A Systematic Study on the Impact of the Evaporation Rate on Lithium Recovery from Brines

Lithium Extraction from hard brines involves a detailed and multi-stage process to maximize lithium recovery. The initial state of brine treatment is to remove or recover the divalent ion-based minerals in their pure or mixed form. Once all the divalent ions are recovered from the brine, mainly sodium and lithium ions are present in the brine with some impurities. The brine samples we have considered in this study have lithium amounts above 50 ppm. One needs to concentrate the brine using a thermal method, such as vacuum-based evaporative crystallization, to recover fresh water and crystallized salts, mainly sodium chloride. In this way, lithium concentration in the brine can be increased above 100 ppm while recovering pure NaCl salts, which have a value. The process that is studied here involves the recovery of all the mineral salts from the brine in their purest form. We have performed a systematic study to determine the rate of evaporation at which we have the maximum amount of Lithium concentration left in the concentrated brine. In the case of salar brine from brine ponds, there has been a literature study that shows that as the brine gets concentrated due to evaporation, the crystals formed in this process are soaked with a brine that becomes richer in lithium as evaporation progresses. In the case of the hard-produced water brine, the loss of lithium to the crystals in a soaked brine is unknown. In this study, we will first perform the systematic evaporation at various evaporation cuts from 10 to 80% and map the loss of lithium to the crystallized salts. The systematic evaporation and sample collection, and testing will allow us to arrive at the maximum evaporation rate at which the lithium loss is the lowest and lithium availability in the concentrated brine is the highest. This will allow us to maximize the lithium recovery from the evaporation process. This study will also allow us to understand the energy required to achieve the maximum lithium recovery in terms of preparing a brine ready for the direct lithium extraction process. In our case, the brin e is higher than 99.5% pure Sodium Chloride with lithium and some minor impurities. The workflow presented in the study will be able to provide a template for conditioning brine for lithium recovery. To optimize lithium extraction, it is essential to carefully manage the balance between evaporation levels and efficiency of lithium recovery, which varies from brine to brine. High evaporation levels can lead to higher lithium concentrations but may result in reduced overall recovery due to the loss of lithium in the mother liquor. Conversely, lower evaporation levels might achieve higher recovery rates but with lower concentrations of lithium. Finding the optimal balance is key to maximizing both the concentration and recovery of lithium from the brine.