Sustainable development of selective iron carbide, silicon carbide and ferrosilicon (low temperature) phases during iron ore reduction using only polymers

Abstract

Production of selective iron phases of iron carbide (nanoscale<2nm), silicon carbide or ferrosilicon using polymer resins and hematite is presented. Commercial epoxy resin, epiglue and silicones are used. Nonrenewable resources such as coke or high pure quartz are not used. A solid-liquid reaction provides for better intimate contact and reaction efficiency. Viscous epoxy and silicone resins can completely wet the reactants forming interfacial covalent bond between the metal oxide and the desired elements in the resins when cured at room temperature for 24h, while facilitating migration of desired elements into iron matrix during reduction of hematite. Secondary ion mass spectroscopy, X-ray diffraction, Scanning Electron Microscopy and off gas studies confirmed the formation of iron alloy phases. The study opens pathway for feedstock recycling of silicones maximizing resource recovery reducing the landfill/depolymerization of silicones. The valuable resources such as silicon, carbon and hydrogen in waste silicones, can replace metallurgical coke and quartzite as alloying elements in FeSi or SiC. Recyclable bioepoxy resin /bio renewable/recycled epoxy resin, which will otherwise be landfilled or incinerated, make this process sustainable, cleaner and cost-effective. FeSi formation at much lower temperature (~1500°C) as opposed to very high temperatures (>1800°C) spells energy savings and emission reductions. A potential replacement of nonrenewable coke by the composites of the resins and iron oxide as spacer provides for added benefit. The SiC, Fe3C and ferrosilicon find application in the economical production of high pure hydrogen and photovoltaic industry.