[ COVER STORY ] lifespan of 40 years , it is still too early to economically justify replacing them .”
Another major constraint is the quality of iron ore . While DRI- EAF technology offers many advantages , it requires highquality iron ore with an iron content of 66 – 67 %. The issue is not with the DRI plant itself — those can operate regardless of ore quality . However , when lower-quality ore is used , placing the resulting DRI into an EAF generates a significant amount of slag , leading to steel losses in the form of iron oxide trapped within the slag and not allowing the furnace to work efficiently .
Tenova , however , has devised an innovative solution to address this problem . “ High-quality pellets are already in short supply , and with the current investment trends in DRI , we are predicting a shortage of these materials in the next five to ten years ,” Mr . Pancaldi highlighted . “ Our solution is a DRI plant combined with an Open Slag Bath Furnace ( OSBF ), which can process DRI of much lower quality . The final product is liquid pig iron , which is identical to what is produced in a blast furnace . This pig iron can then be used in a basic oxygen furnace to make steel . Essentially , this allows us to utilize lower-quality pellets that would be unsuitable for a traditional DRI-EAF plant .”
Rethinking EAF
The second part of the equation for upstream emissions reduction concerns EAF technology . As Mr . Pancaldi elucidated , while EAFs , like DRI , are positioned as ideal solutions for addressing emissions , two significant challenges remain : the availability of scrap and its quality .
“ First of all , there is simply not enough scrap available to produce the 2 billion tonnes of steel required annually by the market . Secondly , while steel is infinitely recyclable , some alloying elements , such as copper , are also melted during the recycling process . This makes it difficult to remove copper from the molten steel . As a result , each time steel is recycled , the copper percentage increases , which can negatively affect the properties of more sophisticated steels ,” Mr . Pancaldi explained .
Modern EAFs are vastly different from their predecessors , as Mr . Pancaldi noted , highlighting the advancements in capacity — from 50 – 100 tonnes to now over 300 tonnes of tapping capacity and over 450t / h of liquid steel . However , these improvements have introduced new challenges .
At Tenova , the term EAF has taken on a revolutionary meaning , as they have made significant enhancements to improve efficiency . “ One of the key innovations we developed is the
Consteel ® system , a continuous charging and preheating mechanism for scrap . Preheating is crucial because it utilizes some of the heat generated by the furnace , reducing the amount of new energy required . But the real transformation lies in the continuous charging aspect , which allows for a fundamentally different operational approach ,” Mr . Pancaldi described .
Traditionally , in an EAF , scrap is added to the melting vessel using large buckets , where electrical energy creates sparks between electrodes and melts the scrap . “ Now , imagine a system where you are never starting from cold , solid scrap . The goal is to maintain a hot liquid steel heel inside the vessel . Instead of melting scrap directly through electrical sparks , we continuously inject solid scrap into this very hot liquid . This method is far more efficient ,” Mr . Pancaldi emphasized .
“ Moreover , by keeping the furnace covered and eliminating the need to open the roof for additional scrap , we minimize heat losses . This leads to lower operational costs , reduced energy consumption , and decreased fugitive emissions — while also enhancing the quality of the final product . This efficiency is particularly important when melting DRI , which is in solid form . In a traditional furnace , DRI is added in large buckets , but with our system , we can continuously
Green Steel World | Issue 15 | November 2024 9