The knowledge of the mechanical properties of rock under hydrothermal conditions is required to develop design methodology for nuclear waste repository and hot dry rock geothermal reservoir. In this study, in order to investigate time-dependent fracture property of Inada granite in hydrothermal environment, uniaxial compression tests have been conducted in 10 MPa water of 200°C under various constant strain rates ranging from 10^-3 to 10^-8s^-1. Furthermore the similar tests have been carried out both in 10 MPa water of room temperature and in dry condition of room temperature to investigate the effects of the environmental factors on the rock fracture property. The results have shown that the strength decreased significantly due to water and temperature. In water, the strength decreased with decreasing strain rate and became almost constant at slow strain rates below a critical value; 10^-6s^-1 for 200°C and 10^-7s^-1 for room temperature. The main mechanism that caused the strength reduction with decreasing strain rate was clarified to be stress corrosion cracking of microcracks, which was experimentally confirmed by examining another possible mechanisms such as dilatancy hardening and mineral dissolution in hot water. The phenomenon that the influence of strain rate on the strength disappeared at very slow strain rate was theoretically discussed by developing Costin's Microcrack Model from the view point of the mechanics of microcrack growth. The discussion has shown that the lower limit of compressive strength was related to the threshold value of the stress intensity factor K_ISCC in stress corrosion cracking, and that the strain rate at which the strength became almost constant was related to both K_ISCC and the crack velocity at K_ISCC.

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A new continuous measurement system has been developed in this study to measure the effective thermal conductivity, λe, of smelting granulated slag-water mixture beds and slag-cement composite materials under dry and wet conditions over the range from room temperature to 220°C. The measurement technique is based on a modified hot wire method. For the slag sample, lead smelting granulated slag, called “Black Sand” in Uguisuzawa, Miyagi Prefecture, was used. For the composite material, three samples, A, B and C that the values of a ratio of cement to Black Sand (C/BS) were different from each other were used. The C/BS values of the samples, A, B and C are 30/70, 25/75 and 20/80 by weight, respectively. The tested temperatures, θ, of the samples were set by considering utilization of the slag for the high level radioactive waste repository as buffer materials.
The measurements of λe were conducted during both heating and cooling processes of the samples to evaluate a thermal hysteresis of λe. For the dry samples, the thermal hysteresis was not observed. The following equations of λe [W/(m.K)] of the dry samples were obtained:(1)λe=-0.000201θ+0.901 for Sample A, (2)λe=0.0004660+0.805 for Sample B and (3) Ae=0.0006820+0.798 for Sample C. On the other hand, for the wet samples, the thermal hysteresis was recognized. The λe values in the heating process were 0.9-1.5W/(m.K), but the values in the cooling process were 0.8-1.1W/(m.k). Thermal conductivity of solid component of the Black Sand, λs, was estimated from the λe of the Black Sand -water mixture beds and a thermal conductance model developed by the authors, and expressed as λs=0.0121θ+1.21. These results mean that Black Sand may be an effective buffer material having sufficiently good heat conducting properties to keep the temperature of deeply buried canisters within a suitable interval.

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A Knowledge of the mechanical properties of rocks is essential for geotechnical engineering problems. Most tests which are usually used to determine the strength of rock require the specimen to be in the precisely prescribed shape. However, it is often difficult, or practically impossible in some cases, to prepare the specimen as required, with weak rocks or potentially fractured rocks.
On the other hand, considering the mechanical cutting of the rocks, it has been investigated to relate the bits with the properties of rocks. However, it is not sufficiently understood that the mechanism of the bit penetration by the reasons of which is dependent on the properties of the rocks, the shape and size of the bits etc. Accordingly, it is possible to obtain the useful correlation between the drillability and the observed chipping or crushing by the rod penetration test.
From this point of view, the rod penetration test has been carried out by using a wide range of rocks from weak to hard. Various correlations have been thoroughly examined in accordance with the properties obtained from the rod penetration test and the usual mechanical tests. It is shown that the strength and deformability can be estimated from the results of the rod penetration test, for a wide strength range of rocks.
In addition, the mechanism of the fracture development during the rod penetration test have been investigated by means of FEM analysis. It is shown that tensile fractures under the loaded rod and the direction of indentation play an important role in effective fragmentation of rocks.

