Some variations provide a composition for reducing a metal ore, the composition comprising a carbon-metal ore particulate, wherein the carbon-metal ore particulate comprisesat least about 0.1 wt% to at most about 50 wt% fixed carbon on a moisture-free and ash-free basis, and wherein the carbon is at least 50% renewable carbon as determined from a measurement of the 14C/12C isotopic ratio. Some variations provide a process for reducing a metal ore, comprising: providing a biomass feedstock; pyrolyzing the feedstock to generate a biogenic reagent comprising carbon and a pyrolysis off-gas comprising hydrogen or carbon monoxide; obtaining a metal ore comprising a metal oxide; combining the carbon with the metal ore, to generate a carbon-metal ore particulate; optionally pelletizing the carbon-metal ore particulate; and utilizing the pyrolysis off-gas to chemically reduce the metal oxide to elemental metal, such as iron. The disclosed technologies are environmentally superior to conventional processes based on coal.