Inorganic Chemicals Industry >
Study on phase equilibrium of ternary system of Na2CO3-NaF-H2O at 298.15 K and 318.15 K
Received date: 2021-04-13
Online published: 2022-03-18
Wastewater containing sodium carbonate and sodium fluoride will be generated in the rare earth extraction process and the preparation process of sodium fluoride.The phase equilibrium of the ternary system of Na2CO3-NaF-H2O was studied to provide theoretical guidance for the preparation of practical production and recovery of sodium fluoride and sodium carbon-ate.The isothermal dissolution equilibrium method was used to study the phase equilibrium relationship of the ternary system of Na2CO3-NaF-H2O at 298.15 K and 318.15 K.The solubility of each component of the system and the density and pH of the equilibrium liquid phase were measured.The phase diagram and the relationship between physicochemical parameters and content of component were drawn according to the solubility data.The solid phase was analyzed and characterized by X-ray diffraction(XRD).The experimental study showed that the system had no double salt and solid solution,and belonged to the I-type phase diagram of hydrate.The phase diagram included 1 all-liquid region,2 single-salt crystallization regions,1 mixed crystallization region,1 all-solid region,3 univariate solubility curves,and 1 co-saturation point.Na2CO3 had a strong salting-out rate for NaF.When the temperature was constant,the mass fraction of Na2CO3 was higher,the density was greater,and the pH of the solution was greater.When the mass fraction of Na2CO3 was constant,the temperature was higher,the density was greater,and the pH of the solution was lower.
Ziyu LU , Zhaogang LIU , Jinxiu WU , YanHong HU , Xingyu LIU . Study on phase equilibrium of ternary system of Na2CO3-NaF-H2O at 298.15 K and 318.15 K[J]. Inorganic Chemicals Industry, 2022 , 54(3) : 66 -70 . DOI: 10.19964/j.issn.1006-4990.2021-0240
[1] | 刘晓红, 卢爱军. 氟化钠制备的新工艺研究[J]. 化肥工业, 2004, 31(6):32-34. |
[2] | 闫余俊, 李梅, 张栋梁, 等. 钠碱焙烧分解混合型稀土精矿工艺中稀土与氟磷的强化分离研究[J]. 中国稀土学报, 2017, 35(4):494-500. |
[3] | 张杰, 史学伟, 赵双良, 等. 水盐体系相平衡研究进展[J]. 化工学报, 2016, 67(2):379-389. |
[4] | NIZOMOV I, SOLIEV L. Solubility in the Na2CO3-NaHCO3-NaF-H2O system at 25 ℃[J]. Russian Journal of Inorganic Chemistry, 2011, 56:803-807. |
[5] | 李红霞. 四元体系NaF-Na3PO4-NaOH-H2O及其子体系离子浓度测定方法探究[J]. 冶金分析, 2020, 40(11):78-85. |
[6] | WANG Linjun, ZHANG Wei, YANG Bin, et al. Solubility measure-ments in Na-F-CO3-HCO3-H2O system at(308.15 and 323.15)K and development of a pitzer-based equilibrium model for the Na-F-Cl-SO4-CO3-HCO3-H2O system[J]. Journal of Chemical Thermody-namics, 2019, 131(1):88-96. |
[7] | FELMY A R, MACLEAN G T. Development of an enhanced ther-modynamic database for the pitzer model in ESP:The fluoride and phosphate components[D]. PNWD-3120,WTP-RPT-018,Batt-elle-Pacific Northwest Division,Richland,WA, 2001. |
[8] | 郝晴, 李梅, 黄兰, 等. Na2CO3-NaF-H2O三元水盐体系在313.15 K和343.15 K相平衡研究[J]. 化学工程, 2020, 48(6):57-62. |
[9] | 郝晴. 基于混合稀土矿氟磷回收多元钠盐体系相平衡研究[D]. 包头:内蒙古科技大学, 2020. |
[10] | 刘晓辉, 于文清. 双指示剂法测定混合碱误差的主要原因[J]. 承德民族师专学报, 2009, 29(2):46-47. |
[11] | 吕辉, 梁秀丽, 王爱萍, 等. 液体密度测定方法及标准应用[J]. 山东化工, 2016, 45(6):49-51. |
[12] | 邓天龙, 周桓, 陈侠. 水盐体系相图及应用[D]. 北京:化学工业出版社, 2013. |
[13] | 焦勇. 强碱弱酸盐溶液中离子浓度大小比较探析[J]. 高中数理化, 2020(12):62. |
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