TY - JOUR
T1 - Leaching of lepidolite and recovery of lithium hydroxide from purified alkaline pressure leach liquor by phosphate precipitation and lime addition
AU - Mulwanda, James
AU - Senanayake, Gamini
AU - Oskierski, Hans
AU - Altarawneh, Mohammednoor
AU - Dlugogorski, Bogdan Z.
N1 - Funding Information:
Authors Authors gratefully acknowledge the support of Murdoch University for by offering a PhD scholarship to James Mulwanda and financial assistance for conducting the laboratory analysis and characterization studies relevant to this project.
Publisher Copyright:
© 2020
PY - 2021/5
Y1 - 2021/5
N2 - This study investigated the pressure leaching of lithium and other valuable metals from lepidolite using NaOH and Ca(OH)2. The findings showed that NaOH concentration, temperature, and stirring rate are the most significant process parameters. The addition of Ca(OH)2 facilitates the leaching of lithium and minimizes the concentration of silicate and fluoride in the leach liquor by forming solid phases identified as Ca3Al2Si3O12, CaF2 and NaCaHSiO4, with a loss of about 7% NaOH. The leaching efficiencies after 2 h were 94% Li, 98% K, 96% Rb, and 90% Cs under the most suitable conditions (250 °C, 320 g/L NaOH, liquid-to-solid ratio of 10, 300 rpm stirring speed, lime addition of 0.3 g/g). Precipitation of lithium as Li3PO4 by adding phosphoric acid and subsequent conversion of Li3PO4 to LiOH using Ca(OH)2 recovered 83% of lithium as LiOH allowing recycling the rest along with residual remnant NaOH for leaching.
AB - This study investigated the pressure leaching of lithium and other valuable metals from lepidolite using NaOH and Ca(OH)2. The findings showed that NaOH concentration, temperature, and stirring rate are the most significant process parameters. The addition of Ca(OH)2 facilitates the leaching of lithium and minimizes the concentration of silicate and fluoride in the leach liquor by forming solid phases identified as Ca3Al2Si3O12, CaF2 and NaCaHSiO4, with a loss of about 7% NaOH. The leaching efficiencies after 2 h were 94% Li, 98% K, 96% Rb, and 90% Cs under the most suitable conditions (250 °C, 320 g/L NaOH, liquid-to-solid ratio of 10, 300 rpm stirring speed, lime addition of 0.3 g/g). Precipitation of lithium as Li3PO4 by adding phosphoric acid and subsequent conversion of Li3PO4 to LiOH using Ca(OH)2 recovered 83% of lithium as LiOH allowing recycling the rest along with residual remnant NaOH for leaching.
KW - Alkaline
KW - Caesium
KW - Leaching
KW - Lepidolite
KW - Lithium
KW - Phosphate/hydroxide precipitation
KW - Potassium
KW - Pressure
KW - Rubidium
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UR - http://www.scopus.com/inward/citedby.url?scp=85100748719&partnerID=8YFLogxK
U2 - 10.1016/j.hydromet.2020.105538
DO - 10.1016/j.hydromet.2020.105538
M3 - Article
AN - SCOPUS:85100748719
SN - 0304-386X
VL - 201
JO - Hydrometallurgy
JF - Hydrometallurgy
M1 - 105538
ER -