A method for the manufacture of a high alumina hydraulic binder comprising hydrating a source of aluminium ions with a source of calcium ions in the presence of water to form mineral hydrates and subsequently heating said mineral hydrates to form said high alumina hydraulic binder.

The invention relates to a method of producing a binder comprising the steps of preparing (20) a residual material comprising amorphous alumina-rich and/or aluminium hydroxide-rich constituents, heating (30) the residual material to produce a fired material, the heating (30) of the residual material being at a temperature of >800° C.

The invention relates to a method of producing a binder comprising the steps of preparing (20) a residual material comprising amorphous alumina-rich and/or aluminium hydroxide-rich constituents, heating (30) the residual material to produce a fired material, the heating (30) of the residual material being at a temperature of >800° C.

The invention relates to the use of a hydraulic binder containing calcium aluminate, obtainable by a method in which a) prepared amorphous residual material rich in aluminium oxide and/or aluminium hydroxide is heated after the addition of a b) calcium ion-containing binder component and c) water, for the production of a constructing material.

The invention relates to the use of a hydraulic binder containing calcium aluminate, obtainable by a method in which a) prepared amorphous residual material rich in aluminium oxide and/or aluminium hydroxide is heated after the addition of a b) calcium ion-containing binder component and c) water, for the production of a constructing material.

A method for processing water treatment residuals, or other amorphous aluminium oxide or aluminium hydroxide rich waste residuals, for use in the manufacture of hydraulic binders, comprising heating the residuals to remove water and oxidise organic material contained therein, comprising controlling the temperature of the residuals during heating such that they are heated to a temperature no higher than 800° C., more preferably no higher than 650° C., to ensure that aluminium compounds in the WTR, in particular aluminium oxide and aluminium hydroxide, remain in an amorphous state. The method may comprise controlling the temperature of the water treatment residuals such that they are heated to a temperature between 350° C. and 650° C., more preferably between 400° C. and 500° C.

A method for processing water treatment residuals, or other amorphous aluminium oxide or aluminium hydroxide rich waste residuals, for use in the manufacture of hydraulic binders, comprising heating the residuals to remove water and oxidise organic material contained therein, comprising controlling the temperature of the residuals during heating such that they are heated to a temperature no higher than 800° C., more preferably no higher than 650° C., to ensure that aluminium compounds in the WTR, in particular aluminium oxide and aluminium hydroxide, remain in an amorphous state. The method may comprise controlling the temperature of the water treatment residuals such that they are heated to a temperature between 350° C. and 650° C., more preferably between 400° C. and 500° C.

Disclosed are a multifunctional gypsum-based mortar and a method of making the same, where the gypsum-based mortar includes 30-40 parts by weight of a gypsum; 30-40 parts by weight of a diatomite; 0.5-3.0 parts by weight of nano TiO.sub.2; and 30-40 parts by weight of a fine aggregate. The gypsum-based mortar provided herein can not only has good adsorption to the formaldehyde based on the hydration structure of gypsum-based cementing material and the diatomite structure, but also decompose the formaldehyde adsorbed by the porous structure, ensuring long-term and effective adsorption to formaldehyde.

Disclosed is a composite gypsum board comprising a board core comprising set gypsum sandwiched between face and back cover sheets. The composite gypsum board also comprises an intermediate sheet between the board core and the face cover sheet, with a thin, dense gypsum layer disposed between the intermediate sheet and the face cover sheet. Optionally, a second dense gypsum layer can be disposed between a first major side of the board core and the back cover sheet. Also disclosed is a method of preparing a composite gypsum board in which an intermediate sheet is applied over a dense gypsum layer disposed on a face cover sheet. A back cover sheet is applied to the other major side of the board core, with a second dense gypsum layer optionally disposed therebetween.

Disclosed is a composite gypsum board comprising a board core comprising set gypsum sandwiched between face and back cover sheets. The composite gypsum board also comprises an intermediate sheet between the board core and the face cover sheet, with a thin, dense gypsum layer disposed between the intermediate sheet and the face cover sheet. Optionally, a second dense gypsum layer can be disposed between a first major side of the board core and the back cover sheet. Also disclosed is a method of preparing a composite gypsum board in which an intermediate sheet is applied over a dense gypsum layer disposed on a face cover sheet. A back cover sheet is applied to the other major side of the board core, with a second dense gypsum layer optionally disposed therebetween.