摘要：为了获取锂钠钾共存硫酸盐体系298.2 K下各盐结晶形式,采用等温溶解平衡法研究了298.2 K下四元体系Li_(2)SO_(4)+Na_(2)SO_(4)+K_(2)SO_(4)+H_(2)O的相平衡关系,测定了该体系的溶解度和密度,采用X-ray粉晶衍射法测定了平衡固相组成,并绘制了相应的稳定相图和多温对比图。研究表明,298.2 K下该四元体系为复杂四元体系,有复盐2Li_(2)SO_(4)·Na_(2)SO_(4)·K_(2)SO_(4)、Li_(2)SO_(4)·3Na_(2)SO_(4)·12H_(2)O、LiKSO_(4)、Na_(2)SO_(4)·3K_(2)SO_(4)生成。其稳定相图由6个四元共饱点、12条单变量曲线以及7个结晶区组成。其中,复盐Na_(2)SO_(4)·3K_(2)SO_(4)结晶区最大,表明其在该体系中最易结晶析出;Li_(2)SO_(4)·H_(2)O结晶区最小。对比273.2 K、288.2 K、298.2 K、323.2 K、373.2 K四元体系多温相图可知,273.2 K时未发现复盐Na_(2)SO_(4)·3K_(2)SO_(4)和2Li_(2)SO_(4)·Na_(2)SO_(4)·K_(2)SO_(4)结晶形式;Na_(2)SO_(4)·10H_(2)O和Li_(2)SO_(4)·3Na_(2)SO_(4)·12H_(2)O结晶形式在323.2 K和373.2 K时转变为Na_(2)SO_(4)和Li_(2)SO_(4)·Na_(2)SO_(4)。288.2~373.2 K时随温度升高,K_(2)SO_(4)和Na_(2)SO_(4)·10H_(2)O结晶相区减小,Li_(2)SO_(4)·H_(2)O、Na_(2)SO_(4)、LiKSO_(4)和Li_(2)SO_(4)·Na_(2)SO_(4)结晶相区增大;Na_(2)SO_(4)·3K_(2)SO_(4)结晶相区先增大后减小,在298.2 K时结晶相区最大;2Li_(2)SO_(4)·Na_(2)SO_(4)·K_(2)SO_(4)结晶相区先减小后增大,298.2 K时结晶相区最小。

摘要：为获取粉煤灰含铝溶浸液中铝与共存钙、镁之间的作用规律,采用等温溶解平衡法开展了298.2 K时四元体系MgCl_(2)+CaCl_(2)+AlCl_(3)+H_(2)O相平衡研究,测定了平衡液相组成及平衡液相密度,同时,绘制了该四元体系的干基相图、水图、密度-组成图。研究发现:298.2 K四元体系MgCl_(2)+CaCl_(2)+AlCl_(3)+H_(2)O稳定相图由2个共饱点、4个结晶区以及5条单变量曲线组成,有复盐溢晶石(2MgCl_(2)·CaCl_(2)·12H_(2)O)生成,为复杂四元体系。4个结晶区分别对应3个单盐结晶区MgCl_(2)·6H_(2)O、CaCl_(2)·6H_(2)O、AlCl_(3)·6H_(2)O和1个复盐结晶区2MgCl_(2)·CaCl_(2)·12H_(2)O,结晶区按照AlCl_(3)·6H_(2)O、MgCl_(2)·6H_(2)O、CaCl_(2)·6H_(2)O、2MgCl_(2)·CaCl_(2)·12H_(2)O顺序依次减小,对应AlCl_(3)·6H_(2)O溶解度最小,2MgCl_(2)·CaCl_(2)·12H_(2)O溶解度最大。