18th Global Slag Conference, Exhibition & Awards 2026

18th Global Slag Conference, 15 - 16 April 2026, Istanbul, Türkiye

The 18th Global Slag Conference has successfully taken place in Istanbul, with around 130 delegates from 33 countries, 18 presentations and 12 hours of networking. The 19th Global Slag Conference will take place in Aachen in April 2027.

Day One

Joe Harder of OneStone Consulting first spoke about global markets for slag. He pointed out that the European steel industry will transition from the use of basic oxygen furnaces (BOF) and electric arc furnaces (EAF) to just using direct reduction iron (DRI) furnaces and EAF by 2050. However, slags from DRI furnaces will have a slightly different composition and cementitious performance to ‘traditional’ slags. Joe suggested that the volume of BOF slags will decrease by nearly 50% in the period to 2050, while EAF tonnage will increase by around 20% in the same period. The price difference between granulated blast furnace slag (GBFS) (up to US$70/t) and BOF/EAF slags (up to US$15/t) is significant, and costs to improve slag properties may offer value for money for both producers and users. Slag and fly ash in Asia will increase in volume in the future, he concluded.

Selçuk Yetimoğlu of Heidelberg Materials Trading outlined the current situation in seaborne supplementary cementitious material (SCM) flows. Heidelberg Materials Trading moved 27Mt of materials in 2025, with over 500 trading partners. Selçuk detailed the various trade disruptions at the moment, foremost of which is the closure of the Strait of Hormuz. Fuel costs are high and variable, while the Baltic Dry Index is strangely unmoved, for now. Higher cement, clinker and slag exports are expected from China, Algeria and Japan. Chinese slag prices are low, and due to their large volumes (currently around 20Mt/yr), they drive the market. However, “producers should not take today’s massive SCM availability for granted in the future,” said Selçuk.

Andreas Ehrenberg of the FEhS Institut für Baustoff-Forschung e.V. next spoke about the properties of slags from DRI, continuously producing electrical iron in a reducing environment. thyssenKrupp Steel in Duisburg is building a DRI plant with a smelter, due to start in 2027, publicly funded with €2bn and fuelled with natural gas. Poor-quality iron ore can be used, and due to the reducing atmosphere, there is very low heavy metal content in the slag. Semi-pilot-scale campaigns have been undertaken and the resultant glassy granulated slag investigated. DRI slag has higher basicity and higher Al₂O3 content, but otherwise has comparable composition to GBFS. The granulated slag was ground and mixed with clinker - and was found to have comparable strength to GBFS - while industry tests by Heidelberg Materials in concrete found comparable strength at similar particle sizes. Freeze-thaw tests showed similar performance at low slag content, but with further work required to determine results at higher slag contents. Heavy metal contents and leaching values were far below German limit values. Andreas concluded that granulated smelter slags are really ‘GBFS 2.0.’ However, a great deal of bureaucracy will be required before DRI slags are allowed to be used in construction.

Gerhard Terblanche next spoke about slag valorisation options by Metix, part of the SMS Group. Metix will supply the 200MW rectangular open bath furnace (OBF) that will be used in Duisburg. However, Gerhard spoke about an electrical slag valorisation furnace (SVF) that will take OBF slag and EAF slag, reduce their metal content and improve their performance as supplementary cementitious materials (SCM). The SVF is a reducing process, and produces recoverable energy in the exhaust gas. In a pilot-scale test, 1t of hot metal was derived from 3.8t of EAF slag. In full-scale units, it would be possible to use various feedstocks, including molten EAF slag and ladle furnace (LF) slag, stockpiled cold slag, fine dusts, reductants and fluxes - or a blend of materials. The refractory lining and furnace cooling system are critical to success.

Hagen Müller of Haver Engineering mentioned that around 45Mt of copper slag is produced annually, but only around 15% is used. The cooling rate controls the slag structure and metal recovery rates: slow cooling leads to larger crystals, metal droplets and higher recovery rates, while granulation leads to much lower metal recovery. In order to optimise recycling rates, copper slag that is being considered for valorisation will need to undergo mineralogical and metallurgical analysis, in order to determine the optimal processing steps and equipment. Metal droplet size determines whether density separation will be used, while variations in grindability will determine the crushing and screening steps used.

