Metal Production
Praxair is the world's leading supplier of industrial gases and application technology used by manufacturers of steel, aluminum, copper and other primary metals, with 1998 sales to this segment of more than $790 million.
Steel producers around the world are among Praxair's largest customers, using Praxair gases - argon, hydrogen, nitrogen, and oxygen - and related technologies for improving their productivity and quality while decreasing their operating costs. As a technology leader in this industry, Praxair has received over 275 patents for steel-making technologies using industrial gases in innovative, money-saving ways, including technology for burners, ladles, melting, refining, and reheating.
Patented CoJet™ technology is now the star of the electric arc furnace industry!
Praxair Surface Technologies coatings applied to critical rolls in continuous galvanizing lines prevent metal pick up and surface wear that can damage the steel being processed.
Praxair is a leading supplier of hydrogen, nitrogen, helium and argon furnace atmospheres. We offer safe, easy-to-use solutions and gas-control technology for annealing, sintering, brazing, carburizing, and powder metallurgy. Our dedicated nationwide team of metals and materials applications specialists is committed to helping you succeed. These specialists work with you to evaluate, design, install and start up cost-effective systems that meet your requirements.
For total capabilities from a single source, dedicated to helping you increase your output and improve your bottom line, Praxair is your partner in success.
Praxair know-how puts industrial gases to work in a number of innovative ways.
The following are patented Praxair technologies for steel producers.
Praxair CoJet™ Technology
Praxair CoJet technology is a new oxygen injection system to lower costs and improve productivity of electric arc furnace (EAF) operations. The technology provides a safe, easy-to-operate method for lancing/decarburization, post combustion and burner operation in a single, integrated system using oxygen supplied by Praxair.
Praxair Post Combustion Technology
Praxair's post-combustion technology, patented in 1996, is used by electric arc furnace (EAF) mills to increase productivity, decrease power consumption and decrease carbon monoxide emissions up to 40 percent. To date, 12 mills around the world use Praxair post-combustion technology, realizing annual savings of about $2.5 million each (savings based on annual production of 750,000 tons).
Slag Splashing
Praxair's slag splashing technology is used in integrated steel mills to quadruple the refractory life of the basic oxygen furnace (BOF), reducing operating costs. For each batch of steel, nitrogen gas is introduced through a lance at high pressure and flow to coat the steel-making vessel with slag. Currently, 20 mills around the world use Praxair slag splashing technology.
Praxair AOD Process (Argon Oxygen Decarburization)
Praxair invented the industry standard for stainless steel refining in 1954. Today, more than 75 percent of the world's stainless steel is made using the Praxair AOD process. Also, this secondary steel-making technology enables the EAF mill to produce stainless steel castings and nickel- and cobalt- based alloys. This cost-saving technology allows steel producers to make high-quality product from low-cost raw materials.
For commercial heat treaters and other metal producers and finishers, Praxair offers these technologies:
Praxair Atmospheres: The Reliable Alternative To Dissociated Ammonia
Using Praxair hydrogen-nitrogen protective atmospheres in heat-treating operations provides a safer, non-toxic alternative to dissociated ammonia in metals and materials processing applications. Other benefits include regulatory compliance, improved safety, lower maintenance requirements, and lower capital costs. All of this while maintaining more consistent atmospheres and improving reliability.
With no heating elements or catalysts to fail, Praxair's atmosphere systems are more reliable than dissociated ammonia generators. Plus, the system can be conveniently shut down for planned maintenance and started up without losing valuable production time. Flexible atmosphere systems from hydrogen concentrations of 1 to 100 percent - can be used for these applications:
Praxair's protective atmosphere systems can also provide practical solutions for glass-to-metal sealing; ceramic metallizing; autoclave operations; and powder production. Additionally, pure nitrogen and nitrogen-based atmospheres play important roles in inerting oil quench tanks and salt bath surfaces; purging ammonia atmospheres in nitriding processes; and heat treating and quenching atmospheres in fluidized bed systems.
