tech details

Use of Mixed Waste Slags for the Conversion of CO2/H2O TO CO/H2


Research is active on the patent pending technology titled, "CO/H2 Production from CO2/H2O Gas Using Exothermic Reactions." This technology is available for licensing and/or further collaborative research from the U.S. Department of Energy’s National Energy Technology Laboratory.


Slag is a molten mixture of oxide components that originates from the carbon feedstock impurities that are normally generated as a by-product of high temperature industrial operations, such as iron manufacturing and gasification processes. The majority of slag waste is landfilled, incurring disposal costs and resulting in the loss of valuable thermal energy. There is an industry need to recovery the thermal energy from slag wastes and to reduce the disposal volume of waste materials.

This invention describes a method to produce a fuel gas (CO/H2) from a waste gas stream (CO2/H2O) in the presence of mixed waste slags. The process involves reacting by-product gases with industrial waste slags containing calcium and vadium oxides. An oxygen atom is removed from the CO2/H2O molecule to form a calcium vanadate compound, generating heat, CO/H2. The highly exothermic reaction can be promoted by mixing appropriate synthetic oxide components, or by fluxing slag with calcium oxide or vanadium oxide. The converted fuel gas and/or heat produced can be used as a fuel for a number of purposes, such as gas turbine power generation, gasifier carbon feedstock, or as a raw material for chemical manufacturing.

The successful integration of this technology into industrial processes could significantly reduce CO2 emission through carbon recycling within power system, as well as reducing the amount of carbon feedstock required to produce the same amount of energy. Additional information about this technology is described in an article appearing in the International Journal of Hydrogen Energy, 39 (10): 4954-4958, 2014.


  • No additional process heat is required for CO2/H2 conversion
  • Reduces waste slag volume
  • Excess heat produced from the exothermic reaction can be used in other processes, such as power generation
  • Potential to significantly reduce CO2 emissions from a variety of industrial processes


  • Gasification
  • Iron, steelmaking, and aluminum industries
  • Gas turbine power generation
  • Chemicals manufacturing

Related Patents

U.S. Non-Provisional Patent Application number 14/790,082 filed July 2, 2015 titled "CO Production from CO2 Gas Using Exothermic Reactions.”

Inventors: Jinichiro Nakano, James Bennett, and Kyei-Sing Kwong

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