Mitsui Mining Research Articles

Polarization Behaviors and Morphology during Zinc Deposition and Dissolution in Zinc Flow Battery

A zinc flow battery is one of the candidates of secondary batteries for stationary energy storage system, and a zinc-air flow battery is the most promising device because of its high theoretical energy density, low cost of anode material, air-breathing cathode, and high safety of non-flammable aqueous electrolyte. The flow of the electrolyte, which is mostly KOH solutions, is believed to be effective to suppress the generation of zinc dendrite and non-uniform distribution of zinc and zinc oxide, while there has been little information on the effects of the charge-discharge conditions and the dimensions, design, and flow parameters of the cell on the polarization behaviors of the zinc anode and on the morphology during zinc deposition and dissolution in zinc flow secondary batteries.1,2 This paper reports the results on the potential measurements of the zinc anode at the current density up to 500 mA/cm2 and the observation of the morphology of zinc growth and dissolution during charge and discharge.The zinc anode was electrodeposited zinc alloy film supplied by Mitsui Mining & Smelting, Co., Ltd, which produces less than 1/100 of hydrogen compared to conventional rolled zinc film, indicating a high hydrogen overpotential and a quite low self-discharge rate. Two-electrode or three-electrode cells were equipped with the zinc film anode and a zinc wire reference electrode, of which the electrolyte was 6 mol/L KOH solutions saturated with ZnO. The electrolyte was pumped into the cell and the flow rate was changed. The potential of the zinc anode during charge and discharge was monitored while constant current electrolysis was performed at 100 mA/cm2 to 500 mA/cm2. The morphological change for zinc deposition and dissolution was observed by video camera during charge and discharge and by SEM after the operation.The results on the polarization of the zinc anode obtained at different current densities are shown in Fig. 1, in which the increase in polarization at the current density from 100 mA/m2 to 500 mA/cm2 was less than 50 mV for both of charge and discharge at 25 mL/min, suggesting that the electrolyte flow enhances the mass transport of zincate ions and suppresses the concentration overpotential. This is also supported by the fact that charge failed with no electrolyte flow. The dependence of the anode’s potential on the flow rate also indicated that the potential hardly increased when the flow rate changed from 250 mL/min to 25 mL/min. The observation of zinc deposition and dissolution was further carried out and some interesting features on the relationship between the morphology of zinc deposits and the operating conditions was found, implying the conditions to suppress zinc dendrite formation.This work was partly supported by JSPS Grant-in-Aid for Scientific Research No. 22H02187.References1) A. L. Zhu, D. P. Wilkinson, X. Zhang, Y. Xing, A. G. Rozhin, S. A. Kulinich, J. Energy Storage, 8, 35-50 (2016).2) A. Abbasi, S. Hosseini, A. Somwangthanaroj, R. Cheacharoen, S. Olaru, S. Kheawhom, Sci. Data, 7, 196 (2020). Figure 1

Degradation Mechanisms of All-Solid-State Lithium-Ion Batteries with Sulfide-Type Electrolytes Based on High-Temperature Studies