Praxair Direct Injection™ Protective Atmosphere System
A cost-effective alternative to endothermic or exothermic generators, the Praxair Direct Injection system is a simple, reliable technique for producing a consistent furnace atmosphere.
In the Direct Injection system, a controlled mixture of oxidant (normally air) and fuel gas is fed to one or more compact reactors positioned adjacent to the furnace. As the mixture flows through a catalyst bed in the reactor, hydrogen, carbon monoxide and residual nitrogen are formed and injected directly into the furnace hot zone.
Additional nitrogen is produced on-site by a Praxair membrane system and introduced into the furnace to maintain a positive furnace pressure. The nitrogen flow and injection location are optimized to prevent air infiltration and subsequent oxidation of product. The residual oxygen in the membrane nitrogen stream is removed by reaction with the reducing atmosphere.
The result is a constant, cost-effective protective atmosphere for applications such as decarb-free annealing of steel bar, rod and wire, and bright annealing of non-ferrous metal products.
The iron and steel industry and metal processing companies are among the largest users of industrial gases and consume significant quantities of oxygen, nitrogen, argon and hydrogen. In addition, a small but growing amount of carbon dioxide is also consumed.
Oxygen
Oxygen is used in heating and melting metals. It is the most widely used industrial gas in steel making due to its continued use in the basic oxygen furnace (BOF), its growing use for air enrichment in the blast furnace, and its ability to provide supplemental chemical heat in the electric arc furnace (EAF). Also, injected oxygen is used for converting potential carbon monoxide into extra energy in the EAF; for heating and generating carbon monoxide to reduce iron ore in the blast furnace; and for producing alternate iron.
Nitrogen
Nitrogen atmospheres are used for cooling, stirring, and protecting metal from oxidation during production. Nitrogen is used for inerting vessels, equipment, and metal transfer streams in tapping and casting operations; to eliminate the formation of explosive mixtures in enclosed spaces; and to prevent undesirable reactions between iron and steel with oxygen and hydrogen in the surrounding atmosphere. Nitrogen is also injected into molten iron and steel to provide metal stirring and slag/metal mixing, and as a carrier gas for powder injection. High purity nitrogen containing 5 to 10 percent hydrogen is used to provide a protective reducing atmosphere in batch- and continuous-type bright annealing furnaces for carbon steel grades. Nitrogen purity for most applications is typically 99.999 percent.
Argon
Argon is used whenever a totally inert gas that does not affect metal chemistry is required. It's used for inerting vessels, equipment, and metal transfer streams in tapping and casting operations;to provide stirring and promote slag/metal refining reactions; to flush out carbon monoxide and reduce chromium loses in the Argon Oxygen Decarburization (AOD) process for producing stainless and high alloy steels; and as a coolant to protect oxygen injection tuyeres in various oxygen converters.
Hydrogen
Hydrogen is used as a protective atmosphere in high-temperature metal finishing and coating operations such as annealing and hot dip galvanizing. Also, it is used in significant quantities for natural gas based production of direct reduced iron.
Carbon Dioxide
Carbon dioxide can be used as a stirring gas in BOFs, ladles, and furnaces in place of nitrogen and argon. It also can be used as a protective atmosphere in casting and to suppress fume emissions.
Helium
Helium is used in heat-treating applications and metal finishing to crate an inert gas shield and prevent oxidation during joining/welding of light metals such as aluminum, copper, stainless steel and magnesium alloys.
Steel producers around the world are among Praxair's largest customers, using Praxair gases - argon, hydrogen, nitrogen, and oxygen - and related technologies for improving their productivity and quality while decreasing their operating costs. As a technology leader in this industry, Praxair has received over 275 patents for steel-making technologies using industrial gases in innovative, money-saving ways, including technology for burners, ladles, melting, refining, and reheating.
Patented CoJet™ technology is now the star of the electric arc furnace industry!
