Showing papers in "The Mining and Materials Processing Institute of Japan in 1991"
TL;DR: In this article, many factors which affect the anode passivation during electrolysis were discussed, such as the amount of slime and slime adhesiveness, the type, concentration, and form of impurities which exists in anode.
Abstract: Many factors which affects the anode passivation during electrolysis were discussed in this paper. These includes the amount of slime and slime adhesiveness. The internal factors which affects the amount of slime include the type, concentration and the form of impurities which exists in the anode. The external factors include the concentration of the dissolved oxygen and the impurity ions in electrolyte or the electrolytic condition such as current density.The anode impurities showed different behaviour of dissolution state according to the various forms of existence and the varying chemical properties of these elements or compounds. The anode slimes are formed either by dissolving of these impurities in the electrolyte at the anode or by remaining on the anode surface. The amount of these slimes greatly affects the occurence of passivation.It was clarified that the coexistence of oxygen together with elements such as S, As and Bi in anode affects the amount of slime, adhesiveness and therefore also affects passivation. The possibility of passivation increased markedly with increasing current density, dissolved oxygen, impurity ions, as well as the concentration of H2SO4.
16 citations
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11 citations
TL;DR: In this article, a study of extraction of metals from deep-sea manganese nodules was made by the sulfating roasting with SO2 gas in a temperature range from 100 to 1, 000°C followed by the water leaching.
Abstract: A study of extraction of metals from deep-sea manganese nodules was made by the sulfating roasting with SO2 gas in a temperature range from 100 to 1, 000°C followed by the water leaching. The effects of roasting conditions on the extraction percentages of Ni, Co, Cu, Mn and Fe by the water leaching were investigated. The selective extraction of Ni, Co and Cu from the roasted ore was also attempted by the ammonia leaching. The results obtained are summarized as follows.The highest degree of sulfation of manganese nodules was effected using a SO2: O2=2: 1 gas mixture at 400°C. The extraction percentages of Mn, Co, Ni, Cu and Fe by the water leaching of the roasted ore were about 90%, 90%, 70%, 70% and 0%, respectively.When the roasted ore was leached in an ammoniacal solution, selective extraction of Ni, Co and Cu was greater using higher concentrations of ammonium ion. Under optimum conditions of ammonia leaching, the extraction percentages of Ni, Co, Cu, Mn and Fe were about 70%, 70%, 70%, 5% and 5%, respectively.
9 citations
TL;DR: The size and surface morphology of the particle were strongly affected by acidity and temperature as discussed by the authors, and it was observed that the particle had rougher surface as the reaction temperature was raised.
Abstract: Manganese dioxide was precipitated from slightly and strongly acidic solution of manganese sulfate by ozone oxidation at temperatures up to 80°C. The particles were characterized by SEM observation and X-ray diffraction.Ozone was found to be very effective to produce manganese dioxide even at acid concentration as high as 5.0mol/l.The size and surface morphology of the particle were strongly affected by acidity and temperature. At pH 2 or 3, the particles were as small as about 0.2μm and had rugged surface. Particles consisted of nearly spherical grains of a size of 1-2μm with smooth surface at 1 or 2mol/l H2SO4. The particle surface turned rougher and finally was covered almost uniformly with thin needle-like crystals as the acid concentration increased up to 5.0mol/l. It was observed that the particle had rougher surface as the reaction temperature was raised.X-ray diffraction analysis showed that γ-MnO2 was a main reaction product under the conditions excluding pH 3.0 and 5.0mol/l H2SO4 at 80°C where α-MnO2 was detected.Also, use of ozone was proved to enable us to produce very fine particles of manganese dioxide with discharge behavior comparable to commercial electrolytic manganese dioxide for a battery-active material.
8 citations
TL;DR: In this article, a drilling model based on onedimensional stresswave theory for piston, rod and bit is presented, which allows continuous simulation of drilling, that is, not restricted to just one blow.
