Discovering the feasibility of using the radiation forces for recovering rare earth elements from coal power plant by-products
Abstract The feasibility of using laser separation for rare earth recovery from coal ashes was explored. To do so, laser-induced motion and travel distances of some rare earth and rare earth oxides (Lu 2 O 3 , Yb 2 O 3 , HfO 2 , Dy 2 O 3 , Ta 2 O 5 , Tm, Lu, Ho, TeO 2 , La 2 O 3 , Ho, TiO 2 , Fe 2 O 3 Y 2 O 3 , GeO 2 , Sc 2 O 3 ) and mineral compounds (MgO, CaO, Al 2 O 3 , SiO 2 , KCl) that are commonly found is coal ashes were numerically investigated. The investigations were carried out for particles in quiescent air, ( T  = 300 K, μ  = 18.46 × 10 −6  N s/m 2 , ρ  = 1.177 kg/m 3 ) exposing to a CW laser beam of 6 mm in diameter and it was focused by a 500 mm focal length lens. The results showed that the separation distances between these elements varied from few micrometers to several millimeters and it became widened as the laser power increased. The important result presented here is that all rare earth oxides were separated and concentrated in a small area located near the beam waist while all other mineral compounds traveled further and concentrated in a small area far from the beam waist.