The high demand for rare earth elements (REEs) was prompted scientists to look for a low-cost technique of REEs extracting from their ores. In this study, a synthetic (BaSO4.CaSO4) composite is prepared by co-precipitation of an equal concentration of barium and calcium chlorides for the recovery of REEs from acidic chloride leach liquor of monazite mineral. The prepared BaSO4.CaSO4 is characterized by FT-IR, XRD, DTA, SEM, particle size analysis, and pore size distribution. Adsorption experiments were carried out at pH = 4 and the sorption equilibrium were reached after 20 minutes. The sorption reaction followed a pseudo 2nd order mechanism. The sorption reaction was regulated with Langmuir adsorption isotherm. The monolayer adsorption capacity is 168.63 mg g-1 at 303 K. Thermodynamic studies showed that the sorption reaction is endothermic and spontaneous.
The desorption of RE3 + is accomplished with 90.14% efficiency using 1 mol L-1 HNO3. BaSO4.CaSO4 could be reused after 5 adsorption-desorption cycles with 73% efficiency. The obtained results discuss the efficient use of 1:1 Barite. Gypsum composite as a natural mixture for REEs extraction. The adsorption capacity of Barite. Gypsum composite was 136 mg g-1.