Molten salt de-oxygenation of metal powders
AssigneeUniversity of Utah Research Foundation
InventorsZhigang Zak Fang, Pei Sun, Yang Xia, Ying Zhang
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Abstract
Methods of removing oxygen from a metal are described. In one example, a method (100) can include forming a mixture (110) including a metal, a calcium de-oxygenation agent, and a salt. The mixture can be heated (120) at a de-oxygenation temperature for a period of time to reduce an oxygen content of the metal, thus forming a de-oxygenated metal. The de-oxygenation temperature can be above a melting point of the salt and below a melting point of the calcium de-oxygenation agent. The de-oxygenated metal can then be cooled (130). The de-oxygenated metal can then be leached with water and acid to remove by-products and obtain a product (140).
Claims21
A method of removing dissolved oxygen from a metal, comprising:
- forming a mixture comprising a metal having a dissolved oxygen content, a calcium de-oxygenation agent, and a salt, wherein the calcium de-oxygenation agent is present in an amount such that a molar ratio of calcium atoms in the calcium de-oxygenation agent to oxygen atoms in the metal is from about 1 to 5;
- heating the mixture at a de-oxygenation temperature for a period of time in a controlled atmosphere to reduce the dissolved oxygen content of the metal to form a de-oxygenated metal, wherein the de-oxygenation temperature is above a melting point of the salt and below a melting point of the calcium de-oxygenation agent;
- and
- cooling the de-oxygenated metal.
A method of removing dissolved oxygen from a metal powder, comprising:
- a) mixing a calcium de-oxygenation agent with a metal powder to be deoxygenated according to a specific ratio depending on an amount of dissolved oxygen to be removed to form a powder mixture, wherein the calcium de-oxygenation agent includes solid calcium (Ca), calcium hydride (CaH2), or both, wherein the specific ratio is a molar ratio of calcium atoms in the calcium de-oxygenation agent to oxygen atoms in the metal is from about 1 to 5;
- b) blending the powder mixture with a salt to form a blended mixture, wherein the salt has a melting point below a melting point of the calcium de-oxygenation agent;
- c) heating the blended mixture to a high temperature for a period of time, in an inert or reducing atmosphere, sufficient to reduce dissolved oxygen content of the metal powder below a predetermined oxygen threshold to form a de-oxygenated metal powder, wherein the high temperature is above a melting point of the salt and below the melting point of the calcium de-oxygenation agent;
- and
- d) cooling the de-oxygenated metal powder.
Dependencies are inferred from the claim text.