The basic characteristics and development potential evaluation of salt lake brine-type lithium deposits

This paper is the result of mineral exploration engineering.

In recent years, the new energy industry sees a robust growth with strong demand for lithium batteries and fierce competition for lithium resources. Compared with hard rock-type lithium deposits, which are currently the main type for lithium exploitation, salt lake brine-type lithium deposits have the advantages in reserves, environment-friendly and financial benefit. With the continuous improvement of lithium extraction technology from brine, the production capacity of salt lake brine-type lithium deposits will be further released. China is one of the countries where salt lake brine-type lithium deposits are mainly distributed, and the resources reserves is ranked 5th around the world. In the world-wide fierce competition for lithium resources, it is of great significance to summarize distribution regularity, hydrochemical classification and mineral combination of salt lake brine- type lithium deposits, while estimating potential resources and proposing an evaluation methods for salt lake brine-type lithium deposits also contribute to the arrangement of protesting and exploitation investment and the scheduling of new energy resources in our country.

We collect the published data of salt lake brine-type lithium deposits, analyze the basic characteristics from the aspects of distribution and geological conditions of metallogenesis, and systematically summarize the estimation of potential resources and evaluation the potential in exploitation.

Lithium resources from salt lake brine-type deposits are abundant in the world, but the distribution is uneven. Salt lake brine-type lithium deposits are mainly located in the three major plateaus, namely the Andes Plateau in South America, the western Plateau of the United States and the Qinghai-Tibet Plateau of China. The genesis is mainly controlled by tectonic background, fault activities, climate and altitude. The difference between salt lake brinetype lithium deposits in the Qinghai- Tibet Plateau and those in other two salt lake accumulation areas is that the tectonic background of the Qinghai-Tibet Plateau is continental collision rather than oceanic crust subduction. The salt lakes in the QinghaiTibet Plateau can be further divided into two parts: the Tibet salt lake area and the Qinghai salt lake area from south to north. On the one hand, the salt lakes in Qinghai area has high Mg/Li ratio, so the exploitation is not suitable for the traditional evaporation precipitation method. On the other hand, new emerging lithium extraction methods cost high, as a result, the exploitation and technical conditions need to be evaluated carefully.

Based on the published data, the ore-bearing coefficient"N"and harvest coefficient"HI"of three salt lake accumulation areas are calculated and the general formula for estimating the potential resources is also established. By considering the key points of exploitation evaluation of salt lake brine-type lithium deposits, the quality of lithium deposits in world-famous salt lake areas is evaluated by using the"lg(Li ⁺)-lg(Mg/Li) combining the price of lithium carbonate discriminant diagram". The results show that if the price of lithium carbonate is below 100, 000 yuan/ton, the quality of salt lakes is ranked as follows: Tibet, China > Andean Plateau of South America > Western Plateau of the United States > Qinghai, China; if the price of lithium carbonate goes above 100, 000 yuan/ton, the order changes to: Andean Plateau of South America > Tibet China > Qinghai China > Western Plateau of the United States.