Praxair Surface Technologies coatings applied to critical rolls in continuous galvanizing lines prevent metal pick up and surface wear that can damage the steel being processed.
Praxair is a leading supplier of hydrogen, nitrogen, helium and argon furnace atmospheres. We offer safe, easy-to-use solutions and gas-control technology for annealing, sintering, brazing, carburizing, and powder metallurgy. Our dedicated nationwide team of metals and materials applications specialists is committed to helping you succeed. These specialists work with you to evaluate, design, install and start up cost-effective systems that meet your requirements.
For total capabilities from a single source, dedicated to helping you increase your output and improve your bottom line, Praxair is your partner in success.
| Applications for Metal Production |
Praxair know-how puts industrial gases to work in a number of innovative ways.
The following are patented Praxair technologies for steel producers.
Praxair CoJet™ Technology
Praxair CoJet technology is a new oxygen injection system to lower costs and improve productivity of electric arc furnace (EAF) operations. The technology provides a safe, easy-to-operate method for lancing/decarburization, post combustion and burner operation in a single, integrated system using oxygen supplied by Praxair.
Praxair Post Combustion Technology
Praxair's post-combustion technology, patented in 1996, is used by electric arc furnace (EAF) mills to increase productivity, decrease power consumption and decrease carbon monoxide emissions up to 40 percent. To date, 12 mills around the world use Praxair post-combustion technology, realizing annual savings of about $2.5 million each (savings based on annual production of 750,000 tons).
Slag Splashing
Praxair's slag splashing technology is used in integrated steel mills to quadruple the refractory life of the basic oxygen furnace (BOF), reducing operating costs. For each batch of steel, nitrogen gas is introduced through a lance at high pressure and flow to coat the steel-making vessel with slag. Currently, 20 mills around the world use Praxair slag splashing technology.
Praxair AOD Process (Argon Oxygen Decarburization)
Praxair invented the industry standard for stainless steel refining in 1954. Today, more than 75 percent of the world's stainless steel is made using the Praxair AOD process. Also, this secondary steel-making technology enables the EAF mill to produce stainless steel castings and nickel- and cobalt- based alloys. This cost-saving technology allows steel producers to make high-quality product from low-cost raw materials.
For commercial heat treaters and other metal producers and finishers, Praxair offers these technologies:
Praxair Atmospheres: The Reliable Alternative To Dissociated Ammonia
Using Praxair hydrogen-nitrogen protective atmospheres in heat-treating operations provides a safer, non-toxic alternative to dissociated ammonia in metals and materials processing applications. Other benefits include regulatory compliance, improved safety, lower maintenance requirements, and lower capital costs. All of this while maintaining more consistent atmospheres and improving reliability.
With no heating elements or catalysts to fail, Praxair's atmosphere systems are more reliable than dissociated ammonia generators. Plus, the system can be conveniently shut down for planned maintenance and started up without losing valuable production time. Flexible atmosphere systems from hydrogen concentrations of 1 to 100 percent - can be used for these applications:
 | » | Annealing |
| » | Carburizing, Neutral Hardening, Carbonitriding |
| » | Sintering |
| » | Brazing |
| » | Back-Filling Vacuum Furnaces |
Praxair's protective atmosphere systems can also provide practical solutions for glass-to-metal sealing; ceramic metallizing; autoclave operations; and powder production. Additionally, pure nitrogen and nitrogen-based atmospheres play important roles in inerting oil quench tanks and salt bath surfaces; purging ammonia atmospheres in nitriding processes; and heat treating and quenching atmospheres in fluidized bed systems.
Praxair Direct Injection™ Protective Atmosphere System
A cost-effective alternative to endothermic or exothermic generators, the Praxair Direct Injection system is a simple, reliable technique for producing a consistent furnace atmosphere.
