Smelting is the process of melting scrap metal in a high-temperature furnace to produce a refined or semi-finished metal product — ingots, billets, or molten metal ready for casting. Different metals require different furnace types: steel scrap is typically smelted in electric arc furnaces (EAFs), while copper and aluminium use reverberatory or rotary furnaces. In New Zealand, NZ Steel’s Glenbrook mill south of Auckland is installing an electric arc furnace (operational from 2026) capable of smelting domestic scrap steel — the country’s largest emissions reduction project, projected to halve the mill’s coal use. Most non-ferrous scrap collected in Auckland is exported to smelters in Southeast Asia, India, and China. The smelting stage is where recycled metal re-enters the manufacturing supply chain as new raw material — and it uses 60–95% less energy than smelting virgin ore from the ground.