A gypsum board according to the invention comprises calcium sulphate dihydrate; Tartaric acid in an amount in the range of 0.01 to 0.1% w based on the weight of calcium sulphate hemihydrate; A fluidizer in an amount of 1.0 to 10.0 kg/m.sup.3; Starch in an amount of 3.0 to 12.0 kg/m.sup.3.

DTPA-coated synthetic calcined gypsum is provided with alpha-like properties and obtained by spray-coating the synthetic caclined gypsum with DTPA. Cementitious compositions comprising DTPA-coated synthetic calcined gypsum and low water demand are provided as well. Methods for controlling an open time of a cementitious slurry by increasing or decreasing the amount of DTPA-coated synthetic calcined gypsum in the slurry are provided as well.

DTPA-coated synthetic calcined gypsum is provided with alpha-like properties and obtained by spray-coating the synthetic caclined gypsum with DTPA. Cementitious compositions comprising DTPA-coated synthetic calcined gypsum and low water demand are provided as well. Methods for controlling an open time of a cementitious slurry by increasing or decreasing the amount of DTPA-coated synthetic calcined gypsum in the slurry are provided as well.

In general, the present disclosure is directed to a method of making a gypsum board. The method comprises: applying a hydrophilic compound to a first gypsum composition to provide a hydrophilic compound modified gypsum composition; calcining the hydrophilic compound modified gypsum composition to provide a calcined gypsum composition; preparing a gypsum slurry by combining water and the calcined gypsum composition; depositing the gypsum slurry on a first facing material; providing a second facing material on the gypsum slurry; and allowing the calcined gypsum to convert to calcium sulfate dihydrate.

A high-toughness magnesium-calcium binder mortar material from multi-component high-salinity solid waste and a preparation method thereof are provided. Raw materials of the high-toughness magnesium-calcium binder mortar material from multi-component high-salinity solid waste include a dry powder mortar material, a shrinkage reducing agent, a water reducing agent and fibers, where an addition amount of the fibers is 1.0-2.0% of a mass of the dry powder mortar material; where in parts by weight, the dry powder mortar material includes: 28-40 parts of aging mixture, 10-15 parts of industrial solid waste gypsum, 5-8 parts of light burned magnesium oxide, 2-5 parts of high alumina cement, 3-8 parts of rubber powder and 30-40 parts of artificial fine sand; and where in parts by weight, the aging mixture includes 50-70 parts of municipal solid waste incineration (MSWI) fly ash and 30-50 parts of magnesite, as well as aluminum dihydrogen phosphate solution and phosphogypsum leachate.

The embodiments herein are directed to dry wall waste mixtures, formed under pressure into example embodiments referred to herein as dry wall waste blocks (DWBs) and/or gypsum wallboard waste blocks (GWWBs) and tile structures. DWBs/GWWBs mixtures in particular, often incorporate a higher percentage in the composite mixtures from about 60% up to 85% of dry wall waste than other mixtures and beneficially often incorporates substantially all of the wallboard facing paper as part of the composite mixture. That is, waste processing is simplified by comingling core and paper layers in the final product. DWBs/GWWBs mixtures utilize demolition and construction waste, replacing a high percentage of Portland cement with waste-derived binder.

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 comprehensive utilization method for iron separation tailings from magnetizing-roasted red mud includes the following steps: performing a wet magnetic separation for tailing discarding on iron separation tailings from magnetizing-roasted red mud, to obtain a rough concentrate and non-magnetic minerals; performing a purification by gravity separation on the rough concentrate to obtain a wet iron concentrate and light minerals; dehydrating the wet iron concentrate to obtain an iron concentrate; combining, and then dehydrating, drying, and disintegrating the non-magnetic minerals and the light minerals, to obtain iron extraction tailings; uniformly mixing the iron extraction tailings, and crushed, ground, and dried limestone, clay, and quartz sand separation tailings according to a predetermined ratio to obtain a cement raw meal; pressing, and then calcining and quenching the cement raw meal to obtain a cement clinker; and mixing the cement clinker and a gypsum followed by a dry grinding to obtain a silicate cement.