Footballers are famous for “giving it 110%”. But can steel have 110% recycled content?
Recycled content is the proportion of recycled material in a new product. If I am making steel cans, and half of the steel I use is scrap and half is made directly from iron ore, then the cans have 50% recycled content – not to be confused with the recycling rate, which would be the proportion of cans that are recovered and recycled.
But two things to be careful about: what counts as recycled content? and how to account for yield loss?
Recycled content
First up, let’s look at what counts as recycled content. In the case of steel, are we only interested in the end-of-life (post-consumer) scrap content, or are we also interested in pre-consumer scrap? If we are interested in the pre-consumer part that will include manufacturing scrap, but should it also include internal scrap, and/or home scrap?
Inevitably, ISO has a standard for this. ISO standard 14021 on environmental labelling1 specifies that recycled content includes both pre- and post- consumer material, but should exclude material ‘such as rework, regrind or scrap’ that is ‘capable of being reclaimed within the same process that generated it’. That clearly excludes internal scrap. But the status of home scrap is potentially ambiguous: is the ‘same process that generated it’ the process of generating crude steel, or should it include additional downstream processing of the crude steel at the same site?
On the one hand, home scrap is simply the result of inefficient on-site processing with high wastage – an argument for excluding it from counting towards recycled content.
On the other, home scrap may be waste from exactly the same processes that generate manufacturing scrap, the only difference being that it would be classified as home scrap if the process takes place at the steelmaking site but as manufacturing scrap if takes place somewhere else.
To be consistent it makes sense to count home scrap along with manufacturing scrap, and count both towards the (pre-consumer) recycled content of crude steel. We can then talk about the overall recycled content of the steel from which steel products are made, including both pre- and post-consumer scrap in line with the ISO 14021 standard.
Does that mean we shouldn’t differentiate between pre- and post-consumer scrap at all? Pre-consumer scrap – including both home and manufacturing scrap – is a valuable material for steelmaking. Supply is regular, it is likely to be of high, consistent and known quality, and free of contamination. Unsurprisingly, it is almost always recovered for recycling, and recycling rates are generally assumed to be close to 100%. Given that this is the case it might be considered greenwashing to imply that its use in the steel sector is ‘green’ at all. Siting an electric arc furnace in a cluster with downstream manufacturers generating scrap may be canny, but it is hard to argue that it is particularly ‘green’. In contrast, the recovery, collection and processing of post-consumer scrap requires some effort, worthy of recognition.
Good practice, therefore, when making green claims about the recycled content of steel, should be to declare the pre-consumer and post-consumer content separately.
Yield loss
The second issue takes us back to those footballers. We need to be careful how we calculate the figure for recycled content. The process of smelting scrap to produce new steel is not 100% efficient. 100 tonnes of scrap may only produce 95 tonnes of new steel – and yield losses can be much higher than that, especially if the scrap comes with contamination and impurities. Because of yield loss, if recycled content is calculated as the amount of scrap used as input in proportion to the amount of crude steel produced, we will end up with a ‘scrap content’ or ‘recycled content’ of more than 100%!2.
It would be odd to make claims to consumers or customers to the effect that ‘this steel has 105% recycled content’. It would also be odd to claim that a product is made with ‘100% recycled content’, if 5% of the input is in fact primary material. ISO 14021 is also clear that recycled content means the proportion of recycled material in the product.
Despite this, reports estimating the recycled content of steel often calculate recycled content as the quantity of scrap out of the volume of final product, ignoring yield, perhaps because data for scrap consumption and crude steel production are easy to come by whereas data for crude steel yields are not.
How much difference does it make? Well, if annual global production of crude steel is 1910 Mt, and that was made using 625 Mt of scrap, the apparent recycled content without taking yield loss into account would be (625/1910) x 100 = 32.7%. But assuming a yield loss of 5%, the figure would be 625/(1910 x (100/95)) = 31.1%. Not a huge discrepancy, perhaps, but still a difference of 33 million tonnes of scrap. If the yield loss were 10%, the difference would be around 63 million tonnes.
We should take a leaf out of the footballers’ book when we’re trying to get to the bottom of scrap statistics. We may not be able to give it 110%, but we should give it at least 105%, and take yield loss into account.
Footnotes