A process for preparing powdered dispersants comprising at least 90% by weight of at least one copolymer CP of the polycarboxylate ether type. The powdered dispersants can be easily dispersed in water. The invention also relates to the use of such powdered dispersants in mineral binder compositions, in particular dry mortars, concrete or gypsum formulations.

The present invention relates to polycondensates containing at least a structural unit, which is an aromatic moiety bearing a polyether side chain, at least a structural unit, which is an aromatic moiety bearing at least one phosphoric acid monoester group, at least a structural unit, which is an aromatic moiety, bearing at least one hydroxy group and at least a methylene unit (—CH.sub.2—), which is attached to two aromatic structural units. The invention also concerns a process for the production of the polycondensates, their use for the dispersion of inorganic binders, for increasing the strength development of concrete and for improving the slump-retention of concrete. The invention relates also to building material mixtures comprising the polycondensates and inorganic binders.

A gypsum fiber board produced in a Siempelkamp dry-process, comprising 75 wt % to 90 wt % (relative to the total dry mix) of calcium sulfate hemi-hydrate and 10 wt % to 25 wt % (relative to the total dry mix) paper fibers, wherein the calcium sulfate hemi-hydrate is a mixture of α-calcium sulfate hemi-hydrate and β-calcium sulfate hemi-hydrate, wherein the content of α-calcium sulfate hemi-hydrate in the mixture is at least 5 wt % (relative to the total calcium sulfate hemi-hydrate) is disclosed. Also disclosed is a method for producing a gypsum fiber board of a thickness of 23 mm in a Siempelkamp dry-process.

A gypsum fiber board produced in a Siempelkamp dry-process, comprising 75 wt % to 90 wt % (relative to the total dry mix) of calcium sulfate hemi-hydrate and 10 wt % to 25 wt % (relative to the total dry mix) paper fibers, wherein the calcium sulfate hemi-hydrate is a mixture of α-calcium sulfate hemi-hydrate and β-calcium sulfate hemi-hydrate, wherein the content of α-calcium sulfate hemi-hydrate in the mixture is at least 5 wt % (relative to the total calcium sulfate hemi-hydrate) is disclosed. Also disclosed is a method for producing a gypsum fiber board of a thickness of 23 mm in a Siempelkamp dry-process.

A building material comprising an inorganic binder a reactive silicon source a reactive calcium source.

A building material comprising an inorganic binder a reactive silicon source a reactive calcium source.

The present invention relates to a method for producing a gypsum-containing foamed prefabricated building material and to a gypsum-containing foamed prefabricated building material.

A composition for forming moulded mantels, columns and other decorative enhancement to fireplace openings is formed of a mixture of alpha hemihydrate gypsum plaster, cement, filler and milled fiber. By using this composition with water and acrylic binder a mixture is formed which sets and gains strength quickly and is an ideal material for manufacturing architectural and decorative structures. Advantageously, a casted piece can be removed from a mould within two to three hours after casting. The finished product has a desired finish that is similar to a casted gypsum cement, referred to sometimes as a honed finish which can withstand high heat, discoloration and cracking while maintaining suitable strength when exposed to typical temperatures of a fireplace surround in indoor applications.

A composition for forming moulded mantels, columns and other decorative enhancement to fireplace openings is formed of a mixture of alpha hemihydrate gypsum plaster, cement, filler and milled fiber. By using this composition with water and acrylic binder a mixture is formed which sets and gains strength quickly and is an ideal material for manufacturing architectural and decorative structures. Advantageously, a casted piece can be removed from a mould within two to three hours after casting. The finished product has a desired finish that is similar to a casted gypsum cement, referred to sometimes as a honed finish which can withstand high heat, discoloration and cracking while maintaining suitable strength when exposed to typical temperatures of a fireplace surround in indoor applications.

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.