Refining device and refining method for titanium scraps and sponge titanium using deoxidising gas

Patent metadata

Field	Value
Publication number	US-9840755-B2
Application number	US-201314777835-A
Country	US
Kind code	B2
Filing date	Jun 12, 2013
Priority date	Mar 18, 2013
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

Provided are a method and apparatus for refining titanium scraps and sponge titanium, which can remove oxygen from a melt by supplying a deoxidizing gas to the surface of the melt in order to refine titanium scraps and sponge titanium. The method for refining titanium scraps and sponge titanium comprises supplying hydrogen ions and electrons in plasma to a titanium melt to remove oxygen from the titanium melt surface having an oxide layer formed thereon. In addition, the apparatus comprises: a vacuum chamber; a crucible located in the vacuum chamber and configured to perform melting by the magnetic field of an induction coil in a state in which a melt and the inner wall of the crucible; a calcium gas supply means configured to supply calcium gas from the bottom of the crucible to the space between the inner wall of the crucible and the melt.

First claim

The invention claimed is:

1. A method for refining titanium scraps and sponge titanium, comprising a step of removing oxygen from a titanium melt by supplying plasma gas from a top of a crucible to a surface of the melt,
wherein an atmospheric oxygen molecule is adsorbed to the surface of the melt to form a titanium oxide layer, and the step of removing oxygen comprises the steps of:
diffusing the plasma gas to the surface of the melt;
allowing hydrogen ions and electrons, released from the plasma gas, to react with oxygen atoms of the melt on the titanium oxide layer; and
allowing an excess of hydrogen atoms, released from the plasma gas, to combine into a hydrogen molecule which is consumed.

2. The method of claim 1 , wherein the plasma gas comprises argon and hydrogen.

3. The method of claim 2 , wherein the argon and the hydrogen are supplied at a volume ratio ranging from 1:0.03 to 1:0.5.

4. A method for refining titanium scraps and sponge titanium, comprising the steps of:
performing melting in a crucible by a magnetic field of an induction coil in a state in which a melt and an inner wall of the crucible do not come in contact with each other; and
supplying calcium gas from a bottom of the crucible to from a space between the inner wall of the crucible and the melt to remove oxygen from the melt.

5. The method of claim 4 , wherein the calcium gas forms a curtain wall flow surrounding the melt.

6. A method for refining titanium scraps and sponge titanium, comprising the steps of:
performing melting in a crucible by a magnetic field of an induction coil in a state in which a melt and an inner wall of the crucible do not come in contact with each other;
supplying plasma gas from a top of the crucible to a surface of the melt to remove oxygen from the melt; and
supplying calcium gas from a bottom of the crucible to a space between the inner wall of the crucible and the melt to remove oxygen from the melt.

7. The method of claim 6 , further comprising the steps of:
bringing unreacted calcium gas of the calcium gas into contact with plasma to produce calcium ions;
removing oxygen from the melt by the produced calcium ions.

8. An apparatus for refining titanium scraps and sponge titanium, the apparatus comprising:
a vacuum chamber;
a crucible located in the vacuum chamber and configured to perform melting by a magnetic field of an induction coil in a state in which a melt and the inner wall of the crucible do not come in contact with each other;
a calcium gas supply means configured to supply calcium gas from a bottom of the crucible to a space between the inner wall of the crucible and the melt.

9. The apparatus of claim 8 , further comprising a collection plate located above the crucible and configured to collect impurity gases which are generated during melting.

10. The apparatus of claim 9 , wherein the calcium gas supply means is configured such that the calcium gas is injected around the melt to form a curtain wall flow surrounding the melt.

11. The apparatus of claim 8 , wherein the calcium gas supply means comprises:
a calcium gas production unit configured to vaporize solid-state calcium by heat to produce calcium gas; and
a plurality of injection units configured to inject the calcium gas, supplied from the calcium gas production unit, from the bottom of the crucible to the top of the crucible.

12. The apparatus of claim 11 , further comprising a mixing chamber connected to the calcium gas production unit and configured to mix an inert gas, supplied from the outside, with the calcium gas supplied from the calcium gas production unit, and to supply the mixed gases to the injection units.

13. The apparatus of claim 12 , wherein the mixing chamber comprises a heating means configured to heat the inert gas.

Assignees

• Korea Inst Ind Tech

Inventors

• Moon Byung Moon
• Kim Gang June
• Lee Jae Yoon

Classifications

• C22B34/1218

  obtaining titanium or titanium compounds from ores or scrap by dry processes · CPC title

• F27D7/06

  Forming or maintaining special atmospheres or vacuum within heating chambers (supplying steam, vapour, gases or liquids F27D7/02) · CPC title

• Y02P10/253

  Cross-Sectional Technologies · mapped topic

• F27B14/061

  Induction furnaces · CPC title

• F27D2007/063

  Special atmospheres, e.g. high pressure atmospheres · CPC title