The Onahama Smelter and Refinery has two green charged reverberatory furnaces and had been consuming 7, 000kl oil per month.
Repeated and high rise of oil price caused the Onahama Smelter and Refinery to introduce the alternative fuels.
Firstly, chipped waste tires have been burned in the reverberatory furnaces since Oct. 1979, saving oil consumption by20%.
Then pulverized coal combustion has been carried out since Aug., 1980.
Further, technique of waste tire pyrolysis was developed and established, replacing the fuels at anode furnaces and secondary air preheaters for the reverberatory furnaces with the oil and gas from the tire pyrolysis.
As a result, more than 95% of oil consumption is replaced with these alternative fuels.
Some problems occurred while using alternative fuels.
For example, reverberatory furnace dust was increased by the ash from coal and caused some problems. They were solved by injecting the dust through tuyeres of P. S. converters with compressed air.
Another main problem was the increase of reverberatory furnace off-gas, and it was solved by the improvement of absorption towers of off-gas treatment facility.
On the other hand, much more electric power is generated at the power station using increased steam from reverberatory furnace boilers.
In summary, cost of fuels and electric power is saved by introducing alternative fuels, and competitive reverberatory furnace smelting is now established.

抄録全体を表示

For the purpose to investigate the behaviour of jointed rock mass, uniaxial compression tests were performed for specimens each including one artificial joint, horizontal or vertical, and stratiform rock specimens composed of two different rock species which were combined longitudinally. Following results were obtained.
1) Strength and deformability of specimens including horizontal joint, are almost equal to those of intact rocks, and are not affected by the planar joint.
2) For specimens including vertical joint, both strength and Young's modulus are lower than those of intact rocks.
3) For the stratiform specimens, failure occur at the stress, that equals the strength of the weaker rock species which ν/E value (ν: Poission's ratio, E: Young's modulus) is higher. But the mode of failure vary according to combinations of rock species and loading rates. For combination of rock species which strengths are relatively high, both rock species will fail si multaneously. Even for those stratiform specimens, which are composed of two rock species which strengths differ considerably, simultaneous failure may occur in the case of low loading rate. It is considered that the mode of failure results from the interaction of two rock species at the joint.
4) It is found by FEM analysis, that failure mode of the stratiform rock specimens mostly depends on the difference of ν/E values of two rock species.

抄録全体を表示

The Los Alamos National Laboratory in the United States, with participation from Japan and West Germany, proved the technical feasibility of hot dry rock energy production. Two inclined wells were drilled into hot rock and reached a vertical depth of about 4, 200 m and a temperature of 320°C at Fenton Hill test site. A hydraulic fracturing test, Exp. 2061 was conducted from June 29 through July 2, 1985 to create a larger and hotter reservoir. Water was injected in the interval between 3, 830 m and 4, 017 m at an average rate of 1.6 m³/min with a wellhead pressure of 48 MPa. Cumulative injection during 63 hours of pumping was 5, 228 m³. No hydraulic connection between injection and production wells was obtained in this experiment.
The radius and aperture of the fracture system were simulated as a single fracture using the finite element code FEHM (Finite Element Heat and Mass Transfer Code). It is found that for the first 12 hours of pumping, the aperture decreased rapidly towards the tip of fracture and the shape of the fracture remained similar at different times. After 12 hours, the aperture remained nearly constant from the center of the fracture to some extent and then decreased rapidly toward the tip. The distance for which the aperture remained constant increased with the pumping time. However, the extension rate of the fracture decreased with time. The fracture extended even after shut-in when the aperture at the fracture center decreased with time.

