The country’s steel industry is at an inflexion point. The industry is given a roadmap by the government to lift crude steel capacity to 150 million tonnes (mt) in the terminal year of the 12th Plan and then to 180-200 mt by 2020 from the present 80 mt. Steel Authority of India Ltd (SAIL) Chairman Chandra Sekhar Verma says to make this happen, “We steelmakers will have to embrace breakthrough ideas to be able to run our mills at new efficiency levels, allowing us to make steel with higher strength to weight ratio.” Capacity growth here will be sustainable provided the industry makes use of leap-forward technologies occurring periodically, from raw material uses to finishing of steel to utilisation of mill waste, argues Verma.
Not only the proposed ventures, but any industry that requires big space will be hitting a roadblock in acquiring land. The luxury of owning large tracts of land, in many cases a lot more than what is actually needed, is a thing of the past.
Harping on the theme that necessity is the mother of invention, Verma says when land supply is becoming increasingly tight, with many attendant challenges like proper resettlement and rehabilitation, integrated steel plants will perforce have to be a lot more compact in their layout than is the case so far. Verma’s pronouncement carries conviction since SAIL is having success in building a uniquely compact 2.5 mt mill at Burnpur in West Bengal on a 953 acre plot, that is 381 acres per 1 mt capacity. In terms of land use, the unit, equipped with finishing mills, compares favourably with plants built in other parts of the world more recently.
Compactness of the Burnpur kind or even better than that is achievable by use of a large blast furnace of 4,060 cubic metre size or even bigger, with stepped-up use of auxiliary fuel leading to lesser number of coke oven batteries. BFs of the size of 5,000 cubic metre capable of producing as much as 3.8 mt of hot metal a year are in operation elsewhere in the world. So, there is scope for replacing three BFs by one super-sized one, leading to considerable saving of land. Furthermore, employment of “endless casting-rolling technologies in flat products” will make a significant cut in the length of the facility under the conventional slab caster hot strip mill, running over a kilometre.
A compelling reason for SAIL to pursue a joint venture with Posco to build a 3-mt steel mill based on Finex technology at Bokaro is the limited land requirement. Verma says Finex technology, as it dispenses with coke ovens and sintering units and allows direct use of ore fines and non-coking coal in a ‘melter gasifier’ after being routed through a hot DRI compactor and coal briquetter, will claim only 250 acres per 1 mt capacity. Land saving is also effected by a mini flat mill in the downstream, facilitating direct and continuous casting and rolling of steel. In fact, Posco for its Orissa venture will be building a steel plant using Finex technology, along with a mini flat mill. There are other non BF technologies which allow making of hot metal using ore fines and non-coking coal. Such processes make sintering and coking plants redundant. The list is led by Siemens Vai, developed Corex, Kobe Steel invented ITMk3 and Rio Tinto’s HIsmelt. All such technologies allow restricted CO2 and waste water emissions and economy of land use.
Using the ‘Global Steel 2012’ platform, Verma built a thesis that technology, if rightly harnessed, will be the game changer in land use for new mills, reduce CO2 emissions from the current 2 tonnes per tonne of finished steel as is the case with the best mills, to first 1.4 tonnes and then ideally to a tonne. It will also allow steel to hold its ground against emerging competition from aluminium, magnesium and carbon composites.
To fend off competition from substitutes, mills will have to focus on making better and better grades of ultra high strength steels through management of alloys and ideal thermo-mechanical rolling. Verma says the Holy Grail for the industry remains the integration of iron and steel making.
The reason for his use of a mythical expression is that such integration could happen only when the industry starts using hydrogen for iron ore reduction, leaving little carbon in hot metal. Hydrogen use will unquestionably usher in a new dawn in steel making. But this will be possible only when a commercially viable technology is available to obtain hydrogen from renewable sources.
Hydrogen-based steelmaking has the potential to cut CO2 emissions to 1 tonne per tonne of finished metal. But the Holy Grail remains in the distant horizon since work on hydrogen-related R&D is still at early stages. Parallel to the local industry taking steps to use growing volumes of ore fines to make pellets and seek substitution of coking coal by non-coking coal, action is needed to find value in dusts, slags and sludge generated in the process of steelmaking through their recycling.
[Source – Business Standard]