Ikram Ahmed Khan of Cemcoa, part of the Shung Shing Group, next spoke about slag trade in Asia. Japan exports around 10Mt/yr of GBFS, mostly to Asia, but also to the US and Europe. China exports around 20Mt/yr, out of its 120Mt of steel slag and 260Mt of BF slag. Cemcoa has a 28% share of the export market from China,  largely to Asia and the Middle East. Vietnam is a major exporter of around 1.3Mt/yr, mostly to Asia and Europe, while Indonesia exports the same tonnage, but with 80% going to Europe. South Korea exports around 1.4Mt/yr, with 70% exported to Taiwan via small vessels due to draught restrictions. India exports 1.3Mt/yr of slag, and Cemcoa has a 65% share of the export market. These countries total around 36Mt/yr of BFS exports. Bangladesh is the top importing country in Asia (7.3Mt/yr), followed by the UAE, Taiwan, Malaysia and Vietnam. Asia uses around 8Mt/yr of imported GBFS.

Ikram Khan commented on the situation in the Strait of Hormuz: slag trade has shifted from the efficient, direct route towards constrained and indirect flows, including via Fujairah in the UAE, located outside of the Strait of Hormuz. Sohar Port in Oman is another option, while Saudi Arabia has the option of transits via the Red Sea. However, raw material supplies have largely halted, and uncertainty reigns. Freight rates have increased by at least US$15/t, if transport is available at all. Diesel costs have increased, leading to higher costs if trucks are used, and existing slag stocks are also diminishing. Contracts may specify penalties if slag is not delivered, and supply constraints are amplifying price volatility. At the moment, the price of delivered slag into the UAE has increased from US$30/t to around US$45/t.

Niklas Törnkvist of Magsort spoke about his company’s slag processing plant in Sohar, Oman, which takes ladle furnace slag and processes it to add value by producing a >80% metal fraction (suitable for feeding directly into an EAF) and ‘SlagZero’ kiln feed products. A historical slag dump is used, which is a mix of LF slag, filter dust, waste, refractories “and anything else you can think of,” said Törnkvist.  The first stage of the process reduces the variance of the materials’ chemistry. Since December 2025, clinker has been produced from SlagZero at the Al Ain cement plant in the UAE, with no observable difference in clinker chemistry or strength. Now, a new facility to process EAF slag will be built at the Al Ain plant, which will allow an increase in use from 2.5% to ~15% LF slag. The SlagZero product uses a Cr+6 reductant to avoid chrome problems, and MgO levels are carefully monitored. The target set out by Emirates Cement is to substitute 18% of limestone with processed steel slag. Production volumes can be increased, and it contributes to fuel savings and a reduction in CO₂ emissions.

Jyri Talja of Finnish company Betolar then spoke about a process for valorising ferro-chromium and stainless steel slags to produce GeoPrime cement-free binder. The company takes (ideally molten) smelter slag and 10-15% mine tailings (or other materials, including other slags), combines them and processes them to produce metals and building materials. Combining the materials reduces the viscosity of the melted material and allows for increased metal recovery. A number of slags have been tested, including FeCr, AOD, BOF, EAF, FeMn, FeNi and TiO₂ slags. The critical step is to ensure that the solution of the chrome-bearing spinel mineral phases in the liquid melt using ‘secret’ fluxes, which allows chrome to be extracted and eliminated from the potential building materials byproduct.

Nicolas David, DALOG, emphasised that his company offers machine monitoring services that go beyond vibration analysis to also look at torque, speed, acceleration, displacement, current, voltage and more parameters from industrial production lines. He gave the example of how DALOG is helping Votorantim Cimentos North America to save money on repair costs in a series of interventions, starting by focusing on critical machines at five plants and then rolling out more sensors and monitoring in waves. Nicolas then discussed how DALOG is working with other suppliers to make it easier to integrate their products and services.