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Centrifugal permeation process of fluid through solid particle deposit was analysed theoretically. In accordance with this analysis, it was shown that the centrifugal permeation process was able to be predicted by the aid of the compression permeability data. The predicted centrifugal permeation processes were favourably consistent with the experimental processes for limestone-, coal- and yeast-water slurries.
The specific flow resistance of particle deposit depends in general on hydraulic pressure, but that of the centrifugal process is able to take different value even under the same hydraulic pressure due to its thickness. For predicting the specific resistance of the centrifugal permeation, it is accordingly essential to take into account both of the hydraulic pressure and the solid compressive pressure distribution in the deposit differed with each thickness. When the specific resistance of filtration or permeation process under pressure or vacuum has to be examined and utilized cocurrently with that of centrifugal to design and scale-up the process, it was shown that the average compressive pressure defined in this paper was effective as the pressure variable.

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Feldspar is separated from quartz by two flotation methods in Japan.
In a conventional method, feldspar is floated using an amine collector with hydrofluoric acid. The other method uses normal alkyltrimethylene diamine acetate (NATMD) and sodium petroleum sulfonate (PS) as collectors without using hydrofluoric acid. The purpose of this paper is to investigate the effect of particle size of feldspar and quartz on their flotation by both methods. Eight different size fractions of feldspar and quartz (-210+149, -149+105, -105+74, -74+53, -53+44, -44+37, -37+10, -10Em) were used for flotation tests. Flotation tests were carried out using artificial mixtures of both minerals (1: 1 by weight). Experimental results are summarized as follows.
1) In the case of mixtures containing -210+10μm fractions of feldspar and quartz, successful separations were obtained using dodecylamine acetate (DAA) with hydrofluoric acid. Fine quartz (-10μm) especially reduced the flotation recovery of coarse feldspar (+105μm). A large amount of DAA and sufficient activation of feldspar by hydrofluoric acid were required to separate feldspar from quartz when the flotation feeds contained fine quartz or fine feldspar, orboth.
2) The non-hydrofluoric acid system performed well when the flotation feeds contained -210+53μm fractions of feldspar and quartz. Fine quartz reduced the floatability of feldspar remarkably, and a large amount of collectors was required to float feldspar. Fine feldspar floated well when a mixed ratio of NATMD to PS is 2: 1, and fine feldspar was separated from coarse quartz (-210+105μm). The separation of fine feldspar from quartz (-105μm) was difficult because the floatability of quartz increased with the reduction of its particle size.

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Lime has been often used as a precipitant for phosphorus removal from wastewater. But the precipitates formed have unfavorable Characteristics such as low sedimentation rate and large sedimentation volume.
In the present investigation the characteristics of the precipitates formed in different conditions has been studied using two different solutions containing HPO₄^2- of 1×10^-3 and 1×10^-2mol/dm³, respectively.
The precipitates formed with weak stirring by hand for a few minutes are amorphous and shows both large sedimentation volume and low sedimentation rate due to the formation of gel-like structure. Although the precipitates are crystallized with aging, the sedimentation characteristics can not be improved. Strong strring by a impeller breaks the gel-like structure of the precipitates, resulting in the decrease of sedimentation volume and in a little improvement of sedimentation rate. Phosphorus concentration is reduced below 1mg/dm³ through filtration at the [Ca²⁺]/[HPO₄^2-] molar ratio above 3 and at the pH value more than about 8. For the solution containing HPO₄^2- of 1×10^-3 mol/dm³, the sedimentation rate of the precipitates is so low that it takes 24 hours to reduce phosphorus concentration of the supernatant below 2mg/dm³ in either stirring methods. On the other hand, for the solution containing HPO₄^2- of 1×10^-2mol/dm³, the precipitates formed by the strong stirring in a narrow pH range of about 8 have relatively high sedimentation rate and phosphorus concentration of the supernatant can be reduced below 2mg/dm³ after standing for 2 hours.

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Improvement in hydrogen pressure reduction process for reduced precipitation of molybdenum dioxide from ammonium molybdate solution was investigated. Water soluble methanol added to ammonium molybdate solutions decomposed at reaction temperature of 250°C to generate reducing hydrogen gas, which made the formation of molybdenum dioxide possible in the absence of initial hydrogen pressure.
Their reduction was enhanced when reducing agent such as hydrazine, hydrate or ascorbic acid was previously added to the solution.
Product obtained by present method was identified as molybdenum dioxide by X-ray diffractometry.

