Gas-treatment plant for molten metal

• US 4,003,560 A
• Filed: 05/12/1976
• Issued: 01/18/1977
• Est. Priority Date: 05/27/1975
• Status: Expired due to Term

• Current Assignee: Groupement Pour Les Activities Atomiques et Advancees "Gaaa"
• Original Assignee: Groupement Pour Les Activities Atomiques et Advancees "Gaaa"
• Inventors: Carbonnel, Henri
• Primary Examiner(s): Dost, Gerald A.
• Application Number:
  US05/685,609
• Time in Patent Office: 251 Days
• Field of Search: 75/68 R, 75/93 E, 266/208, 266/209, 266/217, 266/218, 266/220, 266/234, 266/237
• US Class Current: 266/217
• CPC Class Codes: B22D 1/00 Treatment of fused masses in the ladle or the supply runners before casting for continuous casting B22D11/10; metallurgical processing, e.g. refining of iron or other metal C21, C22, C25C
• CPC Class Codes: B22D 39/003 using electromagnetic field
• CPC Class Codes: C22B 9/05 Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ

Abstract

Molten corrosive metals such as aluminium are treated, especially for purification, by injecting of gases such as chlorine or nitrogen. This gas-treatment plant comprises a gas-treatment device immersed in a part of a furnace containing molten metal; an electromagnetic pump, situated above the gas-treatment device, stirs the mixture of gas and metal by counter-pressure operation and slag is formed in a decanting tank.

Claims

1. Gas-treatment plant for molten metal comprising a gas-treatment device in the form of an electromagnetic pump having a pipe of porous material forming a bore surrounded by a metal tube and sealed thereto to form a chamber around the porous material, means connecting said chamber to a source of pressurized gas for treating molten metal, a decanting and degassing tank, and an intermediate electromagnetic pump overlying said gas-treatment device and connecting the gas-treatment device to said decanting and degassing tank, and said gas-treatment device being immersible in molten metal whereby;

in operation, molten metal passes through the gas-treatment device to the intermediate pump and thence to the decanting and degassing tank.

2. Gas-treatment plant for molten metal according to claim 1, wherein the electromagnetic pump of the gas-treatment device has an annular stator surrounding the metal tube and including means for air cooling said stator while immersed in molten metal.

3. Gas-treatment plant for molten metal according to claim 1, wherein the electromagnetic pump of the gas-treatment device has a magnetic core located in the bore of the pump and coated in ceramic material.

4. Gas-treatment plant for molten metal according to claim 1, wherein the intermediate pump has a magnetic core located in its bore, which core is coated in ceramic material.

5. Gas-treatment plant for molten metal according to claim 4, wherein the intermediate pump has an active region with a relative large diameter bore, the said core is located in the region of larger diameter bore.

6. Gas-treatment plant for molten metal according to claim 5, wherein the said core is fixed in the bore by a metal sheet helical screw.

7. Gas-treatment plant for molten metal according to claim 1, wherein the intermediate pump has a metal casing which is connected to the tube of the gas-treatment device by fluid-tight metallic bellows.

8. Gas-treatment plant for molten metal according to claim 1, wherein the intermediate pump is arranged to operate in opposition to the pump of the gas-treatement device so that in operation molten metal flows from the gas-treatment device to the decanting and degassing tank through a region of increased turbulence for improved mixing of gas and metal.

9. Gas-treatment plant for molten metal according to claim 1, further including a high-discharge vacuum pump coupled to said decanting and degassing tank to remove gas from the decanting and degassing tank.