抄録全体を表示

In this paper, the measuring results of gas emission into seam road on the large diameter boring and after the blasting of drivage are described.
Main results obtained are as follows.(1) The large diameter (250 mmφ) boring was effective to relieve not only seam stress but also seam gas, particularly in fault zone. It had a marked tendency to increases the gas emission rate to the heading of seam road under such circum stances as the boring penetrates in front and rear of faults.
(2) Gas emission characteristics after the blasting of drivage is classified into seven types as shown in Fig. 8. The kind of the characteristics of places where gas was remarkably emitted in 30 minutes after the blasting was mostly patterned by type A.
(3) The mutual relation between the gas emission volume in 30 minutes after the blasting and the difference of gas concent ration before and after the blasting was able to be found.
(4) Just before the region where a large amount of gas was emitted on the large diameter boring, it was recognized that large gas emission was causedby the blasting of drivage.

抄録全体を表示

For the design and safety control of a mining system in the deep ocean, the dynamic behavior of a submerged, twostepped pipe string, which was hanging from a ship and equipped with a buffer at its lower end, was theoretically analysed, considering the effect of the ocean current.
The main results obtained are as follows:(1) The relative displacement of the stepped pipe-string to the ship continues to increase even in the towing period of a constant velocity, which follows the period of acceleration, and then it approaches to the steady-state value after a considerably long time, just in the same manner as the case of the pipe string with a uniform cross-section. However, the shape of deflection of the stepped string is convex at its lower part, while that of the other string is concave at the same part.
(2) The bending stress induced in the stepped pipe-string is much smaller than the maximum axial stress produced at the top of each part of the stepped string. Therefore, the bending stress does not play an important role in designing the above-mentioned mining system.
(3) When the other quantities are constant, the relative displacement of the string increases remarkably as the mass of the buffer decreases or as the constant towing velocity (the maximum towing velocity) increases. From the practical sense, however, the effect of size of the buffer on the displacement is comparatively small as compared with the effects of the above-mentioned two factors when the mass of the buffer is constant.
(4) The relative displacement of the string is considerably affected by the ocean current. Namely, the displacement in creases in case of the current whose direction is opposite to that of towing the string, and decreases in case of the current whose direction is the same as that of towing.
(5) The maximum tensile stress in the axial direction produced in the pipe string could be reduced by about 20% if the two-stepped pipe string designed in this study were used instead of the pipe string with a uniform cross-section.

抄録全体を表示

Contrary to the most investigators' opinions that the deposit regime is uneconomical, some papers have reported this regime to be not necessarily uneconomic since the power requirement may decrease for velocities below the limit deposit velocity. Also, it is said that in all applications of industrial significance the system should be designed to prevent occurrence of this unsafe region because there is imminent danger of pipe blockage. Nevertheless, for the slurry pipeline system transporting coarse solid particles and involving difficulties in controling operational variables rigorously such as hydraulic dredging or hydraulic conveying of run-of-mine coal, it is inevitable for some or all of solids to deposit temporarily on the bottom of the pipe.
On these bases there is an immediate need for relationships to use in estimating both the bed thicknesses and the hydraulic gradients under the flow conditions in the deposit regime.
This paper presents results of investigations of design methods in this regime. Experiments were conducted to support the theoretical modeling effort for the particle size range 1.71-3.10 mm using a 25.9mm (ID) transparent plastic pipeline, with total length of approximately 10 m, mounted on the frame horizontally.
The correlation of experimental data has shown that the ratio h_r of the bed thickness to the pipe diameter D and the hydraulic gradient i_m of slurry flow may be determined from following equations if the functions of f₁ (Cv) and f₂ (Cv) are given experimentally:_??_in which: Va=apparent mean velocity of slurry flow; g=gravitational constant; Cv=delivered volumetric concentration of solids; v=kinematic viscosity of water; R, R0=hydraulic radii of the free flow section above the bed and of the pipe; Vt=terminal settling velocity of single particle;δ=specific gravity of solids.

