In Yanahara Mine, the sinkages of the roof rock above the iron deposit, induced by pillar extractions, were measured by using the vessels communicated by a flexible tube, rock stresses were measured by means of flatjack and hydraulic fracturing techniques, and the stress changes have been monitored as the pressure changes of the capsules set in rock/pillar. The measurements have been carried out over an extended period of time and a part of stress measurement has been carried out until the mine is abandoned.
The induced roof displacements were predicted by numerical analysis using Boundary Element Method which was found to comparatively agree with the measured roof sinkages.
The results of the stress measurements suggest that the stresses at the portions near the extracted blocks in the center pillar have gradually decreased with extraction progress while the stresses around the orebody are not significantly changed and the pillar stress at a portion relatively distant from the extracted blocks has slightly increased.

抄録全体を表示

The effect of rake angles on the performance of polycrystalline diamond compact (PDC) bits was investigated by rock cutting tests, drilling tests and durability tests. Two types of PDC cutters, a conventional one and a new one, were used for these tests. The structure of the new PDC cutter, whose diamond layer is protected by a tungsten' carbide layer, is different from that of the conventional one. Rake angles of bits for the rock cutting tests were changed between negative 10 deg. and negative 40 deg. Core bits for the drilling and the durability tests had both backrake and siderake angles of negative 5 deg., 10 deg., 15 deg. and 20 deg. Marble, granite and two types of andesite were used for the tests. The results are summarized as follows:
1. Horizontal and vertical forces were minimized at negative rake angle of 10 deg. independent of rock type.
2. Core bits with negative 10 deg. and 15 deg. both backrake and siderake angles showed better performance concerning penetration rate and cutter strength.
3. The new PDC core bit showed higher penetration rate and better cutter strength than the conventional PDC core bit. The new PDC cutter may be able to apply to drilling of hard formations.

抄録全体を表示

The cutting characteristics of a point attack bit, especially the effects of cutting speed and depth of cut on cutting force, were investigated. Point attack bits are becoming more popular as a cutting tool for boomheader, but its performances are still open to discussion. A series of rock cutting experiments was conducted with various cutting depths and speeds.
It was found that the horizontal component of cutting force increases linearly with cutting depth. This simple relation is true all for the mean, the mean peak and the peak values. It was also found that the build-up nose develops on the clearance face of the bit when a hard andesite is cut at higher cutting speed. As a result, cutting force, especially its vertical component, increases considerably with cutting speed.

抄録全体を表示

Aluminothermic reduction of Nb₂O₅-ZrO₂ mixture and subsequent electron beam refining of Nb-Zr-Al alloys were carried out.
In the 2kg batch of aluminothermic reduction, the alloy containing more than 1% of Zr was obtained when the ZrO₂-Nb₂O₅ mixture containing more than 20% of Zr was reduced by Al with more than 15% in excess of stoichiometric requirement.
Nb-Zr-Al alloys containing Zr of 0.1 to 8 and Al of 7 to 28% were used for electron beam refining tests. Al contents in the alloy were reduced to below 50 ppm after refining. It was found that Nb-1%Zr alloy can be produced by adjusting beam conditions during refining.

抄録全体を表示

Pacific Ocean Manganese nodules were leached in a water or in an ammoniacal solution using sulfur dioxide as a reductant, and studies were made of the effects of various factors on the percent extraction of nickel, cobalt, copper, manganese and iron.
When the ore was leached in a water using sulfur dioxide as a reductant, almost all metals were extracted completely in a short time at a room temperature. Extraction of iron was suppressed as elevating the leaching temperature, while selective extraction of nickel, cobalt and copper was not attained as far as water was used as a solvent.
The selective extraction of nickel, cobalt and copper from manganese nodules was attained by using ammoniacal solution as a solvent and using sulfur dioxide as a reductant. The leaching residue was mainly composed of manganese ammonium sulfite hydroxide in an ammonia solution, while manganese carbonate was detected at the ammonium carbonate solution leaching. The extraction percentages of metallic components under optimum conditions were 99% for copper, 98% for nickel, 95% for cobalt, 3% for manganese and 1% for iron, respectively.

