A mixed batch settles according to its weakest fraction, not according to an average of what is in it. That single sentence explains most of the gap between the valuation a supplier expected and the one they received. The good news is that in a production plant the biggest gain comes not from sorting before delivery, but from segregation at source — separate containers where the waste arises.
Why a mixed batch loses value
A mill pays for a predictable charge. When clean aluminium profile, wheels and some steel fittings travel in one container, the buyer is not purchasing three materials — they are purchasing one, with the parameters of the weakest component, because that is all that can be guaranteed without re-sorting. The cost of that re-sorting has to appear in the valuation, and it appears on the supplier's side.
The same logic works in reverse. Separated streams are valued individually, each by its own grade — and the sum is higher than a single rate for the whole. We describe the mechanism in more depth for copper grades and aluminium grades.
What is genuinely worth separating
Not everything is worth separating — what counts is the ratio of work to the difference in valuation. In practice four splits give the greatest return:
- Non-ferrous metals from steel. The basic and most profitable split. Aluminium or copper in a container with steel will settle as steel.
- Grades within one metal. Clean profile apart from castings, Millberry apart from unsorted copper.
- Clean material from material with hardware. Profile without fittings and gaskets is a different class from the same profile fully fitted.
- Heavy melting from light steel. Thick, solid scrap apart from sheet and fines — a difference we describe in the piece on the W2 and N10 classes.
Typical contaminants and where they come from
Three groups of contaminants recur most often:
Foreign metal — steel screws, hinges, embedded bushings, reinforcements. Usually this is not carelessness but a feature of how the product was built, which is why it is worth catching where dismantling takes place anyway.
Non-metallic materials — rubber, plastics, insulation, concrete residue, pallet timber. They inflate the weight and lower the yield, and at a larger share they push the whole batch into a lower class.
Moisture and oil — mainly a problem of turnings and fines. Turnings collected together with coolant settle markedly worse than drained or centrifuged ones.
Segregation on the shop floor
Sorting a heap before delivery is expensive. Segregation at source is not. A separate container on the shop floor, labelled with the type of material, costs once and works for every subsequent batch. Three to five streams are usually enough: non-ferrous metals, steel, material with hardware, turnings, packaging.
It also simplifies record-keeping: separated streams are easier to declare with the right waste codes, without a catch-all "mixed metals" entry.
What you do not have to do yourself
Sorting does not mean you have to guess grades. We handle commercial grade identification and valuation at the branch — an experienced employee assesses the material and can verify a non-obvious alloy with a handheld spectrometer. This does not replace legal waste classification and code selection by the entity responsible for record keeping. Nor do you need to strip cables, motors or radiators; we price those items by type and estimated yield.
What to prepare for a declaration
Four things are enough for a valuation: the type of material, an approximate tonnage, photos and the location. Location matters because for larger batches we can arrange transport or place a container if needed — most often, though, the supplier brings the material in themselves.
Do you have a recurring stream of production waste? Send photos and a description — we will price it by grade, and for an ongoing relationship we will work out the split of streams that makes sense at your site.