The present and future aspects of maldistribution and lifetime calculated from the worldwide production and reserves of rare metals are examined based on the database presented in this study. A positive correlation between maldistribution and lifetime is also shown. It remarkably indicates that if the larger is maldistribution at a given metal, the longer is its lifetime. Some rare metals, which have lower maldistribution rate and shorter lifetime, such as antimony and bismuth, reveal the increase of production, however no considerable variation of reserves is observed. In other words, the quantities of the remaining resources of these metals have the possibility to be smaller in the near future.
The supplies and demands of rare metals in Japan are also examined. Consequently, the result presented in this paper supported the conclusion that two investigated rare metals such as antimony and bismuth have the tendency of developing new various applications, alternatively the tendency of the previous major application have been decreased simultaneously.

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Five rocks were compressed and crashed up to 20 % of the initial height and the fragments were collected and sieved. The main results are summarized as follows:
(1) Particle size distribution of fragments follows the mixed Weibull distribution depending on the grain sizes of rock.
R = R₁ + R₂ + R₃
R_i = W_i exp(-(d_p / d_ei)^1.5)
R is the weight percentage retained on the sieve of aperture d_p, and d_e is the absolute size constant (d_e1 < d_e2 < d_e3).
(2) In case of Akiyoshi marble, weighing function W₂ is nearly zero. Except Akiyoshi marble, all other four rocks show the similar particle distribution trend in which W₂ is considerably larger than W₁.
(3) End-surface condition, moisture and size effect of rock specimen has only small influences on the particle size distribution.
(4) Energy required during testing has close relationship with the size distribution of fragments.

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A constitutive equation of variable compliance type had been proposed by Okubo in 1987. The equation is simple and its parameters are relatively easy to obtain. The equation can be applicable to creep of rock, however, experimental result in primary creep region in which strain rate is decreasing with time does not conform well to the calculated result.
Recently Okubo and Fukui (2002) proposed a constitutive equation especially focusing on low stress level creep. In this study, old one proposed in 1987 and new one proposed in 2002 are combined to extend an applicable range of the constitutive equation of variable compliance type.
For validation of the proposed constitutive equation, calculated results are compared with the experimental data by Okubo and Nishimatsu (1986) and Fukui et al. (1992, 1993), and it can be said that experimental results in uniaxial compression can be well simulated by the proposed equation. The equation is also tested against the creep performed in uniaxial tension and possible applicability of the equation to tensile stress field is discussed.

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Platinum group metals, such as palladium (Pd) and platinum (Pt), are commonly used in a wide range of industrial applications as an elemental metal and various kinds of alloys. Conventionally, Pt and Pd were dissolved together followed by separation. It is difficult to recovery high-grade Pd and Pt from the primary raw materials and solid wastes. In this study, the selective leaching of Pd and Pt from a secondary resource by using sodium chloride and sodium hypochlorite has been investigated. Results indicate that about 100% of palladium could be initially extracted by using the 0.27 mol / l (active chlorine) sodium hypochlorite and 0.068 mol / l sodium chloride (NaCl) at pH1.2 and 298K in 1.5 hours or 0.005 mol/l sodium chlorate (NaClO₃) and 6.0 mol / l hydrochloric acid (HCl) at 298K in 0.5 hours. About 100% Pt could be extracted from the residue by using 0.47 mol / l sodium chlorate (NaClO3) and 12 mol / l hydrochloric acid (HCl) at 298K in 2 hours.

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With increasing importance of the electroless nickel plating technology in many fields such as electronic and automobile industries, the treatment of the spent baths is becoming a serious problem. Although the spent baths are currently treated by the conventional precipitation method, a method without sludge generation is desired. This work aims at establishing a recycling process of nickel from the spent baths. Solvent extraction of nickel, iron, and zinc in two types of spent baths (A and B) has been investigated using 2-hydroxy-5-nonylacetophenone oxime (LIX84I) and the acidic organophosphorus compounds such as bis (2-ethylhexyl)phosphoric acid (D2EHPA), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A) and bis (2, 4, 4-trimethylpentyl) phosphinic acid (Cyanex272) as the extractants. Spent bath A is weakly acidic (pH 4.8) and contains 70 g m^-3 of zinc as an impurity, and spent bath B is very weakly acidic (pH 6.0) and contains boron. The following results have been obtained: (i) Nickel in spent bath A can be extracted with LIX84I at the pH larger than 6 with high efficiency leaving most of zinc and iron in the aqueous phase. Also, nickel in spent bath B can be efficiently extracted without adjusting pH. (ii) According to the McCabe-Thiele analysis, the concentrated nickel sulfate solution (> 100 kg-Ni m^-3) with low sulfuric acid content is obtained by the countercurrent two stage stripping from the Ni-bearing LIX84I using the mixed solution of 0.9 kmol m^-3 NiSO₄ and 1 kmol m^-3 H₂SO₄ as the stripping reagent. (iii) Iron and zinc in spent bath A can be selectively extracted with the acidic organophosphorus compounds. PC88A and Cyanex272 are more advantageous than D2EHPA because, in the former extractants, the coextraction of nickel is lower and the stripping of iron and zinc is easier. Based on these results, the flowsheets for recovering nickel from the spent baths are proposed.

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Sodium bicarbonate is an unstable compound forming various related compounds on the surface. To understand the stability of sodium bicarbonate and the decomposition mechanism on the surface, the time-dependency of changes in compositions and kind of phases were examined at various temperatures and humidityies. Sodium sesquicarbonate was found to be formed on the sodium bicarbonate surface in the ambient climate conditions in Japan. Comparing phase relations of sodium carbonate quoted from literatures with those examined on the surface of sodium bicarbonate, phase stability of sodium carbonate was found to affect seriously the kind of phases on the surface of sodium bicarbonate.

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