抄録全体を表示

A diamond thin films was deposited both on SiC and on SS304 steel in the inner flame of C₂H₂-O₂ mixturegas. The structures of deposits were analyzed by Raman spectroscopy and X-ray diffraction, and the morphology was estimated by the SEM observation. It was confirmed that the deposits were consisted of diamond and icarbon. The amount of i-carbon in the deposits tended to increase at the substrate temperature over 1000°C and under 600°C. For the thin films deposited at temperatures of 600°C to 900°C, the orientation of the plane having high surface energy appeared strongly at low temperature, and the intensity of the plane having low surface energy increased with an increase in the substrate temperature

抄録全体を表示

To develop an oxygen flash smelting technology for copper concentrates, the combustibility of two concentrates with different fuel ratios was investigated in an industrial oxygen stream in terms of oxygen pressure, temperature, sulfur elimination, particle size and so on. The experiments were carried out in an Outokumpu flash smelting fUrnace, of which the smelting rate was about 1t/h of coPPer concentrate. Another experiment was also implemented under the condition of using oxygen-enriched air with about 35% O₂, and smelting performances of oxygen flash smelting were compared in dust generation as well as oxygen efficiency with those of oxygen-enriched air flash smelting.

抄録全体を表示

Electrical resistivity of commercial pure titanium previously annealed at 973K and its change by isothermal annealing were investigated in relation to behaviours of several impurities.
Resistivity minima observed by annealing above 673K were due to precipitation of Fe and diffusive invasion of O from surface oxide film. Maximum decrement of resistivity by annealing up to 773K was interpreted by difference of equilibrium concentration of Fe between annealing temperatures and precipitation of solute Feremaining after commercial annealing for 3.6 ks at 973K.
Below 393K, maximum increment of resistivity due to dissolution of hydride increased with dissolution temperature and was larger in specimen containing more H. The relation between saturated value of maximum increment and the dissolution temperature suggested that O and other impurities might decrease the solid solubility of H.
Calculated resistivity at 77K was always lower than, but had a good correlation to, the measured value. The resistivity of annealed commercial pure titanium plate is determined mainly by the content of O. Thus, the resistivity can be used as an index of purity, or at least of O content of the commercial pure titanium.

抄録全体を表示

Tantalum fine powder has been prepared by means of arc-plasma CVD method. Tantalum chloride was used as raw materials for the formation of the powder. The prepared amount of the powder increased with the reaction time, and a constant mean particle-sized powder was formed without relation to reaction time. On the other hand, the mean particle size decreased with an increase in the ratio of H₂/TaCl₅ in the reactant gases. From the SEM observation, the powder was found to have a complicated shape. According to the distribution measurement of particle size, the mean particle size of the powder was found to be in the range of 0.08 to 0.3μm and its distribution curve showed normal one. The bulk density, particle density and specific surface area of the powder having the mean particle size of 0.15μm were 1.4×10³ kg/m³, 7.0×10³kg/m³ and 15.8×10³ m²/kg respectively.
The mean particle size of tantalum fine powder was found to be controlled by changing the concentration ratio of tantalum chloride and hydrogen in reactant gases.

抄録全体を表示

The present study was undertaken to investigate the practical use of SO₂ gas sensor employing β″-alumina solid electrolyte in the field of industry. In the cell with β″-alumina solid electrolyte, the use of (β″+β″)-alumina coexistent mixture in air as a solid reference electrode lead to a simple structure of the SO₂ gas sensor. In this paper we reported the practical application of SO₂ gas sensor with the following cell in copper smelting plants.
Pt, (β+β″)-alumina in air/β″-alumina/S0₂+O₂+SO₃, Pt
From the present experiments the following conclusions were obtained.
1) The present experimental cell showed a satisfactory response and the data agreed very closely with those obtained by another analytical method (non-dispersive infrared rays).
2) In a long period of measuring, the emf's of this sensor varied with the lapse of time. However it was confirmed that its reproducibility is obtained by the correction of the calibration curve once a few days.

