The present disclosure belongs to the technical field of harmless treatment of phosphogypsum and building materials, and particularly provides a phosphogypsum-based building material, and preparation and use thereof. The method includes: adding a pretreated phosphogypsum premix having a temperature above 60 C., a free water content 10% and an organic matter content of 5-20 wt % into a ceramsite at a temperature above 800 C., continuing mixed calcination after combustion by using residual heat of the ceramsite, separating out ceramsite coarse aggregate to obtain a residual material, and performing post-treatment on the residual material to obtain the phosphogypsum-based building material. The method of the present disclosure not only fully utilizes phosphogypsum solid waste, but also simultaneously achieves harmless treatment of phosphogypsum. More importantly, the method achieves a synergistic enhancement between the ceramsite and phosphogypsum, resulting in the prepared phosphogypsum-based building material with higher strength, a more uniform structure and a wider application range.

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.

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.

A carbonized brick of recycled concrete powders and a preparation method thereof are provided, belonging to the field of concrete materials. The preparation method includes: adding composition A to a liquid storage tank; introducing composition B into the liquid storage tank to react with a solid waste solution to generate calcium bicarbonate solution; filling recycled powders into a molding die, decomposing the calcium bicarbonate solution by heat, reacting generated carbon dioxide with calcium ions leached from a CSH gel in the recycled powders to produce calcium carbonate, and precipitating, crystallizing and cementing in the molding die together with calcium carbonate produced by decomposing calcium bicarbonate solution, and resulting in strength of the recycled powders.

A process may involve treating calcium sulfate separated from phosphoric acid with acid to obtain a suspension comprising purified calcium sulfate, separating the purified calcium sulfate in solid form from a liquid phase of the suspension, treating the purified calcium sulfate with water or with a salt- and/or chelate ligand-containing aqueous solution to leach rare earths out of the calcium sulfate, separating the further-purified calcium sulfate in solid form from the liquid phase of the suspension, mixing the purified calcium sulfate that is separated off with admixtures and reducing agents to obtain a raw meal mixture for cement clinker production, burning the raw meal mixture to obtain the cement clinker and thereby forming sulfur dioxide as offgas, and feeding the sulfur dioxide as raw material to sulfuric acid production to produce the sulfuric acid.

A process may involve treating calcium sulfate separated from phosphoric acid with acid to obtain a suspension comprising purified calcium sulfate, separating the purified calcium sulfate in solid form from a liquid phase of the suspension, treating the purified calcium sulfate with water or with a salt- and/or chelate ligand-containing aqueous solution to leach rare earths out of the calcium sulfate, separating the further-purified calcium sulfate in solid form from the liquid phase of the suspension, mixing the purified calcium sulfate that is separated off with admixtures and reducing agents to obtain a raw meal mixture for cement clinker production, burning the raw meal mixture to obtain the cement clinker and thereby forming sulfur dioxide as offgas, and feeding the sulfur dioxide as raw material to sulfuric acid production to produce the sulfuric acid.

A full solid-waste micro-expansive concrete and its preparation method are provided, and relate to the field of concrete material technologies. The full solid-waste micro-expansive concrete includes the following components in parts by weight: 920-1060 parts of a coarse aggregate, 460-582 parts of a fine aggregate, 11-19 parts of an expansive agent, 389-512 parts of a modified solid-waste-based cementitious material, and 231-268 parts of water. The coarse aggregate is coal gangue. The fine aggregate is waste ceramic. The modified solid-waste-based cementitious material includes a solid-waste-based clinker, modified polyvinyl alcohol, and a modified anion exchange resin. The solid-waste-based clinker is prepared from the coal gangue, carbide slag, and desulfurization gypsum. The expansive agent is obtained by calcining the carbide slag. The concrete prepared can ensure the initial strength of the concrete, and guarantee continuous micro-expansion in the later stage, compensating for shrinkage and thereby increasing the overall strength of the concrete.

Systems and methods for manufacturing a gypsum board having oxidized modified cellulose fibers are provided. A gypsum board includes a gypsum layer formed from a gypsum slurry, where the gypsum layer has a bottom and a top. The gypsum slurry includes oxidized modified cellulose fibers. The gypsum board further includes a first mat placed on the bottom of the gypsum layer, and a second mat placed on the top of the gypsum layer.

Systems and methods for manufacturing a gypsum board having oxidized modified cellulose fibers are provided. A gypsum board includes a gypsum layer formed from a gypsum slurry, where the gypsum layer has a bottom and a top. The gypsum slurry includes oxidized modified cellulose fibers. The gypsum board further includes a first mat placed on the bottom of the gypsum layer, and a second mat placed on the top of the gypsum layer.

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.