Recovery, or yield, is the share of good metal you get back after melting a lot of scrap or dross. Two lots of the same grade can give very different recovery, and since scrap is usually bought by gross weight, recovery decides whether a deal makes money. This guide explains how buyers check recovery in practice and what to agree with the seller before the truck leaves. See also recovery and yield.
What reduces recovery
- Non-metallic material: plastic, rubber, paper, paint, coatings and dirt add weight but no metal.
- Iron and other metals: steel inserts, bolts, copper and brass must be removed or will contaminate the melt.
- Oil and moisture: common in turnings and wet bales. They burn off as weight loss and are a safety hazard in the furnace.
- Oxidation: thin or fine material such as foil, chips and painted sheet oxidises more during melting and forms more dross.
- Melting practice: furnace type, flux and temperature all change the result, so the same scrap can recover differently in two plants.
Step 1: inspect before you agree
Ask for clear photos and, if possible, a video of the actual lot, not stock images. For baled scrap, ask to see an opened bale, since contamination often hides in the middle. For larger lots, a site visit or a third-party inspection is worth the cost. Note the grade, the form (loose, baled, briquetted), visible contamination and whether the material is dry.
Step 2: take a representative sample
- Pick material from several points in the lot, not just the top layer.
- For turnings and chips, sample from different bags or heaps and keep the sample sealed so moisture and oil are not lost.
- Agree in advance who takes the sample, how large it is and where it will be tested.
Step 3: sort and weigh
A simple hand sort on a weighed sample gives a quick picture. Separate clean aluminium, aluminium with attachments, iron, other metals and non-metallics, then weigh each fraction. This shows how much of the lot is really aluminium before melting.
Step 4: trial melt
A trial melt is the most reliable check. Melt a weighed sample in a small furnace or crucible under normal practice, skim, pour and weigh the metal recovered. The ratio of metal out to material in is the trial recovery. Then take a sample of the molten metal for spectro analysis to see whether the chemistry suits your end product, for example whether iron or zinc is too high for your target alloy.
| Check | What it tells you |
|---|---|
| Visual inspection and photos | grade, form, obvious contamination |
| Hand sort of sample | share of aluminium versus iron, other metals and non-metallics |
| Moisture and oil check | weight that will be lost before melting |
| Trial melt | actual metal recovered under your practice |
| Spectro on melt | whether the chemistry fits your target alloy |
Recovery in dross
For dross, the measure is usually metal content. White dross from primary or clean melting holds more metal than black dross or salt cake from scrap melting. Testing is typically done by a lab melt or a recognised method, and both parties should agree the method and lab beforehand. See aluminium dross and our blog on selling aluminium dross.
Step 5: put it in writing
- Grade and description of the material, with reference photos attached.
- Basis of price: gross weight, net weight after deductions, or a recovery-linked rate.
- Deductions: how iron, moisture, oil and non-metallics will be deducted, and the limits beyond which the buyer can reject.
- Weighment: which weighbridge counts, at loading or at receiving, and how differences are settled.
- Testing and disputes: sample method, lab, and what happens if results differ.
- Documents: tax invoice with GST, e-way bill and weighbridge slips.
Practical tips
- Start with a small lot from a new supplier and track recovery before committing to regular volumes.
- Keep a record of recovery by supplier and grade. Over time it becomes the best guide to fair rates.
- Do not compare rates for different grades directly; compare the cost per kg of recovered metal instead.
- Dry wet turnings and remove free oil before charging, both for recovery and for safety.
How AluminumBazaar helps
When you post a requirement for aluminium scrap or dross, the sourcing desk asks suppliers for photos, grade details and contamination notes, and can arrange samples and spectro checks before dispatch. Read aluminium scrap grades explained to describe your requirement precisely.