base metals (base metals)

Base metals in e-waste are the high-volume, low-unit-value metallic elements that form the bulk physical mass of recovered material: copper, aluminium, iron and steel, nickel, tin, zinc, and lead. Although their per-kilogram price is one to three orders of magnitude lower than precious metals, base metals contribute the majority of revenue at most Indian e-waste plants because they constitute 50-70% of inbound feed weight.

Typical mass fractions of e-waste: Across mixed Indian e-waste (a basket of monitors, desktops, laptops, ACs, refrigerators, and small appliances), the recovered base-metal split is approximately copper 8-14% by inbound mass, aluminium 5-9%, iron and steel 35-45%, with zinc, tin, nickel, and lead combined at 1-3%. Cables and motor windings yield copper at gate-grade prices of Rs 650-750 per kg; clean aluminium fetches Rs 150-180 per kg; bulk steel Rs 25-35 per kg. A 1 TPH plant processing 7,000 tonnes per year of mixed e-waste can generate Rs 6-9 crore INR per year in base-metal revenue alone.

Recovery technology: Base metals are separated by physical methods rather than chemical leaching. The standard sequence is: primary shredding to fragments under 100 mm, magnetic separation to pull ferrous, eddy-current separation to recover non-ferrous, density separation (air classification or sink-float) to split heavy non-ferrous (copper) from light (aluminium), and finally an optical sorter using XRF or XRT sensors for final grade upgrades. Cable-recovery lines use chopping granulators followed by gravity tables to separate copper from PVC insulation.

Trade-offs and quality grading: The price difference between mixed and graded base metals is dramatic. Mixed copper-aluminium chops sell for Rs 400-450 per kg; clean number-2 copper for Rs 650-700; bright-bare copper wire for Rs 780-820. Most informal Indian operators stop at mixed chops; formal plants invest in eddy-current and density separation to capture the grade premium. The principal failure mode is contamination of copper with aluminium from poorly separated coils — even 1-2% aluminium drops the grade from number-2 to number-3, costing Rs 100-150 per kg.