青藏高原南部地热型锂资源

Geothermal-type lithium resources in Southern Tibetan Plateau

高温地热水中含有丰富的锂资源,世界各国对其中锂资源的开发利用的研究越来越多。对青藏高原丰富的地热资源中富锂地热资源进行了综述,得出其具有以下特点:(1)构造控制强烈,地热型锂资源主要分布在雅江缝合带两侧及其南部地区强烈活动的高温地热田中,受到沿近NS向正断层发育的裂谷或地堑盆地的强烈控制;(2)品质好,锂含量可高达239 mg/L;Mg/Li非常低,多数富锂地热系统Mg/Li介于0.03~1.48;Li/TDS相对较高且介于0.25%~1.14%(扎布耶富锂盐湖为0.19%;玻利维亚乌尤尼盐湖为0.08%~0.31%);持续稳定排放数十年,部分达到工业品位(32.74 mg/L);伴生可以综合利用的B、Cs和Rb元素等;(3)规模大:据不完全统计,当前锂含量达到或超过19 mg/L的富锂温泉至少有19处,年排出金属锂约4281 t,折合碳酸锂25686 t,并且最新钻孔数据表明地热田深部潜力巨大;(4)属于非火山型,火山岩缺失;(5)深部来源成因,富锂地热系统的形成与印度和欧亚大陆碰撞引起的地壳深部部分熔融密切相关,深部熔融岩浆为富锂地热系统提供了稳定的热源,富锂的母地热流体沿着青藏高原南部广泛发育的断裂带上涌至地表形成高温富锂热泉。由此,认为青藏高原南部广泛发育的高温富锂地热资源是一种非常有价值、值得开发利用的地热型锂资源,随着地热水中锂提取技术的不断提升,青藏高原南部地热型锂资源有望成为一种可有效开发利用的锂矿床新类型——地热型锂矿床。

The high-temperature geothermal water contains abundant lithium resources,and the development and the utilization of the geothermal-type lithium resources are increasingly paid attention around the world.This paper reviews the lithium-rich geothermal resources among the geothermal resources on the Qinghai-Tibet Plateau,and it is concluded that these resources have the following characteristics:(1)strong structural control:the lithium-rich geothermal spots in Southern Tibetan Plateau are often found in the intensely active high-temperature geothermal fields and are distributed on both sides of the Yarlung Zangbo suture zone and its southern part,strongly controlled by north-south trending rifts or grabens formed by E–W extension;(2)good quality:the lithium concentration is up to 239 mg/L;the Mg/Li ratio is extremely low and ranges from 0.03 to 1.48 for most of the lithium-rich geothermal fluid;the Li/TDS value is relatively high and ranges from 0.25%-1.14%(Zhabuye lithium-rich salt lake:0.19%;Salar de Uyuni(Bolivia):0.08-0.31%);the continuous discharge is stable at least for several decades,in some parts reaches the industrial grades(32.74 mg/L:according to the industrial grades of Salt lake brine),and in addition,the elements such as B,Cs,and Rb are rich and can be comprehensively utilized;(3)large scale:according to incomplete statistics,there are at least 16 lithium-rich hot springs with lithium concentration of 19 mg/L or more,and the total discharge of lithium metal is about 4281 tons every year,equivalent to 25686 tons of lithium carbonate,moreover,drilling data show that the depth is still very promising;(4)lack of volcanism(non-volcanic geothermal system);(5)deep origin:the formation of lithium-rich geothermal resources are closely related to the deep crust partially melting caused by the collision of the Indo-Asia continent,the deep molten magma provides a stable heat source for the high-temperature lithium-rich geothermal field and the lithiumrich parent geothermal fluid rushes to the surface to form hot springs along the extensively developed tectonic fault zones in Southern Tibetan Plateau.Therefore,the widely developed high-temperature lithium-rich geothermal resources in the southern Qinghai-Tibet Plateau are valuable and worthy lithium resources.With the continuous advancement of the lithium extraction technologies on lithium-rich geothermal fluid,the lithium resource in Southern Tibetan Plateau is becoming a promising new type of mineral deposit—the geothermal-type lithium deposit and will be effectively exploited.