---
title: Iron and Steel Slag
description: Iron and Steel Slag (BF & Steel Slag) is the non-metallic byproduct of metal refining, used to absorb impurities like sulfur.
---

[Glossary ](https://www.o2oh.com/glossary)

# [Iron and Steel Slag](https://www.o2oh.com/glossary/iron-and-steel-slag)

 Written by [one to ONE Holdings](https://www.o2oh.com/glossary/author/one-to-one-holdings) | Oct 18, 2025 2:08:11 AM

[Iron](https://www.o2oh.com/glossary/iron) and [Steel](https://www.o2oh.com/glossary/steel) Slag is a comprehensive term for the essential non-metallic byproducts from the entire ferrous metal production chain, encompassing both **[blast furnace](https://www.o2oh.com/glossary/blast-furnace) **slag (from [pig iron](https://www.o2oh.com/glossary/pig-iron) production) and steelmaking slag ([BOF](https://www.o2oh.com/glossary/basic-oxygen-furnace-bof) and [EAF](https://www.o2oh.com/glossary/electric-arc-furnace-eaf) slags).

Primarily composed of oxides, slag's fundamental purpose is metallurgical purification—it absorbs harmful impurities like sulfur and phosphorus from the molten metal. Crucially, these materials are no longer viewed as waste but are established as secondary raw materials, used extensively in civil engineering and cement production, which significantly bolsters the [sustainability](https://www.o2oh.com/glossary/sustainability) and circularity of the construction sector.

[View full post](https://www.o2oh.com/glossary/iron-and-steel-slag)

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