The production of flat steel products is commonly linked to highly integrated sites, which include hot metal generation via the blast furnace, basic oxygen furnace (BOF), continuous casting, and subsequent hot-rolling. In order to reach carbon neutrality a shift away from traditional carbon-based metallurgy is required within the next decades. Direct reduction (DR) plants are capable to support this transition and allow even a stepwise reduction in CO emissions. Nevertheless, the implementation of these DR plants into integrated metallurgical plants includes various challenges. Besides metallurgy, product quality, and logistics, special attention is given on future energy demand. On the basis of carbon footprint methodology (ISO 14067:2019) different scenarios of a stepwise transition are evaluated and values of possible COequivalent (COeq) reduction are coupled with the demand of hydrogen, electricity, natural gas, and coal. While the traditional blast furnace-BOF route delivers a surplus of electricity in the range of 0.7 MJ/kg hot-rolled coil; this surplus turns into a deficit of about 17 MJ/kg hot-rolled coil for a hydrogen-based direct reduction with an integrated electric melting unit. On the other hand, while the product carbon footprint of the blast furnace-related production route is 2.1 kg COeq/kg hot-rolled coil; this footprint can be reduced to 0.76 kg COeq/kg hot-rolled coil for the hydrogen-related route, provided that the electricity input is from renewable energies. Thereby the direct impact of the processes of the integrated site can even be reduced to 0.15 kg COeq/kg hot-rolled coil. Yet, if the electricity input has a carbon footprint of the current German or European electricity grid mix, the respective carbon footprint of hot-rolled coil even increases up to 3.0 kg COeq/kg hot-rolled coil. This underlines the importance of the availability of renewable energies.

The largest outputs of rare earth mining are the low-value byproducts cerium and lanthanum, which burden rare earth supply chains because they must be separated from more desirable rare earths used in magnet production. Promoting demand for cerium and lanthanum can potentially diversify the economics of rare earth mining and improve supply chain stability for all rare earth elements. A promising avenue for increasing byproduct rare earth element demand is their use in aluminum alloys; an application for cerium and lanthanum offering multiple benefits to manufacturing such as energy reduction and improved throughput. Experimental materials science and economic implications of Al-rare earth element alloys will be discussed. We show that Al-La/Ce alloys have elevated mechanical strength compared to more traditional aluminum alloys, in some formulations can be used without heat treatment, and possess a highly castable eutectic microstructure. This report presents the use of cerium and lanthanum in aluminum alloys as an example of how supply chain focused approaches to technological development can benefit stakeholders at every step in production.

Aluminum is widely used in buildings, transportation, and home appliances. However, primary aluminum production is a resource, energy, and emission-intensive industrial process. As the world's largest aluminum producer, the aluminum industry (ALD) in China faces tremendous pressure on environmental protection. This study combines material flow analysis and scenario analysis to investigate the potential of resource conservation, energy saving, and emission reduction for China's ALD under the import and export trade transition. The results show China's per capita aluminum stock will follow a logistic curve to reach 415 kg/capita by 2030. However, unlike the continued build-up of stocks, domestic demand for aluminum will peak at 44 million tons (MT) in 2025 and fall to 36 MT in 2030. The scenario analysis reveals that China's primary aluminum output could peak in 2025 at around 52 MT if the restrictions are not implemented (Scenario A). Compared to Scenario A, demand for primary aluminum is effectively limited in Scenarios B and C where exports of aluminum products are reduced. Correspondingly, both scenarios also have obvious benefits in reducing the environmental load of China's ALD. Besides, if hydropower used in aluminum electrolysis increases to 25% by 2030, the total GHG emissions in 2030 will be reduced by 12%. Therefore, promoting import/export and energy mix transformation can become an essential means for the sustainable development of China's ALD.

A hydrometallurgical process is described for conversion of an aqueous solution of lithium chloride into an aqueous solution of lithium hydroxide via a chloride/hydroxide anion exchange reaction by solvent extraction. The organic phase comprises a quaternary ammonium chloride and a hydrophobic phenol in a diluent. The best results were observed for a mixture of the quaternary ammonium chloride Aliquat 336 and 2,6-di--butylphenol (1:1 molar ratio) in the aliphatic diluent Shellsol D70. The solvent extraction process involves two steps. In the first step, the organic phase is contacted with an aqueous sodium hydroxide solution. The phenol is deprotonated, and a chloride ion is simultaneously transferred to the aqueous phase, leading to in situ formation of a quaternary ammonium phenolate in the organic phase. The organic phase, comprising the quaternary ammonium phenolate, is contacted in the second step with an aqueous lithium chloride solution. This contact converts the phenolate into the corresponding phenol by protonation with water extracted to the organic phase, followed by a transfer of hydroxide ions to the aqueous phase and chloride ions to the organic phase. As a result, the aqueous lithium chloride solution is transformed into a lithium hydroxide solution. The process has been demonstrated in continuous counter-current mode in mixer-settlers. Solid battery-grade lithium hydroxide monohydrate was obtained from the aqueous solution by crystallization or by antisolvent precipitation with isopropanol. The process consumes no chemicals other than sodium hydroxide. No waste is generated, with the exception of an aqueous sodium chloride solution.

