Magnesium Leachability of Mg-Silicate Peridotites: The Effect on Magnesite Yield of a Mineral Carbonation Process

• Published in: Minerals
• Main Authors: Muhammad Imran Rashid, Emad Benhelal, Faezeh Farhang, Michael Stockenhuber, Eric M. Kennedy
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2020
• Subjects: acid dissolution; dunite rock; olivine; carbonic acid dissolution; peridotites; Mineralogy; QE351-399.2; Carbonic acid
• Online Access: https://doi.org/10.3390/min10121091; https://doaj.org/article/f1735b87102a4886b87ff0b470bb14de

The aim of this study was to increase feedstock availability for mineral carbonation. Acid dissolution and carbonic acid dissolution approaches were used to achieve higher Mg extractions from peridotites. Acid dissolution studies of raw dunite, heat-activated dunite, heat-transformed dunite, and twin sister dunite have not been reported in the literature. Heat-activated dunite is more reactive as compared to heat-transformed dunite, raw dunite, and twin sister dunite. The fraction of magnesium extracted from heat-activated dunite was 57% as compared to 18% from heat-transformed dunite, 14% from raw dunite, and 11% from twin sister dunite. Similarly, silicon and iron extractions were higher for heat-activated dunite compared to that of heat-transformed dunite, raw dunite, and twin sister dunite. Materials rich in forsterite (twin sister dunite and heat-transformed dunite) showed preferential Mg release and exhibited incongruent dissolution similar to that of forsterite. Heat-activated dunite (amorphous magnesium silicate rich) on the other hand behaved differently and showed congruent dissolution. Olivine did not dissolve under carbonic acid dissolution (with concurrent grinding) and acidic conditions. Under carbonic acid dissolution with concurrent grinding conditions, olivine was partially converted into nanometer sized particles (d 10 = 0.08 µm) but still provided 16% Mg extraction during 4 h of dissolution.