Recovery of phlogopite (mica) by hindered settling from molybdenum tailings in an ascending current separator based on particle shape differences

Abstract

A novel gravity concentration approach for recovering phlogopite from molybdenum tailings in an ascending current separator (ACS) was proposed. The settlement behavior of coarse-grained minerals with different particle shapes was investigated. The results indicated that the particle shape difference between coarse-grained minerals brought about the gravity concentration of phlogopite. Phlogopite had a lower shape correction factor due to its flaky shape. Under the condition of the same particle size and solid volume concentration of the fluidized bed, the free and hindered settling terminal velocities of phlogopite were much lower than those of albite and calcite. The equal settling factors of phlogopite to albite and phlogopite to calcite in the hindered settlement process were 2.40–4.06 and 3.27–5.81, respectively, with solid volume concentrations ranging from ∼0.055 to 0.175. The operating parameters of the ACS during the phlogopite recovering process were optimized by response surface methodology with a three-level Box-Behnken design. Under optimum conditions, the K2O grade and K2O recovery of concentrate are 8.77% (phlogopite content is 92.41%) and 75.17%, respectively.