Scrap Metal Identification and Classification
Why identification comes first
Every downstream decision - price, processing route, buyer, and regulatory handling - depends on correctly identifying what a material is. Candidates must know the major ferrous grades (heavy melting scrap, shredded or auto shredder feed, plate and structural, busheling, turnings, cast iron) and the nonferrous families (copper, aluminum, lead, zinc, nickel alloys, stainless, and the precious metals). Know the difference between an alloy family and a specific grade: "aluminum" is a family; "6061 extrusion" is a grade with its own chemistry limits.
Tools and tests
Expect questions on field identification: magnet response (ferrous and nickel attract; aluminum, copper, and most stainless do not), spark testing for steel and iron, density and heft, color and oxide appearance, fracture surface, and hardness or file tests. Chemical and handheld X-ray fluorescence analysis confirm alloy content when visual methods are ambiguous. Understand that mixed loads are downgraded or rejected - cleanliness and freedom from attachments matter as much as base metal.
Traps to watch
- Confusing stainless with nonmagnetic grades of other alloys; some stainless is weakly magnetic.
- Treating "mixed aluminum" as a single price; cast and extrusion must be separated.
- Ignoring contamination (plastic, rubber, iron attachments, moisture) that changes grade.
- Assuming color alone identifies copper alloys; brass, bronze, and copper differ in value.
Worked example
A load is mostly clean copper wire but contains soldered fittings and steel clips. Rule of thumb: separate by hand before sale; a small percentage of iron or solder can push a load from a high-grade wire category into a lower mixed or "insulated wire" category, cutting recovery value. Estimate the clean weight first, then price the separated streams.