Claims
- 1. A process for maintaining chromium ions in a +3 valence state, the valence of the chromium ions being determined by the temperature and the oxygen partial pressure at the chromium ions, the process comprising the steps of:
- maintaining the chromium ions at a temperature between about 1600.degree. C. and 1800.degree. C.; and
- introducing a gas mixture through a porous refractory wall of a vessel in which the porous refractory wall includes the chromium ions, the gas mixture maintaining an oxygen partial pressure between about 10.sup.-10 and 10.sup.-8 atmospheres at the chromium ions, the gas chemically protecting the chromium ions to control the valence state of the chromium ions.
- 2. A process for producing steel by a direct steel-making process in a vessel having a porous refractory lining, the lining having chromium for the purpose of resisting corrosion, comprising the steps of:
- placing iron ore materials in the vessel, said ore materials contacting the lining;
- heating said materials and the lining to a temperature of between about 1600.degree. C. and about 1800.degree. C., said temperature causing said ore materials to melt and react to form steel and a layer of undesired end products over said steel and adjacent said lining, said undesired end products including FeO; and
- introducing a gas mixture through the pores of the lining, the gas mixture creating an oxygen partial pressure of between about 10.sup.-10 and 10.sup.-8 atmospheres where said ore contacts the lining.
- 3. The process of claim 1 wherein said gas is a mixture of gases selected from the group consisting of carbon monoxide, carbon dioxide, and hydrogen.
- 4. The process of claim 1 wherein said gas mixture includes water vapor.
- 5. The process of claim 1 wherein said chromium is in a plurality of spinels containing chromium oxide, said spinels being in a porous refractory lining in a vessel, said vessel containing molten metal, and said molten metal including FeO.
- 6. The process of claim 2 wherein said gas mixture has gases selected from the group consisting of carbon monoxide, carbon dioxide, hydrogen and water vapor.
- 7. The process of claim 2 wherein said FeO is typically between about 25 to 35 percent of said undesired end products.
Government Interests
The United States has rights in this invention pursuant to Contract No. DE-AC02-84GC20057 between the U.S. Department of Energy and Argonne National Laboratory.
US Referenced Citations (8)