Raw materials
Thermite welding of railways rails

Oxides are hot-rolling scale scraps, in the form of coarse oxide films formed in the blooms or slabs reheating furnace and recovered after the descaling stand; these oxides are coarse (grain size 2 mm), dirty, irregular and contain mainly FeO; they therefore need to be crushed and degreased before passing them through a reoxidation furnace at the filler manufacturer.

Oxides are also found in the form of high-surface-area flakes, rich in Fe ₃ O ₄ , from the surface scale of finished products undergoing cooling (rounds, rails, tubes, etc.); their grain size is finer and their reactive surface area greater.

In practice, a half-and-half mixture gives an acceptable TO oxygen level: