现代盐湖低品位固体钾盐溶矿数值模拟研究——以察尔汗盐湖别勒滩矿区为例  

Numerical simulation analysis on potash dissolution extraction from low-grade solid potash ore in modern salt lake——a case study from Bieletan mining area in the Qarhan salt lake

作　　者：李瑞琴[1,2] 刘成林 焦鹏程[1] 刘万平 王石军[3] LI Ruiqin;LIU Chenglin;JIAO Pengcheng;LIU Wanping;WANG Shijun(MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;School of earth and space Sciences,Beijing 100871,China;Peking University,QingHai Salt Lake Industry Co.,Ltd.,Qinghai 816000,China)

机构地区：[1]中国地质科学院矿产资源研究所,自然资源部成矿作用与资源评价重点实验室,北京100037 [2]北京大学地球与空间科学学院,北京100871 [3]青海盐湖工业股份有限公司,青海816000

出　　处：《地质学报》2021年第7期2150-2159,共10页Acta Geologica Sinica

基　　金：青海省自然科学基金(编号2019-ZJ-917);国家重点研发计划课题(编号2018YFC0604801);中央级公益性科研院所基本科研业务费专项(编号KK2005);全国矿产资源国情调查与综合评价(编号DD20190606)联合资助的成果。

摘　　要：察尔汗盐湖拥有2.96亿t低品位固体钾盐,这些资源相当于一个超大型钾矿。通过溶解转化技术将其转化成与盐层晶间卤水组成相似的富钾卤水,方可利用。本文采用PHREEQC软件对察尔汗盐湖低品位固体钾盐溶解转化过程进行了反向模拟,旨在定量研究该溶矿过程。通过模拟计算出了溶矿过程中主要矿物相的转移量,结果表明:溶矿过程中,每1 mmol L溶液中石膏析出量在10.85~12.97 mmol之间,石盐的溶解量在494.2~1616 mmol之间,杂卤石的溶解量在0.63~3.119 mmol之间,光卤石的溶解量在4.732~380.2 mmol之间,钾石盐的溶解量在63.64~387.6 mmol之间,方解石的溶解量在0.141~0.381 mmol之间,NaX与MgX_(2)发生的离子交换量在101.1~918 mmol之间。察尔汗盐湖地层中的主要钾盐矿物为杂卤石、光卤石和钾石盐,溶矿过程中这些矿物的溶解使溶液中K^(+)含量不断增加,不同溶矿区域液相中K^(+)浓度增加量不同,是盐层地质构造差异及钾盐矿物分布不均匀造成的;推测杂卤石的溶解是造成微量石膏析出的主要原因;溶剂含有浓度较高的MgCl_(2),NaCl与MgCl_(2)之间同离子效应及阳离子交换作用共同影响着液相中石盐的溶解度。Thereare 296 million tons of low-grade solid potash minerals in the Qarhan salt lake,which have potential utilization value.These low-grade solid potash minerals are equivalent to a super large potash deposit.The low-grade solid potash minerals can be transformed into brine with the same properties as the intercrystalline brine existing in the salt layers through the dissolution transformation technology.In this paper,the dissolution and transformation process of low-grade solid potash ore in the Qarhan salt lake was simulated by PHREEQC software in order to quantify the process.The transfer amount of the main minerals in the process of potash ore dissolution was calculated by simulation.The results show that in the process of potash minerals dissolving in per 1 L solution,the amount of gypsum precipitation is between 10.85 and 12.97 mmol,the amount of halite dissolved is between 494.2 and 1616 mmol,the amount of polyhalite dissolved is between 0.63 and 3.119 mmol,the amount of carnallite dissolved is between 4.732 and 380.2 mmol,the amount of sylvite dissolved is between 63.64 and 387.6 mmol,the amount of calcite dissolved is between 0.141 and 0.381 mmol,and ion exchange capacity between NaX and MgX_(2) is 101.1 to 918 mmol.The study indicates that the main potash minerals in Qarhan salt lake are polyhalite,carnallite and sylvite.The dissolution of these potash minerals causes the content of K^(+)in the solution to continuously increase.However,the increase in K^(+)concentration in liquid phase is different in different areas,which is caused by the differences in the geological structure of salt bed and the uneven distribution of potash minerals.It is proposed that the dissolution of polyhalite is the main reason for the precipitation of trace gypsum.Due to the high concentration of MgCl_(2 )in the solvent,the same-ion effect and cation exchange between NaCl and MgCl_(2 ) jointly controls the solubility of halite in liquid phase.

关 键 词：察尔汗盐湖 低品位固体钾盐 PHREEQC 反向数值模拟 水化学 

分 类 号：P619.211[天文地球—矿床学]