Process for producing metals, alloys and metal powders using reactive gas and oxygen scavenging reaction

Abstract

A process for producing metals, alloys and metal powders includes providing a feed material; heating the feed material in a melting hearth into a molten metal; and reducing oxygen in the molten metal using a reactive gas in an ionized or unionized state and an oxygen scavenging reaction wherein reaction sites in the molten metal containing oxygen react with the reactive gas. A first system configured to perform a process for producing metals and alloys includes a melting hearth and a heat source system in a melting chamber configured to melt a feed material into a molten metal for atomization, casting or further processing. A second system configured to perform a process for producing metal powders includes a foundry system configured to melt a feed material into a molten metal and an atomization system configured to atomize the molten metal into a metal powder comprised of metal particles.

What is claimed is: 
     
         1 . A process for producing metals and alloys comprising:
 providing a feed material selected from the group of metals consisting of titanium, tantalum, niobium, vanadium, hafnium, nickel, iron and alloys thereof, with at least some the metals in recycled form;   heating the feed material in a melting hearth into a molten metal; and   reducing oxygen in the molten metal using a reactive gas and an oxygen scavenging reaction wherein reaction sites in the molten metal containing oxygen react with the reactive gas, the reactive gas comprising a gas selected from the group consisting of hydrogen, argon, helium, carbon dioxide, carbon monoxide and nitrogen in pure forms, or as gas mixtures.   
     
     
         2 . The process of  claim 1  further comprising stirring the molten metal during the reducing step to expose additional reaction sites of the molten metal to the reactive gas. 
     
     
         3 . The process of  claim 1  further comprising pouring the molten metal during the reducing step. 
     
     
         4 . The process of  claim 1  wherein the feed material comprises titanium and the reactive gas comprises hydrogen. 
     
     
         5 . The process of  claim 1  wherein the feed material comprises an item selected from the group consisting of machining chips, scrap metal cut into chunks, out-of-specification metal powder, and metal pucks made of recycled material. 
     
     
         6 . The process of  claim 1  further comprising providing a first system comprising a heat source system and a melting chamber for the melting hearth configured to perform the melting step and the reducing step. 
     
     
         7 . The process of  claim 6  wherein the melting hearth includes an electromagnetic stirring system and further comprising stirring the molten metal during the reducing step using the electromagnetic stirring system. 
     
     
         8 . The process of  claim 6  wherein the melting hearth includes a tilting linkage and further comprising tilting the melting hearth during the reducing step using the tilting linkage. 
     
     
         9 . The process of  claim 6  wherein the heat source system includes a conduit for injecting the reactive gas onto the molten metal as an ionized plasma. 
     
     
         10 . The process of  claim 6  wherein the heat source system includes a heat source selected from the group consisting of a plasma torch system, a plasma transferred arc system, an electric arc system, an induction system, a photon system, and an electron beam energy system. 
     
     
         11 . A process for producing metal powders comprising:
 providing a feed material selected from the group of metals consisting of titanium, tantalum, niobium, vanadium, hafnium, and alloys thereof, with at least some the metals in recycled form;   heating the feed material in a melting hearth into a molten metal;   atomizing the molten metal; and   reducing oxygen in the molten metal during the atomizing step using a reactive gas and an oxygen scavenging reaction wherein reaction sites in the molten metal containing oxygen react with the reactive gas, the reactive gas comprising a gas selected from the group consisting of hydrogen, argon, helium, carbon dioxide and carbon monoxide, in pure form, or as a gas mixture.   
     
     
         12 . The process of  claim 11  further comprising providing a second system comprising a foundry system comprising a melting chamber for the melting hearth, a heat source system configured perform the heating step, and an atomization system configured to perform the atomizing step, and introducing the reactive gas during atomizing of the molten metal as an atomizing gas. 
     
     
         13 . The process of  claim 11  further comprising directing the reactive gas onto a pour stream of the molten metal proximate to the atomization system. 
     
     
         14 . The process of  claim 11  further comprising correcting a composition of the feed material during the heating step. 
     
     
         15 . The process of  claim 11  wherein the feed material comprises an item selected from the group consisting of machining chips, scrap metal cut into chunks, out-of-specification metal powder, and metal pucks made of recycled material. 
     
     
         16 . A system configured to perform a process for producing metal powders comprising:
 a feed material selected from the group consisting of titanium, tantalum, niobium, vanadium, hafnium, and alloys thereof, with at least some the metals in recycled form;   a foundry system comprising a melting hearth and a heat source system configured to melt the feed material into a molten metal;   an atomization system configured to atomize the molten metal into a metal powder comprised of metal particles, the atomization system comprising an atomization die having an orifice for receiving the molten metal and a plurality of gas jets; and   a reactive gas supply in flow communication with the gas jets configured to inject a reactive gas through the gas jets onto the molten metal as an atomization gas, the reactive gas comprising a gas selected from the group consisting of hydrogen, argon, helium, carbon dioxide and carbon monoxide, in pure form, or as a gas mixture.   
     
     
         17 . The system of  claim 16  wherein the atomization system includes a reaction chamber in flow communication with the reactive gas supply. 
     
     
         18 . The system of  claim 16  wherein the melting hearth of the foundry system comprises a tilting melting hearth. 
     
     
         19 . The system of  claim 16  wherein the heat source system includes a heat source selected from the group consisting of a plasma torch system, a plasma transferred arc system, an electric arc system, an induction system, a photon system, and an electron beam energy system. 
     
     
         20 . The system of  claim 16  wherein the metal comprises titanium and the reactive gas comprises hydrogen.