柴达木盆地砂砾型孔隙卤水夏季自然蒸发实验

Natural Evaporation Experiment of Sand Gravel Type Pore Brine in Qaidam Basin in Summer

这是一篇矿业工程领域的论文。柴达木盆地深层砂砾型孔隙卤水属高钙、高钠、低钾的不饱和氯化物型卤水,尚未开发。选取大浪滩矿区地下1000~2000 m处砂砾型孔隙卤水480 kg,在夏季自然状态下蒸发结晶,分析各离子在固、液相中的分布规律及盐类结晶规律、结晶形态,研究钾的主要析出特点。结果表明:在室外自然状态下蒸发时,析盐过程主要分为石盐→光卤石→水氯镁石→溢晶石四个阶段,其中石盐阶段析盐规律符合Na^(+),K^(+),Mg^(2+)//Cl^(-)—H_(2)O体系25℃相图,光卤石、水氯镁石阶段符合K^(+),Ca^(2+),Mg^(2+)//Cl^(-)—H_(2)O体系25℃相图;钾有单独的析出阶段,该阶段钾主要以光卤石形态析出,钾的回收率达85.76%,钾混盐中K^(+)含量9.27%,是生产钾肥的优质原料;钙在水氯镁石阶段之后析出。实验结果可为该类型卤水的开发利用提供参考。

This is an article in the field of mining engineering.The deep sand gravel type pore brine in Qaidam Basin belongs to the unsaturated chloride type brine with high calcium,high sodium and low potassium.480 kg of gravel-type pore brine at 1000~2000 meters underground in Dalangtan mining area was selected for the test,and evaporated and crysta-llized in the natural state in summer.The distribution law of ions in the solid and liquid phases,the salt crystallization law and crystal morphology were analyzed,and the main precipitation characteristics of potassium were studied.The results show when evaporating in the outdoor natural state,the salt precipitation process is mainly divided into four stages:halite→carnallite→bischofite→tachyhydrite.The salt evolution law in the halite stage conforms to the phase diagram of Na+,K^(+),Mg^(2+)//Cl^(-)—H2O at 25℃,and that in carnallite and bischofite stages conforms to the phase diagram of K^(+),Ca^(2+),Mg^(2+)//Cl^(-)—H_(2)O system at 25℃.There is a separate precipitation stage of potassium,at which potassium is mainly precipitated in the form of carnallite,and the recovery rate of potassium is 85.76%.The K^(+)content in the potassium mixed salt can reach 9.27%,which is a high quality raw material for the production of potassium fertilizer.Calcium precipitates after the brucite stage.The experimental results can provide references for the development and utilization of this type of brine.