If you are in the metallurgy industry and would like to carry out an analysis of your steelmaking slag
Steel slag
Steelmaking slag is a solid residue generated during metal smelting processes (steelworks, foundries, etc.). Although they are often considered as waste, they can also be recycled as secondary materials, provided that their chemical composition and physico-chemical properties are perfectly controlled.
Why analyse your steel slag
Characterise your slag for reuse in other materials. A controlled composition is essential for obtaining outlets.
Assess the pollution risks associated with storage or disposal (presence of heavy metals, leaching behaviour, etc.). This is often a regulatory requirement.
Understand the nature of slags to adjust your melting parameters, improve yields or avoid the formation of undesirable slag..
Investigate quality drift, alloy defects or furnace malfunctions. Slag is often a good indicator of what is happening in the process.
Monitor production batches, qualify a new process or compare materials from different suppliers.
The different types of steel slag
Blast furnace slag is produced during the reduction of iron ore in the blast furnace. It is mainly composed of calcium silicates, alumina, magnesia and other oxides. It is found in two forms depending on the cooling method: vitrified when cooled rapidly, or crystallised when cooled slowly. This type of slag is widely used, notably as aggregate for concrete and bituminous mixes, as a calcium amendment in agriculture, and in cement works for the manufacture of blast furnace cement.
Converter slag, also known as LD or BOF slag, is generated when cast iron is converted to steel in oxygen furnaces. Its composition is rich in calcium oxide, iron oxide, silicates and phosphates. It is characterised by its high basicity and free lime content. This type of slag is mainly used for soil treatment. It can also be partially recycled in the steelmaking process, although it is generally less valuable than blast furnace slag, due to its more reactive composition.
Electric arc furnace slag, or EAF slag, is generated in electric arc furnaces, mainly used to produce steel from recycled materials. Its composition is highly variable, including silicates, metal oxides (iron, chromium, manganese) and lime. It may contain undesirable elements, such as hexavalent chromium, depending on the nature of the charge treated. It can be used in road applications, provided certain precautions are taken, but its use in the construction sector remains limited due to its potentially restrictive composition.
Secondary slag, also known as ladle metallurgical slag, is formed during secondary metallurgical operations, in particular during the refining of steel in the ladle. Its composition is highly variable, depending on the additions made during processing, such as desulphurisation or deoxidation. This type of slag is generally not recovered to any great extent; it is often stored or partially recycled internally.
The FILAB laboratory can help you analyse iron and steel slag
Why choose FILAB for steel slag analysis?
For more than 30 years, FILAB, an expert in metallurgical analysis, has been providing high added-value steel slag analysis services to several thousand customers. Some of our analysis services are COFRAC ISO 17025, Pr 6000 and Pr 7210 accredited by Safran or linked to our customer approvals.
Analysis of steel slag
Support at every level: from simple analysis to full interpretation of results
Advanced analytical techniques
A team with expertise, responsiveness and experience in the metallurgy sector
The ability to work with you on your most complex issues
Our analysis services for iron and steel slag
Chemical analysis:
- CaO, MgO, SiO₂, Al₂O₃, Fe₂O₃, MnO, TiO₂...
- Determination of trace metals (Cr, Ni, Zn, Pb, etc.)
Physico-chemical characterization:
- particle size, porosity, crystalline structure glassy
- phase content, thermal properties
Environmental behaviour studies:
- Leaching tests (standards EN 12457, NF X31-210, etc.)
- Characterization of risks of release or pollution
Analysis of process problems:
- Investigation of abnormal slag formation
- Detection of unexpected contaminants or inclusions
Our technical resources
Scanning Electron Microscopy (SEM-EDX)
Our accreditations
The FILAB laboratory is accredited by COFRAC (French Accreditation Committee) – Laboratories section – for its departments in Chemistry, Metallurgy, Organic Chemistry, Chemical Expertise, Materials Expertise, and Environment in the following fields:
✔️ Physicochemical analysis of metallic materials
✔️ Physicochemical analysis of cosmetic and pharmaceutical products
✔️ Physicochemical analysis of medical devices, medical equipment, and chemical and biological products
Scope available No. 1-1793
This Nadcap accreditation notably covers:
✔️ Chemical analysis (ICP-OES) of critical metallic alloys (Al, Fe, Ni, Ti)
✔️ Metallography
An international recognition that confirms our commitment to quality and reliability for the most demanding applications, particularly in the aerospace sector.
