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REE behavior and sorption on weak acid resins from buffered media
James P. Bezzina,Mark D. Ogden,Ellen M. Moon,Karin L. Soldenhoff 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.59 No.-
Rare Earth Elements (REEs) are of great importance to modern day societies. Although abundant, concentration of REE minerals in ores are generally quite low, with high concentration of impurities. To counteract this, selective extraction processes must be undertaken. Selective adsorption of REE from buffered media solutions on Purolite S910 and Amberlite IRC86 weak acid resins has been studied. Batch experiments have been carried out on solutions containing a selection of REEs, Y3+, Fe3+ and Al3+ in unbuffered media, malic acid, formic acid, acetic acid, alanine and lactic acid to determine the best extracting media. Isotherm behavior and extraction kinetics of IRC86 were determined for acetic acid media, at the most effective pH that was determined to be 4.38. The isotherms were conducted for La3+, Sm3+, Er3+ and Y3+ determining extraction maxima of 0.29, 0.34, 0.49 and 0.60 mmol L−1, respectively, with adsorption energies increasing with the same trend. Kinetic experiments determined that mid REEs were the fastest adsorption, with light REEs and heavy REEs displaying similar half-lives and Y3+ measuring the smallest half-life out of the studied ions.
Charlie R. Adams,Christopher P. Porter,Thomas J. Robshaw,James P. Bezzina,Victoria R. Shields,Alan Hides,Richard Bruce,Mark D. Ogden 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.92 No.-
This study reports the development of a hydrometallurgical treatment for activated carbon ash (ACA); awaste product of the carbon-in-pulp (CIP) process used in the gold mining industry, rich in adsorbedprecious metals. After an initial screening of known leaching chemistries, the research focusses on duallixiviant(thiourea and thiocyanate) and thiourea systems, both of which have lower environmentalimpact than traditional cyanide leaches. Comparing ferric sulfate and hydrogen peroxide as oxidantsshowed that a thiourea leach is more suited to ferric sulfate whereas the dual-lixiviant leach achievedgreater extraction with hydrogen peroxide. This was believed to be due to a more favourable effective[thiourea]:[thiocyanate] molar ratio in solution. The latter demonstrated faster kinetics and improvedefficiency for dissolution of gold and silver. However, both leaches had issues with silver extraction due toformation of passivating layers on the surface of the silver nanoparticles. Kinetic modelling showed bothsystems tended towards a mixed-controlled process. Gold extraction of 89%, with leaching reachingequilibrium within 100 min, using the dual-lixiviant process demonstrated that there is an alternative tocyanide leaches employed in gold recovery.