Introduction Sulfide-based all-solid-state Li-ion batteries (LIBs) are potential next-generation energy storage devices due to their increased safeties and energy densities compared to those of conventional LIBs with liquid electrolytes. However, our understanding of the durabilities and degradation mechanisms of such batteries remains limited. Via industry-academia collaboration, a project that aims to develop a sulfide-based all-solid-state LIB for use in electric vehicles (NEDO “Development of Fundamental Technologies for All-Solid-State Battery Applied to Electric Vehicles (SOLiD-EV),” 2018-2023) has been undertaken in Japan. Under this project, we conducted high-temperature cycling and storage studies using a SOLiD-EV prototype cell to gain insight into the durability and degradation mechanism of the sulfide-based all-solid-state LIB. [1] Experimental The SOLiD-EV prototype cell, which was a developed laminate-type single-layer all-solid-state LIB with a capacity of approximately 8 mAh, was assembled by combining LiNbO3-coated LiNi0.5Co0.2Mn0.3O2 (NCM, Sumitomo Metal Mining, Tokyo, Japan) as the positive active material, graphite (Mitsubishi Chemical Holdings, Tokyo, Japan) as the negative active material, and argyrodite-structured Li(7–x)PS(6–x)Cl x (x ≈ 1.2 × 10−3 S cm−1; Mitsui Mining & Smelting, Tokyo, Japan) as the solid electrolyte (SE). All assembly processes were conducted in a glove box under an Ar atmosphere with a dew point below −76 °C and an O2 concentration of <1 ppm.In the high-temperature cycling study, the prototype cell was charged at a rate of C/10 to 4.2 V in constant current mode and further charged in constant potential voltage (CC-CV) mode. It was then discharged at a rate of C/3 to reach 3.0 V in constant current (CC) mode at 100 °C. In the high-temperature storage study, the prototype cell was stored in a thermostatic chamber at 60, 80, or 100 °C after CC-CV charging. In both studies, the following performance measurements were conducted at intervals of 7 days: charge/discharge evaluations at the same current condition as that used in the high-temperature cycling study at 25 °C, charge/discharge evaluations at a rate of C/20 at 45 °C, and electrochemical impedance spectroscopy at a depth of discharge (DOD) of 50% at 25 °C. Both studies were conducted for a total of 28 days.X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and inductively coupled plasma atomic emission spectrometry (ICP-AES) component analysis of the SE at each electrode were performed using the prototype cells that were degraded in the high-temperature studies as disassembly analyses. Results and discussion Each evaluation reduces the capacity of the SOLiD-EV prototype cell, and the loss of capacity at high temperatures is faster than that at low temperatures, as shown in Figure 1. This reduction in the capacity during the cycling study at 100 °C is lesser than that during the storage study at 100 °C in the first 7 days; however, the reduction during the cycling study increases after 14 days. The degradation of the electrodes was caused by the repeated charging and discharging of the prototype cell. Increases in internal resistance are also confirmed, and the trend of the temperature dependence is almost identical to the capacity trend. The partial substitution of PS4 3− in Li(7–x)PS(6–x)Cl x by P–S–P, –S–S–, and S components, as revealed by XPS, and the decrease in the Li/P ratio, as revealed by ICP-AES, indicate that the SE (Li(7–x)PS(6–x)Cl x ) is oxidatively decomposed at the positive electrode due to its (noble) potential. S, which is a product of oxidative decomposition, is a poor conductor of Li+ ions and may increase the charge transfer and path resistances in the positive electrode. The substitution of PS4 3− in Li(7–x)PS(6–x)Cl x with Li3P and Li2S and the increase in the Li/P ratio indicate that the SE (Li(7–x)PS(6–x)Cl x ) is reductively dissolved at the negative electrode due to the negative electrode (low) potential. The capacity degradation of the cell is due to the loss of active Li+ ions caused by the reduction of the sulfide electrolyte at the negative electrode. Furthermore, the change in the composition of the SE, as determined via ICP-AES (Figure 2) before and after the high-temperature storage study, suggests that the SE degradation reactions at the positive and negative electrodes are temperature-dependent and roughly follow the Arrhenius law, with different activation energies. Acknowledgement This study was supported by the “Development of Fundamental Technologies for All Solid State Battery Applied to Electric Vehicles” project (SOLiD-EV, JPNP18003) commissioned by the New Energy and Industrial Technology Development Organization (NEDO). Reference [1] K. Ando, T. Matsuda, T. Miwa, M. Kawai, D. Imamura, Battery Energy, 20220052 (2023). Figure 1

A study on welfare measures of Mitsui Mining and its affiliated companies before World War II

A study on welfare measures of Mitsui Mining and its affiliated companies before World War II

Role of experts and public participation in pollution control: the case of Itai-itai disease in Japan&lt;sup&gt;1

