Abstract
Phosphoric acid sludge contains acid (∼54% P2O5) and solid precipitates including rare earth elements (REEs) at concentrations of ∼2200 ppm. Low-cost recovery of valuable P2O5 and simultaneous solid separation could be an economically feasible approach to recovering REEs while increasing the production of phosphoric acid. The sludge, however, is a complicated stream that cannot be separated by traditional technologies because of high viscosity and a large solid content (30-40%). Guided by a force balance model, an efficient solid/liquid separation method is demonstrated, using a continuous-flow centrifugal contactor. The shear regime is bypassed by introducing the sludge directly into the rotor where a centrifugal force is exerted on the fluid, inducing phase separation. Solid particles are trapped in the contactor. High liquid recovery is demonstrated and the effects of process parameters on solid capture are investigated. Three contactors in series yield 94% recovery of solids containing 1500-2895 ppm of REEs.
| Original language | English |
|---|---|
| Pages (from-to) | 21901-21913 |
| Number of pages | 13 |
| Journal | Industrial and Engineering Chemistry Research |
| Volume | 59 |
| Issue number | 50 |
| DOIs | |
| State | Published - Dec 16 2020 |
Funding
This work was supported by the Critical Materials Institute, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office. The research was conducted at Oak Ridge National Laboratory (ORNL), which is managed by UT Battelle, LLC, for the US Department of Energy (DOE) under contract DE-AC05-00OR22725. Some of the materials characterization (SEM and XRD) was conducted at the Center for Nanophase Materials Sciences (proposal ID: CNMS 2018-300), which is sponsored at ORNL by the Scientific User Facilities Division, U.S. Department of Energy. This work was supported by the Critical Materials Institute, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office. The research was conducted at Oak Ridge National Laboratory (ORNL), which is managed by UT Battelle, LLC, for the US Department of Energy (DOE) under contract DE-AC05-00OR22725. Some of the materials characterization (SEM and XRD) was conducted at the Center for Nanophase Materials Sciences (proposal ID: CNMS 2018-300) which is sponsored at ORNL by the Scientific User Facilities Division U.S. Department of Energy.