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4成分溶液HX-CuX₂-MX_n-H₂0 (Xは1価の陰イオン, Mは陽イオン) からの, ヒドロキシオキシムによる銅 (II) の溶媒抽出挙動の, 平衡論的予測法を記述した。この方法は水相内の溶質の量論的活量係数と, 水相の過剰体積をPitzer法により推算することを特徴としている。銅 (II) の抽出実験が, Acorga P-5100を抽出剤として, 種々のアルカリ金属塩化物 (LiCl, NaCl, KCl) 存在下で行われ, 分配比はアルカリ金属塩化物の濃度の増加に伴って, わずかに減少し, その程度はアルカリ金属の種類に依存しないことが認められた。分配比の計算結果と実測値の比較によれば, LiCl共存およびNaCl共存の場合には, 一致はきわめて良好であった。KCl共存の場合には, その濃度が比較的低い場合には, 一致は良好であるが, 高濃度になると若干のずれが生じた。その原因は, pitzer法で活量係数を求める際に必要であるKClとCuCl₂間の混合係数が, 現段階では未知なので無視したためであると推定された。抽出挙動の水素イオン濃度依存性およびアルカリ金属塩化物濃度依存性が, 銅イオンおよび水素イオンの活量係数の変化という観点から議論された。

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The study was carried out on the mechanism of stripping and crystallization of Co extracted in Versatic Acid 10-kerosene solution by applying high pressure CO2 and water. At the experimental condition of 25°C, 0.5 mol/l of VA10 concentration and 15 atm CO₂ pressure, the degree of Co stripping was found to decrease slightly from 99.9 to 98.4% with initial concentration of Co in organic phase in its range of 2.56×10^-3 to 0.109 mol/l. In these runs, any solids were not observed in aqueous phase inside the autoclave after opening it. At more than 0.124 mol/l, there were observed two different appearances of crystallization. In one case (0.124, 0.134 mol/l), organic and aqueous phases were separated each other clearly and the latter contained fine powders, which was probably caused by reducing pressure. In the other one (0.216mol/l), the content in a vessel showed a mixed state of suspension of organic, aqueous and solid phases, which was supposed to have already occurred under high pressure. The distribution ratio in the stripping runs was found much smaller at the same pH values than in the extraction ones. The thermodynamic equilibrium on Co stripping reaction by CO₂ was calculated using the extraction data and found to represent the actual behaviors of stripping qualitatively. Furthermore, the calculation of ionic product for CoCO₃ revealed that the aqueous phase after stripping was supposed to be under supersaturation throughout the corresponding region of non-crystallization.

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As a basic study of copper anode passivation phenomena which are closely related with physico-chemical properties of the slimes formed on the anode, this study has investigated the anodic dissolution reaction of pure copper by the in-situ, chemical impedance measurement; the measurement has been done with a pure copper anode and a one attached with a porous filter, and attention has been focused on the Warburg impedance, which appears at lower frequencies and represents the diffusion contribution of cupric ions through a boundary layer. The experimental observation has shown that the Warburg impedance is larger with the anode with a porous filter than the one without a filter. It has been also suggested that this Warburg impedance may adequately indicate the in-situ properties of the slimes in the copper electrolytic refining process.

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Calorimetric investigations were conducted for some arsenides and antimonides as a fundamental study of the speiss phase in nonferrous pyrometallurgical processes.
Heat contents of four arsenides (Fe₂As, Co₅As₂, Ni₅As₂ and Cu₃As) and four antimonides (Fe₃Sb₂, CoSb₂, Ni₅Sb₂ and Cu₂Sb) were determined over a temperature range of 800 to 1, 500K using a drop calorimeter. Temperature coefficients of the heat content were determined by a regression analysis method using the Shomate function. Heat capacities of these compounds at high temperatures were also derived from the heat content temperature coefficients.
Heats of formation of four arsenides (Fe₂As, Co₅As₂, Ni₅As₂ and Cu₃As) were determined at 298K using a Tian-Calvet type solution calorimeter. By combining the heats of formation and heat capacities obtained in this study with literature values of standard entropy, the standard Gibbs free energy changes of formation of these arsenides were determined as a function of temperature.
Distributions of copper, iron, cobalt and nickel between speiss and metal, matte or slag phases were thermodynamically discussed based on the free energy data for the arsenides.

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