With the vigorously growing demand of the steel industry, corrosion resistance alloys, clean energy industries, and a variety of engineered infrastructure or technology, high-grade nickel ores are being exhausted gradually in the world. This review outlines metallurgical processes for nickel production from various nickel sulfide ores resources, particularly focusing on recent developments in metallurgical processes to identify potential trends and technical requirements in nickel metallurgy. The main methods have been extensively reviewed for nickel extraction from nickel sulfide ores which maybe are potentially applicable to provide new ideas for smelting technology innovation of nickel and even other similar metals. The main metallurgical methods include pyrometallurgical and hydrometallurgy, containing smelting, leaching, and purification. The advantages and disadvantages of each typical process have been analyzed and compared in this review, and a special emphasis is put forth. Biological metallurgy is highly selective for recovery of nickel and the most promising method recommended for future research and development. Moreover, ion exchange offers useful method for extraction and purification of nickel. In addition, many of the typical new methods involved are also introduced in this article.

Titanium products play an important and irreplaceable role in national defense and military applications and are considered as strategic resources by many governments. Although China developed a large-scale titanium industrial chain that affects the global market, it is still weak in high-end titanium-based alloys and needs an urgent upgrade. Few policies have been implemented at the national level to explore the development strategies of China's titanium industry and related industries. One major issue is the lack of reliable statistical data, which is essential for setting the national strategies of China's titanium industry. Additionally, waste management and scrap recycling in titanium products manufacturers are not yet considered, which would significantly impact the lifetime of titanium scrap and demand for virgin titanium metal resources. To address this gap, this work has developed a titanium products flow chart for China and presented trends in the titanium industry from 2005 to 2020. The results show that only about 65% to 85% of domestic titanium sponge is finally sold as ingots, and only about 60% to 85% of ingots are finally sold as mills, indicating excessive production has been a characteristic of China's titanium industry. The average recovery ratio of prompt swarf for ingots is about 63%, and that for mills is about 56%, which can be recycled into ingots by remelting, relieving constraints on high-grade titanium sponge and reducing dependence on it to some extent.

Indonesia is one of the countries in the world that has been utilizing geothermal as a renewable energy source to generate electricity. Depending on the geological setting, geothermal brine possesses critical elements worthwhile to extract. One of the critical elements is lithium which is interesting in being processed as raw material for the battery industries. This study thoroughly presented titanium oxide material for lithium recovery from artificial geothermal brine and the effect of Li/Ti mole ratio, temperature, and solution pH. The precursors were synthesized using TiO and LiCO with several variations of the Li/Ti mole ratio mixed at room temperature for 10 min. The mixture of 20 g of raw materials was put into a 50 mL crucible and then calcined in a muffle furnace. The calcination temperature in the furnace was varied to 600, 750, and 900 °C for 4 h with a heating rate. of 7.55 °C/min. After the synthesis process, the precursor is reacted with acid (delithiation). Delithiation aims to release lithium ions from the host LiTiO (LTO) precursor and replace it with hydrogen ions through an ion exchange mechanism. The adsorption process lasted for 90 min, and the stirring speed was 350 rpm on a magnetic stirrer with temperature variations of 30, 40, and 60 °C and pH values of 4, 8, and 12. This study has shown that synthetic precursors synthesized based on titanium oxide can absorb lithium from brine sources. The maximum recovery obtained at pH 12 and a temperature of 30 °C was 72%, with the maximum adsorption capacity obtained was 3.55 mg Li/gr adsorbent. Shrinking Core Model (SCM) kinetics model provided the most fitted model to represent the kinetics model (R = 0.9968), with the constants k, Ds, and k, are 2.2360 × 10 cm/s; 1.2211 × 10 cm/s; and 1.0467 × 10 cm/s.

In this study, the reducing smelting of chromite concentrates by EAF-assisted metallothermic method was investigated. The effect of Al and Al addition amount, time, and the ratio of flux addition on the produced metal and slag compositions and metal recovery were investigated. It was seen that ferrochrome can be produced from fine-grained chromite concentrate by this method. As a result of EAF-assisted semi-pilot metallothermic smelting, the highest chromium content in produced alloys was 59.5 wt. %, while the highest chromium recovery from chromite concentrate to alloys was 76.7 wt. % in these experiments.

This investigation aims to identify the reasons for the plumes' visibility, compare the stacks with other sinter plant stacks worldwide, and suggest countermeasures to completely stop the visibility of emissions. The appearance of the sinter plant stack emission changes with time and the background color of the sky due to the scattering effect of the sunlight and incidence angle. The flue gas samples were collected at the outlet of the emission control equipment and observed under optical and scanning electron microscopes. The characterization was performed with the help of an electron dispersive spectroscope and mapping technique. The contents of the stack of a sinter plant without a bag filter had much higher levels of PM, SO and NO. The emissions from all the sinter plants were invariably found to have particulates of SO and NO of size less than 2.5 microns. It is suggested to opt for state-of-the-art fabric filter technology to eliminate PM emissions also.

Hydrogen-based direct reduction (HyDR) of iron ores has attracted immense attention and is considered a forerunner technology for sustainable ironmaking. It has a high potential to mitigate CO emissions in the steel industry, which accounts today for ~ 8-10% of all global CO emissions. Direct reduction produces highly porous sponge iron via natural-gas-based or gasified-coal-based reducing agents that contain hydrogen and organic molecules. Commercial technologies usually operate at elevated pressure, e.g., the MIDREX process at 2 bar and the HyL/Energiron process at 6-8 bar. However, the impact of H pressure on reduction kinetics and microstructure evolution of hematite pellets during hydrogen-based direct reduction has not been well understood. Here, we present a study about the influence of H pressure on the reduction kinetics of hematite pellets with pure H at 700 °C at various pressures, i.e., 1, 10, and 100 bar under static gas exposure, and 1.3 and 50 bar under dynamic gas exposure. The microstructure of the reduced pellets was characterized by combining X-ray diffraction and scanning electron microscopy equipped with electron backscatter diffraction. The results provide new insights into the critical role of H pressure in the hydrogen-based direct reduction process and establish a direction for future furnace design and process optimization.