Creating Value from Waste


Creating Value from Waste

Marta Guzzon
Marta Guzzon
R&D Global Senior Scientist
3 minutes

White slag becomes a precious resource to steel producers.

Circular Economy is a challenging, though vital, strategy for the 21st century and can potentially reshape the steel industry, considering waste as a secondary resource, a crucial part of sustainable material's life cycle. This requires redesigning some of present practices to avoid waste being landfilled.

In 2014, the European steel industry generated about 21.4 million tons of slag, of which about 24% is not being reused, representing a severe environmental problem in Europe, but also a huge amount of available material for potential recycling.


Ladle Furnace (LF) slag handling – also known as white slag, secondary refining slag or secondary metallurgy slag (SMS) – currently represents a significant safety, environmental, operational and financial concern for Electric Arc Furnace steel producers. Ladle furnace slag is produced in the so-called secondary metallurgy process, representing the final stages of steelmaking where steel is desulfurized in the transport ladle to remove impurities.

white slag

How to handle white slag to make it reusable?

This question triggered a project at TenarisDalmine aiming to replace the traditional slag-handling methods with a new technology in partnership with Tenova.

Fabio Praolini
Fabio Praolini
Environmental Director at TenarisDalmine

Today, slag handling is a costly and time-consuming operation that poses significant safety and operational risks, requires water consumption and is a potential source of fugitive dust and fumes emissions. We tested a pilot plant for SMS slag valorisation as a raw material, selecting forced air granulation as the most appropriate and promising method for TenarisDalmine.

Forced air granulation of secondary metallurgical slag

TenarisDalmine conducted industrial tests to recover CaO (lime), which represents approximately 55% of the total SMS slag stream. The industrial process, developed and designed with Tenova, consists in the fast cooling of the liquid SMS slag mixed with residual steel by forced air stream during slagging to allow their rapid solidification.

Marta Guzzon
Marta Guzzon
R&D Global Senior Scientist

Residual valorization is a key activity to achieve a sustainable steelmaking process. Secondary raw materials are important resources for the future from a circular perspective, therefore, Tenova is constantly engaged in finding innovative solutions, like the dry slag granulation implemented at TenarisDalmine.


The tests prove that the air granulation process of SMS slag can minimize the related environmental impact – reducing CaO (lime) mining and therefore saving natural resources and protecting the landscape – while increasing workers’ safety significantly – by overtaking the traditional wet slag granulation methods which entail risks of explosion and dangerous emissions due to the use of water. The industrialization of this process will allow full recovery of residual steel and reuse of the SMS slag within the EAF process or as by-product with a number of potential applications and significant market value. LF slag can be used in many different areas such as soil stabilization, fertilization, production of cement and concrete, to name a few, or it can be reused in EAF as lime.

white slag test

The advantages of air granulation technology

Air granulation technology offers an improved way of handling SMS slag against the existing industrial practice. Preliminary results from full industrial tests performed at the TenarisDalmine demonstrated that air granulation is technically feasible and bears several advantages:

• Resources conservation

• Energy saving potential

• GHG emission saving potential

Want to know more?

Get in touch with our experts on the subject

Enzo Chiarullo
Enzo Chiarullo
Product Line Director - Environmental Technologies

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