The invention concerns a method for producing pulverulent hardening accelerators by reactive spray drying, where an aqueous phase I comprising calcium ions, and an aqueous phase II comprising sulphate ions, the molar ratio of the calcium ions to the sulphate ions being from 1/5 to 5/1, are contacted at a spray nozzle, and the phases I and II contacted with one another at the spray nozzle are sprayed in a streaming environment of drying gas. Likewise concerned are the pulverulent hardening accelerators producible by the method of the invention, and their use for accelerating the hardening of bassanite and/or anhydrite with formation of gypsum.

The invention concerns a method for producing pulverulent hardening accelerators by reactive spray drying, where an aqueous phase I comprising calcium ions, and an aqueous phase II comprising sulphate ions, the molar ratio of the calcium ions to the sulphate ions being from 1/5 to 5/1, are contacted at a spray nozzle, and the phases I and II contacted with one another at the spray nozzle are sprayed in a streaming environment of drying gas. Likewise concerned are the pulverulent hardening accelerators producible by the method of the invention, and their use for accelerating the hardening of bassanite and/or anhydrite with formation of gypsum.

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 present invention relates to a self-levelling compound with high moisture resistance.

The invention relates to plasterboard comprising a plaster core arranged between two cover sheets; wherein said plaster core comprises a matrix of gypsum crystals and air pores; wherein at least 90%, preferably at least 94%, more preferably at least 98%, of the air pores are connected by a constriction; and wherein the average neighbor coordination of the connected air pores is between 2 and 6, preferably between 3 and 5.

A high solids, sprayable, fast drying, ready-mixed setting-type joint compound comprising a blend of a joint compound mixture comprising: joint compound mixture ingredients comprising: calcium sulfate hemihydrate (e.g. US Gypsum's HYDROCAL C-Base), a chelating agent, and water; and an activator mixture, wherein the activator mixture comprises: activator mixture ingredients comprising: inert filler, set accelerator, and water, wherein a weight ratio of joint compound mixture:activator mixture is 1:1 to 100:1, wherein the activator mixture viscosity is the same as the joint compound mixture viscosity plus or minus 50 percent, and wherein the joint compound has about 55 to about 80 wt. % solids and a viscosity of 2,500-28,000 cps.

An underlayment material composition is disclosed that includes a binder, a filler, a polymer, and a retarder. The binder includes calcium sulphate alpha hemihydrate, the filler includes cork, the polymer includes superplasticizer, and the retarder includes modified amino acid. The underlayment material exhibits a thermal resistance value that exceeds a threshold value for a defined thickness value. Further, a method of using the underlayment material composition in non-structural applications of one or more construction-related activities includes mixing the underlayment material composition, that includes the binder, the filler, the polymer, and the retarder, with a defined amount of water for a defined amount of time to produce an underlayment material composition mix having a defined consistency. The method further includes applying a coat of the underlayment material composition mix on a primer-coated surface.

Perlite-free, lightweight setting-type joint compounds which comprise calcium sulfate hemihydrate with a dry density of less than 50 lb/ft.sup.3, a foaming agent having a HLB value of at least 10 and preferably comprising an alkylbenzene sulfonic acid having a linear alkyl chain containing 8 to 14 carbons and/or a salt thereof, and a combination of rheology modifiers. Methods for building wallboard assemblies and methods for wall patch and repair projects that include applying the perlite-free, lightweight setting-type joint compounds to a substrate.

This invention discloses a synthetic gypsum and gypsum boards produced therefrom. Limestone (Calcium Carbonate), slaked lime (calcium hydroxide), water, and sulfuric acid are mixed, and alpha hemihydrate gypsum is optionally added as crystal seed to produce synthetic gypsum. The synthetic gypsum is then used to make gypsum boards. The gypsum board produced according to this invention contains at least 10% alpha hemihydrate gypsum.

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.