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.

A ceramic article and method of manufacturing. The ceramic article comprises a porous ceramic material having a microstructure comprising an interconnected network of porous spheroidal ceramic beads. The microstructure has a total open porosity defined as the sum of an open intrabead porosity of the beads and an interbead porosity defined by interstices between the beads in the interconnected network. The microstructure has a bimodal pore size distribution having an intrabead peak corresponding to the open intrabead porosity and an interbead peak corresponding to the interbead porosity. An intrabead median pore size of the intrabead porosity is less than an interbead median pore size of the interbead porosity.

A ceramic article and method of manufacturing. The ceramic article comprises a porous ceramic material having a microstructure comprising an interconnected network of porous spheroidal ceramic beads. The microstructure has a total open porosity defined as the sum of an open intrabead porosity of the beads and an interbead porosity defined by interstices between the beads in the interconnected network. The microstructure has a bimodal pore size distribution having an intrabead peak corresponding to the open intrabead porosity and an interbead peak corresponding to the interbead porosity. An intrabead median pore size of the intrabead porosity is less than an interbead median pore size of the interbead porosity.

Provided is a member for optical glass manufacturing apparatus. The member is used for optical glass manufacturing apparatus and exposed to a gas containing a halogen element in a high temperature environment of 1100° C. or higher. The member includes dense ceramics containing silicon nitride as a main component, and a porosity of a surface layer of the member is smaller than a porosity of the inside of the member.

Provided is a member for optical glass manufacturing apparatus. The member is used for optical glass manufacturing apparatus and exposed to a gas containing a halogen element in a high temperature environment of 1100° C. or higher. The member includes dense ceramics containing silicon nitride as a main component, and a porosity of a surface layer of the member is smaller than a porosity of the inside of the member.

A particulate filter and method of manufacture. The particulate filter comprises a ceramic honeycomb body comprising a plurality of intersecting walls that define a plurality of channels extending longitudinally though the ceramic honeycomb body. The intersecting walls comprise a porous ceramic material having a microstructure that comprises an interconnected network of porous spheroidal ceramic beads. The microstructure has a total porosity defined as the sum of an open intrabead porosity of the beads and an interbead porosity defined by interstices between the beads in the interconnected network. The microstructure has a bimodal pore size distribution in which an intrabead median pore size of the intrabead porosity is from 1.5 μm to 4 μm and an interbead median pore size of the interbead porosity is from 6 μm to 20 μm.

A particulate filter and method of manufacture. The particulate filter comprises a ceramic honeycomb body comprising a plurality of intersecting walls that define a plurality of channels extending longitudinally though the ceramic honeycomb body. The intersecting walls comprise a porous ceramic material having a microstructure that comprises an interconnected network of porous spheroidal ceramic beads. The microstructure has a total porosity defined as the sum of an open intrabead porosity of the beads and an interbead porosity defined by interstices between the beads in the interconnected network. The microstructure has a bimodal pore size distribution in which an intrabead median pore size of the intrabead porosity is from 1.5 μm to 4 μm and an interbead median pore size of the interbead porosity is from 6 μm to 20 μm.

A porous refractory cast material contains a closed refractory aggregate fraction having a minimum particle size and a maximum particle size; the ratio of maximum particle size to minimum particle size is 10:1 or less. This closed refractory aggregate fraction comprises all of the porous refractory cast material having a particle diameter greater than 0.1 mm. The porous refractory cast material also contains a binder phase containing refractory selected from calcium aluminate cement, alumina phosphate, hydratable alumina, colloidal silica and combinations thereof. Also disclosed is a metallurgical vessel with an interior lining incorporating the porous refractory cast material.

Object

To provide a liquid contact member having high hydrophilicity and exhibiting high dirt removal efficiency by cleaning.

Solution

A liquid contact member includes a ceramic including a plurality of crystal grains and a grain boundary phase, and the concentration of silicon on a liquid contact surface of the ceramic is higher than that of silicon on a virtual internal surface parallel to the liquid contact surface.