Direct Synthesis of Needlelike Aragonite CaCO3 Whiskers Using H3PO4 as an Additive
Calcium carbonate has three polymorphs: calcite, aragonite, and vaterite. Needlelike aragonite CaCO3 with a high ratio of length to diameter (aspect ratio) is widely used in plastics, rubber and ceramics as a filler and in pigments and paints as a carrier. This paper investigated the influence of H3PO4 dosage, reaction temperature, CO2 flow rate, and initial Ca(OH)2 concentration on formation of needlelike aragonite CaCO3. It was found that the presence of H3PO4 in Ca(OH)2 suspension resulted in rapid formation of (Ca5(PO4)3(OH)) crystal nuclei, which facilitated nucleation and growth of aragonite CaCO3 on the formed (Ca5(PO4)3(OH)) crystal surfaces. The results revealed that H3PO4 addition of P/Ca of 0. 2-0. 3, high temperature of 75～85℃, low CO2 flow rate and initial Ca(OH)2 solid concentration of 1. 5 %～5.6 % are beneficial to formation of aragonite. Well crystallized needlelike aragonite CaCO3 whiskers with length ＞ 20 μm and aspect ratio ＞15 were directly synthesized.
Calcium carbonate Aragonite Whisker Synthesis Phosphoric acid Additive
Y. X. Han L. X. Li Z. T. Yuan Y. B. Wang
School of Resources & Civil Engineering, Northeastern University, Shenyang, China
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
3182-3189
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）