Innovative non-furnace treatment methods are making steel production cleaner, smarter, and more efficient
Imagine a world without steel—no skyscrapers, no bridges, no automobiles. Yet few consider the crucial ingredients that transform iron into steel, giving it strength, durability, and corrosion resistance. Among these, manganese ferroalloys play an indispensable role, serving as the workhorse additive that removes impurities and enhances steel's properties. Traditionally produced in energy-intensive furnaces, these alloys account for staggering 14.2 million tons of CO₂ emissions annually in Europe alone 1 . But a technological revolution is underway that could transform this vital industry through innovative non-furnace treatment methods that are cleaner, smarter, and more efficient.
The PreMa project (Energy Efficient, Primary Production of Manganese Ferroalloys) represents a monumental collaboration between European and South African researchers and industrial partners to reimagine how we produce these essential materials. By harnessing solar thermal energy and industrial off-gases, this initiative has developed groundbreaking pretreatment technologies that reduce energy consumption while maintaining the quality steelmakers demand .
Manganese is the second most abundant transition metal after iron, but its significance in steelmaking far exceeds its natural abundance. When added to steel, manganese performs several critical functions: it deoxidizes the molten metal, prevents sulfur-induced brittleness, and enhances strength, toughness, and hardenability.
Most manganese is added to steel in the form of ferromanganese (FeMn) and silicomanganese (SiMn) alloys—carefully formulated combinations of iron, manganese, silicon, and carbon. The global production of manganese alloys reached approximately 4 million tons in 2017, requiring a massive 12,200 GWh of electrical energy 1 .
Conventionally, manganese ferroalloys are produced in submerged arc furnaces (SAFs)—massive electrical installations that operate at extremely high temperatures. These furnaces consume tremendous amounts of energy as they reduce manganese oxides from ore to metallic form using carbon-based reductants.
The traditional method faces several limitations beyond its environmental impact. SAFs require high-quality ore lumps rather than fine powders, limiting the types of raw materials that can be used efficiently. They also lack operational flexibility, as they're designed to run continuously rather than adapting to fluctuations in energy availability.
Tons of CO₂ emissions annually in Europe
Tons of manganese alloys produced globally (2017)
GWh of electrical energy required annually
The EU-funded PreMa project has taken on the challenge of reimagining manganese alloy production through an ambitious pretreatment approach. Instead of performing all reduction in the submerged arc furnace, the process is divided into two stages: pretreatment of manganese ores followed by final reduction in a modified furnace setup .
The project brings together an impressive consortium of 11 production facilities across Europe and South Africa, representing an aggregated process capacity of 380 MW 1 . This collaboration between industry and research institutions enables testing at various scales.
A cornerstone of the PreMa approach is utilizing energy streams that would otherwise be wasted. The project explores three primary alternative energy sources:
This diversified energy approach increases flexibility while reducing both operating costs and environmental impact.
In operating costs
In energy efficiency
In total CO₂ emissions
To validate their approach, the PreMa consortium conducted an extensive series of pilot-scale tests across multiple research facilities in Europe and South Africa. The experimental campaign was designed to evaluate different pretreatment methods and their effects on downstream processing.
Trondheim, Norway
Researchers employed a specialized 440 kVA pilot submerged arc furnace capable of processing up to 500 kg of material per day .
Jülich, Germany
Engineers demonstrated solar thermal pretreatment using an experimental solar tower facility achieving temperatures exceeding 800°C .
Different manganese ores from South African and European sources were analyzed for chemical composition, physical properties, and reduction behavior .
Ores underwent various pretreatment methods including preheating to 600-800°C using conventional energy sources, solar thermal preheating, and prereduction using CO-rich off-gases.
Both pretreated and untreated ores were processed in pilot-scale submerged arc furnaces under identical conditions to enable direct comparison.
Comprehensive measurements were taken throughout the process, including electrical energy consumption, total energy input, CO₂ emissions, and process efficiency.
