Aiming to realize sustainable resource recycling
through innovative environmentally friendly
smelting processes.

Experimental scene in the laboratory

Main Research Themes

  1. 1Environmentally friendly tantalum (Ta) and niobium (Nb) smelting processes without hydrofluoric acid
  2. 2Promotion of resource recycling of by-products generated during steel smelting (electric pulse disintegration and magnetic separation)
  3. 3New ironmaking process using ammonium salts as a secondary raw material (de-carbonization and utilization of unutilized resources)
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Greetings

Associate Professor Hironari KUBO
Associate Professor
Hironari KUBO
(Specially Appointed Associate
Professor at Tohoku University)

Since my school days, I have always wanted to contribute to solving and mitigating environmental problems. I have studied all genres of engineering, economics, law, ethics, and environmental archaeology. Thus, I conclude that metallurgy (metal smelting) is one of the most powerful tools in the environmental field.Although metallurgy is often thought of as old technology, it is comprehensive engineering of separation, on which many resource and waste treatment processes are based. With a focus on metallurgy, our laboratory is engaged in research to develop environmentally friendly smelting processes that enable waste reduction, resource conversion, detoxification, and the utilization of unutilized resources.Our three research policies are as follows.

Research Policies

  1. 1. True environment-conscious process is "beautiful"

    Even if the target component can be separated, it is meaningless if it consumes enormous amounts of energy and secondary materials and generates large amounts of wastes that are difficult to dispose of.In our laboratory, we strive to create a process with a total balance of recovery rate, energy consumption, secondary raw materials, secondary waste, and cost.

  2. 2. Practical application first

    I worked in the research and development department of a private company that dealt mainly with waste materials. Waste materials and natural ores are heterogeneous and contain impurities. There are many studies in which favorable results have been obtained in experiments using reagents or simulated samples, but they are not useful in practical applications.In our laboratory, we used actual samples from the initial stage of research to verify the results.

  3. 3. Target large industries

    The steel industry accounts for more than 10% of CO2 emissions in Japan. If the energy efficiency of the steel industry can be improved by 10%, CO2 emissions can be reduced by more than 1%. In addition, slag, a byproduct of the ironmaking process, contains strategic resources such as phosphorus (P) and manganese (Mn). Although these strategic resources are unutilized currently, they are equivalent to more than half of Japan's existing domestic demand. If these resources could be converted efficiently, there would be a drastic change in the current flow of resources.The main focus of this laboratory was on issues related to ironmaking and other large-scale industries.

Main Research Themes

  1. Research Theme1Environmentally friendly tantalum (Ta) and niobium (Nb) smelting processes without hydrofluoric acid

    Molten salt produced by heating ammonium hydrogen sulfate and Ta and Nb oresWhite precipitates containing Ta and Nb

    Since ores containing Ta and Nb are persistent, hydrofluoric acid (HF) is used to dissolve them in the smelting process. However, HF is an extremely hazardous chemical that has caused fatal accidents, and the disposal of sludge generated during liquid waste treatment is problematic. Recently, our laboratory has developed an innovative Ta and Nb smelting process that does not require the use of HF.

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  2. Research Theme2Promotion of resource recycling of byproducts generated during steel smelting (electrical pulse disintegration and magnetic separation)

    Pulverized particles of steelmaking slag Pulverized particles of stainless-steel slag

    In ironmaking, components other than Fe derived from raw materials are removed as slags. For example, steelmaking slag contains phosphorus (P) and manganese (Mn), which are strategic resources, and stainless-steel slag contains chromium (Cr), an environmentally controlled substance.In our laboratory, we are studying the efficient separation of these components using electrical pulse disintegration and magnetic separation.

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  3. Research Theme3New ironmaking process using ammonium salts as secondary raw material (de-carbonization and utilization of unutilized resources)

    Test sample of ammonium salt ironmaking process Ammonium chloride powder

    More than 10% of CO2 emitted in Japan is generated by the steel industry. New ironmaking methods with environmental benefits that utilize hydrogen, ammonia and electricity instead of coal have been promoted as the sustainable path forward. However, the utilization of low-grade ores, conversion of slag into resources, and reduction of limestone-derived CO2 are challenges that are yet to be overcome.Our laboratory has proposed an innovative ironmaking method that can address these problems.

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Other Research Themes

  • Process that significantly reduces electric furnace dust (EAF dust)
  • Ocean dumping of pumice (volcanic products from Fukutoku-Oka-no-Ba or Hunga Tonga-Hunga Ha'apai Volcano)

Research Introduction Video

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Our Research
Research Achievements Equipment

What's New

  • Externship

    Mr. Ibuki Itoyama (M1) was selected and participated in the overseas training program (Australia) of the Mining and Materials Processing Institute of Japan.

  • Conference

    Mr. Kento Ikeda, B4 (research theme: “Development of Fe3C mass production technology”) and Mr. Kota Oba, B4 (research theme: “Detoxification of stainless steel slag”) received the Best Student Award from The Iron and Steel Institute of Japan, Kyushu Branch.

  • Conference

    Mr. Ibuki Itoyama, B4 (research theme: “Research on smelting method using ammonium salts”) received the Outstanding Student Award, Kyushu MMIJ, The Mining and Materials Processing Institute of Japan, Kyushu Branch.

  • Media

    As part of our safety awareness activities, we appeared on a news program of KBC Kyushu Asahi Broadcasting Co., Ltd. to explain the precautions for hydrogen sulfide generation experiments in junior high school science classes.

  • Announcement

    Our laboratory's website is now open.We will update the information on conference presentations, publications, patents, etc., as needed.

Go to "What's New" page

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Experimental scene in the laboratory

Contact & Access

Address: 3-30-1, Wajiro-higashi,Higashi-ku, Fukuoka-shi,Fukuoka 811-0295, Japan

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