The 2018 IPCC (The Intergovernmental Panel on Climate Change’s) report defined the goal to limit global warming to 1.5 °C by 2050. This will require “rapid and far-reaching transitions in land, energy, industry, buildings, transport, and cities”. The challenge falls on all sectors, especially energy production and industry. In this regard, the recent progress and future challenges of greenhouse gas emissions and energy supply are first briefly introduced. Then, the current situation of the steel industry is presented. Steel production is predicted to grow by 25–30% by 2050. The dominant iron-making route, blast furnace (BF), especially, is an energy-intensive process based on fossil fuel consumption; the steel sector is thus responsible for about 7% of all anthropogenic CO₂ emissions. In order to take up the 2050 challenge, emissions should see significant cuts. Correspondingly, specific emissions (t CO₂/t steel) should be radically decreased. Several large research programs in big steelmaking countries and the EU have been carried out over the last 10–15 years or are ongoing. All plausible measures to decrease CO₂ emissions were explored here based on the published literature. The essential results are discussed and concluded. The specific emissions of “world steel” are currently at 1.8 t CO₂/t steel. Improved energy efficiency by modernizing plants and adopting best available technologies in all process stages could decrease the emissions by 15–20%. Further reductions towards 1.0 t CO₂/t steel level are achievable via novel technologies like top gas recycling in BF, oxygen BF, and maximal replacement of coke by biomass. These processes are, however, waiting for substantive industrialization. Generally, substituting hydrogen for carbon in reductants and fuels like natural gas and coke gas can decrease CO₂ emissions remarkably. The same holds for direct reduction processes (DR), which have spread recently, exceeding 100 Mt annual capacity. More radical cut is possible via CO₂ capture and storage (CCS). The technology is well-known in the oil industry; and potential applications in other sectors, including the steel industry, are being explored. While this might be a real solution in propitious circumstances, it is hardly universally applicable in the long run. More auspicious is the concept that aims at utilizing captured carbon in the production of chemicals, food, or fuels e.g., methanol (CCU, CCUS). The basic idea is smart, but in the early phase of its application, the high energy-consumption and costs are disincentives. The potential of hydrogen as a fuel and reductant is well-known, but it has a supporting role in iron metallurgy. In the current fight against climate warming, H₂ has come into the “limelight” as a reductant, fuel, and energy storage. The hydrogen economy concept contains both production, storage, distribution, and uses. In ironmaking, several research programs have been launched for hydrogen production and reduction of iron oxides. Another global trend is the transfer from fossil fuel to electricity. “Green” electricity generation and hydrogen will be firmly linked together. The electrification of steel production is emphasized upon in this paper as the recycled scrap is estimated to grow from the 30% level to 50% by 2050. Finally, in this review, all means to reduce specific CO₂ emissions have been summarized. By thorough modernization of production facilities and energy systems and by adopting new pioneering methods, “world steel” could reach the level of 0.4–0.5 t CO₂/t steel and thus reduce two-thirds of current annual emissions.

The world of stainless steel production was 52 Mt in 2019, and the annual amount of slags including electric furnace, AOD converter, ladle, and casting tundish, was estimated at 15–17 Mt. Nowadays, only a minor fraction of slags from stainless steel production is utilized and a major part goes to landfilling. These slags contain high-value elements (Cr, Ni, Mo, Ti, V…) as oxides or in metallic form, some of them being environmentally problematic if dumped. Thus, any approach toward circular economy solutions for stainless steel slags would have great economic and environmental impacts. This contribution examines the slags from different process stages, and the available and new potential means to increase internal recycling and to modify slags composition and structure by optimizing their properties for reclaiming in high-value applications. Eventual methods are, e.g., fast controlled cooling and modifying additives. Means to recover valuable metals are discussed as well as potential product applications to utilize various slags with different chemical, physical, and mechanical properties. By integrating the treatments and steering of slags′ properties to the total process optimization system, the principles of circular economy could be achieved. Graphical

In FY-20, India’s steel production was 109 MT, and it is the second-largest steel producer on the planet, after China. India’s per capita consumption of steel was around 75 kg, which has risen from 59 kg in FY-14. Despite the increase in consumption, it is much lower than the average global consumption of 230 kg. The per capita consumption of steel is one of the strongest indicators of economic development across the nation. Thus, India has an ambitious plan of increasing steel production to around 250 MT and per capita consumption to around 160 kg by the year 2030. Steel manufacturers in India can be classified based on production routes as (a) oxygen route (BF/BOF route) and (b) electric route (electric arc furnace and induction furnace). One of the major issues for manufacturers of both routes is the availability of raw materials such as iron ore, direct reduced iron (DRI), and scrap. To achieve the level of 250 MT, steel manufacturers have to focus on improving the current process and product scenario as well as on research and development activities. The challenge to stop global warming has forced the global steel industry to strongly cut its CO₂ emissions. In the case of India, this target will be extremely difficult by ruling in the production duplication planned by the year 2030. This work focuses on the recent developments of various processes and challenges associated with them. Possibilities and opportunities for improving the current processes such as top gas recycling, increasing pulverized coal injection, and hydrogenation as well as the implementation of new processes such as HIsarna and other CO₂-lean iron production technologies are discussed. In addition, the eventual transition to hydrogen ironmaking and “green” electricity in smelting are considered. By fast-acting improvements in current facilities and brave investments in new carbon-lean technologies, the CO₂ emissions of the Indian steel industry can peak and turn downward toward carbon-neutral production.

The role of nitrogen varies in different stainless steels from a harmful impurity to a valuable alloying element. Therefore, the strict control of nitrogen content is a very important issue in the steel making process. Better understanding about the thermodynamics of nitrogen solubility is the basis for this control. The aim of this study was to determine whether the nitrogen solubility at atmospheric pressure at any given composition and temperature in an Argon Oxygen Decarburization (AOD) converter could be reliably predicted. This was done by comparing different equations for nitrogen solubility to industrial measurements of several different steel grades with a wide range of compositions and temperatures. The test set consisted of 100 heats to ensure reproducibility and sufficient variability. The focus was on examining the effect of the main alloying elements (Cr, Ni, Mo, Mn) and temperature on nitrogen solubility. Nitrogen solubility is increased most by the chromium content, followed by manganese and molybdenum, whereas nickel decreases the solubility. The interaction effect of an alloying element on nitrogen declines at increasing temperatures, resulting in a negative temperature dependence, i.e., the maximum nitrogen solubility is obtained near the liquidus temperature. The study showed that most of the examined thermodynamic equations predicted the nitrogen solubility quite well in common stainless steels and even in high alloyed steels. On the other hand, clear discrepancies were observed for steels with a high manganese content as well as with strongly deviating temperatures. Therefore, based on the present measurements and the literature data, a new equation was developed for predicting the solubility of nitrogen in a wide range of stainless steels. This equation can be coupled with the existing process models to control the AOD process.