等压法测定298.15K下LiCl-CaCl2-H2O体系的活度系数

The isopiestic method was used to determinate isopiestic molality and osmotic coefficients in single-salt solutions of LiCl-H2O(molality range from 0.5 to 9.0 mol· kg-1),CaCl2-H2O(molality range from 0.35 to 5.2 mol· kg-1) and multisalt solution LiCl-CaCl2-H2O(ionic strength range from 0.5 to 15.7 mol· kg-1) at 298.15K,from which Pitzer's interaction parameters of single salt ,mixed salts of the systems were obtained.The mean ionic activity coefficients of LiCl、 CaCl2 in pure and mixed solutions were reported.     

等压法测定298.15K下LiCl-CaCl2-H2O体系的活度系数

电解质水溶液热力学性质的研究一直是一个很活跃的研究领域.对含锂水盐体系热力学性质的研究不仅对电解质水溶液理论,而且对盐湖锂资源的开放利用都有非常重要的意义.姚燕等对ＬｉＣｌＫＣｌＨ2Ｏ[1],ＬｉＣｌＭｇＣｌ2Ｈ2Ｏ[2],ＬｉＣｌＭｇＳＯ4Ｈ2Ｏ[3,4],ＬｉＣｌＬｉ2ＳＯ4Ｈ2Ｏ[5]体系多温下热力学性质进行了研究,应用Ｐｉｔｚｅｒ电解质水溶液理论模型进行处理,计算出ＬｉＣｌ在不同体系中,很大的浓度范围内的活度系数.但在盐湖卤水中,ＣａＣｌ2的存在很普遍.对ＬｉＣｌＣａＣｌ2混合物在水溶液中的热力学性质研究对理解ＬｉＣｌ在盐…     

三元体系LiCl-LiNO3-H2O 273.15 K和323.15 K等温溶解度的测定

Solubility of the ternary system LiCl-LiNO₃-H₂O was measured at 273.15 K and 323.15 K by analyzing the equilibrated phase composition. Experimental result shows that there are three solubility branches at 273.15 K, corresponding to the solid phases LiCl·2H₂O，LiNO₃ and LiNO₃·3H₂O, respectively, while there are two solubility branches at 323.15 K, corresponding to the solid phase LiCl·H₂O and LiNO₃. The invariant point compositions are (1) 33.68wt% LiCl, 14.32wt% LiNO₃ and (2) 27.70wt% LiCl, 20.60wt% LiNO₃ at 273.15 K and (3) 39.07wt% LiCl, 16.89wt% LiNO₃ at 323.15 K. Also, the experimental results show that the solid phases in equilibrium with the solution {x(2.8LiCl+LiNO₃)-(1-x)H₂O} are LiNO₃·3H₂O or LiNO₃ at 273.15 K and LiNO₃ at 323.15 K.     

LiCl-Li2B4O7-H2O体系在298.15 K下热力学性质的等压研究

用等压法研究了298.15 K下LiCl-Li2B4O7-H2O体系在不同LiB4O7质量摩尔浓度时的等压平衡浓度,  水活度; 计算了LiCl和Li2B4O7混合盐溶液的渗透系数等热力学性质. 用298.15 K下的实验数据对Pitzer离子相互作用模型进行了参数化研究, 拟合求取了298.15 K下Pitzer离子相互作用参数, 用获得的参数计算了LiCl和Li2B4O7在LiCl-Li2B4O7-H2O体系中的活度系数. Pitzer模型计算的渗透系数值与实验结果一致.     

