In the latest decade, nonferrous metallurgy in Japan is laid under the severe circumstances by high yen rate, higher energy cost and relatively low metal prices.
It is the common but hard problems for nonferrous metallurgists in Japan that what way should be taken at R & D in nonferrous metallurgy seeing through the comming century.
In this report, the titles of the lectures and projects which were taken up for nonferrous metallurgy in this decade were summarized in tables and discussed on the possible direction of future research projects with the comments from some intellectuals in nonferrous industries.
In conclusions, firstly, basic and technical studies should be proceeded for upgrading of Japanese nonferrous metallurgy. It is expected that the results will contribute to solve the problems based on costs, energy and automation and to develop the rational processes for sulfur treatment and slag utilization.
Secondly, the more efforts will be expected for development and production of advanced materials.
And thirdly, various recycling and environmental technologies should be developed with emphasis from the view point of global preservation of resources.

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The Earth has evolved since the birth at 4.6 Gy B. P. Especially, the evolution has been remarkable on the surface that is the boundary between the fluid sphere and the solid sphere. Many kinds of mineral and fuel deposits were formed in the process of the evolution, and are used as resources by human being. For most of the resources, reproduction rates in the Earth's history are slower than consuming ones in the human activity. This is the resources problem. All of the materials mined are dumped after using them. This process is a bypass which is added on the material cycle in the Earth. The bypass changes the evolution of the Earth. This is the environmental problem. The increasing carbon dioxide is one of the big environmental problems. In order to solve the problem many ideas are proposed, such as fixing by calcium carbonate, deep-sea disposal of liquid carbon dioxide, fixing by carbon dioxide hydrate, and storage in abandoned natu al gas reservoir. Any idea among them has not been evaluated from the viewpoint of the Earth's history. The lack of the evaluation based on this point of view should not guarantee the safety of the disposal processes of carbon dioxide.

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An in-situ hydraulic fracturing test was conducted in the Kamioka mine to estimate a fracture aperture and a pressure distribution within a fracture. The test was carried out in a borehole at a depth of 1.7m. The borehole had been drilled vertical to the wall of the opening. After making an artificial fracture which was parallel to the wall, water was injected into the fracture. Another borehole which had an offset of 1.5m away from the injection borehole was drilled to measure the pressure within the fracture at that location. The injection rate of water was increased step by step and a distribution of displacements of wall surface was measured by twenty-four LVDTs during the injection tests. Assuming that the water flow was straight, the distribution of water pressure within the fracture was calculated by the Lomize's equation. By using this pressure distribution as a boundary condition, an two-dimensional FEM model together with the Gangi bed-of-nails model was used to estimate the distribution of the fracture aperture and pressure distribution within the fracture to match the measured result of wall surface displacements, injection pressure and a pressure within the fracture. There is a good agreement between measured results and calculated values. Thus, the proposed analysis is thought to be effective. From this estimation, the distribution of the fracture aperture has two peaks. One peak is located near the injection borehole and another peak is located about 2m away from the borehole. The maximum aperture of the fracture was estimated to be 230 micro-m.

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The purposes of this study are to obtain designing data and safety operational conditions for air-lift pumps of lifting marine mineral resources such as maganese nodules from deep-sea floor of about 5, 000m to a mining ship. A large amount of air is absorbed into water, because the air is injected in a deeper position of conveying pipe at high pressure; therefore, the numerical procedure based on the drift flux model for steady gas-liquidsolid three-phase flow takes account of the mass transfer between gas-phase and liquid-phase.
In this paper, we discuss effects of several factors, such as coefficients of the constitutive equations; air absorption into water; inner diameter, wall roughness and length of each section of conveying pipe; pressure drop coefficients; physical properties and delivered concentration of solid particles on flow characteristics. The results of this numerical simulation serve a basic performance of a large scale air-lift pump.

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In order to clarify systematically the stability of cylindrical offshore structures, the buckling problem of circular cylindrical shells surrounded with liquid under axial compression is analyzed. A theoretical analysis is performed by means of the Galerkin method on the basis of the Donnell-type equations for shells, taking the effect of the axisymmetric deformation due to the static liquid pressure into consideration. Calculations are carried out for both simply supported and clamped shells and the critical compressive load k_c are determined for various values of the shell geometric parameter Z, liquid pressure parameter p_x and liquid depth ratio l₀.
The main results obtained are summarized as follows:
(1) The critical compressive load ratio k_c decreases monotonously with an increase in the value of l₀ and/or p_x. With an increase in l₀, the buckling wave number ratio β increases for small value of Z and decreases to less than unity for large value of Z.
(4) The effects of the surrounding liquid and the axial compression on the prebuckling deformation and the change of buckling mode for the rapid change of buckling load and buckling wave number are clarified by means of the contour map representation.

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Garnierite ore containing quartz, magnetite and other impurities was ground in a planetary ball mill. Ground ore was subjected to leaching at 297 K in 0.5mol/dm³ HC1 solution. Dry grinding of the ore induces structural change of garnierite from crystalline state into amorphous one, while silica and magnetite still remain as crystalline state. Such mechanically activated garnierite leads to high magnesium (Mg) and nickel (Ni) extraction in the HC1 solution. About 80% Mg and Ni are extracted, while only about 20% Si is extracted. Short time grinding is recommended for an effective extraction of Mg and Ni fromthe ore, with suppressing Si extraction.

