The present invention provides an apparatus and a method for producing cement through flue gas desulfurization, and specifically provides an apparatus and a method for simultaneously producing magnesium sulfate cement during a magnesium oxide based flue gas desulfurization process. The apparatus of the present invention includes a flue gas desulfurization equipment, a concentration equipment, a crystallization equipment, a centrifugation equipment, a drying equipment, a waste ash supplying equipment, a slag material supplying equipment, a mixing equipment, etc. By adopting the apparatus and method of the present invention, the problems in the present conventional cement production such as high energy cost, severe damage to the environment and so on can be solved, and the problems like high production cost of ordinary magnesium sulfate cement and high transportation cost of supplies thereby causing incapability in a large scale market spreading and application can also be solved.

A method of manufacturing a concrete product includes mixing a composition including a binder, an aggregate, and water to produce a concrete mixture, and imparting a form to the concrete mixture to provide a formed intermediate. The formed intermediate is carbon cured to obtain a cured intermediate. A post-hardening treatment to the cured intermediate is done by exposing the cured intermediate to a temperature above an ambient temperature to obtain the concrete product.

A method of manufacturing a concrete product includes mixing a composition including a binder, an aggregate, and water to produce a concrete mixture, and imparting a form to the concrete mixture to provide a formed intermediate. The formed intermediate is carbon cured to obtain a cured intermediate. A post-hardening treatment to the cured intermediate is done by exposing the cured intermediate to a temperature above an ambient temperature to obtain the concrete product.

The invention provides cement additives comprising calcium sulfate and silica which are derived from a material comprising perovskite and silica, along with cements and cementitious products comprising the cement additives. The invention also provides methods for the making the cement additive and cements and cementitious products comprising the cement additives.

The invention provides cement additives comprising calcium sulfate and silica which are derived from a material comprising perovskite and silica, along with cements and cementitious products comprising the cement additives. The invention also provides methods for the making the cement additive and cements and cementitious products comprising the cement additives.

The present invention is proposed to disclose a method for preparing an all-solid waste-based carbonated unburned lightweight aggregate. The method includes the following steps: (1) subjecting an active component type solid waste, a lightweight filling type solid waste, and an alkali activation type solid waste to grinding and mixing to obtain a mixed solid waste powder; and (2) subjecting the mixed solid waste powder and water to granulation to obtain particles, and subjecting the particles to precuring and mineralization curing with CO.sub.2 to obtain the all-solid waste-based carbonated unburned lightweight aggregate. The active component type solid waste includes blast furnace slag, steel slag, or furnace slag. The lightweight filling type solid waste includes fly ash, river silt, or red mud. The alkali activation type solid waste includes carbide slag. In the present invention, all raw materials are selected from solid wastes, the alkali activation type solid waste is used as an alkali activator to replace traditional quicklime, sodium hydroxide, and sodium silicate, and a CO.sub.2 mineralization strengthening technology is used, so that the carbon fixation potential of the solid wastes is fully exerted, natural resources are saved, and the all-solid waste-based carbonated unburned lightweight aggregate prepared has excellent compressive strength.