298.15K下Li2B4O7-H2O体系水蒸汽分压及渗透系数的等压测定和离子相互作用模型

在已有研究含硼体系的文献中仅考虑了硼酸根B4O7^-2或B(OH)4^-和H3BO3的存在，而对Li2B4O7-H2O体系具有多种硼物种聚合平衡体系的热力学性质的研究尚未见报道．本文用等压法研究了Li2B4O7-H2O体系于298．15K下浓度由稀到过饱和溶液的平衡气相蒸汽压及渗透系数．考虑了水溶液中多种硼物种的存在，以Pitzer方程为基础，建立了可描述该含硼体系的离子相互作用模型。     

Me-NaHCO3-NH3-H2O体系和Me-NaOH-NaHCO3-H2O体系的热力学分析

通过对Me(Fe2+,Ni2+,Cu2+,Zn2+)-NaHCO3-NH3-H2O体系以及Me-NaOH-NaHCO3-H2O体系的热力学分析,得到各金属离子总浓度cMe与pH值的关系,确定了2种体系的完全共沉淀区域.热力学分析结果表明:在Me-NaHCO3-NH3-H2O体系中,Ni2+,Cu2+,Zn2+这3种离子和氨的配位能力很强.当总碳的浓度cC=1 mol·L-1且总氮的浓度cN=0.01 mol·L-1时,在pH=7.5～11范围内可实现完全共沉淀:当cN=0.05 mol·L-1且cC=3 mol·L-1时,在pH=70.5时可实现完全沉淀,但共沉淀范围较窄,不利于铁氧体组分的精确控制.在Me-NaOH-NaHCO3-H2O体系中,共沉淀区域由cC决定,当cC=1 mol·L-1,pH=7.5～11时可实现完全共沉淀.     

298.15 K Li2B4O7-MgCl2-H2O体系热力学性质的电动势法测定及离子相互作用模型的研究

测定了298.15 K下, 无液接电池Li-ISE│Li₂B₄O₇ (m_A)(aq.), MgCl₂(m_B)(aq.)│AgCl/Ag的电动势, 利用测定结果计算了Li₂B₄O₇-MgCl₂-H₂O体系离子强度在0.05～3 mol•kg^－1范围内, 不同MgCl₂离子强度分数的溶液中LiCl的平均活度系数, 并给出了其随离子强度I, B₄O₇^2－和Mg^2＋浓度的变化规律. 结合以往关于该体系和Li₂B₄O₇-LiCl-H₂O, Li₂B₄O₇-H₂O体系的等压研究结果, 用迭代和多元线性回归方法对Li^＋-Mg^2＋-Cl^－-B₄O₇^2－-H₂O体系的离子相互作用模型进行了研究. 具体方法为考虑了该体系在不同的总硼浓度范围H₃BO₃, B(OH)₄^－, B₃O₃(OH)₄^－和B₄O₅(OH)₄^2－四种含硼化合物的存在以及各硼化合物间的化学平衡, 以修正了的Pitzer渗透系数方程和活度系数方程为基础, 对该体系的等压法和电动势法研究结果进行最小二乘拟合, 拟合的标准偏差为0.0167, 用该模型计算的该体系的渗透系数、活度系数与实验值基本一致.     

298.15 K Li2B4O7-MgCl2-H2O体系热力学性质的电动势法测定及离子相互作用模型的研究

测定了298.15 K下, 无液接电池Li-ISE│Li₂B₄O₇ (m_A)(aq.), MgCl₂(m_B)(aq.)│AgCl/Ag的电动势, 利用测定结果计算了Li₂B₄O₇-MgCl₂-H₂O体系离子强度在0.05～3 mol•kg^－1范围内, 不同MgCl₂离子强度分数的溶液中LiCl的平均活度系数, 并给出了其随离子强度I, B₄O₇^2－和Mg^2＋浓度的变化规律. 结合以往关于该体系和Li₂B₄O₇-LiCl-H₂O, Li₂B₄O₇-H₂O体系的等压研究结果, 用迭代和多元线性回归方法对Li^＋-Mg^2＋-Cl^－-B₄O₇^2－-H₂O体系的离子相互作用模型进行了研究. 具体方法为考虑了该体系在不同的总硼浓度范围H₃BO₃, B(OH)₄^－, B₃O₃(OH)₄^－和B₄O₅(OH)₄^2－四种含硼化合物的存在以及各硼化合物间的化学平衡, 以修正了的Pitzer渗透系数方程和活度系数方程为基础, 对该体系的等压法和电动势法研究结果进行最小二乘拟合, 拟合的标准偏差为0.0167, 用该模型计算的该体系的渗透系数、活度系数与实验值基本一致.     