Liandra Taljaard, Mpangilio Consultants, compared the legal definitions of waste in relation to slag between South Africa and the EU. She described a series of legal battles between the steel and slag sectors in South Africa to differentiate slag from waste specifically for current usage and subsequent use. Meanwhile, in the EU, the focus is on disposal, although this has started to change with regulations on critical raw materials that view waste as a strategic resource. Liandra noted that the EU focuses on resource security, whilst South Africa looks at environmental control.

Global Slag Awards dinner

At the end of the first day, delegates boarded buses for the short trip to the local marina to embark onto a dining yacht, which cruised up the Bosphorus and past many of Istanbul’s most historic and spectacular sights. The Global Slag Awards were presented during the cruise. Shung Shing Group won ‘Company of the year,’ while Gebr. Pfeiffer won the award for ‘Equipment supplier of the year.’ Betolar won ‘Slag-based product of the year’ for its GeoPrime SCM, and Swecem won ‘Plant of the year’ for its Oxelösund plant in Sweden. ‘Slag user of the year’ was CRH Group and DALOG won the ‘Technical innovation’ award for its multi-sensor diagnostics offering to the slag industry. Three Global Slag ‘Personality of the year’ awards were presented, to Andreas Ehrenburg of the FEhS; to Marc Fixaris of ArcelorMittal; and to Adib El-Hachem of Çiment de Cibline, Lebanon.

The location of the 19th Global Slag Conference in April 2027 was announced as Aachen, Germany, a location that is very centrally-positioned for access by the European (and global) slag industry.

Day Two

Martin Sprunk, Secopta Analytics, described how the laser-induced breakdown spectroscopy (LIBS) approach his company uses has advantages for both online raw material scanning of slag to recover metals, and with a sampling approach when using slag as a raw material itself. For online applications, operators can then use the near-instant data to adjust process parameters or the material feed to obtain the desired output. LIBS analysis for slag as a raw material still requires sampling, but it reduces both the preparation and the analysis time. Sprunk said that XRF analysis might take as little as seven minutes, but that LIBS cuts this down to two minutes.

Christian Altherr, Gebr. Pfeiffer, gave examples of recent slag terminal references, including a 1.2Mt/yr project with Ozinga in Chicago, which is expected to start operations in mid-2026. An MVR 5300 C-6 mill with a power of 5700kW will be able to grind slag to a fineness of 6200cm²/g Blaine. Two case studies then demonstrated how the company’s GPpro software-as-a-service uses AI to save specific grinding energy and increased throughput. Preparing for this requires one to three months to train a model, with improvements reached via an iterative process in conjunction with human operators.

Will Knapp, Cocoon Carbon, outlined his company’s progress towards commercialising steel slag as an SCM and obtaining regulation for their product. The process uses a proprietary rapid water quenching phase with a modular unit that can be installed directly into a slag pit at a steel plant. It is currently preparing to open a demonstration plant in the US later in 2026, following a successful pilot. Commercial-scale production is forecast for 2028, with the first commercial sales expected around the same time. Cocoon is also working with ASTM and industry partners to develop a new specification covering EAF and SAF slag. Balloting on a first draft of the new standard to an ASTM sub-committee is expected later in 2026.

Timo Parviainen, Revis, explained how his company has been testing the use of steel slag as a filter for industrial wastewater. Most of the work so far has been in the laboratory or at the pilot level. Smaller grain sizes appear to be better for long-lasting special treatments with a high load capacity, medium grain sizes are good for sludge capacity, and larger grain sizes work best for low-filtration rate treatment. Generally, smaller grain sizes act as better filters but don’t last as long. Steel slags could be used in a variety of applications, including mining, waste dumps, and even for domestic water treatment such as waste water from saunas. If the process proves economically viable, then full-scale projects will follow.

