The medium – long time rare earth demand forecast is important issue in order to create the material security strategy for enhancement of the global economic growth and implementation of innovation. In recent studies, there are several researches of medium – long term rare earth demand forecast, such as DOE (U.S. Department of Energy), Roskill, NIMS (National Institute for Material Science), and other researches by Yale University, MIT, and Tokyo University. Therefore, this paper aims to evaluate and compare these forecasts, focusing on data, method, and the results to clarify the trends of rare earth forecast. Moreover, this paper aims to introduce the new methodology of medium – long time demand forecast of dysprosium (Dy), a rare earth element, which being broadly used in automobiles, home appliances, HDD, etc. This new methodology of AIST is using ratio of dysprosium-carrying end-use products, weight ratio of dysprosium in end-use products, production of end-use products, which able to estimate quantitatively the influence of the strategies (for example, changes in recycling ratio or Dy ratio in end-use application). From the result, 740 (t/y) of domestic Dy demand was forecasted to be reduced, by producing Dy less permanent magnet and recycle in 2030. This new methodology was validated by evaluating the relationship between the future scenario of the Dyless strategy, and domestic Dy demand forecast. The result of this paper evidently confirms that rare earth demand forecast for each end use products is useful for strategy making of critical material security.

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In order to develop the“ Bio-filter”, silicon nitride porous bodies with micro-macro complex pore structure were fabricated using the tape casting process. Using Saccharomyces cerevisiae and Lactobacillus casei as the aerobic and anaerobic model microbes, aqueous solutions containing these microbes were passed through the porous bodies for 72 hrs. Then, the aqueous solution of 1% glucose saturated with oxygen in air was passed through them. It was confirmed that both microbes were simultaneously fixed on the surface of the macro-pores with the formation of the bio-film, suggesting the successful formation of the microbe consortium. In the case that only Saccharomyces cerevisiae was fixed on the surface of the macro-pores, the formation of the bio-film was hardly observed. In contrast, when only Lactobacillus casei was used, the network structure of the bio-film was observed inside the micro-pores between the macro pores. The pH values and the kinds and concentrations of the products contained in the effluents were different for these three cases. It was found that the concentration of lactic acid was much larger in the case that two microbes were simultaneously fixed than in the case that only Lactobacillus casei was fixed, suggesting the successful formation of the anaerobic condition through the oxygen consumption by the aerobic metabolism of Saccharomyces cerevisiae.

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