抄録全体を表示

(Ti, Al) N films possessing various composition ratios of Ti and Al were deposited onto slide glass and a hard alloy substrate by rf sputtering. The power was supplied from a single electric power source which was spilt by a variable coupling capacitor. A series of (Ti, Al) N specimens was obtained by changing the electric power distribution to Ti and Al targets in argon-nitrogen gas mixtures. The film compositions was measured by EDX and EPMA, and X-ray diffraction method was studied by the structure of the films. The corrosion rate of (Ti, Al) N films was judged from weight loss after immersion in 5% H₂SO₄ solution at 70°C.
The results showed that all the (Ti, Al) N films possess homogeneous distribution of Ti and Al elements. X-ray patterns revealed formation of TiN for concentrated Ti side and AIN formation for Al riched side. The film phase having Ti-to-Al ratios approximating 1:1 was TiAIN. The corrosion resistance of films for concentrated Ti side showed better properties than that for Ti to Al ratios about 1:1. Hardness of (Ti, Al) N films of Ti to Al composition ratio about 1:1 was approximately Hv 1200.

抄録全体を表示

This paper describes copper foils with superior mechanical, metallurgical and chemical characteristics. These are needed to satisfy customer needs for Printed Circuit Boards having finer lines and greater reliability. Manufacturing and characteristics of high performance copper foils are discussed in terms of: 1) adhesion to various resins 2) the deterioration of peel strength at high temperatures, and 3) the formation of fine lines using low profile foils.

抄録全体を表示

TiO₂ powder has been used from old materials of white paints. Its demand has been recently expanding from its great ability of ultraviolet absorption. It is, however, difficult to estimate the ability of ultraviolet absorption. Therefore, photoacoustic spectroscopy (PAS) was applied to the characterization of the UV absorption ability in TiO₂ composite powders.
Two types of TiO₂ powders, one is so-called “coated powder” with Si0₂ and ZnO and the other is MgOTiO₂ composite powder, were prepared by wet method. It was revealed by XPS analysis to the coated powder that SiO₂ was thinly coated with relative uniformity, but smooth and uniform coat was not achieved on the powder coated with ZnO. UV spectra of these coated powders showed the same spectra as the original TiO₂ powder without any coating. It indicates that coating did not have any effect on the ability of UV absorption of TiO₂.
Crystal phases in MgO-TiO₂ composite powder depended on the initial molar ratio of MgO to TiO₂ and the heat treatment conditions, and each crystal phase showed a characteristics of UV absorption. For instance, an absorption spectrum with sharp peak at 280nm was obtained when the composite powder (MgO/TiO₂=5/8) was calcined at 1223K. UV spectra could be controlled by controlling the initial composition and the heat treatment conditions.

抄録全体を表示

Slags produced from iron and steel making industry or non-ferrous smelting plants are now considered one of the important domestic resources in various fields. Although the most copper smelting slags have been used in cement plant as a component of iron oxide in clinker, the market is not big enough to consume the amount of slag available, and furthermore, advanced usage of slag with higher value will be expected.
In this study, the copper slags are oxidized in air at 1, 000°C for 1-20 hours. After oxidation the X-ray diffraction pattern, infra-red absorption spectra, and EPMA images showed an existence of iron oxide (Fe₂0₃, Fe₂O₄), CaO-Al₂O₃-Si0₂ system, and discrete Si0₂ in different phases. The dissolution test with HCl, H₂SO₄ and NaOH solution was carried out for Fe and SiO₂ in the samples. The results indicate that the oxidized slags exhibit high resistance against the dissolution of both Fe and SiO₂. According to the Seger cone test, the oxidized slags were stable at higher temperature than that for non-oxidized slags. As a result of slag lining tests on a steel plate, the strong anchoring effect was observed at the interface probably due to the reaction between iron plate and Fe ions in slag. The alkali-aggregate reaction of slags in concrete was examined by the ASTM chemical method, resulting in finding all spots inside the safe range of figure.

抄録全体を表示