Nippon Steel has produced more than 1,000 tonnes of direct reduced iron cumulatively in tests using 100% hydrogen and lower-grade iron ore, while demonstrating over 300 hours of continuous operation at its Hasaki research centre in Japan. The results address two operational difficulties in developing hydrogen-based ironmaking as an alternative to conventional carbon-intensive production.
The tests were conducted in a pilot-scale shaft furnace approximately 60 metres high, with a stated production capacity of one tonne per hour. The furnace began operating in March 2026. Nippon Steel announced the latest results on 4 November as part of its work to establish a direct reduction process suitable for future industrial deployment.
The project uses blast furnace-grade pellets, which generally contain less iron and more impurities than the direct reduction-grade material used in existing commercial systems. The reducing agent is hydrogen alone rather than the carbon-containing gas mixtures normally used in conventional direct reduction.
In a shaft furnace, iron ore pellets descend through the equipment while a reducing gas passes through the bed and reacts with oxygen contained in the iron oxides. The process produces direct reduced iron, or DRI, without first melting the feedstock in a blast furnace. That material can subsequently supply an appropriate steelmaking route, including an electric arc furnace.
Natural gas-based direct reduction is already established commercially, but its carbon-containing reducing gases result in carbon dioxide emissions. Hydrogen changes the chemistry of the reduction reaction: removing oxygen from the ore produces water vapour instead. The overall emissions benefit nevertheless depends on how the hydrogen is produced and the energy required by the installation.
Hydrogen reduction introduces a significant heat-management problem. Nippon Steel identifies reduction using hydrogen alone as endothermic, meaning that the reaction absorbs heat and can lower the temperature inside the furnace. Maintaining a suitable temperature profile is essential to keeping the reduction reaction and the movement of material through the shaft stable.
A fall in temperature can reduce reaction rates and alter conditions within the bed of pellets. The thermal energy supplied must therefore compensate for the requirements of the process without producing unsuitable operating conditions elsewhere in the equipment. The company has developed thermal compensation techniques for this purpose, although the detailed energy balance of the test installation has not been published.
The characteristics of the iron ore create a separate constraint. Lower-grade pellets are more susceptible to breaking down into fine particles during reduction. The resulting powder can restrict the passage of reducing gas through the bed, affecting gas distribution, pressure conditions and contact between the hydrogen and the remaining iron oxides.
Gas permeability is central to shaft furnace operation. Where fines accumulate, the gas may encounter greater resistance or move unevenly through the material. That can make the reduction process more difficult to control and create differences between areas of the furnace, even when the incoming gas and feedstock remain nominally consistent.
Nippon Steel reports that it has developed operating methods to suppress this deterioration in the lower-grade pellets. Combined with the thermal compensation measures, they enabled stable DRI production under the conditions tested at Hasaki.
The company records two distinct performance milestones. One is continuous operation lasting more than 300 hours; the other is cumulative production of more than 1,000 tonnes of DRI during the testing programme. The announcement does not state that the full cumulative tonnage was produced during the single continuous operating period, and the figures should not be combined to infer a production rate for that run.
Expanding the available iron ore feedstock is a significant engineering objective. Current direct reduction facilities generally depend on higher-grade material, while much of the ore produced for conventional blast furnaces does not meet the same specifications. A process capable of reliably using blast furnace-grade pellets would broaden potential sourcing options, provided it could be scaled economically.
Feedstock flexibility does not remove the need to control ore quality. Mineral composition, pellet strength and changes during heating and reduction still influence the behaviour of the furnace. Industrial operation would require suitable acceptance criteria for the incoming material and controls that remain effective across the permitted range.
The Hasaki work is supported by Japan’s New Energy and Industrial Technology Development Organization through its Green Innovation Fund. Nippon Steel, JFE Steel and the Japan Research and Development Center for Metals participate in the consortium developing direct hydrogen reduction technology. The project was selected for funding in January 2022, with an expansion approved in November 2023.
Nippon Steel is pursuing other steelmaking decarbonisation research alongside this programme, including hydrogen use in blast furnaces and production of high-grade steel using large electric arc furnaces. These approaches involve different equipment and operating requirements, and progress in one does not establish the commercial performance of the others.
The pilot results demonstrate that the selected thermal and material-handling measures can support sustained operation at the research scale. They do not yet establish the hydrogen consumption, lifetime equipment performance, total energy requirement or production economics of a commercial installation. Those measures will be important when assessing how the process could compete with established ironmaking routes.
Further work will concentrate on optimising furnace conditions and developing technology for larger equipment. From fiscal 2027, the company intends to advance scale-up development, with an objective of establishing technology suitable for practical implementation around 2040.
The immediate achievement remains a controlled pilot demonstration using 100% hydrogen and a broader grade of iron ore than conventional direct reduction plants normally accept. Commercial adoption will require the process to reproduce that stability at substantially greater output and within the operating and supply conditions of an industrial steelworks.
