Patent
Process for producing an aquous suspension of calcium and/or magnesium carbonates from dolomite
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TLDR
In this article, a method of producing an aqueous suspension of carbonates of calcium or magnesium from dolomite is described, where the dolmite is converted into a mixture of calcium oxide and magnesium oxide by heating to approx. 1000-1100 degrees C, whereafter the resultant oxide mixture is suspended in water in the proportion by weight of at least 20 parts of water to 1 part of the oxides and wherein the hydroxides which form in the suspension are converted back to the corresponding carbonates by the introduction of carbon dioxide according to DE-AAbstract:
1. A method of producing an aqueous suspension of carbonates of calcium or/and Magnesium from dolomite, wherein the dolomite is converted into a mixture of calcium oxide and magnesium oxide by heating to approx. 1000-1100 degrees C, whereafter the resultant oxide mixture is suspended in water in the proportion by weight of at least 20 parts of water to 1 part of the oxides and wherein the hydroxides which form in the suspension are converted back to the corresponding carbonates by the introduction of carbon dioxide according to DE-A-26 00 485 characterized by that the carbonate-containing suspension is heated to a temperature above 160 degrees C in a pressurized vessel suitable for hydrothermal treatment and maintained at such temperature until lamellar, basic magnesium carbonates of a Shape factor of less than 1 : 30 have formed.read more
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Rhombohedral calcium carbonate and accelerated heat-aging process for the production thereof
TL;DR: A form of calcium carbonate having a blocky-six-sided rhombohedral final crystal morphology, with a surface area of from about 3 to about 15 m/g, an average discrete particle size of from 0.2 to about 0.9 microns, wherein the discrete particles have an aspect ratio less than 2, and a particle size distribution such that at least about 60 weight percent of the particle lies within 50 percent of an equivalent discrete particle sherical diameter, suitable for use as a filler material in papermaking to improve the optical properties of the resulting paper,
Patent
Calcium carbonate in a platelet-like particulate form and a method for the preparation thereof
TL;DR: In this article, a two-step carbonation method for the preparation of a calcium carbonate powder has been proposed, in which the first step is to blow carbon dioxide into the milk of lime until 10 to 70% of the calcium hydroxide is carbonated and the second step is performed by admixing the thus partially carbonated milk-of-lime with an aqueous carbonating solution containing an alkali metal carbonate or ammonium carbonate in specified concentrations.
Patent
Process for the preparation of magnesium compounds
TL;DR: In this article, a process for basic magnesium carbonate prodn. from dolomite comprises (a) complete calcination to CaO and MgO; (b) hydration to the hydroxides; (c) bubbling of CO2 (opt. mixed with inert gas) into an aq. soln. to be carbonated.
Patent
Process for the preparation of anhydrous magnesium carbonate.
TL;DR: Anhydrous magnesium carbonate is obtained from magnesium salt solutions or from suspensions of sparingly soluble magnesium compounds, for example nesquehonite, magnesium hydroxide, and the like by mixing the solution or suspension with ammonium carbonate, alkali metal carbonate or carbon dioxide such that the MgO:CO2 molar ratio is /=110 DEG C as discussed by the authors.
Patent
Process for the preparation of a mixture of calcium carbonate and magnesium carbonate having a mainly lamellar crystal form
TL;DR: In this paper, a mixture of calcium carbonate and magnesium carbonate having a mainly lamellar crystal form and shape factors of 20 to 30 is prepared by wet quenching of calcined dolomite at 50 to 70 DEG C, keeping to solid/water ratios of 1:12 to 1:20 and introducing CO2 until saturation at 25 to 50 DEGC, after which the precipitated carbonates are filtered off and the residue is treated hydrothermally at temperatures between 130 and 160 DEG
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Calcium and magnesium carbonates suitable for paper mfr - made by feeding carbon dioxide into aq suspension of calcined dolomite
Werner Dr Schultze,Reinhard Dipl Ing Feige,Roland Dr Thome,Guenter Prof Dr Winkhaus,Heinz Kendziora,Johann Nenner +5 more
TL;DR: In this article, the initial starting material is pref. natural dolomite calcined in a rotary drum furnace and the gas fed into the suspension is pref CO2 or a mixt. of CO2 and N2, esp. the exhaust gas from the drum furnace.