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.

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 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.

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.

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.

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.

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.

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.