The present invention relates to a process for the preparation of precipitated calcium carbonate comprising the steps of a) providing and calcining calcium carbonate comprising material; b) slaking the reaction product obtained from step a) with an aqueous ammonium chloride solution; c) separating insoluble components from the calcium chloride solution obtained from step b); d) carbonating the calcium chloride solution obtained from step c); e) separating the precipitated calcium carbonate obtained from step d); the precipitated calcium carbonate obtained by this process, as well as uses thereof.

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.

Process for manufacture of purified alkaline earth metal carbonate The invention concerns a process for the manufactore of a purified alkaline earth metal carbonate, the purified alkaline earth metal carbonate obtainable by said process, and its use in the manufacture of products and devices in the field of electronics and glass. The process comprises the steps of calcinating the alkaline earth metal carbonate with an aqueous phase comprising a salt. The alkaline earth metal carbonate might be barium carbonate or strontium carbonate.

A surface-treated heavy calcium carbonate is provided which is useful for a film exactly controlled in its pore diameter and for easily hydrolyzable polyester resins. A heavy calcium carbonate is also provided which is compounded in a curable resin such as a one-component moisture-curable adhesive and a sealant either without any pre-drying treatment or by simple pre-drying treatment. A surface-treated heavy calcium carbonate satisfying 13,000≤A≤25,000, 0.8≤B≤3.0, C≥0.55, and 0≤D1≤1000, or 8,000≤A≤25,000, 0.8≤B≤15, 0≤C1≤1000, and 0≤C2≤150 wherein: A: specific surface area (cm.sup.2/g), B: average particle diameter (μm): 50% particle diameter (d50) (μm), C: 10% particle diameter (μm), D1, C1: water content at between 25° C. and 300° C. by a Karl-Fischer method (heating vaporization method) (ppm), and C2: water content at between 200° C. and 300° C. by the same method.

The calcium carbonate filler for a resin is provided in which a volatile component such as water present in a surface of calcium carbonate is likely to be degassed even when the filler is incorporated into and kneaded with a resin having high processing temperature at a high concentration, and foaming or the like can be suppressed. In particular, the calcium carbonate filler is useful in optical fields that require reflectivity and light resistance. The calcium carbonate filler for a resin has a content rate of particles having a particle diameter of 0.26 μm or less is 30% or less in a number particle size distribution diameter measured from an electron micrograph, and satisfies the following expressions (a) Dms5/Dmv5≤3.0, (b) 1.0≤Sw≤10.0 (m.sup.2/g) and (c) Dma≤5.0 (% by volume): Dms5: a 5% diameter (μm) accumulated from a small particle side in a volume particle size distribution measured with a laser diffraction particle size distribution measurement device; Dmv5: a 5% diameter (μm) accumulated from a small particle side in a number particle size distribution in a particle diameter measured with an electron microscope; Sw: a BET specific surface area (m.sup.2/g); and Dma: a content rate (% by volume) of particles having a particle diameter of 3 μm or more in a volume particle size distribution measured with a laser diffraction particle size distribution measurement device.

A method of producing a product inorganic compound including: immersing a raw material inorganic compound having a volume of 10.sup.−13 m.sup.3 or more in an electrolyte aqueous solution or an electrolyte suspension; exchanging anions in the raw material inorganic compound with anions in the electrolyte aqueous solution or the electrolyte suspension; cations in the raw material inorganic compound are exchanged with cations in the electrolyte aqueous solution or the electrolyte suspension; or including a component (that excludes water, hydrogen, and oxygen) in the electrolyte aqueous solution or the electrolyte suspension not included in the raw material inorganic compound in the raw material inorganic compound; and obtaining a product inorganic compound having a volume of 10.sup.−13 m.sup.3 or more from the raw material inorganic compound.

Methods of making carbonate aggregates are provided. Aspects of the methods include: preparing a carbonate slurry, subjecting the carbonate slurry to rotational action, e.g., by introducing the carbonate slurry (optionally with an aggregate substrate) into a revolving drum under conditions sufficient to produce a carbonate aggregate, e.g., made up of a spherical coating on a substrate and/or agglomeration particles. Also provided are aggregate compositions produced by the methods, as well as compositions that includes the carbonate coated aggregates, e.g., concretes, and uses thereof.

The present invention discloses the systems of producing calcium and magnesium carbonate from the Ca/Mg containing solution leached by a CO.sub.2-based hydrometallurgical process which includes: a precipitation reactor that the Ca/Mg containing leached solution is continuously added and fully mixed with the alkaline reagent at specific mole ratio into the precipitation reactor and the reactor also comprises a CO.sub.2 bubbling module where CO.sub.2 is captured and recirculated from the thermal decomposition process as needed; a solid-liquid separation unit that the treated slurry is treated by the solid-liquid separation unit to produce precipitated calcium and magnesium carbonate products where the recirculating water is recycled back into the precipitation reactor; a thermal decomposition unit that the calcium and magnesium carbonate products is calcined by the thermal decomposition unit to produce an alkaline reagent and the alkaline reagent is recycled back into the precipitation reactor for the next batch of reaction.

Disclosed herein are compositions comprising oolitic aragonite particles, wherein the oolitic aragonite particles have an average particle size of between 100 nm to 1 mm, and a Hunter brightness level greater than 88. Further disclosed herein are personal care and/or cosmetic compositions, comprising a carrier and the aforementioned oolitic aragonite particles. Further disclosed herein are methods of making and using the oolitic aragonite particles.

Provided is a method for producing a calcium carbonate sintered body whereby a good sintered body can be obtained without having to use any sintering aid. A method for producing a calcium carbonate sintered body includes the steps of: compacting calcium carbonate to make a green body; heating the green body under a condition of a temperature of 500° C. or lower to remove an organic component contained in the green body; and sintering the green body under conditions of a carbon dioxide atmosphere and a temperature of 450° C. or higher to obtain a calcium carbonate sintered body.