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Better Slag, better Degassing
QLX9 at Štore Steel

Redefining Slag Analysis

Short Summary:
At Štore Steel in Slovenia, the introduction of fast slag analysis significantly improved secondary metallurgy control. With the QuantoLux QLX9 system, slag composition is now measured within seconds, enabling precise adjustments before vacuum degassing. This optimizes pumpdown times, more stable processes, and consistently high product quality.

Initial Situation / Plant Context:
Štore Steel d.o.o., based in Slovenia, is a well-established European producer of high-quality special steel grades. The company focuses on demanding applications in engineering, automotive, and tool manufacturing, where tight chemical composition and consistent material properties are critical. The product portfolio includes alloyed and carbon steels such as engineering steels, spring steels, and tool steels, often used in safety-relevant and wear-intensive components. This requires precise metallurgical control and reliable process stability across all production steps.

The plant operates an Electric Arc Furnace (EAF) followed by Ladle Furnace (LF) and Vacuum Degassing (VD). Annual production is approximately 150,000–200,000 tons. The production strategy combines a high share of scrap-based input materials with strict quality requirements and a strong focus on secondary metallurgy. With the commissioning of a new VD unit, the importance of stable and well-controlled slag conditions before vacuum treatment increased significantly, as this directly influences degassing efficiency, inclusion control, and final steel quality.

Challenge (Pain Points):
In many steel plants relying on traditional XRF-based slag analysis, controlling slag composition prior to VD remains a challenge. Due to varying tapping conditions from the EAF, key parameters such as basicity and FeO + MnO content can fluctuate significantly and are difficult to predict. Conventional laboratory slag analysis is too slow to support real-time adjustments. As a result, slag may enter the VD process in a non-optimal condition. This leads to longer pumpdown times, reduced degassing efficiency, and increased process variability.

QLX9 in operation at Store Steel, Slovenia
QLX9 in operation at Store Steel, Slovenia
QLX9 in Operation at Store Steel, Slovenia
QLX9 in Operation at Store Steel, Slovenia

Solution (Implementation of QuantoLux Technology):
Štore Steel implemented the QuantoLux QLX9 slag analyzer in their laboratory, located within short walking distance to the melt shop. The system allows slag to be analyzed within seconds using a simple workflow: sampling, crushing, and immediate measurement. The fast availability of results enables targeted corrections directly before VD treatment. The system is easy to use and integrates smoothly into daily operations. It complements existing lab methods such as XRF, especially where immediate feedback is required.

Results (Measured Impact):
The introduction of QLX9 created a clear improvement in process performance: Slag analysis is now available 10–15 times faster than before, enabling shorter VD pumpdown times, more precise control of FeO + MnO and basicity, and typically only one or two targeted correction steps before vacuum treatment

Operational Impact (Daily Work):
In daily operation, decision-making has become faster and more reliable. Operators can now verify slag composition directly before VD and adjust it with confidence and precision. The process is more stable, with fewer correction loops and less dependency on delayed lab results. This improves coordination between EAF, LF, and VD, while reducing manual effort and uncertainty.

Strategic Context:
As steel producers increasingly rely on flexible scrap-based production and advanced secondary metallurgy, fast and reliable process data becomes essential. LIBS-based slag analysis enables real-time process control and supports data-driven steelmaking. Compared to conventional methods, it closes the gap between measurement and action, which is critical for efficiency, quality, and sustainability.

Customer Voice:
“With the commissioning of our new VD unit, online control of the ladle slag composition became one of the most important steps in our secondary metallurgy process. Due to varying tapping conditions, during preparation for VD, both basicity and FeO+MnO content were often difficult to predict, directly affecting process stability and degassing performance. The QuantoLux slag rapid analyzer presents a very effective solution to the problem: we can now analyze slag within seconds and adjust it precisely with only one or two targeted correction steps. It also enables us to make calculated tapping additions from one heat to the other to achieve the targeted slag compositions. As a result, we massively improved degassing efficiency by shortening pumpdown times and consistently are able to achieve high product quality right from the start.” — Vid Vengust - Melt Shop Metallurgist Štore Steel

Conclusion:
With QLX9, Štore Steel transformed slag control into a real-time process step—resulting in faster degassing, improved stability, and consistently high steel quality.