Inclusion, occlusion and adsorption of rare earth elements from chloride media onto barite-gypsum composite

In this study, a synthetic BaSO4 & BULL;CaSO4 composite was prepared by co-precipitation technique, characterised and examined for REE sorption. The sorption parameters were; pH = 4, equilibrium time = 20 min, temperature = 303 K, and REE liquor volume to composite mass ratio of 0.2:1 L g(-1). The sorption reaction was controlled by pseudo 2nd order kinetic mechanism and Langmuir adsorption isotherm with an adsorption capacity of 168.63 mg g(-1). 90.14% of REE (III) was desorbed using 1 mol L-1 HNO3. The process was endothermic and spontaneous. Accordingly, 1:1 barite-gypsum (natural ingredient for BaSO4 & BULL;CaSO4), with 136 mg g(-1) loading capacity, was used for REEs extraction.