等压法测定Li2SO4-MgSO4-H2O体系的渗透和活度系数

在25 ℃下, 离子强度范围分别为0.2—8.7、0.6—12.7和1.4—13.5 mol·kg~(-1)时, 测定了纯Li_2SO_4、MgSO_4及Li_2SO_4-MgSO_4混盐水溶液的渗透系数. 计算了Pitzer方程和Scatchard方程的离子作用参数. 用上述两种方程及由热力学关系式直接推导出的Mckay-Perring方程计算并比较了Li_2SO_4和MgSO_4在混合溶液中的平均活度系数, 三者在实验误差范围内一致. 利用获得的Pitzer参数计算该体系的溶解度与文献值基本一致.     

25℃时三元体系SrCl2-CaCl2-H2O相平衡研究

采用等温溶解平衡法,研究了三元体系SrCl2-CaCl2-H2O 25℃相平衡,同时测定了平衡溶液的物化性质(密度和折光率)。平衡液相所对应的平衡固相由湿渣法、偏光显微镜观测法和XRD法确定。根据实验研究数据,绘制了该三元体系相图。相图由3个无变量点、4条单变量曲线和4个盐类结晶区构成,4个结晶区分别对应CaCl2.6H2O、钙盐为基固溶体、锶盐为基固溶体和SrCl2.6H2O结晶区。     

Thermodynamics study of the Cs2SO4-MgSO4-H2O system at the temperature 298.15 K

The Pitzer ion-interaction model has been used for thermodynamics simulation of the ternary system Cs₂SO₄-MgSO₄-H₂O at 298.15 K. The Pitzer ternary mixing parameter $ \psi _{CsMgSO_4 } $ \psi _{CsMgSO_4 } and thermodynamic characteristics for double salt Cs₂SO₄ · MgSO₄ · 6H₂O have been calculated and the theoretical solubilities isotherm has been plotted.     

Isopiestic Osmotic Coefficients of Tetra-n-methylammonium Chloride with Guanidinium Salts at 298.15 K

Isopiestic osmotic coefficients are presented for aqueous mixtures of tetra-n-methylammonium chloride, (CH₃)₄NCl, with guanidinium salts such as GnCl, CH₃COOGn, GnNO₃, GnClO₄ and Gn₂SO₄ at 298.15 K up to an ionic strength of 2 mol?kg^?1. The osmotic coefficients are analyzed in terms of the Scatchard-Rush-Johnson equations. The activity coefficients of each electrolyte in the mixtures were calculated and fitted by the Harned-type equations. The molar excess Gibbs energy of mixing, Δ_m G ^E, of the mixtures were analyzed with Friedman’s equations.     

Phase equilibria in the system Na,K,Mg,Ca∥SO4,Cl-H2O at 25°C in the crystallization regions of MgCl2·6H2O, CaCl2·6H2O, and 2MgCl2·CaCl2·12H2O

The translation method is used to study equilibria in the system Na, K, Mg, Ca∥SO₄, Cl-H₂O at 25°C in the crystallization regions of MgCl₂·6H₂O, CaCl₂·6H₂O, and 2MgCl₂·CaCl₂·12H₂O. The participation of these salts in the formation of the geometrical images of the title system is determined. The relevant fragments of the equilibrium phase diagram are designed. Original Russian Text ? L. Soliev, 2007, published in Zhurnal Neorganicheskoi Khimii, 2007, Vol. 52, No. 5, pp. 841–845.     

Solubility prediction for the system of MgCl2-MgSO4-MgB4O7-H2O at 298.15 K using the ion-interaction model

Solubilities for the system of MgCl₂-MgSO₄-MgB₄O₇-H₂O at 298.15 K were calculated by using Pitzer and its extended HW model. The values of the parameters were derived from either literature or through fitting with the solubility data of the relative ternary system in literature. A comparison with the experimental values and calculated solubility data shows that the model can be used successfully to predict the solubilities of the mentioned system. Parameters got in this study can be further used for solubility prediction of more complicated system containing MgB₄O₇, and the results could provide a theoretical basis for exaction of magnesium borate from salt lake brine resources.