The resulting ferroalloys were analyzed to ensure they met quality standards for steel treatment applications.
The pilot tests demonstrated substantial improvements across multiple performance metrics compared to conventional processing. The data revealed that pretreated ores required significantly less electrical energy in the furnace stage because much of the reduction work had already been accomplished during pretreatment.
Perhaps most impressively, the integration of solar thermal energy proved technically viable despite concerns about intermittency. With adequate thermal storage, the system maintained consistent operating temperatures regardless of weather conditions, enabling 24/7 operation .
Beyond the numbers, researchers observed several operational advantages. Pretreated materials showed more consistent behavior in the furnace, leading to smoother operation and reduced operator intervention.
The ability to use ore fines that would otherwise be unsuitable for traditional processing emerged as another significant benefit, potentially expanding the range of economically viable raw materials.
The flexibility of the pretreatment approach allows plant operators to switch energy sources based on availability and cost—using solar thermal when sunshine is abundant, off-gases when furnace operation generates sufficient byproduct, and conventional energy as a backup.
| Process Type | Electrical Energy (kWh/ton) | Thermal Energy (kWh/ton) | Total Energy (kWh/ton) |
|---|---|---|---|
| Traditional SAF | 3,050 | 0 | 3,050 |
| PreMa (Off-gas) | 2,200 | 800 | 2,500 |
| PreMa (Solar) | 2,100 | 900* | 2,100 |
*Solar thermal energy counted at zero CO₂ cost
| Process Type | CO₂ Emissions (kg/ton) | Reduction vs. Traditional |
|---|---|---|
| Traditional SAF | 1,450 | Baseline |
| PreMa (Off-gas) | 1,100 | 24% |
| PreMa (Solar) | 850 | 41% |
| PreMa (Hybrid) | 950 | 34% |
| Ore Source | Optimal Temperature (°C) | Energy Reduction | Quality Rating |
|---|---|---|---|
| South African | 800 | 22% | Excellent |
| European A | 750 | 18% | Good |
| European B | 650 | 15% | Very Good |
| Norwegian | 700 | 20% | Excellent |
The development of advanced manganese ferroalloys relies on a sophisticated array of research reagents, materials, and technologies. Here are the essential components that made this innovation possible:
Various grades from South Africa and Europe, selected based on manganese content, impurity profile, and physical properties.
Both traditional fossil-based carbons and innovative bio-carbons derived from renewable biomass.
Captured from industrial processes, these gases serve as both reducing agent and heat source for pretreatment.
Advanced heliostats that concentrate sunlight to achieve temperatures exceeding 800°C .
Molten salt or ceramic systems that store thermal energy for use during periods without sunlight.
X-ray fluorescence spectrometers, electron microscopes, and other tools for characterizing materials.
The PreMa project's successes demonstrate that even traditionally conservative, energy-intensive industries like ferrous metallurgy can undergo revolutionary changes. The 20% reduction in energy consumption and 20% decrease in CO₂ emissions targeted by the project represent significant progress toward decarbonizing steel production 1 .
The flexibility inherent in the PreMa approach offers additional strategic benefits. By enabling operators to switch between energy sources based on availability and cost, the technology creates resilience against energy price volatility. This adaptability will become increasingly valuable as electricity grids incorporate higher percentages of variable renewable generation.
While initially developed for manganese ferroalloys, the pretreatment concept shows promise for other metallurgical processes. Similar approaches could be applied to production of ferrosilicon, ferrochromium, and other energy-intensive alloys.
Perhaps most exciting is the potential application in direct steelmaking itself. The same principles of divided processing and energy flexibility could inspire innovations beyond alloy production into the core steelmaking process, potentially revolutionizing one of humanity's most important industrial activities.
The development of new complex manganese ferroalloys for non-furnace treatment represents more than just an incremental technical improvement—it signals a fundamental shift in how we approach industrial processes. By reimagining traditional methods and boldly integrating renewable energy, the PreMa project points toward a future where heavy industry and environmental sustainability coexist productively.
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