Method of reducing metal oxide in a rotary hearth furnace heated by an oxidizing flame

A method of reducing metal oxide, comprising:

• providing a furnace having an annular platform and at least one fuel burner,
• placing a first layer of a mixture containing an oxygen-bound metal and a reductant onto an upper surface of the platform,
• rotating the platform past the burner to heat the first layer with an oxidizing flame to a temperature of at least 1000.degree. C.,
• charging a second layer of the reductant covering the heated first layer,
• continue heating the layers for an additional 30 minutes to at least partially reduce the oxygen-bound metal,
• the partially reduced mixture contains at least 1% metal as metal or as a metal carbide, whereby the second layer prevents reoxidation of the metal within the furnace.

A method of reducing metal oxide, comprising:

• providing a furnace having an annular platform and at least one fuel burner,
• placing a fast layer of a mixture containing a reductant and oxygen-bound chromium and iron onto an upper surface of the platform,
• rotating the platform past the burner to heat the first layer with an oxidizing flame to a temperature of at 1200.degree. C.,
• charging a second layer of the reductant covering the heated first layer,
• continue heating the layers to at least 1300.degree. C. to partially reduce the oxygen-bound chromium and iron,
• the partially reduced mixture containing at least 40% chromium or a chromium carbide and at least 70% of iron or an iron carbide, whereby the second layer prevents reoxidation of the chromium or iron within the furnace,
• providing a refining vessel containing an iron bath,
• feeding the partially reduced mixture into the bath,
• refining the bath until the oxygen-bound chromium and oxygen-bound iron are reduced to chromium and iron thereby forming a stainless steel.