DOE OSTI2018
Aluminum is increasingly used in consumer products and in lightweighting applications for airplanes, passenger cars and other vehicles. However, smelting primary aluminum is an energy-intensive process, and advanced low-energy smelting technologies have not yet been successfully scaled up to commercial production. Another way to reduce energy consumption associated with aluminum use is to increase the amount of secondary aluminum (recovered from manufacturing scrap and from recycled products) used as a raw material, thereby increasing the circularity of aluminum flows. This too has proven difficult due to the relatively low rates of recycling for most aluminum-containing products in the U.S., and the inevitable alloy mixing that occurs when end-of-life products are broken down during recycling. We previously investigated strategies for increasing secondary aluminum use, within limitations imposed by the presence of alloying elements and alloy requirements for new products. In this work, we provide context and assess the feasibility of those strategies by investigating established patterns and attitudes around recycling, remanufacturing, and other methods that promote circular material flows. Our objective is to identify technological, logistical, economic, and other barriers that exist to implementing such methods in aluminum-intensive sectors. A secondary objective is to construct a hypothetical blue-sky scenario in which aluminum use in the U.S. approaches a fully circular material flow. The blue-sky scenario allows us to identify future barriers to increasing material flow circularity and to gauge the scenario's attainability relative to current industrial practice. Our focus goes beyond recycling, in which an end-of-life product is disassembled, processed, and then separated into its component materials which serve as inputs for new products. While common in the U.S. and globally, this type of recycling involves non-trivial energy expenditures in the scrapping and processing stages and leads to impure streams of mixed secondary materials that may not be feasible or economical to use. We also consider consumer and manufacturer practices including refurbishing, remanufacturing, repair and reuse. None of these practices require that products are broken down into separate material streams before reconstitution into new products; the energy requirements are therefore lower, and the secondary components potentially easier and more economical to use. We evaluate each of these methods in terms of their economic viability for the consumer, the (re-)manufacturing firm and the scrapping and recycling firm. We also investigate barriers to and drivers of these circular practices, with particular attention paid to consumer attitudes. Initial research indicates that for consumer recycling, convenience of the recycling system is of paramount importance, with pre-existing attitudes towards recycling on a personal and community level almost as important. On the manufacturer side, a variety of logistical and economic barriers exist to instituting widespread product take-back and refurbishment programs. To better understand these barriers and how they can be overcome, we investigate several U.S. manufacturers that currently operate take-back, refurbishment and repair programs for their products, and conduct a review of similar programs in European countries where such programs are mandated by law rather than being conducted voluntarily.
29 ENERGY PLANNING, POLICY, AND ECONOMY↗