摘要
用等温蒸发方法研究了 NaCl 饱和下的Na^+,K^+∥Cl^-,SO_4~2,CO_3^(2-)-H_2O 五元体系25℃介稳相图,测定了溶液的密度、粘度、折光率、电导率、pH 和蒸汽压,并由蒸汽压数据求得了水活度和渗透系数.在 Jnecke 相图上有五个结晶区,即 Na_2SO_4,Na_2CO_3·2Na_2SO_4,Na_2SO_4·3K_2SO_4,Na_2CO_3·7H_2O 和 KCl 相区.与 Harvie 和 Weare 计算相图比较,无水芒硝和七水碳酸钠结晶区明显扩大,碳钠矾相区明显缩小,钾石盐和钾芒硝相区基本相近.用经验或半经验公式描述了溶液的密度、折光率和粘度随浓度的变化规律.用 Pitzer 电解质溶液模型计算了水活度和析出盐的溶度积.结果是令人满意的.
The metastable phase diagram in the quinary system Na^+,K^+∥Cl^-,CO_3^(2-),SO_4^(2-)-H_2O saturated with NaCl at 25℃ was studied by the isothermal evaporating method.The metastable solubilikies were given and densities,viscosities,refractive indices,conductivities,pH,and vapor pressures of solutions were determined.Wateractivities and osmotic coefficients were calculated from vapor pressure.There arefive crystallization fields (Na_2SO_4,Na_2CO_3·2Na_2SO_4,Na_2SO_4·3K_2SO_4,Na_2CO_3·7H_2O,and KCl) on the J(?)necke phase diagram.In comparison with the diagram,calculatedby Harvie and Weare,thenardite and sodium carbonate heptahydrate crystallizationfields enlarge distinctly,burkeit field reduces obsviously,and sylvite and glaseritefields are almost same.No Na_2CO_3·H_2O and 9Na_2SO_4·2Na_2CO_3·KCl crystallizationfields appear in the titled system.Relationships of densities,refractive indices andviscosities of solutions to concentration were described by terms of empirical orsemiempirical formulae.Water activities and solubility products of the precipitatingsalts wers caloulated using Pitzer's model of aqueous electrolyte solution.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1991年第11期1062-1070,共9页
Acta Chimica Sinica
基金
中国科学院自然科学基金课题
