Short answer
The value of scrap steel is set not only by its weight but by how cleanly it is delivered. Rebar with concrete still attached, piles containing mixed metals and pieces too large to transport are priced lower because they require further processing at the buyer. Separation done on site converts that difference directly into income; clean separation also raises haulage efficiency, because more valuable material fits in the same truck. The separation decision belongs inside the demolition plan, not after it.
Three factors that set the price
- Cleanliness: concrete residue on rebar is dead weight and extra processing for the buyer. As residue rises, unit price falls.
- Homogeneity: mixing different metals (steel, aluminium, copper, stainless) pulls the value of the pile towards its lowest component. Metal collected separately is worth markedly more than a mixed pile.
- Size and shape: pieces of a transportable, stackable size raise haulage efficiency and are easier for the buyer to accept. Long, irregular pieces leave voids in the truck.
The double gain from separating on site
The first gain is price: clean, homogeneous scrap sells at a higher unit rate.
The second is haulage, and it usually goes uncounted. A mixed, irregular pile uses truck volume inefficiently; less valuable material fits into the same load. Metal cut to size and stacked raises the value carried per load.
There is a third gain on the recycling side: concrete with its rebar removed enters a crusher bucket without trouble and can be reused on site. So separating the metal creates value not only for the metal but for the concrete as well.
Where separation happens
Separation happens during demolition, not after it. Picking metal out of a mixed rubble pile costs many times more than separating it with a pulveriser during demolition, and full separation is never achieved. So separation is not a "clean-up job" but a stage of the demolition plan.
A practical layout on site
- Set separate stock areas by metal type; a single pile means separation will be done later, and it usually is not.
- Separate high-value metals (copper, aluminium, stainless) in the first stage, alongside stripping the services; these are the group that gets mixed most and loses most value.
- Cut rebar to a transportable size with a shear; uncut long pieces waste haulage space and create a safety risk on site.
- Remove as much concrete residue as possible at the pulveriser stage; the cleanliness of what goes to the buyer is decided there.
- Keep weighing and delivery records; knowing how much of each material came out makes pricing future projects realistic.
The role of the shear and blade economics
The shear is the attachment at the centre of this work: it brings rebar and sections down to a transportable size. But the blade set is the most expensive maintenance item on a shear, so protecting the blade affects the margin directly.
The one rule that protects the blade is keeping it out of concrete. Rebar cut after it has been freed of concrete gives long blade life; going straight into rebar embedded in concrete blunts it quickly.
So skipping the pulveriser stage damages not only scrap quality but the maintenance cost of the shear. The two stages depend on each other.