info:eu-repo/semantics/article
Membrane electrolysis for the removal of Mg2+ and Ca2+ from lithium rich brines
Fecha
2019-05Registro en:
Díaz Nieto, César Horacio; Palacios, Noelia Anahí; Verbeeck, Kristof; Prévoteau, Antonin; Rabaey, Korneel; et al.; Membrane electrolysis for the removal of Mg2+ and Ca2+ from lithium rich brines; Pergamon-Elsevier Science Ltd; Water Research; 154; 5-2019; 117-124
0043-1354
CONICET Digital
CONICET
Autor
Díaz Nieto, César Horacio
Palacios, Noelia Anahí
Verbeeck, Kristof
Prévoteau, Antonin
Rabaey, Korneel
Flexer, Victoria
Resumen
Lithium is today an essential raw material for renewable energy technologies and electric mobility. Continental brines as present in the Lithium Triangle are the most abundant and the easiest to exploit lithium sources. Lithium is present in diluted concentrations together with different ions, and it is imperative to fully remove both magnesium and calcium before lithium carbonate can be precipitated. Here we use membrane electrolysis as a novel method to generate hydroxyl groups in situ in a two-chamber electrochemical cell with a side crystallizer, omitting the need for chemical addition and not leading to substantial loss of lithium rich brine. Batch electrolysis experiments fully removed more than 99.99% of both Mg2+ and Ca2+ for three different native South-American brines treated at current densities ranging from 27 to 350 A m-2 (final concentrations were below ICP detection limit: < 0.05 mg L-1). For a brine containing 3090 mg L-1 of Mg2+ and 685 mg L-1 of Ca2+, 62 kWh m-3 are needed for the full removal of both cations when a current density of 223 A m-2 is employed. Most importantly, the Li+ concentration in the brine is not affected. The removed cations are precipitated as Mg(OH)2 and Ca(OH)2. Our process has the potential to simultaneously recover lithium, magnesium, and calcium compounds, minimizing waste production.