A composition contains a mixture of an inorganic binder and alkyl-modified silsesquioxane resin particles, where the alkyl-modified silsesquioxane resin particles are distributed throughout the inorganic binder and have an average particle size in a range of 20 to 200 nanometers as determined by dynamic light scattering.

A method of processing plasterboards or plasterboard for recover a calcium sulphate source for producing a hydraulic binder, includes comminuting plasterboards or a gypsum fraction thereof so as to obtain plasterboard particles and, thereafter, subjecting the plasterboard particles to a heat treatment at an elevated temperature so as to volatilize and/or decompose organic components present in the plasterboard particles.

A method for preparing calcium sulphate comprising a production of DCP by the attack of a source of phosphate by an acid, a digestion of the isolated DCP by the sulphuric acid under conditions giving rise to the formation of a first slurry of gypsum suspended in an acidic aqueous phase having a content of free SO.sub.3 equal to or less than 1.5% and a content of free P.sub.2O.sub.5, a conversion of at least part of said first slurry by heating to a temperature greater than 80 C. and potentially by adding sulphuric acid, with solubilisation of the gypsum crystals and recrystallisation of the solubilised calcium sulphate in a second slurry of -calcium sulphate hemihydrate crystals suspended in an aqueous phase based-on phosphoric acid, wherein the content of free SO.sub.3 is less than 10% by weight, and a separation between said aqueous phase and a filter cake based on particularly pure -calcium sulphate hemihydrate.

A method for preparing calcium sulphate comprising a production of DCP by the attack of a source of phosphate by an acid, a digestion of the isolated DCP by the sulphuric acid under conditions giving rise to the formation of a first slurry of gypsum suspended in an acidic aqueous phase having a content of free SO.sub.3 equal to or less than 1.5% and a content of free P.sub.2O.sub.5, a conversion of at least part of said first slurry by heating to a temperature greater than 80 C. and potentially by adding sulphuric acid, with solubilisation of the gypsum crystals and recrystallisation of the solubilised calcium sulphate in a second slurry of -calcium sulphate hemihydrate crystals suspended in an aqueous phase based-on phosphoric acid, wherein the content of free SO.sub.3 is less than 10% by weight, and a separation between said aqueous phase and a filter cake based on particularly pure -calcium sulphate hemihydrate.

Gypsum derived from waste gypsum boards is calcined and converted into gypsum granules including hemihydrate and/or anhydrous type III gypsum. The calcined gypsum granules are dropped into water to prepare a gypsum slurry. Then, dihydrate gypsum particles are crystalized in the slurry. The temperature of the gypsum granules just before being dropped into the water is 90 C. or higher.

Gypsum derived from waste gypsum boards is calcined and converted into gypsum granules including hemihydrate and/or anhydrous type III gypsum. The calcined gypsum granules are dropped into water to prepare a gypsum slurry. Then, dihydrate gypsum particles are crystalized in the slurry. The temperature of the gypsum granules just before being dropped into the water is 90 C. or higher.

A method for preparing a cementing material by sintering and activating coal gangue is provided. The method includes the following steps: (1) crushing coarse-grained coal gangue to predetermined particle size; (2) fully and evenly mixing the crushed coal gangue, the composite additive and water according to a set proportion, and granulating the obtained mixture; (3) distributing, igniting and exhausting the granulated pellets in the sintering machine to obtain decarburized coal gangue sinter; (4) cooling the decarburized coal gangue sinter in a cooler; (5) crushing and finely grinding the cooled coal gangue sinter to obtain a coal gangue active mixture; and (6) mixing the coal gangue active admixture, the fly ash, the quicklime and the gypsum according to a predetermined ratio, and then carrying out injection moulding, mold removal and curing to obtain the coal gangue-based cementitious material.

A method for preparing a cementing material by sintering and activating coal gangue is provided. The method includes the following steps: (1) crushing coarse-grained coal gangue to predetermined particle size; (2) fully and evenly mixing the crushed coal gangue, the composite additive and water according to a set proportion, and granulating the obtained mixture; (3) distributing, igniting and exhausting the granulated pellets in the sintering machine to obtain decarburized coal gangue sinter; (4) cooling the decarburized coal gangue sinter in a cooler; (5) crushing and finely grinding the cooled coal gangue sinter to obtain a coal gangue active mixture; and (6) mixing the coal gangue active admixture, the fly ash, the quicklime and the gypsum according to a predetermined ratio, and then carrying out injection moulding, mold removal and curing to obtain the coal gangue-based cementitious material.

A method of manufacturing a lightweight thermal insulating cellular cement-based material and a lightweight thermal insulating cellular cement-based board made thereof are disclosed. A binder, an activator, and a blowing agent are mixed to obtain a mixture. The mixture is homogenized to form a cement slurry, which is poured into a mold afterwards. With the help of the activator and an increased temperature of the mold, the cement slurry in the mold will be activated and start foaming and curing to form a cellular cement-based material. The cellular structure is constructed by decomposition of the blowing agent to form a plurality of closed-cell bubbles, which are fixed in the cement slurry during the curing. After the formation, the mold is removed to obtain the cellular cement-based material. The material exhibits high integrity fire resistance and extraordinary insulation fire resistance.

A method of manufacturing a lightweight thermal insulating cellular cement-based material and a lightweight thermal insulating cellular cement-based board made thereof are disclosed. A binder, an activator, and a blowing agent are mixed to obtain a mixture. The mixture is homogenized to form a cement slurry, which is poured into a mold afterwards. With the help of the activator and an increased temperature of the mold, the cement slurry in the mold will be activated and start foaming and curing to form a cellular cement-based material. The cellular structure is constructed by decomposition of the blowing agent to form a plurality of closed-cell bubbles, which are fixed in the cement slurry during the curing. After the formation, the mold is removed to obtain the cellular cement-based material. The material exhibits high integrity fire resistance and extraordinary insulation fire resistance.