4/5/2023 0 Comments Crystal size in jmicrovision![]() In addition, it has good flowability in a high particle density slurry state, improves the whiteness and opacity of coated paper, and shows good printing characteristics due to its good lubrication of the coated paper surface. Columnar calcium aragonite has good dispersibility in water. In the past, most of the PCC used calcite, but recently, columnar aragonite has been attracting attention as a paper coating pigment. For example, fine crystals of CaCO 3 and crystals with large specific surface areas have the effect of increasing the strength of rubber and the glossiness of paper when added. In industrial applications, it is also desirable to control the size and morphology of the crystals according to the application. When calcium bicarbonate saturated solution contains a small amount of calcite, the product is 100% calcite, and when a small amount of aragonite is present, only aragonite is obtained. In addition, calcium carbonate polymorphism is affected by the polymorphism present in the reaction system. ![]() For example, it has been reported that the addition of metal ions to the reaction system stabilizes aragonite by Ni 2+ addition, Mg 2+ promotes the transition to calcite, and Fe 3+ stabilizes the satellite. The polymorphism of calcium carbonate crystal is also affected by the additives. Therefore, the control of crystal polymorphism by various methods has been studied. Thus, it is desirable to control the crystal polymorphism of calcium carbonate according to the application because it shows different physical properties depending on the crystal polymorphism. ![]() Vaterite is the most unstable and easily transfers to aragonite and calcite under ambient temperature and pressure. For this reason, calcite transferred from aragonite is often found in fossils. Aragonite is stable at room temperature and pressure, but it is easily transferred to calcite when heat or pressure is applied. Thermodynamically, calcite is the most stable, and calcite is the main component of limestone. Calcium carbonate has three crystalline polymorphs: calcite, aragonite, and vaterite. Other methods of PCC include the sodium carbonate lime method and the calcium nitrate-ammonium carbonate method. GCC is produced by the crushing and classifying process and has irregular particle size and shape, while PCC is mainly produced by the lime milk coal oxidation method, in which calcium carbonate is precipitated by blowing CO 2 into calcium hydroxide slurry. The industrially used CaCO 3 is classified into two types: ground calcium carbonate (GCC), which is made by finely grinding natural lime, and precipitated calcium carbonate (PCC), which is produced through chemical synthesis. Calcium carbonate (CaCO 3), the main component of limestone, has good stability and economy and is widely used industrially in rubber, plastics, paints, and paper-making. Limestone is one of the few mineral resources that are self-sufficient in the country, and veins of limestone, the raw material of limestone, are scattered throughout the country. Experiments on the addition of dissolved SrCO 3 showed that the supersaturation formation rate could be controlled to control the crystal polymorphism. The addition of solid strontium carbonate affected the crystal polymorphism and size of the calcium carbonate produced, depending on the properties of the solid particles and the amount of SrCO 3 added. In this study, the effect of SrCO 3 on the size control of fine aragonite-type calcium carbonate crystals by uniform urea precipitation and the effect of SrCO 3 addition was investigated by adding solid strontium carbonate and dissolved strontium carbonate. In addition, the control of crystal size and shape is similarly required for different applications. ![]() Therefore, the control of crystal polymorphism is required for industrial applications. ![]() Calcium carbonate has three types of crystalline polymorphism, calcite, aragonite and vaterite, each with different properties. Calcium carbonate, the main component of lime, has been widely used in industry due to its stability and economy. ![]()
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