Provided is fibrous cellulose used for producing a concrete-pump pressure-feeding primer containing calcium carbonate powder, which is excellent in a dispersion stability and a pressure-feeding property. The fibrous cellulose is used for producing the concrete-pump pressure-feeding primer through mixing with the calcium carbonate powder. The fibrous cellulose contains ultrafine fibrous modified cellulose which has an ionic group and has a fiber width of 1,000 nm or less.

Provided is fibrous cellulose used for producing a concrete-pump pressure-feeding primer containing calcium carbonate powder, which is excellent in a dispersion stability and a pressure-feeding property. The fibrous cellulose is used for producing the concrete-pump pressure-feeding primer through mixing with the calcium carbonate powder. The fibrous cellulose contains ultrafine fibrous modified cellulose which has an ionic group and has a fiber width of 1,000 nm or less.

The present application concerns a method for the production of a gypsum article, which includes introducing a measured quantity of carbon dioxide into the process water and mixing the stucco with the thus treated water. The CO.sub.2-enriched water has the advantage of providing compositions with sufficient processing properties at considerably lower water contents, thus allowing for significant energy savings. The invention also concerns slurries prepared according to this method as well as an apparatus which is adapted to implement this method.

The present application concerns a method for the production of a gypsum article, which includes introducing a measured quantity of carbon dioxide into the process water and mixing the stucco with the thus treated water. The CO.sub.2-enriched water has the advantage of providing compositions with sufficient processing properties at considerably lower water contents, thus allowing for significant energy savings. The invention also concerns slurries prepared according to this method as well as an apparatus which is adapted to implement this method.

Beads of materials such as activated alumina, zeolite and silica gel, are used as chloride salt absorbers. The beads are mixed with high-salt gypsum. After mixing for a short time, the mixtures are dried, and the beads and the powder are separated by using a sieve or other physical separation device resulting in a low-salt gypsum which can be used as a gypsum source to make gypsum wallboard.

Beads of materials such as activated alumina, zeolite and silica gel, are used as chloride salt absorbers. The beads are mixed with high-salt gypsum. After mixing for a short time, the mixtures are dried, and the beads and the powder are separated by using a sieve or other physical separation device resulting in a low-salt gypsum which can be used as a gypsum source to make gypsum wallboard.

A filler for production of cement-bound shaped bodies, comprising a material group mixture of comminuted and sorted waste materials, conditioned with chemical reagents/compounds in the presence of water, wherein the material group mixture is composed of comminuted and sorted waste materials, selected from the following material groups: PPK: paper, paperboard, cardboard plastics inert material textiles wood
which are mixed according with a mass-related material group vector and then comminuted.

The embodiments herein are directed to dry wall waste mixtures, formed under pressure into example embodiments referred to herein as dry wall waste blocks (DWBs) and/or gypsum wallboard waste blocks (GWWBs) and tile structures. DWBs/GWWBs mixtures in particular, often incorporate a higher percentage in the composite mixtures from about 60% up to 85% of dry wall waste than other mixtures and beneficially often incorporates substantially all of the wallboard facing paper as part of the composite mixture. That is, waste processing is simplified by comingling core and paper layers in the final product. DWBs/GWWBs mixtures utilize demolition and construction waste, replacing a high percentage of Portland cement with waste-derived binder.

The embodiments herein are directed to dry wall waste mixtures, formed under pressure into example embodiments referred to herein as dry wall waste blocks (DWBs) and/or gypsum wallboard waste blocks (GWWBs) and tile structures. DWBs/GWWBs mixtures in particular, often incorporate a higher percentage in the composite mixtures from about 60% up to 85% of dry wall waste than other mixtures and beneficially often incorporates substantially all of the wallboard facing paper as part of the composite mixture. That is, waste processing is simplified by comingling core and paper layers in the final product. DWBs/GWWBs mixtures utilize demolition and construction waste, replacing a high percentage of Portland cement with waste-derived binder.

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.