## Rio Tinto and Alcoa announce world’s first carbon-free aluminum smelting process; Apple assist; Elysis JV to commercialize

##### 11 May 2018

Rio Tinto and Alcoa Corporation announced a revolutionary process to make aluminum that produces only oxygen as a by-product, eliminating all direct greenhouse gas emissions from the traditional smelting process. In Canada alone, use of the technology could eliminate the equivalent of 6.5 million metric tonnes of greenhouse gas emissions, if fully implemented at existing aluminum smelters in the country. That represents an amount roughly equal to taking nearly 1.8 million light-duty vehicles off the road.

The conventional Hall–Héroult process (invented in 1886) for smelting aluminum involves dissolving alumina (Al2O3) in molten cryolite, and electrolyzing the molten salt bath, typically in a purpose-built cell with carbon electrodes. The mixture is electrolyzed by passing a low voltage direct current at 100–300 kA through it, causing liquid aluminium metal to be deposited at the cathode. Oxygen from the alumina combines with carbon from the anode to produce mostly carbon dioxide.

The cells operate 24 hours/day; temperature in the cells is maintained via electrical resistance. Oxidation of the carbon anode increases the electrical efficiency at a cost of consuming the carbon electrodes and producing carbon dioxide.

The new Rio Tinto/Alcoa process eliminates the carbon, using proprietary materials instead; the only by-product is oxygen.

Québec is home to eight smelters with a combined production capacity of 2.9 million metric tons of primary aluminium. This represents 90% of Canada’s production, which ranks fourth in the world behind that of China, Russia and the Middle East.

Apple helped facilitate the collaboration between Alcoa and Rio Tinto on the carbon-free smelting process, and has agreed to provide technical support to the JV partners.

To advance larger scale development and commercialization of the new process, Alcoa and Rio Tinto are forming Elysis, a joint venture company to further develop the new process with a technology package planned for sale beginning in 2024. The name refers to the process at the center of aluminum smelting, the electrolysis of alumina; the new technology is also named the Elysis process.

Elysis, which will be headquartered in Montreal with a research facility in Québec’s Saguenay–Lac-Saint-Jean region, will develop and license the technology so it can be used to retrofit existing smelters or build new facilities. Alcoa, Rio Tinto, the Government of Canada, the Government of Québec and Apple agree to provide a combined investment of $188 million (CAD). • Canada and Québec are each investing$60 million (CAD) in Elysis. The provincial government of Québec will have a 3.5 percent equity stake in the joint venture with the remaining ownership split evenly between Alcoa and Rio Tinto.

• Apple is providing an investment of $13 million (CAD). The company helped facilitate the collaboration between Alcoa and Rio Tinto on the carbon-free smelting process, and Apple has agreed to provide technical support to the JV partners. • Rio Tinto and Alcoa will invest$55 million (CAD) cash over the next three years and contribute specific intellectual property and patents.

When fully developed and implemented, the new process will eliminate direct greenhouse gas emissions from the smelting process and strengthen the closely integrated Canada-United States aluminum and manufacturing industry. The new joint venture company will also sell proprietary anode and cathode materials, which will last more than 30 times longer than traditional components, the partners said.

The technology represents the culmination of decades’ worth of research and development. Elysis will have access to a host of patents and intellectual property. The patent-protected technology, developed by Alcoa, is currently producing metal at the Alcoa Technical Center, near Pittsburgh in the United States, where the process has been operating at different scales since 2009.

The joint venture intends to invest up to $40 million (CAD) in the United States, which would include funding to support the supply chain for the proprietary anode and cathode materials. Vincent Christ, with more than 30 years’ experience at Rio Tinto aluminum, has been named Chief Executive Officer of Elysis. Most recently, he has served as head of technology, research and development and automation programs. He holds an engineering degree in electronics and industrial information technology. ### Comments Elimination of carbon electrodes also means elimination of perfluoromethane (CF4) emissions from the process. As it has a GWP of 6500 and an atmospheric lifespan of 50,000 years, this is a huge improvement. This could have been done decades ago, better late than never. Yes SJC. The technology was there but GREENS were not active enough. Also, the 70% subsidy from Canada and Quebec governments + the$13M from APPLE is a deal difficult to refuse?

In the last paragraph, they mention the need for "the supply chain for the proprietary anode and cathode material"

They are also lost in the process it seems.
I wonder what these are.

I hope it is not platinum.

Carbon electrodes are CHEAP, this is why they used them for many decades, it was about the bottom line.

The ELysis Process probably uses a Nickel Ferrite Cermet for the Inert Anode. There is a 2001 MIT article by Daniel Sadoway (Inert Anodes for the Hall-Héroult Cell:
The Ultimate Materials Challenge, http://web.mit.edu/dsadoway/www/100.pdf) that discusses these anodes.
Alcoa has numerous patents, like this one "Method of converting Hall-Heroult cells to inert anode cells for aluminum production" (see Patent US6558526B2).
Of course a new supply chain will need to replace the Carbon based electrodes which are based on Coke byproducts that is well established and low cost.
Elysis will also sell proprietary anode and cathode materials, which will last more than 30 times longer than traditional components, and the new production process should cut operating costs by 15 percent and increase production by 15 percent.

Carbon electrodes are cheap in some ways, but in making aluminum, they're consumed. They're part of the Hall-Heroult electrochemical reaction. For every three kilos of aluminum produced, two kilos of carbon are oxidized to CO2.

The Elysis process sounds good, but the absence of CO2 byproduct comes at an energy cost. The electrolysis cell voltage will be something like 50% higher. If the electricity is from low carbon sources, then the new process is good for the environment. It's probably good for the producer's bottom line also, as the cost of making consumable carbon electrodes is almost certainly greater than the cost of the electricity their use saves. But it is a tradeoff that has to be weighted.

The electric energy used by the 9 Canadian aluminum factories is 100% clean very low cost ( less than 1/3 normal selling price) Hydro. That is the main reason they were built in Canada (most of them in Quebec). The raw material is all imported.

The first factories were built in the late 1930s to produce aluminum for war planes.

Carbon electrodes are made from petroleum coke, that is a waste product that is very low cost.

Petcoke is hard to even give away.  A refinery south of Detroit is under fire for leaving heaps of it out in the open where they generate toxic dust.  It's just a short barge trip to the coal-fired plants in Monroe, but those plants will not burn the petcoke to help get rid of it.  Apparently they cannot meet their emissions limits if they use it as fuel.

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