 Lukas Höber of Sequestra next spoke about the use of slags as a sequestration medium for CO₂. He claimed that mineralisation is the only legally accepted form of CCU within the EU ETS. He suggested that mineralisation by direct air capture has a large potential in voluntary carbon markets, and pointed out that mineralisation works with gases with variable CO₂ contents. Calcium and magnesium must be present in the mineralising medium, so that a variety of slags are well-suited as mineralisation mediums. The problem is that residues react variably with CO₂, and process parameters dramatically influence the CO₂ uptake. Sequestra analyses mineral residues (not just slags) for their uptake potential using an autonomous standardised test, and now has a large database of mineral sequestration performance. Sequestration potential may be sensitive to both temperature and pressure of the mineralisation process.

 Eirik Rudd of MCi Carbon spoke about his company’s CO₂ sequestration process, which again involves a grinding step and a mixing step with CO₂. Ladle, EAF and BOF slags have shown the potential to absorb 142-360kg CO₂/ of feedstock. Variation between samples of the same slag highlight the need to optimise the slag before potential mineralisation. The company is trying to find commercial homes for the resultant materials, potentially for substitution of fly ash, limestone, fillers and fine aggregates. Testing shows no diminution of strength and workability when using the resultant minerals.

The penultimate presentation was the first of two linked papers from Tenova, and was presented by Hugo Joubert, on valorising EAF slag using the company’s Novacycle technology. More EAF slag will be produced in the future, and less BF slag, with most EAF slag being used for lower-value road-building at near-zero profit for steel-makers. Landfill costs are rising and regulations on slag use are tightening, so producers will look for alternative uses. GBFS is becoming scarce, and cost up to US$140/t in the US in 2025. The possibility of using EAF slag (and LF slag) as an SCM is tempting. Novacycle can take ‘dirty’ slag from EAF and LF, and can reduce FeO (which would lead to low glass and low reactivity if not removed), can reduce CaO, can modify the chemistry to allow glass forming, can reduce the possibility of Cr/V leaching, and can homogenise different slag batches. This is done through a reduction process using carbon/coke for example, modifying the slag by adding SiO₂ and/or Al2O₃, and through granulation to improve its physical performance, using a slag treatment furnace. A hot pig iron metal is produced during the process, which has its own high value. Tenova has extensive experience in treating slags in other non-ferrous industries, for example in platinum smelting. Concept design and basic engineering studies have been completed for previous designs of electric slag treatment furnaces for European clients. However, the capital expenditure would have been high, with large footprint, low reductant efficiency and high operational expenditure. The new Novacycle slag treatment furnace design will avoid all of these problems, for projects using from 24,000-300,000t/yr of EAF slag, and with very positive economic results. Pilot-scale production will take place in 2026.

Marco Corbella and co-authors from Tenova gave details about air-cooled granulation that would be applied downstream from the Novacycle process previously presented. Two types are offered: on-line where the slag is poured directly from the EAF; and off-line where the slag is put into a slag pot (or LF slag into a ladle). In both cases, a fan is used to blow the slag into a granulation chamber. Granulated slag can replace slag in mortar without affecting material properties, while leaching tests on mortar specimens confirm immobilisation of heavy metals and compliance with legal limits. In both cases, rapid slag chemical analysis is essential to predict granulability and process optimisation, and this is achieved using pulsed LIBS technology. The technology has been used at the Ferriere Nord plant of Gruppo Pittini. This avoids the creation of falling slags, and gives rise to a commercial product.

Prizes and farewells

At the end of the conference programme, delegates met once more to say their final goodbyes. After delegate voting, the best presentation awards were announced: Joe Harder was third for his paper on the global slag trade, Ikram Ahmed Khan of Shun Shing Group was second for his paper on Asian slag markets, and Hugo Joubert of Tenova was first for his presentation on the Novacycle process.

The event was highly praised by delegates for its slick organisation, for the quality of the networking and high level of technical content and for its friendly atmosphere. The 19th Global Slag Conference will next take place in Aachen, Germany, in April 2027.