Abstract: A drilling model which consists of drill-body, piston, rod and bit is presented. The model is based on onedimensional stress-wave theory for piston, rod and bit. A force/penetration relationship with hysteresis is assumed for bit/rock interaction. A computer program based on the model is also developed which allows continuous simulation of drilling, that is, not restricted to just one blow.The simulation for a heavy drifter is carried out to test the proposed model. The calculated results of piston displacement, force applied to piston, stress-wave in rod, force applied to rock etc. are presented and discussed. displacement, force applied to piston, stress-wave in rod, force applied to rock etc. are presented and discussed.It can be said that the calculated resultsare reasonable and the model is able to use in research and development of rock drills. However, two points are still open to discussion: 1) bit/rock interaction and 2) attenuation of stress-wave in piston, rod and bit.
7 citations
TL;DR: In this article, the authors derived dimensionless numbers for static pressure profile, flow pattern and average holdup from the experimental results of a 200m vertical test plant and laboratory size small equipments and clarified the influence of length and diameter of lifting pipe for them.
Abstract: In the case of lifting of manganese nodules by air lift pump, gas-liquid-solid three phase flow is formed in lifting pipe. Accordingly, its lifting characteristics are influenced by the length and diameter of the lifting pipe.We considered static pressure profile, flow pattern and average hold-up from the experimental results of a 200m vertical test plant and laboratory size small equipments and clarified the influence of length and diameter of lifting pipe for them.Main results of this study are summarized as follows: 1) From theoretical consideration, we derived dimensionless numbers shown in the equation (8).2) Analyzing wave form of static pressure at the adjacent point of discharge, fundamental property of flow pattern of both tests is similar and it is noregard to the length of lifting pipe.3) Profile of static pressure in axial direction of lifting pipe was obtained as shown in Fig. 5.4) Profile of flow pattern in axial direction of lifting pipe was clarified as shown in Fig. 6.5) Relations between average hold-up and Froude number in two phase operation and three phase operation were presented by the equations (19) and (26).
6 citations
5 citations
TL;DR: In this paper, the oxidation of manganous ion by ozone has been investigated in sulfate solutions under the following conditions: the initial concentration of Mn2 ion was determined to be MnO2 in this pH range, and the reaction was found to proceed at pH lower than 4.5 according to the relationship.
Abstract: The oxidation of manganous ion by ozone has been investigated in sulfate solutions under the following conditions: the initial concentration of manganous ion. 0.4to2.0g/l; pH, 1.0 to 7.0; temperature, 25.0 to 80.0°C ozone partial pressure, 7.1×10-3 to 2.3×10-2 atm.1) The oxidation was found to be significantly promoted by an increase in an ozone partial pressure and a vigorous agitation.2) The oxidation reaction followed a zero order at pH below 4.5, the rates being virtually constant down to low concentration of Mn2+. The final product was determined to be MnO2 in this pH range.3) The reaction was found to proceed at pH lower than 4.5 according to the relationship.-d [Mn2+]/dt=κ[O3 (aq)][H+] -0.12 exp (-5000 (cal/mol)/RT)(mol/l/min)4) Mn2O3 as well as MnO2 was considered to take part in ozone oxidation at pH above 5.0, where the rates slightly decreased as the reaction proceeded.5) The oxidation was not remarkably promoted by a rise in temperature. A reduced reaction rate was observed at 80°C probably due to a reduced stability of ozone in the solution at elevated temperatures.
5 citations
TL;DR: In this paper, the authors used the Shomate function to determine the heat contents of four arsenides and four antimonides (Fe2As, Co5As 2, Ni5As2 and Cu3As) over a temperature range of 800 to 1, 500K using a drop calorimeter.
Abstract: 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.
5 citations
TL;DR: In this article, two types of zinc leaves, spoke-like and filmy deposits, were observed at the interface; spokelike deposits grew at higher applied potentials, i.e., at higher current densities, and Filmy deposits at lower applied potential, such that they formed two layers: one on the organic liquid side was lustered and dense, the other on the aqueous solution side was dark-grey and composed of aggregate of fine spokes.
