Lithium Extraction From North Sea Oilfield Brines Using Ion Exchange Membranes

Abstract

The annual demand for lithium for low-carbon technologies applications has been trading exponentially forward, 965% more in 2050 than the quantity demanded in 2017. In the current chain of demand, there is a necessity for continuous lithium production from both conventional sources (i.e., salt lakes and rock minerals) as well as the incorporation of novel extraction sites from alternative brine resources such as Oilfield and Geothermal. In the present paper, the lithium potentiality of the North Sea is evaluated with fields in the Central-East and Southern-West reaching the highest regional concentration of 40 ppm. Those include oilfields such as Montrose, Arbroath, Ula, Nelson, Brisling, Gyda, Ekofisk and Bream, as well as gas fields such as the Esmond, Anglia, Lemman, Ann, and Viking, with the possibility of brine enrichment extending itself even to shallow waters fields around the Groningen region. To experimentally evaluate the potential extractability of lithium from those oilfield brine resources in the North Sea, ion-sieve adsorbents (Li1.6Mn1.6O4) were prepared from commercially available LiMnO2 and formed into three different ion-exchange membranes. The foam had the best performance out of those structures, displaying a higher and much stabler powder insertion capacity compared to granular and flat sheet membranes, which registered significant material loss. At an optimum polymeric concentration of 10% and MNO/PVA ratio of about 50%, the foam membrane had the highest theoretical extraction capacity of 9.94 mg/g, followed by granular and flat sheet, with 7.36 and 7.24 mg/g, respectively. Those membranes had good selectivity forward lithium ion in the presence of other competing cations when used on synthetic oilfield brine with concentration mimicking that of Buchan field, being able to efficiently recover 18.4% (foam), 17% (granular), and 14.37% (flat sheet) of lithium. However, the recovery capacity was increased up to 50% when non-formed HMO powder was used, with selectivity in the following decreased order of affinity, Li+ > Mg2+ > Na+ > Ca2+ > K+. The powder recoverability raises the lithium production prospect from North Sea brine to about 26.2 kg per day with an estimated market value of 1834 USD for the produced quantity.