Alcoa

Primary production of lightweight metals such as aluminum is an energy-intensive and expensive process that results in significant carbon dioxide (CO2) and other emissions. Lowering the energy consumption, cost, and emissions associated with processing aluminum would make it competitive with incumbent structural metals such as steel. Enabling its widespread use in vehicles in particular—without compromising performance or safety—would substantially reduce fuel consumption and CO2 emissions from transportation.

Alcoa is designing a new, electrolytic cell that could significantly improve the efficiency and price point of aluminum production. Conventional cells reject a great deal of waste heat, have difficulty adjusting to electricity price changes, and emit significant levels of CO2. Alcoa is addressing these problems by improving electrode design and integrating a heat exchanger into the wall of the cell. Typically, the positive and negative electrodes—or anode and cathode, respectively—within a smelting cell are horizontal. Alcoa will angle their cathode, increasing the surface area of the cell and shortening the distance between anode and cathode. Further, the cathode will be protected by ceramic plates, which are highly conductive and durable. Together, these changes will increase the output from a particular cell and enable reduced energy usage. Alcoa’s design also integrates a molten glass (or salt) heat exchanger to capture and reuse waste heat within the cell walls when needed and reduce global peak energy demand. Alcoa’s new cell design could consume less energy, significantly reducing the CO2 emissions and costs associated with current primary aluminum production.

If successful, Alcoa’s redesigned cell could offer significant improvements over current cells while consuming less energy, thus producing more cost-effective aluminum.