298.2 K四元体系MgCl_(2)+CaCl_(2)+AlCl_(3)+H_(2)O相平衡研究

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。