Inexpensive composite copper ore/red mud oxygen carrier: Industrial granulation via hydroforming and multiple-cycle evaluation in chemical looping combustion.

• The hydroforming method is developed for hundred-ton industrial granulation. • The resource utilization of natural materials and industrial wastes is realized. • An inexpensive composite oxygen carrier is prepared with negligible sintering. • Cu10.9Red89.1@C reaches 97 % of CH 4 conversion and 98 % of CO 2 selectivity. • The production cost of Cu10.9Red89.1@C is as low as $0.95/kg. The industrial granulation of low-cost and high-performance oxygen carriers (OCs) is critical to developing MW or larger-scale chemical looping combustion (CLC) demonstration units. In this work, an inexpensive composite OC, Cu10.9Red89.1@C (8.72 wt% copper ore and 71.28 wt% red mud bonded by 20 wt% cement), is innovatively prepared at a large scale by the hydroforming method. Its long-period performance is comprehensively evaluated in a thermogravimetric analyzer (TGA) and a batch fluidized bed, and TGA results show that Cu10.9Red89.1@C exhibits excellent stability and reactivity even in the case of deep reduction by H 2 in TGA. In addition, an obvious activation of Cu10.9Red89.1@C is observed during the CH 4 CLC test, indicated by the increased CH 4 conversion and CO 2 selectivity from 81.58 % and 74.65 % in the 1st cycle to 97.53 % and 98.24 % after activation, respectively. With Cu20Fe80@C (16 wt% copper ore and 64 wt% iron ore bonded by 20 wt% cement) as a reference, Cu10.9Red89.1@C presents a higher CH 4 conversion, CO 2 selectivity, and faster oxygen transfer rate due to its larger specific surface area and alkali metals in it. Finally, the cost analysis concludes that its production cost is only $0.95/kg for Cu10.9Red89.1@C, much cheaper than other large-scale prepared OCs. This work provides theoretical support for the applicability of the hydroforming method and the oxygen carrier Cu10.9Red89.1@C. [ABSTRACT FROM AUTHOR]