标题：Studies of phase relations and AFm solid solution formations in the system CaO-Al2O3-CaCl2-CaCrO4-H2O

作者： Zhou, X (Zhou, Xian); Zhou, M (Zhou, Min); Wu, X (Wu, Xian); Wan, S (Wan, Sha); Gen, JJ (Gen, Junjun); Hou, HB (Hou, Haobo)

来源出版物：APPLIED GEOCHEMISTRY卷：80页码：49-57 DOI：10.1016/j.apgeochem.2017.02.014 出版年：MAY 2017

摘要：The Friedel's salt (Cl-AFm) as a major hydration phase in chlorinated cement-based materials plays an important role in the immobilization of chromate through ion exchange with chloride. To study the solid solutions of Ca-4[Al(OH)(6)](2)CrO4 center dot nH(2)O (CrO4-AFm) and the composition of coexisting aqueous phase, AFm phases containing Cl- and CrO2- 4 were synthesized and characterized with XRD, SEM, FTIR, FAAS and Ion chromatography (IC).

Based on the determined total solubility of products and ion concentrations in solution, a solid solution-aqueous solution (SSAS) model for binary mixing of Cl-AFm and CrO4-AFm phases was established to predict aqueous solubility of Ca-4[Al(OH)(6)](2)[(CrO4)x(Cl)(2-2x)]center dot nH(2)O as a function of total Cl/Cr ratio in solid solution system. The solubility constant (pK) of pure Cl-AFm is 27.09 and its free energy of formation (Delta Go f) is -7047.80 kJ mol(-1) at 27 degrees C. pK of pure CrO4-AFm is 29.07 and its Delta Go f is -8238.66 kJ mol(-1) at 27 degrees C. Both the experimental and modeled data showed that the formation of solid solutions between Cl-AFm and CrO4-AFm could greatly lower the chromate concentration in aqueous solution. Therefore, this study suggested that (Cl, CrO4)-AFm compounds could efficiently immobilize the trace metal CrO42- in cement-stabilized wastes. (C) 2017 Published by Elsevier Ltd.

入藏号：WOS:000400219000004

文献类型：Article

语种：English

作者关键词： Chromate; AFm phases; Lippmann diagrams; Solid solution; Aqueous solution

扩展关键词： AQUEOUS-SOLUTION; FRIEDELS SALT; THERMODYNAMIC PROPERTIES; HEAVY-METALS; DEGREES-C; CEMENT; SOLUBILITY; CHROMATE; IMMOBILIZATION; ETTRINGITE

通讯作者地址：Hou, HB (reprint author), Wuhan Univ, Sch Resource & Environm Sci, Wuhan 430072, Hubei, Peoples R China.

电子邮件地址： houhb@whu.edu.cn

地址：

[Zhou, Xian; Zhou, Min; Wan, Sha; Gen, Junjun; Hou, Haobo] Wuhan Univ, Sch Resource & Environm Sci, Wuhan 430072, Hubei, Peoples R China.

[Wu, Xian] Huazhong Univ Sci & Technol, Sch Environm Sci & Engn, Wuhan 430074, Hubei, Peoples R China.

研究方向：Geochemistry & Geophysics

ISSN：0883-2927

影响因子：2.468