In the Direct Injection system, a controlled mixture of oxidant (normally air) and fuel gas is fed to one or more compact reactors positioned adjacent to the furnace. As the mixture flows through a catalyst bed in the reactor, hydrogen, carbon monoxide and residual nitrogen are formed and injected directly into the furnace hot zone.
Additional nitrogen is produced on-site by a Praxair membrane system and introduced into the furnace to maintain a positive furnace pressure. The nitrogen flow and injection location are optimized to prevent air infiltration and subsequent oxidation of product. The residual oxygen in the membrane nitrogen stream is removed by reaction with the reducing atmosphere.
The result is a constant, cost-effective protective atmosphere for applications such as decarb-free annealing of steel bar, rod and wire, and bright annealing of non-ferrous metal products.
| Applied Gases for Metal Production |
The iron and steel industry and metal processing companies are among the largest users of industrial gases and consume significant quantities of oxygen, nitrogen, argon and hydrogen. In addition, a small but growing amount of carbon dioxide is also consumed.
Oxygen
Oxygen is used in heating and melting metals. It is the most widely used industrial gas in steel making due to its continued use in the basic oxygen furnace (BOF), its growing use for air enrichment in the blast furnace, and its ability to provide supplemental chemical heat in the electric arc furnace (EAF). Also, injected oxygen is used for converting potential carbon monoxide into extra energy in the EAF; for heating and generating carbon monoxide to reduce iron ore in the blast furnace; and for producing alternate iron.
| » | Oxygen in Blast Furnaces |
| » | Oxygen in the Basic Oxygen Furnace (BOF) |
| » | Oxygen in the Electric Arc Furnace (EAF) |
| » | Oxygen in Cutting and Burning |
| » | Oxygen in Steel Reheating |
Nitrogen
Nitrogen atmospheres are used for cooling, stirring, and protecting metal from oxidation during production. Nitrogen is used for inerting vessels, equipment, and metal transfer streams in tapping and casting operations; to eliminate the formation of explosive mixtures in enclosed spaces; and to prevent undesirable reactions between iron and steel with oxygen and hydrogen in the surrounding atmosphere. Nitrogen is also injected into molten iron and steel to provide metal stirring and slag/metal mixing, and as a carrier gas for powder injection. High purity nitrogen containing 5 to 10 percent hydrogen is used to provide a protective reducing atmosphere in batch- and continuous-type bright annealing furnaces for carbon steel grades. Nitrogen purity for most applications is typically 99.999 percent.
| » | Nitrogen in Integrated Steel Mills |
| » | Nitrogen in Electric Arc Furnace (EAF) Steel Mills |
Argon
Argon is used whenever a totally inert gas that does not affect metal chemistry is required. It's used for inerting vessels, equipment, and metal transfer streams in tapping and casting operations;to provide stirring and promote slag/metal refining reactions; to flush out carbon monoxide and reduce chromium loses in the Argon Oxygen Decarburization (AOD) process for producing stainless and high alloy steels; and as a coolant to protect oxygen injection tuyeres in various oxygen converters.
| » | Argon in Integrated Steel Mills |
| » | Argon in Electric Arc Furnace (EAF) Steel Mills |
Hydrogen
Hydrogen is used as a protective atmosphere in high-temperature metal finishing and coating operations such as annealing and hot dip galvanizing. Also, it is used in significant quantities for natural gas based production of direct reduced iron.
| » | Hydrogen for Annealing |
| » | Hydrogen for Direct Reduced Iron |
Carbon Dioxide
Carbon dioxide can be used as a stirring gas in BOFs, ladles, and furnaces in place of nitrogen and argon. It also can be used as a protective atmosphere in casting and to suppress fume emissions.
| » | Carbon Dioxide for Stirring Ladles and Vessels |
| » | Carbon Dioxide for other metal applications |
Helium
Helium is used in heat-treating applications and metal finishing to crate an inert gas shield and prevent oxidation during joining/welding of light metals such as aluminum, copper, stainless steel and magnesium alloys.