Abstract: Zinc leaves electrodeposited at the zinc-sulfate solution/n-hexyl acetate interface at various applied potentials were investigated electrochemically and metallographically. Two types of zinc leaves, spoke-like and filmy deposits, were observed at the interface; spoke-like deposits grew at higher applied potentials, i.e., at higher current densities, and filmy deposits at lower applied potentials, i.e., at lower current densities. The filmy deposit consisted of two layers: one on the organic liquid side was lustered and dense, the other on the aqueous solution side was dark-grey and composed of aggregate of fine spokes. The thickness of the layer on the organic liquid side was about 1 μm and that on the aqueous solution side was about 30 μm at an applied potential of 0.5 V. As the applied potential became higher, the layer thickness increased.
4 citations
TL;DR: In this paper, the effects of various factors on the percent extraction of nickel, cobalt, copper, manganese, and iron from manganized nodules were investigated, and the results showed that almost all metals were extracted completely in a short time at a room temperature.
Abstract: 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.
TL;DR: In this article, the authors show some examples of valuable recycling from waste metal solutions, i.e., acid and iron components are recovered from waste pickling solutions; i. e., iron oxide with thermaldecomposition process, or with wet process; ferrous sulfate with evaporation; and ferric chloride synthesis are introduced.
Abstract: Various techniques are applied for the treatment of waste water. This paper shows some examples of valuable recycling from waste metal solutions.At steel works, a great deal of acid water is employed in pickling line. Acid and iron components are recovered from waste pickling solutions; i.e. iron oxide with thermaldecomposition process, or with wet process; ferrous sulfate with evaporation; and ferric chloride synthesis are introduced.Considerable amounts of poisonousmaterials such as cyanide and chromic anhydride are used in electroplating factories. Cu, Ag and Au from high concentrated cyanide solutions and of chromic anhydride are recycled from such solutions.
TL;DR: In this paper, the copper slags are oxidized in air at 1, 000°C for 1-20 hours, and the results indicate that the oxidized slags exhibit high resistance against the dissolution of both Fe and SiO2.
Abstract: 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.
TL;DR: In this article, the characteristics of the precipitates formed in different conditions has been studied using two different solutions containing HPO42- of 1×10-3 and 1× 10-2mol/dm3, respectively.
Abstract: 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 HPO42- 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+]/[HPO42-] molar ratio above 3 and at the pH value more than about 8. For the solution containing HPO42- 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 HPO42- 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.
TL;DR: In this article, the DSCA (Differential Strain Curve Analysis) was applied to measure in-situ stress in the Kan-etsu 2nd tunnel and the results showed that the ratio of the maximum, intermediate and minimum principal stresses was estimated using both Strickland and Ren's method and Dey and Brown's method.
Abstract: The DSCA (Differential Strain Curve Analysis) which was proposed by Strickland and Ren in 1980 was applied to measure in-situ stress in the Kan-etsu 2nd tunnel. The basic assumption of the DSCA is that microcracks will be generated in a rock specimen by the stress relief when it is taken from borehole and the microcrack density is related to the earth stress. The object of this study is to validate this method. The overburden of the boreholes from which test specimens were taken was about 800m. Fourteen test pieces were carefully formed into a cubic shape with a side length of about 30mm. Total number of 18 foil strain gages were attached to each test piece, and hydro-static pressure up to about 50 MPa was applied on the test piece. The directions of principal strains were calculated using the outputs of 18 strain gages as a function of hydro-static pressure. From the relations between hydro-static pressure and principal strain, the directions of in-situ principal stresses were estimated. As a result, azimuths of principal stresses estimated from fourteen samples had almost the same tendency, although the dips of those were divided into two groups of different tendency. The ratio of the maximum, intermediate and minimum principal stress was estimated using both Strickland and Ren's method and Dey and Brown's method. The ratio estimated by the former method was 1.00: 0.69: 0.42 while the latter gave the ratio of 1.00: 0.64: 0.45. Finally, these results estimated from DSCA were compared with another method such as hydraulic fracturing method or stress relief methods. There were no apparent contradiction between these results.
TL;DR: In this paper, a three-point-bending test under the constant load was conducted on Sanjome-andesite to investigate the time dependency of crack extension of Mode I. The model of crack growth proposed by Okubo et al. was found to be applicable through the tests carried out in this study including the first region where the crack extension rate decreases.
