The present application pertains to methods for making alkali hydroxide, or alkali carbonates, or alkali bicarbonates, or alkaline—earth sulfates. In one embodiment, a material comprising an alkaline earth is converted to an alkaline earth sulfite or bisulfite and reacted with an alkali sulfate to form an alkaline earth sulfate and alkali sulfite or bisulfite. The alkali sulfite or bisulfite is converted into an alkali hydroxide, or an alkali carbonate, or an alkali bicarbonate. In another embodiment, ammonium carbonate or ammonium bicarbonate is reacted with an alkali sulfate, to form ammonium sulfate and an alkali carbonate or alkali bicarbonate. A material comprising an alkaline earth is converted to an alkaline earth sulfite or bisulfite and reacted with the ammonium sulfate to form an alkaline earth sulfate and ammonium sulfite or ammonium bisulfite. The ammonium sulfite or bisulfite is regenerated into ammonia, or ammonium hydroxide, or ammonium carbonate, or ammonium bicarbonate.

Provided herein is a method of preparing a ceramic material, the method including: providing a ceramic gel including a plurality of metal salts and compressing the ceramic gel thereby inducing stress-induced mineralization of the ceramic gel and formation of the ceramic material, wherein the ceramic gel exists in isolated form.

The present invention refers to a process for producing nano precipitated calcium carbonate (nano-PCC), as well as to the nano precipitated calcium carbonate (nano-PCC) obtained by such a process and a system for producing the nano precipitated calcium carbonate (nano-PCC) comprising at least one dry mill, preferably a dry sandmill. Furthermore, the present invention refers to the use of the nano precipitated calcium carbonate (nano-PCC) as well as to the use of the inventive system for producing nano precipitated calcium carbonate (nano-PCC).

The present invention provides a new method for fixing carbon dioxide. The method for fixing carbon dioxide of the present invention includes a contact step of bringing a mixed liquid containing sodium hydroxide and further containing at least one of a chloride of a Group 2 element or a chloride of a divalent metal element into contact with a gas containing carbon dioxide.

The invention discloses an artificial nacre material with layered structure and preparation method thereof. The preparation method includes the following steps: uniformly mixing a carbonated cementitious material and water at a water-solid ratio of 0.3 to 1.2 to obtain a carbonated cementitious material suspension; treating the carbonated cementitious material suspension by a freeze-casting process to obtain a carbonated cementitious material coagulation with layered structure; treating the carbonated cementitious material coagulation with the layered structure by a freeze-drying process to obtain a carbonated cementitious material with layered structure; treating the carbonated cementitious material with layered structure by a carbonization process to obtain an artificial nacre material with layered structure. The obtained artificial nacre material with layered structure has higher fracture toughness and durability, and the preparation method has the advantages of low energy consumption, carbon dioxide fixation and environmental friendliness.

Provided is an automobile exhaust gas bottle-reactor having a carbon dioxide capture device or an exhaust gas carbon dioxide reactor to reduce the emission of carbon dioxide. The exhaust gas carbon dioxide reactor may include a calcium hydroxide inlet through which calcium hydroxide is provided to the carbon dioxide capture device, a calcium carbonate outlet allowing the calcium hydroxide to be discharged from the carbon dioxide capture device, a calcium carbonate partition membrane 6 partitioning the calcium carbonate, a calcium carbonate sensor 7 sensing a level of the calcium carbonate, a calcium hydroxide partition membrane partitioning the calcium hydroxide and a calcium hydroxide sensor sensing a level of the calcium hydroxide.

The present invention refers to a process for the preparation of an aqueous solution comprising at least one earth alkali hydrogen carbonate and its uses. The process is carried out in a reactor system that comprises a tank (1) equipped with a stirrer (2) and at least one filtering device (4).

The present invention refers to a process for the preparation of an aqueous solution comprising at least one earth alkali hydrogen carbonate and its uses.

Techniques for growing crystalline calcium carbonate solids such that the crystalline calcium carbonate solids include a volume of 0.0005 mm.sup.3 to 5 mm.sup.3, include a slaker to react quicklime (CaO) and a low carbonate content fluid to yield a slurry of primarily slaked lime (Ca(OH).sub.2); a fluidized-bed reactive crystallizer that encloses a solid bed mass and includes an input for a slurry of primarily slaked lime, an input for an alkaline solution and carbonate, and an output for crystalline calcium carbonate solids that include particles and an alkaline carbonate solution; a dewatering apparatus that includes an input coupled to the crystallizer and an output to discharge a plurality of separate streams that each include a portion of the crystalline calcium carbonate solids and alkaline carbonate solution; and a seed transfer apparatus to deliver seed material into the crystallizer to maintain a consistent mass of seed material.

The present invention is directed to a process for producing precipitated calcium carbonate with improved resistance to structural breakdown, wherein the milk of lime is carbonated in the presence of at least one gas other than carbon dioxide, or the carbonation is carried out in the presence of a static gas bubble comminution unit as well as to precipitated calcium carbonate obtained by such a process.