Table 1.
Experimental conditions and results.
Fig 1.
Images of oxide and phosphate producing experiments.
(a): Platinum crucible after experiment cooling. Cm scale crystals of MoO3/Na2CO3 flux with dark crystals of Na-Ce-Mo oxide floating on surface. (b) Separated brown crystals of Na-Ce-Mo oxide, variable sizes due to fragmentation, viewed under stereo microscope. Coarse pale crystals are flux prior to dissolution. (c) Euhedral monoclinic grain of Nd-monazite surrounded by fragments of Na-Nd-Mo oxide. Phase ID confirmed by chemical analyses; note color difference between phases. Material photographed just after separation from flux, surrounding material remains in water so that multiple phases could be imaged. Scale bars in (b) and (c) are 1 mm.
Fig 2.
X-Ray Diffractogram/spectrum analyses of generated oxide crystals.
Peaks identified as NaCe(MoO4)2 by internal XRD Jade analysis software using ICCD database.
Fig 3.
Materials produced in type 3 synthesis experiments.
(a) shows 4 colors of phosphate crystals tested here, with full recovered crystal batches from each, labeled by REE variety. (b) full crystal recovery from Nd-phosphate run NX-15. (c) full crystal recovery from La phosphate run NX-23. Tweezers for scale in (c). (d) Coexisting powder from Nd phosphate run NX-15 after being allowed to fully settle out; vial is filled with water and layering was produced during settling.
Fig 4.
SEM InLens imagery of fine-grained oxides that coexist with REE phosphates.
(a) and (b) Nd oxides from experiment NX-15. (c) and (d) Yb oxides from experiment NX-22.
Fig 5.
Electron Microprobe Backscattered Electron Images of natural monazite reaction experiments.
(a) Experiment performed in Ni capsule (not pictured). Rounded/irregular monazite grains are surrounded by lathe-like growths of Na-REE-Mo oxides, with measurable Ni substituting for Mo in all measured grains. Dark areas surrounding grains were filled with MoO3-Na2CO3 flux and are difficult to polish, likely due to carbonate fluids in pore space. (b) Experiment done in Ag capsule (shown at top left). Large monazite grain at center of frame shows rounded edges and unstable, irregular texture, with smaller grains of Na-REE-Mo oxides forming surrounding it. Some larger lathes of MoO3 grown from the flux are shown at the lower right.