A method and plant for recycling metal oxides

This patent application introduces an innovative recycling method specifically developed for efficiently recovering zinc oxide from electric arc furnace (EAF) dust and similar metal oxide wastes. Central to the invention is a sealed rotary kiln utilizing a hydrogen-rich gas atmosphere that directly reduces metal oxides at precisely controlled high temperatures. Notably, zinc vapor formed during reduction is intentionally reoxidized using steam, regenerating hydrogen gas and capturing heat, both of which are recirculated back into the process. This unique closed-loop design substantially reduces energy consumption and emissions, distinguishing it significantly from conventional carbon-based recycling methods. Additionally, the process generates direct-reduced iron (DRI) as a valuable coproduct, enhancing economic viability and transforming hazardous waste streams into sustainable resources.