Recovery of scandium, yttrium and lanthanides from zircon sand
First Claim
1. A process for extracting scandium from ore comprising zirconium silicate;
- said process comprising;
a. feeding scandium-containing zircon ore to a fluidized bed chlorinator at 800°
-1250°
C. to produce a vaporous phase, said vaporous phase principally comprising zirconium and silicon chlorides, and to produce a solid scandium-containing residue; and
b. recovering the scandium as a compound from said solid residue, whereby the very low level of scandium present in zircon ore is concentrated in the residue, making recovery of scandium from the zircon ore economically feasible.
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Accused Products
Abstract
This is a process for extracting scandium from zircon ore. It utilizes feeding zircon sand to a fluidized bed chlorinator at about 1000° C. to produce a vaporous (principally zirconium and silicon chlorides) phase and a solid residue and recovering scandium from the solid residue. Surprisingly, despite the relatively low sublimation temperature of scandium chloride the very low level of scandium present in zircon ore is concentrated in the residue (rather than going with the vapor phase, where it would not be concentrated), making recovery of scandium from the zircon ore economically feasible. Generally, the process can be part of the production of zirconium metal, whereby scandium is a byproduct of zirconium production. Preferably, the recovery is performed by leaching the residue with aqueous acid (e.g. HCl) to produce a scandium-containing aqueous solution, followed by contacting the aqueous solution with a polyalkyl phosphate-containing organic phase, the polyalkyl phosphate (e.g. tributyl phosphate) extracting scandium into the organic phase, followed by scandium precipitation by an ammonium addition to produce a scandium hydroxide precipitate and the scandium hydroxide is calcined, whereby scandium is recovered as an oxide. The residue generally also contains yttrium and lanthanides, and the yttrium and lanthanides can also be recovered from the residue as a part of the scandium recovery process. The recovering of the scandium chloride from the residue can also be performed by leaching the residue with alcohol (preferably methanol) to produce a scandium-containing alcohol solution (the remaining residue can then be recycled to the chlorinator). The leaching with alcohol can be followed by contacting the alcohol solution with oxalic acid to precipitate oxalates of scandium, thorium, and lanthanides.
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Citations
15 Claims
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1. A process for extracting scandium from ore comprising zirconium silicate;
- said process comprising;
a. feeding scandium-containing zircon ore to a fluidized bed chlorinator at 800°
-1250°
C. to produce a vaporous phase, said vaporous phase principally comprising zirconium and silicon chlorides, and to produce a solid scandium-containing residue; andb. recovering the scandium as a compound from said solid residue, whereby the very low level of scandium present in zircon ore is concentrated in the residue, making recovery of scandium from the zircon ore economically feasible. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- said process comprising;
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8. A process for extracting zirconium and scandium from zircon sand;
- comprising silica said process comprising;
a. feeding scandium-containing zircon sand to a fluidized bed chlorinator at 800°
-1250°
C. to volatilize zirconium and silicon chlorides from said sand and to produce a residue containing a scandium compound and other solids;b. separating said scandium-compound from the other solids of said residue; c. separating said zirconium chloride from said silicon chloride; and d. reducing said zirconium chloride to produce zirconium metal. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
- comprising silica said process comprising;
Specification