西藏扎北盐湖秋季卤水(硫酸钠亚型)5℃等温蒸发实验研究

5℃-Isothermal Evaporation Experiment of Autumn Brines from the Sodium Sulfate Subtype Zhabei Salt Lake in Tibet

西藏扎北盐湖硫酸钠亚型卤水中富含元素Li、B、K和微量元素Rb、Cs等。为了更好地了解卤水在自然条件下的蒸发结晶规律,需对相应卤水进行低温室内等温蒸发实验研究。本文对该盐湖卤水进行了5℃等温蒸发试验,并利用Na+、K+、Mg2+//Cl-、SO42-H2O五元水盐体系0℃相图,构筑了从干基立体图Na2SO4角顶的放射投影图,来分析蒸发过程。结合矿物鉴定给出了卤水5℃等温蒸发时盐类结晶路线和析出规律,为该盐湖卤水的综合开发利用提供重要的基础依据。结果表明:在低温蒸发时,硼在蒸发过程中以硼砂形式析出;钾以氯化钾和钾芒硝形式沉淀;在蒸发浓缩的后期(蒸失率达77.07%以上)大量析出。

The sodium sulfate subtype Zhabei salt lake in Tibet contains abundant special elements Li,B and K and trace elements Rb and Cs.It is necessary to carry out an isothermal evaporation experiment at lower temperatures to probe into the crystallization path of salt minerals at ambient temperatures.The authors conducted an experiment of 5℃-isothermal evaporation of autumn brines and studied the crystallization paths and precipitation regularities of salts in the process of isothermal evaporation by referring to the metastable diagram of the quinary water-salt system of Na＋,K＋,Mg2＋//Cl-,SO42-H2O.The experiment and study provide an important basis for the comprehensive exploitation and use of brines of this salt lake.The experimental results show that boron is precipitated as borax in the whole evaporation process,and potassium is precipitated as sylvite and aphthitalite until the brine is extremely concentrated.