01843nas a2200217   4500008004100000022001400041245010600055210006900161260009500230300001400325490000700339520100500346653001401351653001201365653002401377653002301401653002401424653002201448100002501470856013001495       2011                        eng d  a1533-488000aMorphology and polymorphic phase changes of calcium carbonate micro/nanocrystals using fruit extracts0 aMorphology and polymorphic phase changes of calcium carbonate mi  a25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USAbAMER SCIENTIFIC PUBLISHERScMAY  a3997-40030 v113 a<p>This study reveals the morphology and polymorphic phase changes of calcium carbonate crystals into a mixture of calcite and aragonite micro/nanocrystals of interesting morphology at room temperature by a simple reaction with fruit extracts of Tamarindus indica and Emblica officinalis respectively by mixing CaCO(3) solutions with their corresponding extracts. The control experiments were carried out to establish the plausible role of tartaric acid from Tamarindus indica and ascorbic acid from Emblica officinalis in this regard. The quantitative determination of CaCO(3) phases was done based on the use of intensities obtained from corresponding XRD spectrum. The molar %. of aragonite was found to be more in case of TA and AA rather than TI and EO respectively, however the calcite was observed to be the predominant phase in all four reactions. Interestingly, the TI changes the rhombohedral morphology of calcite to elongated rods, whereas EO induces a great polymorphic phase change.</p>10aAragonite10aCalcite10aEmblica officinalis10aMorphology Changes10aPolymorphic Changes10aTamarindus indica1 aAnkamwar, Balaprasad  uhttps://library.ncl.res.in/content/morphology-and-polymorphic-phase-changes-calcium-carbonate-micronanocrystals-using-fruit-002133nas a2200253   4500008004100000022001400041245007700055210006900132260007300201300001200274490000700286520130200293653001201595653001901607653001501626653001501641653001801656653001501674100002101689700002101710700001801731700001901749856011101768       2015                        eng d  a1350-417700aContinuous precipitation of calcium carbonate using sonochemical reactor0 aContinuous precipitation of calcium carbonate using sonochemical  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY  a132-1390 v243 a<p>The continuous production of calcium carbonate (CaCO3) by precipitation method at room temperature was carried out in a stirred reactor under ultrasonic environment and was compared with the conventional stirring method. The effect of various operating parameters such as Ca(OH)(2) slurry concentration, CO2 flow rate and Ca(OH)(2) slurry flow rate on the particle size of CaCO3 was investigated. The calcium carbonate particles were characterized by Fourier transform infrared (FTIR), wide angle X-ray diffraction (WXRD) and particle size. The morphology was studied by using scanning electron microscopic (SEM) images. The particle size obtained in the presence of ultrasonic environment was found to be smaller as compared to conventional stirring method. The particle size is found to be reduced with an increase in the concentrations of Ca(OH)(2) and increased with increasing CO2 flow rate for both the methods. The slurry flow rate had a major effect on the particle size and the particle size decreased with increased slurry flow rate. Only calcite phase of CaCO3 was predominantly present as confirmed by the characterization techniques for both the preparation methods. In most of the cases rhombohedral calcite particles were observed. (C) 2014 Elsevier B.V. All rights reserved.</p>10aCalcite10aCrystal growth10aMorphology10aNucleation10aParticle size10aUltrasound1 aShirsath, S., R.1 aSonawane, S., H.1 aSaini, D., R.1 aPandit, A., B.  uhttps://library.ncl.res.in/content/continuous-precipitation-calcium-carbonate-using-sonochemical-reactor-0