Abstract: Three-point-bending test under the constant load was conducted on Sanjome-andesite to investigate the time dependency of crack extension of Mode I. Crack length was calculated from the crack mouth opening displacement using the unloading compliance method.After the loading, the crack extension rate continuously decreases at first while the stress intensity factor increases. Thereafter, the crack extension rate takes its minimum, and then accelerates toward the final failure. In the last region where crack extension rate accelerates, it was found that the crack extension rate α can be expressed asα=Kn/Awhere K is stress intensity factor and A is a constant. This equation has the same form with that obtained by the double torsion tests.The mathematical model of crack growth proposed by Okubo et al. is(Δα)=Kn·(C1·(Δα)-m+C2)where Δα is the crack extension, and C1, C2 are constants. It was found that the equation can be applicable through the tests carried out in this study including the first region where the crack extension rate decreases.
TL;DR: In this paper, a formulation of the basic equations in three-phase flow for practical applications is presented, and the derivation of the equations was carried out for the mixture model in neglecting the interfacial force and energy.
Abstract: Three-phase gas-liquid-solid flow phenomena in pipes are observed in air-lift pumps for transporting solid materials, coal liquefaction plants, and so forth. In analyzing or numerically simulating three-phase flow phenomena, one needs a set of basic equations which describe the conservations of mass, momentum and energy for three-phase media.The purpose of this paper is a formulation of the basic equations in three-phase flow for practical applications. The derivation of the equations was carried out for the mixture model in neglecting the interfacial force and energy. First, using a characteristic function of each phase in the mean of distribution, the physical parameters of three-phase flow were defined as field quantities, and then the local instantaneous and averaged conservation equations of mass, momentum and energy were derived. Secondly, taking radial distribution of the physical parameters into account, one-dimensional basic equations were represented by means of the drift flux model on the basis of the local averaged equations.
TL;DR: In this paper, a 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.
Abstract: 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.
TL;DR: In this paper, the current situation and problems on this matter are discussed and it is important for these industries to resolve these problems in order to develop new processes or to produce new materials which have higher values added.
Abstract: Since the amount of slag generated in ferrous and non-ferrous metals production isconsiderably large, its effective utilization is one of the most significant issues in the industries. Therefore the great effort has beenmade to develop their new applications.In this paper, the current situation and problems on this matter are discussed.In the steel industry, most of ferrous slag is now utilized as a law material for cement production, road construction and so on. Non-ferrous slags are becoming widely used in these days, the usage is however far from satisfactory level in respect both of quantity and price. It is important for these industries to resolve these problems in order to develop new processes or to produce new materials which have higher values added.
TL;DR: In this article, a numerical analysis is presented which predicts the fracture behavior of granite under high confining pressures, using a modified boundary element method, and incorporating the tension-softening model developed for characterizing the growth of the fracture process zone in rock.
Abstract: A numerical analysis is presented which predicts the fracture behavior of granite under high confining pressures. The numerical simulation uses a modified boundary element method, and incorporates the tension-softening model developed for characterizing the growth of the fracture process zone in rock.Fracture toughness tests of granite have been conducted under confining pressures of 15.68 MPa and 26.46 MPa using compact tension specimens which were jacketed with urethane coating to eliminate the pore pressure effect.It is demonstrated that the numerical method developed in this investigation can well simulate the experimentally obtained load-displacement records under a wide range of confining pressure from a knowledge of the tension-softening law. Based on the result the tension-softening law is found to be independent material property. Furthermore, source mechanism for the pressure sensitive fractures of the granite is discussed by exaamining the growth behavior of the fracture process zone simulated using the numerical method.
TL;DR: In this paper, the antimonide speiss properties of the component elements were determined in the Pb-Fe-Sb and pb-Cu-sb ternaries at 1, 200°C by the transportation method.