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In the pyrometallurgical treatment of tin, it is necessary to identify the proper chemical composition of slag based on the thermodynamic behavior and phase diagram for decreasing of tin losses with effective recovery of tin from slag. Although some studies were reported about the phase diagram of SnO-SiO₂ binary system, which is basic system of slag in the tin smelting, those results show always disagreement. W hereas it is necessary to consider closely the stability of solid SnO with increasing in temperature when the specimen contains SnO component, because solid SnO decomposes easily by a disproportionation with increasing in temperature.
In the present study, firstly, the disproportionation of solid SnO with increasing in temperature was examined, and then the liquidus of SnO-SiO₂ binary system was also investigated by SnO or SiO₂ saturation method.Furthermore the influence of CaO and FeO addition on the liquidus in SnO-SiO₂ system was investigated. The results obtained were summarized as follows:
Solid SnO decomposed with increasing in temperature in the following manner: SnO→Sn, SnO, Sn₃O₄→Sn, Sn₃O₄→Sn, Sn₃O₄, SnO2→Sn, SnO₂.
It was confirmed that the phase diagram of SnO-SiO2 system is an eutectic type and the rising of liquidus at SiO₂ side is very sharp. And it was thought to be appropriate that a metasilicate phase, such as SnO·SiO₂is existed in this system, and it seemed metastably intermediate product.
The melting point of SnO-SiO₂ system raised by CaO addition, while it lowered by FeO addition.

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To measure hydrogen activity in a molten copper, a galvanic cell-type hydrogen sensor had developed. The special feature of this sensor was to be used in the in site measurement of hydrogen activity in molten copper. The sensor consists of a hydrogen concentration cell utilizing a perovskite-type oxide, CaZr_0.9In_0.1O₃-δ, as a solid electrolyte. The electromotive force of the cell was found to be generated by difference of not only hydrogen but also oxygen activities between electrodes in high temperature region more than about 1, 200 K. In this paper, the hydrogen activities in molten copper held in the atmosphere with controlled hydrogen and oxygen activities were measured and the values were compared with the theoretical ones calculated by a method developed by the present authors. The performance of this hydrogen sensor was checked with monitoring the hydrogen activity changes on some treatment to the melt in air and on solidification of the melt in hydrogen atmosphere.

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As a basic study of the oxidizing roasting in a Dwight-Lloyd sinterig machine in the ISP, lead-zinc concentrate, zinc concentrate, recycled sinter fines, and pulverized sinter fines were roasted in air, and behavior of sulfur-containing compounds was investigated.
The results can be summarized as follows.
1. The charge to the sintering machine is discharged before it is brought, as a whole, to equilibrium with the gas phase in the machine.
2. The roasting reactions are complicated owing to competitive formation and/or decomposition of oxides, sulfates, and basic sulfates.
3. Most sulfur remains in the sinter as basic sulfates of lead and zinc.
4. Desulfurization of recycled sinter fines and pulverized sinter fines by roasting in air is slow at temperatures below 1, 200°C which prevail in the sintering machine.

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Hectorite is a smectite clay having an ideal composition of Na_0.33 (Mg_2.67Li_0.33) Si₄O₁₀ (OH) ₂·nH₂O, which has been used as an effective colloidal dispersion system due to its favorable rheological properties.
When amorphous slurry comprising approximately 2-5 weight % of hectorite composition, which is prepared from sulfuric-acid solved water glass mixed with aqueous solutions of MgC1₂, LiOH and NaOH, is hydrothermally treated at 150-350°C conditions for 1-2 hour, viscous hectorite gel is formed above 200°C: the process may be applicable to water control of flowing and/or plugging in the geothermal reservoir fractures. Laboratory test for a water control system has been carried out using a simulator, a newly designed thermal gradient-type reactor. The results are satisfied: the flow path between the granite fragments filled in the reactor is plugged with hectorite gel formed by hydrothermal process of amorphous slurry comprising 2 weight % of hectorite compositon at 200°C and 250°C conditions.
Such gel material for the underground high temperature conditions may be useful to make design of extracting huge geothermal energy through artificial fractures developed in the hot dry rock.

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Soda lime glass beads were solidified by hydrothermal hot-pressing at 300°C for a period of 1 hour with NaOH, KOH, NaCl, KCl, Na₂SO₄, HCl solutions and deionized water, respectively. Shrinkage was monitored during experiment, and the solidified products were examined by SEM-EDX, XRD, FT-IR, TG and Shore hardness tester. The cross-section of the reacted glass bead showed three distinct layers of varying thickness that have undergone different degrees of alteration. The degree of alteration was higher approaching the surface of the glass beads. The surfaces of the glass beads were highly altered, deformed and cemented with each other. The final shrinkage increased in the order of acidic, neutral and alkali solution. The Shore hardness was found to increase with any increase in shrinkage for solutions containing same cation but was higher for Na⁺ solution than K⁺ solution. Thermogravimetric results indicated that the water contents in solidified products with K⁺ solutions were higher than the ones with Na+ solutions. This suggests that the drop in the hardness was caused by the presence of larger amount of water in solidified products with K⁺ than Na⁺.

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