Study On Resource Elemnet Migration During Crystallization Of Brine Of Xitaijinaier Salt Lake

Xitaijinaier salt lake brine in insolation evaporation crystallization process such as lithium,potassium,magnesium,boron resources elements of soil infiltration,entrainment,crystal mother liquor package,and the possible loss way such as adsorption,the face makes resources element in the development of low recovery efficiency in the process of extraction,extraction of potassium magnesium salt and rich lithium brine into the workshop further losses in the machining process,The recovery rate of lithium,potassium and boron is less than 30%,50%and 40%respectively,which causes great loss and seriously affects the comprehensive development and utilization of resource elements.Based on this,this paper systematically studied the migration rules of lithium,potassium,magnesium and boron in liquid and solid phases during evaporation and crystallization of brine from Xitaijinaier Salt Lake,using natural evaporation and boiling evaporation-isothermal equilibrium two research methods.Different evaporation of Xitaijinaier salt lake brine salting stage of resource elements loss and migration and enrichment in the liquid phase,solid phase entrainment in the mother liquor,adsorption and crystal crystal inclusions loss way has carried on the qualitative and quantitative analysis,such as evaporation and investigates groove depth and evaporation area of the influence of different natural evaporation crystallization process.The results show that the evaporation water loss rate of0%～81.9%is sodium salt stage,81.9%～91.8%is potassium mixed salt stage,91.8%～96.4%is carnallite stage.The loss rate of Li⁺and boron in carnallite stage was 20.5%,27.2%,29.4%and 30.3%,31.0%,37.7%,respectively.The total loss rates of potassium and magnesium in the three groups were 22.7%,14.3%,21.8%and 26.4%,23.1%,24.8%,respectively.The total loss rate of Li⁺was 55.7%,55.6%in natural evaporation experiment and 39.1%in boiling evaporation-isothermal equilibrium experiment.X-ray diffraction（PXRD）,microscopic Raman spectroscopy（Raman）,scanning electron microscopy（SEM）,polarizing microscope,X-ray photoelectron spectroscopy（XPS）and other characterization methods were used to analyze and identify the solid phase in different evaporation and salting stages,and determine the entrap and non-entrap amounts of the resource elements in the mother liquor.It is proved that liquid inclusions,bubble inclusions and gas-liquid inclusions exist simultaneously in different solid phases.The loss of lithium and boron in solid phase is less and less with the increase of evaporation loss rate,which proves that the loss of lithium and boron is mainly absorbed by inclusion and crystal plane in sodium salt stage and potassium mixed salt stage,and mainly absorbed by mother liquor in carnallite stage.There is a Raman characteristic peak caused by BO₃^3-stretching vibration in the liquid inclusions of potassium mixed salt stage,which proves that boron element is lost in the form of liquid inclusions with evaporation crystallization.The analysis of the chemical composition of the solid phase,XPS and EDS results showed that the proportion of each ion was significantly different,indicating that there were three kinds of loss pathways of resource elements in the solid phase obtained from the evaporation and salting process of the brine of Xitaijinaier Salt Lake,including crystal surface adsorption,crystal inclusion and entraining of mother liquor.