抄録全体を表示

In order to make progress in the performance of flotator, it is necessary to develop a new type of energy saving flotator in which it is also possible to prevent a pulp from short circuit. The author invented formerly the TACUB jig, and now developed a flotator designed by using new principle, and it was named the HSR·Sevonett·90 flotator.
In the present paper, the experimental studies on the development of the new type flotator were mentioned. In each main step in the modification of Sevonett type flotator, tests were carried out in comparison with some commercial size machines under the existing plant conditions. After so many improvements, the type of flotator was once settled for HSR·Sevotett·7781 which was equipped with the top cut conical type stabilizer. The HSR means High Set Rotor. After that, a series of laboratory tests on the shape of stabilizer were carried out, and finally the HSR·Sevonett·90 flotator equipped with radial plates type stabilizer was completed. It is certified that this flotator has a low power consumption, high frothing ability and better performance in comparison with some commercial size machines.

抄録全体を表示

Densities and surface tensions of FeS -Cu₂S system and fayalite slags containing alumina have been measured by sessile drop method in order to investigate the interfacial phenomena in copper smelting such as mechanical copper loss and settling of matte particles in Cu-slags.
Densities of Cu-matte ranged from 4.2×1⁰³ kg/m³ to 5.2×10³ kg/m³ at 1473 K and increased with increasing Cu mass% in the matte. Surface tensions of Cu-matte were about 0.38-0.45 N/m^-1 at 1473 K and also increased with an increase of Cu mass%.
Densities of fayalite slags containing alumina lay between 2.9×10³ kg/m³ and 3.5×10³ kg/m³ and surface tensions of the slags were found in the range of 0.30-0.45 N/m^-1 at 1473 K. Both densities and surface tensions showed a tendency to increase with increasing Fe/SiO₂ mass ratio and alumina content. On the other hand, oxygen partial pressure showed litte influence on densities and surface tensions of the slags.

抄録全体を表示

The main obstacle in directly reducing zinc sulfide concentrate in a commercial vertical retort is the difficulty to produce strong briquettes. The authors have successfully applied a new method to the preparation of strong briquettes which have satisfactory strength even after almost all the zinc sulfide in the concentrate has been reduced to zinc vapor. The method consists of mixing zinc sulfide concentrate with pulverized coal and calcium oxide, preheating and briquetting the mixture into a cylindrical briquette of 1.3 cm in diameter, and then coking the briquette. Effects of mixing ratio, preheating temperature and time, particle sizes of concentrate, coal and calcium oxide on the strength of the briquette have been examined. Sinze almost no sulfur has been observed to come out of the briquettes and also since they have considerably low specific resistance of 5.1Ω·cm, it has been suggested that the briquettes may be fed not only into a vertical retort but also into an electrothermic furnace without additional coke.

抄録全体を表示

The extraction characteristics of molybdenum and tangsten were examined by using D2EHPA and LIX63 as an extractant. The method for separation of molybdenum and tangsten was investigated on the basis of solution chemistry of both metal ions.
Since molybdenum exists as the form of MoO₂²⁺ in acidic solutions, molybdenum can be extracted with D2EHPA and LIX63. On the other hand, tangsten does not form such cationic species and then no extraction of tangsten takes place with D2EHPA. In the extraction of molybdenum and tangsten from the equimolar solution of both metal ions, separation facter of 180 and 150 obtained in the use of D2EHPA and LIX63, respectively. When the tangsten concentration increases compared with the concentration of molybdenum in the aqueous solution, the extraction of molybdenum with D2EHPA is depressed and the extent of depression increases with an increase in the tangsten concentration. LIX63 can be applied to the aqueous solution containing high tangsten concentration, because the extraction of molybdenum is not almost depressed even in the presence of high tangsten concentrations.
The separation of molybdenum and tangsten in leach solutions of scheelite ores can be accomplished by the process where molybdenum is extracted and separated from the leach solution with LIX63 and then molybdenum is extracted again with D2EHPA from the stripped solution of the loaded LIX63 phase. Molybdenum can be easily stripped with diluted sodium hydroxide solution, although the stripping does not take place with mineral acid solutions of the concentration less than 6 normal.

抄録全体を表示