Method for recycling of rare earth and zirconium oxide materials
AssigneeXylon Technical Ceramics, Inc.
InventorsNicholas H. Burlingame, Samuel Burlingame
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Abstract
A method is presented for recovery, in reusable form, of rare earth minerals and zirconia from waste materials containing them. The method includes: mixing an ammonium sulfate powder and a powder containing the oxide waste material; heating the mixture to decompose the waste into a residue; dissolving the residue in water; separating rare earth constituents from the solution; and subsequently using the separated rare earth constituent (salt or solution) as a raw material. Moreover, the reactants used in the recovery may be recovered by appropriate precipitation and concentration operations.
Claims33
A method for the recovery, in reusable form, of rare earth minerals from waste materials containing rare earth and zirconia, comprising:
- a. mixing an ammonium sulfate powder and a powder containing the oxide waste material;
- b. firing the mixture at a temperature sufficient to decompose a waste residue which is, to a large degree, soluble in an aqueous solution;
- c. dissolving the residue in water to obtain a solution that includes rare earth constituents in salt form;
- d. separating rare earth constituents from the solution using at least one separation method;
- and
- e. subsequently using a separated rare earth constituent as a raw material.
The method according to claim A1 wherein the rare earth constituents are separated from the solution using methods selected from the group consisting of:
- ion-exchange, solvent extraction, fractional crystallization and precipitation.
The method according to claim A1 wherein the rare earth constituents are separated from the solution by precipitation of rare earths using an oxalate precipitation agent.
A method for the recovery of rare earth minerals from rare earth waste materials, comprising:
- a. mixing an ammonium sulfate powder and a powder containing the oxide waste material;
- b. firing the mixture at temperatures sufficient to decompose the waste residue, wherein at least a portion of the waste residue is soluble in aqueous solution;
- c. dissolving the soluble portion of the residue in water to obtain a solution which comprises the rare earth constituents in salt form;
- d. separating rare earth constituents from the solution using at least one separation method;
- and
- e. subsequently using a separated rare earth constituent as a raw material.
A method for the recovery of zirconia from zircon waste materials, comprising:
- a. at least partially fusing and solidifying the zircon waste materials;
- b. mixing an ammonium sulfate powder and a powder containing the zircon waste material;
- c. firing the mixture at temperatures sufficient to decompose the waste residue, wherein at least a portion of the waste residue is soluble in aqueous solution;
- d. dissolving the soluble portion of the residue in water to obtain a solution which comprises zirconia in salt form;
- e. filtering out any insoluble components from the solution;
- f. separating the zirconia from the solution using precipitation of hydrous zirconia by adding ammonium hydroxide;
- and
- g. washing and calcining the hydrous zirconia to form zirconium oxide which can be reused as a raw material.
Dependencies are inferred from the claim text.