Optimization and modeling of solid-phase extraction of rare earth elements with chert using design methodology

•Cherty rocks, the most abundant byproduct of the mining industry, were applied as an adsorbent in solid-phase extraction of six rare earth elements.•Extraction recovery percentages of all the REE were 80.13, 95.25, 97.30, 88.10, 82.80, and 91.99% for Eu(III), Yb(III), La(III), Gd(III), Ce(III), and Nd(III), respectively.•With the purified chert, we notice, on the one hand, the disappearance of crystalline phases of hydroxyapatite, calcite, and dolomite but, on the other hand, the appearance of the clinoptilolite-Ca phase.