 5 m at a density within the range of from 10 voids/mm.sup.3 to 4,000 voids/mm.sup.3 (inclusive), while having a closed porosity of from 0.01% by volume to 1.05% by volume (inclusive). With respect to this light-transmitting ceramic sintered body, a test piece having a thickness of 1.90 mm has an average transmittance of 70% or more in the visible spectrum wavelength range of 500-900 nm, and the test piece having a thickness of 1.90 mm has a sharpness of 60% or more at a comb width of 0.5 mm.

The present invention relates to a light-transmitting ceramic sintered body which contains air voids having pore diameters of 1 m or more but less than 5 m at a density within the range of from 10 voids/mm.sup.3 to 4,000 voids/mm.sup.3 (inclusive), while having a closed porosity of from 0.01% by volume to 1.05% by volume (inclusive). With respect to this light-transmitting ceramic sintered body, a test piece having a thickness of 1.90 mm has an average transmittance of 70% or more in the visible spectrum wavelength range of 500-900 nm, and the test piece having a thickness of 1.90 mm has a sharpness of 60% or more at a comb width of 0.5 mm.

A lightweight micro-closed-pore corundum composite refractory and a method preparing the same, wherein raw materials of the refractory comprise 95-99 parts by weight of -Al.sub.2O.sub.3 micro-powder and 1-5 parts by weight of dolomite clinker; and additives of the refractory comprise 2-15 parts by weight of nano alumina sol, 5-15 parts by weight of a carbohydrate polymer, and 30-50 parts by weight of an organic alcohol. and the lightweight micro-closed-pore corundum composite refractory is prepared by: mixing and wet grinding the raw materials and the additives to obtain a slurry; placing the slurry in a mold, keeping the mold at 15-25 C. for 6-12 hours and then keeping the mold at 60-90 C. for 6-12 hours, then demolding; drying a demolded green body at 110-200 C. for 24-36 hours, and keeping the green body at 1800-2000 C. for 2-5 hours. A method preparing a lightweight micro-closed-pore corundum composite refractory is also provided. The lightweight micro-closed-pore corundum composite refractory of the present invention has characteristics of low bulk density, small average pore size, high closed porosity, low thermal conductivity, strong thermal shock resistance, abrasion resistance and slag resistance.

A lightweight micro-closed-pore corundum composite refractory and a method preparing the same, wherein raw materials of the refractory comprise 95-99 parts by weight of -Al.sub.2O.sub.3 micro-powder and 1-5 parts by weight of dolomite clinker; and additives of the refractory comprise 2-15 parts by weight of nano alumina sol, 5-15 parts by weight of a carbohydrate polymer, and 30-50 parts by weight of an organic alcohol. and the lightweight micro-closed-pore corundum composite refractory is prepared by: mixing and wet grinding the raw materials and the additives to obtain a slurry; placing the slurry in a mold, keeping the mold at 15-25 C. for 6-12 hours and then keeping the mold at 60-90 C. for 6-12 hours, then demolding; drying a demolded green body at 110-200 C. for 24-36 hours, and keeping the green body at 1800-2000 C. for 2-5 hours. A method preparing a lightweight micro-closed-pore corundum composite refractory is also provided. The lightweight micro-closed-pore corundum composite refractory of the present invention has characteristics of low bulk density, small average pore size, high closed porosity, low thermal conductivity, strong thermal shock resistance, abrasion resistance and slag resistance.

This invention provides low dust low density gypsum wallboard products having high total core void volumes, corresponding to low densities in the range of about 10 to 30 pcf. The wallboards have a set gypsum core formed between two substantially parallel cover sheets, the set gypsum core preferably having a total void volume from about 80% to about 92%, and made from a slurry including stucco, pregelatinized starch, and a naphthalenesulfonate dispersant. The combination of the pregelatinized starch and the naphthalenesulfonate dispersant also provides a glue-like effect in binding the set gypsum crystals together. The wallboard formulation, along with small air bubble voids (and water voids) provides dust control during cutting, sawing, routing, snapping, nailing or screwing down, or drilling of the gypsum-containing products. This invention also provides a method of making the low dust low density gypsum products including the introduction of soap foam in an amount sufficient to form a total void volume, including air voids, preferably from about 80% to about 92% in the set gypsum core, corresponding to a set gypsum core density from about 10 pcf to about 30 pcf. The wallboards produced by the method generate significantly less dust during working.

This invention provides low dust low density gypsum wallboard products having high total core void volumes, corresponding to low densities in the range of about 10 to 30 pcf. The wallboards have a set gypsum core formed between two substantially parallel cover sheets, the set gypsum core preferably having a total void volume from about 80% to about 92%, and made from a slurry including stucco, pregelatinized starch, and a naphthalenesulfonate dispersant. The combination of the pregelatinized starch and the naphthalenesulfonate dispersant also provides a glue-like effect in binding the set gypsum crystals together. The wallboard formulation, along with small air bubble voids (and water voids) provides dust control during cutting, sawing, routing, snapping, nailing or screwing down, or drilling of the gypsum-containing products. This invention also provides a method of making the low dust low density gypsum products including the introduction of soap foam in an amount sufficient to form a total void volume, including air voids, preferably from about 80% to about 92% in the set gypsum core, corresponding to a set gypsum core density from about 10 pcf to about 30 pcf. The wallboards produced by the method generate significantly less dust during working.

An apparatus contains at least one pressure-rated apparatus shell and at least one modular framework system containing ceramic fiber composite materials and arranged within the apparatus shell. A modular lining apparatus includes the modular framework system and refractory bricks. The apparatus can be used for high-temperature reactors, especially electrically heated high-temperature reactors.

An apparatus contains at least one pressure-rated apparatus shell and at least one modular framework system containing ceramic fiber composite materials and arranged within the apparatus shell. A modular lining apparatus includes the modular framework system and refractory bricks. The apparatus can be used for high-temperature reactors, especially electrically heated high-temperature reactors.

Manufactures, methods and apparatus are provided through which in some implementations a structural cellular lightweight concrete comprises a concrete mixture that is no more than 65% by volume of the manufacture of structural cellular lightweight concrete, the concrete mixture including concrete conforming to the requirements of ASTM C33; foam that has a density of at least 5 lbs./ft.sup.3, having high stability characteristics, and having a closed cell bubble structure; mix water being potable and free of contamination or deleterious materials; and Portland cement conforming to ASTM C150, the Portland cement being Type I, Type III or White Portland cement, and at least 35% air by volume of the manufacture of structural cellular lightweight concrete.

Manufactures, methods and apparatus are provided through which in some implementations a structural cellular lightweight concrete comprises a concrete mixture that is no more than 65% by volume of the manufacture of structural cellular lightweight concrete, the concrete mixture including concrete conforming to the requirements of ASTM C33; foam that has a density of at least 5 lbs./ft.sup.3, having high stability characteristics, and having a closed cell bubble structure; mix water being potable and free of contamination or deleterious materials; and Portland cement conforming to ASTM C150, the Portland cement being Type I, Type III or White Portland cement, and at least 35% air by volume of the manufacture of structural cellular lightweight concrete.