Talking Trash 2: Getting Scrappy

I was recently interviewed for this CNBC story on sorting technologies and its role in the future of the scrap metal industry. It’s a great primer for what’s going on in the space. If you’d like a little more of my perspective, we’ve re-publishing this story from spring of last year.

From CNBC | This smarter sorting technology is allowing for the reuse of aluminum back into domestic industries

In Talking Trash 1: Why Sortation Matters, we wrote about how trash becomes trash when materials degrade, diffuse, and/​or get mixed, and highlighted the importance of sorting trash, or ​“sortation”, in the recovery of valuable resources. Now let’s dig into some of the most recycled materials in the world – metals – and how we might make metals recycling even better. We are obsessed with metals because they are critical materials to human civilization and well-being, which is why improved scrap metal recovery is good for the economy, good for the environment, and good for people – exactly the kind of win-win-wins we live for at Planetary Health.

Scrap metal recycling is an awesome market with significant economic, environmental and human benefits. People have been recycling metals since their discovery for clear economic reasons. Because of the physics and chemistry of metals, it takes up to 95% less energy, far fewer resources and costs significantly less to recycle metal than to make new metal from ore. And because metals are infinitely recyclable, the cost savings and efficiencies can go on forever. The environmental and human benefits are clear as well: pollution related to metals production can be reduced toward zero with recycling and the combination of stronger economy and less pollution is great for people’s health, wellbeing and productivity. Given all that, it’s no surprise most metal is recycled. Consider aluminum and steel: it’s estimated that 75% of the aluminum ever made is still in use and 90% of aluminum used in cars and buildings is recycled; steel is the single most recycled material in the world, with more than a billion tons recycled every year. Recycled scrap accounts for 40% of all steel production, reducing carbon dioxide emissions and the need for iron ore by about one billion tons each, annually. Its an awesome market, but we need it to be even better because metals are critical to the increased production of renewable energy and the expanded electrification of transportation and industry often referred to as the energy transition, and they are a critical resource for a growing global middle class. So how do we take an already awesome market and turn it up to 11? Better sortation. There are multiple pain points in the scrap metal industry that can be addressed by improved sortation. We will consider two large opportunities: mixed alloys and copper contamination of scrap steel.

First up: Alloys. Alloys are like chemically mixed ​“flavors” of metal that behave in different ways than their pure metal counterparts. Pure aluminum is too soft for many applications; add – or alloy – copper to aluminum, and you get an aluminum alloy useful in aircraft production. Add silicon and magnesium to aluminum and we get alloys useful in automobile production. Cold-work aluminum with manganese and you can make soda cans. Alloys involve chemical mixes, which is why making alloys is something like making soft drinks in a soda fountain: you start with water, add concentrate, and the water is transformed into Coca-Cola or Fanta or lemonade. You can think of those drinks as ​“alloys” that are mostly water, but with different flavors and qualities you may not want to mix.

Today most metal recycling does not separate alloys. It’s the equivalent of combining that Coca-Cola, Fanta and lemonade and labeling the result ​“water”. Yes, they are mostly water, but not pure water, and you wouldn’t want to use the mix in a recipe calling for pure water. Mixing metal alloys has the same sort of outcome, and that’s why if a manufacturer today wants to make a high-performance alloy, they often have to limit recycled content inputs because a mix of random alloys may introduce unwanted contaminants that render their final product too brittle, too weak or otherwise unusable. The ideal for metal production is to sort scrap to the alloy level rather than to the level of mixed aluminum alloys, mixed steel alloys, mixed copper alloys, etc. as occurs today. If metal producers receive scrap composed of just the alloy they want to make, they can go to higher – potentially 100% – recycled content. Higher recycled content means less energy, less ore, lower costs, and lower emissions. That win-win-win via alloy-level aluminum sortation is what our friends at Sortera Technologies are up to.

Second, let’s consider copper contamination of scrap steel. Scrap steel is collected from old cars, appliances, and building materials that are shredded into a mix of metals. Steel is magnetic, so magnets are used to separate it from most other non-magnetic metals such as copper and aluminum. However, small amounts of non-steel metals (sometimes called ​“tramp” metals) inevitably end up stuck to the steel. The quantities are generally small, less than 1% by weight, but that can still be enough to cause problems with steel production. Scrap steel tends to have an average copper content of about 0.1% to 0.5%, the equivalent of one to five pounds of copper for every 1,000 pounds of steel (or one to five kilograms for every 1,000 kilograms). That may not sound like much, but it’s up to ten times higher than the acceptable levels of copper in high performance steel and can cause performance problems such as cracks in the surface of the steel. Today, copper contamination is often dealt with by diluting the contamination with pure iron in electric arc furnaces (EAFs), sending contaminated scrap to coal-fired blast furnaces, and generally using contaminated scrap to make rebar (steel reinforcement for concrete). If we can pull more copper out of scrap steel, less new steel will be needed for electric arc furnaces, less steel will have to be produced in coal-fired blast furnaces, and more scrap could be used in more high value applications, like cars and appliances. Some good news: EAFs can be powered by any electric power source, including renewables; they are already widely used around the world — especially in the U.S. — and the cost of steel production from EAFs can be significantly lower than from blast furnaces. Making steel with high purity scrap in EAFs powered by low-carbon energy is a near-term, profitable pathway to decarbonizing steel with little or no change to existing infrastructure. A recent study pointed to the aforementioned approach as a great way to jumpstart decarbonization of the steel industry. The data is clear, removing copper contamination from steel is a win-win-win opportunity.

There is a potential bonus to removing copper contamination from scrap steel. A huge amount of copper is wasted annually when it ends up in scrap steel as a contaminant, as waste matter (or ​“slag”) at blast furnaces, or otherwise trapped in rebar. The 0.1% to 0.5% of copper in the billion annual tons of recycled steel is equivalent to one to five million tons. At today’s market rate for copper of about $8.5k/ton, that’s anywhere from $8.5B — $42.5B of copper wasted annually. Meanwhile, the copper supply gap, which is the gap between today’s copper supply and what is needed for continued growth of renewable energy and electric vehicles, is projected to grow to about 6.5 million tons per year in the next decade. If copper contamination can be removed from scrap steel and added to the copper scrap supply, the copper supply gap could be at least partially closed. There is a tremendous opportunity to both decarbonize steel and address a supply chain problem that could slow the energy transition.

There you have it, two incredible opportunities to benefit planetary health through alloy sortation and removal of copper contamination from scrap steel. If you are working on solutions in these areas, or generally working on ways to better utilize scrap metals, we would love to hear from you. Let’s get scrappy together and find innovative ways to transform scrap metal and sortation into opportunities for people, planet and profits!

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