Abstract: To elucidate some basic properties in the fundamental antimonide speiss systems, activities of the component elements were determined in the Pb-Fe-Sb and Pb-Cu-Sb ternaries at 1, 200°C by the transportation method.In the Pb-Fe-Sb system, the activity of antimony exhibits a slightly negative deviation from ideality for the entire composition range. A negative deviation of antimony activity is also seen from the additivity of the Pb-Sb and Fe-Sb binaries. In the two phase region, the activity of antimony ranges from 0.16-0.35, which is relatively large in comparison with arsenide speiss, suggesting a less stable speiss than the arsenic system. Lead activity on the other hand is below 0.77, indicating that gold and silver extraction by lead may be minimal.In the two phase region of the Pb-Cu-Sb system, antimony activity is below 0.1, displaying a large negative deviation from Raoult's law, while the activity of lead is greater than 0.75, comparatively larger than in the Pb-Fe-Sb system.Based on the interaction parameters determined in this study, the activity coefficient of antimony in molten lead containing minute amounts of copper and iron may be expressed as follows:InγSb=-0.422+0.08XSb-2.6XCu-XFe
TL;DR: In this paper, the authors investigated the effect of cutting speed and depth of cut on cutting force of a point attack bit and found that the horizontal component of cutting force increases linearly with cutting depth.
Abstract: 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.
TL;DR: In this article, the applicability of seismic velocity tomography for exploration of ore deposits and for evaluation of in-situ rock mass is discussed, and the velocity distribution which is obtained as the result of tomography analysis shows good agreement with both the results of laboratory measurements and that of geological observations.
Abstract: In order to discuss how we can obtain a more accurate two-dimensional distribution of seismic velocity in a rock mass, field measurements for tomographic analysis were performed. The accuracy of reconstructed image is greatly controlled by the accuracy of data. Therefore, at first, in order to accomplish more accurate travel time data, travel time data which were read out initially was corrected by using several checking methods. Then, in order to achieve an accurate analysis, an optimum inversion technique and optimum required parameters are selected. The velocity distribution which is obtained as the result of tomography analysis shows good agreement with both the result of laboratory measurements and that of geological observations. The applicability of seismic velocity tomography for exploration of ore deposits and for evaluation of in-situ rock mass is discussed.
TL;DR: In this article, the authors have carried out the laboratory and in situ experiments to investigate the failure mechanism of the rock around the caverns and the monitoring technique of the occurrence and progress of loosened zones by acoustic emission (AE) measurements.
Abstract: The behavior of the loosened zone around rock caverns plays an important role in the mechanical stability of rock pillars during construction and after completion. The authors have carried out the laboratory and in situ experiments to investigate the failure mechanism of the rock around the caverns and the monitoring technique of the occurrence and progress of loosened zones by acoustic emission (AE) measurements.This paper describes the results of these experiments and discusses the available procedures to predict the initiation of the loosening of the rock mass by the indicators “count rate (the rate of occurrence of AE per minute or hour)”, “AE energy (the square of amplitude of AE)” and “m-value” (the ratio of amplitude to count rate of AE).(1) As the results of comparison between AE measurements by laboratory triaxial test and in situ rock shear test, the loosening of the rock mass is considered to be strongly affected by the presence of preexisting fractures.(2) As the results of AE measurements by in situ rock shear test and during tunnel excavation, it is clarified that the decrease ratio of m-value and the increase ratios of count rate and AE energy for the heavily jointed rock mass show smaller figures than those of the intact rock mass.(3) The decrease ratio of m-value and the increase ratios of count rate and AE energy could be appropriate indicators for the determination of the criteria for the judgement of occurrence of loosening based on the relationship between three AE parameters mentioned above and the seismic wave velocity.
TL;DR: In this paper, the authors deal with recycling techniques of these metals from scaraps containing these elements, such as IC boads, button type batteries containing silver oxide, etc., for gold and silver, and auto exhaust emission control catalysts, precious metal plating chemicals etc.
Abstract: It is important to recycle the elements of gold, silver and the platinum group metals which often put to industrial use for their stability (against heat and chemical reaction), high electroconductivity, and high catalytic activity. This paper deals with recycling techniques of these metals from scaraps containing these elements. These include IC boads, button type batteries containing silver oxide, etc., for gold and silver, and auto exhaust emission control catalysts, precious metal plating chemicals etc., for platinum group, of which the demand seems to be expanded. It also introduces a method proposed by A.J. Gilmore, i.e., goldrecovery from flotation plant effluents with activated charcoal.