Solid hydrocarbon assisted reduction: a new process of generating micron scale metal particles
McCabe, Ryan M.
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The goal of this research is to test a central hypothesis: that gas species generated by the thermal and/or catalytically assisted decomposition of hydrocarbons in an inert atmosphere can reduce metal oxides to a metallic state. It is postulated that the decomposition releases gas phase radicals that can bind with oxygen in the metal oxides, forming volatile, stable oxides such as CO2 and water. This research consisted of thermally decomposing several types of solid hydrocarbon, including wax and low-grade coal, both with and without catalysts, in a nitrogen environment at >600 °C, located immediately below beds of micron scale particles of either NiO or Fe3O4. X-ray diffraction and scanning electron microscopy analysis showed, in support of the hypothesis, both metal oxides reduced to some extent. Nickel oxide reduced fully in many cases, but iron oxide never fully reduced and the extent of reduction was found to be a function of hydrocarbon, catalyst and temperature. These results suggest solid hydrocarbon assisted reduction (SHAR) with further testing and development may be a practical means to make sub-micron particles suitable in terms of price and quality for use in particle injection molding and 3D manufacturing of precision metal parts.