Influence of synthesis conditions on the calcium carbonate microparticle properties obtained by homogeneous and heteroge
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ORIGINAL PAPER
Influence of synthesis conditions on the calcium carbonate microparticle properties obtained by homogeneous and heterogeneous precipitation Viktoriia Arkhypova1 · Roman Smotraiev1 · Kateryna Sorochkina1 · Yevheniia Manidina2 Received: 9 August 2019 / Revised: 14 January 2020 / Accepted: 27 January 2020 © Associação Brasileira de Engenharia Química 2020
Abstract CaCO3 microparticles were obtained by chemical precipitation from C aCl2 solution using N a2CO3 or ( NH4)2CO3 solutions (heterogeneous precipitation) or carbamide (homogeneous precipitation) as precipitation agents. The effects of various experimental conditions, such as the temperature, duration and reagent ratio on the properties of precipitated C aCO3 were experimentally investigated. It was found that the shape of particles and CaCO3 polymorphs depended on the precipitation agent and process temperature; the size of particles—on the reagent ratio, the precipitation agent and the deposition time. Biphasic calcite-vaterite spherical microparticles with the highest polydispersity coefficient (K = 0.98 with an average particle size ln ≈ 3 μm) were obtained using Na2CO3 solution as a precipitation agent under low temperature (20 °C). Calcite rhombohedral crystals (ln ≈ 3 μm) were obtained using carbamide at high temperature (100 °C). Increasing the temperature of Na2CO3 and ( NH4)2CO3 solutions (70–100 °C) led to formation of the biphasic aragonite–calcite druses of needle crystals (druses size ≈ 10–30 μm). Increasing the aging time for sediments in the mother liquor up to 1 h did not affect the shape of CaCO3 particles. Keywords Calcium carbonate · Chemical precipitation · Size distribution · Calcite · Vaterite · Aragonite
Introduction Calcium carbonate ( CaCO3) in the form of chalk powder is widely used as filler in the production of building materials, plastics, rubber, paper, etc. (Thenepalli et al. 2010; Vogel et al. 2013; Tangboriboon et al. 2015; Hubbe and Gill 2016; Penkin et al. 2016; Lourenço et al. 2016; Lourenço et al. 2015b). At the same time, increasing requirements for chemical composition, dispersity and surface characteristics significantly narrow the application area of ground chalk due to its low consumer properties, such as lots of impurities, polydisperse composition, tendency to agglomerate, insufficient surface hydrophobicity, etc. In addition, some industries require certain crystalline modifications of * Viktoriia Arkhypova [email protected] 1
Ukrainian State University of Chemical Engineering, 8 Gagarin Avenue, Dnipro 49005, Ukraine
Engineering Institute of Zaporizhzhia National University, 226 Soborny Avenue, Zaporizhia 69006, Ukraine
2
CaCO3 (Thenepalli et al. 2010; Vogel et al. 2013; Kojima et al. 1992). Therefore, calcium carbonate of the required quality is more frequently obtained by chemical methods. Two of the most widespread methods to obtain CaCO3 are the carbonization of natural dolomite or other calcium-containing raw materials (Chilakala et al. 2016; Teir et al. 2016) and the chemical
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