Industrial extraction of lithium from Urmia Lake using precipitation and evaporation methods

TL;DR

This study explores methods to extract lithium from Urmia Lake brine, focusing on chemical treatments and evaporation to improve recovery rates.

Contribution

A novel sequential chemical process is proposed for lithium extraction from high Mg/Li ratio brine, achieving 42.7% recovery using LiAl-LDH synthesis.

Findings

A pre-treatment route removed 99.5% of Mg2+ and 97% of Ca2+ with minimal lithium loss.

LiAl-LDH synthesis achieved a 42.7% lithium recovery rate under optimized conditions.

Phase competition and irreversible Li2O formation limited further improvements in recovery.

Abstract

Recent surges in lithium driven by battery technologies have spurred interest in recovering lithium from unconventional sources. This study presents a sequential chemical process for lithium extraction from Iran’s Urmia Lake brine, a resource characterized by a high Mg/Li mass ratio of approximately 440. An economically optimized pre-treatment route involving Ca(OH)2​, H2SO4​, and NaOH successfully removed 99.5% of Mg2+ and 97% of Ca2+, with an associated lithium loss of 17.9%. Controlled evaporation concentrated the purified brine to 382 ppm Li+ at an optimal concentration factor (CF = 3.409), a trade-off that incurred a further 33% lithium loss to prevent excessive co-precipitation at higher CFs. Two final recovery methods were evaluated: phosphate precipitation, yielding a 21.6% overall process recovery, and a more effective reaction-coupled LiAl-LDH synthesis, which achieved a 42.7% overall recovery under an optimized 3 h reaction. The primary limitation for the promising LDH route was identified as phase competition from alunite and irreversible Li2O formation at longer reaction times. While the achieved yield is competitive with similar brines, it remains below the commercial threshold, highlighting the need for future optimizations focused on mitigating losses during evaporation and improving LDH synthesis selectivity.

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