Effects of Impurities on CaSO4 Crystallization in the Ca(H2PO4)2-H2SO4-H3PO4-H2O System
Effects of Impurities on CaSO4 Crystallization in the Ca(H2PO4)2-H2SO4-H3PO4-H2O System
复制标题
Ca(H2PO4)(2)-H2SO4-H3PO4-H2O体系中杂质对CaSO4结晶的影响
DOI：
10.1021/acsomega.9b01114
复制
发表时间：
2019-07-01
期刊：
影响因子：
4.1
通讯作者：
Sun, Guoxin
中科院分区：
文献类型：
--
作者：
Mu, Xinru;Zhu, Ganyu;Sun, Guoxin
湿法磷酸是化肥工业的基础工艺。采用混合悬浮液混合产物去除结晶器，研究了Ca(H2PO4)(2)-H2SO4-H3PO4-H2O体系中杂质对CaSO4结晶动力学的影响。通过扫描电子显微镜和高分辨率透射电子显微镜研究了高酸性体系中 Si、Al、Fe、Mg、K 和 Na 对晶体形态和结构的影响。结果表明，Mg、K、Na含量的增加有利于晶体生长。 Si、Al、Fe在一定浓度范围内有利于CaSO4晶体生长。杂质也会影响晶体形貌，与其他杂质相比，Si、Fe、Na的添加更促进针状晶体的形成。 X射线衍射结果表明，晶体的择优生长方向为(020)，晶体的面间距受杂质元素半径的影响。
Wet-process phosphoric acid is a fundamental process in the fertilizer industry. The influence of impurities on crystallization kinetics of CaSO4 was investigated in the Ca(H2PO4)(2)-H2SO4-H3PO4-H2O system using a mixed suspension mixed product removal crystallizer. Effects of Si, Al, Fe, Mg, K, and Na on crystal morphology and structure were examined in the highly acidic system through scanning electron microscopy and high-resolution transmission electron microscopy. Results show that the increase of Mg, K, and Na content facilitates crystal growth. Si, Al, and Fe are beneficial to CaSO4 crystal growth at a certain concentration range. Impurities also affect the crystal morphology, and the addition of Si, Fe, and Na promotes the formation of needle-like crystals compared with other impurities. X-ray diffraction results show that the preferred crystal growth direction is (020), and the interplanar spacing of the crystals is affected by the element radius of the impurities.