ESEP Ethics in Science and Environmental Politics Contact the journal RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections ESEP 12:99-111 (2012) - DOI: https://doi.org/10.3354/esep00126 Role of experts and public participation in pollution control: the case of Itai-itai disease in Japan1 Masanori Kaji Graduate School of Decision Science and Technology, Group of History of Science and Technology, Tokyo Institute of Technology, W9-79, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan *Email: kaji.m.aa@m.titech.ac.jp ABSTRACT: Itai-itai disease was first noticed in the Junzu River basin region in Toyama prefecture in central Japan around the 1930s. However, it was not identified as a cadmium poisoning disease until the 1960s. A local physician, with cooperation from outside experts, confirmed that the disease was caused by pollution from the Kamioka mine (owned by the Mitsui Mining & Smelting Company Ltd) located in the upstream region of the river. In the mid-1960s, the victims of Itai-itai disease filed a suit against the company and won their case in 1972. The victims received compensation and signed a pollution control agreement with the company. The case of Itai-itai disease is a rare example of successful pollution control in Japan: the annual inspections of the ensuing 40 yr, based on the pollution control agreement, show a reduction of cadmium concentrations in the river to natural levels. By analyzing the roles of various experts involved, this case study has contributed substantially to an understanding of the nature of expertise and the significance of public participation in the resolution of environmental problems. 1The present publication is a revised and expanded version of papers in Japanese by Kaji (2005, 2009), published in English with permission of the copyright holder. KEY WORDS: Itai-itai disease · Pollution control · Cadmium · Public participation · Victims · Mining pollution Full text in pdf format PreviousNextCite this article as: Kaji M (2012) Role of experts and public participation in pollution control: the case of Itai-itai disease in Japan1. Ethics Sci Environ Polit 12:99-111. https://doi.org/10.3354/esep00126 Export citation Mail this link - Contents Mailing Lists - RSS Facebook - Tweet - linkedIn Cited by Published in ESEP Vol. 12, No. 2. Online publication date: July 06, 2012 Print ISSN: 1863-5415; Online ISSN: 1611-8014 Copyright © 2012 Inter-Research.

Fracture toughness of Al 2O 3 fibers with an artificial notch introduced by a focused-ion-beam

The present work was carried out to estimate the fracture toughness of two types of Al 2O 3 fibers (85Al 2O 3–15SiO 2, Altex ® (Sumitomo Chemical Co., Ltd) and α-Al 2O 3, Almax ® (Mitsui Mining Co., Ltd)) and to elucidate the transition from the intrinsic defects-induced fracture to introduced notch-induced one. With an application of the focused-ion (Ga +)-beam micromachining method, a mode I type straight-fronted edge notch with a notch-tip radius around 25 nm was introduced in fiber specimen. The fracture toughness K Ic was estimated for each fiber specimen based on the fracture mechanical approach in which the measured values of notch depth, fiber diameter, fracture strength and calculated correction factor were substituted. The fracture toughness values of the 85Al 2O 3–15SiO 2 and α-Al 2O 3 fibers were estimated to be 1.86 ± 0.24 and 2.05 ± 0.13 MPa m 1/2, respectively. The fracture toughness value was almost independent of the fiber diameter and notch depth in both fibers tested. From the obtained fracture toughness value and the measured fracture strength of the original fiber, the notch depth at the transition from intrinsic defects-induced fracture to notch-induced one, corresponding to the equivalent size of the intrinsic defects that determines the strength of the original fiber, were estimated to be 0.3 and 0.8 μm for 85Al 2O 3–15SiO 2 and α-Al 2O 3 fibers, respectively.

Mitsui Mining to manufacture auto-cats in India

Land Readjustment (LR) is a land development technique used in many countries around the world including Germany, Sweden, Japan, Taiwan and Korea. In essence it is a method whereby an irregular pattern of agricultural land holdings is re-arranged into regular building plots and equipped with basic urban infrastructure such as roads and drains. A percentage of each landowner’s holding is contributed to provide land for roads and parks, and for some plots to sell to pay the costs of the project. Its use has been particularly widespread in Japan where it is responsible for some 30% of the existing urban area, and is commonly referred to as ‘The Mother of City Planning’ (Toshi Keikaku no Haha). LR has for 20 years also been the focus of an international effort to introduce the technique to the developing countries of South East Asia. Although there is now a large literature on Japanese LR as a result of that project, however, virtually all of that literature focusses on practical aspects of how to implement projects, and on case studies of individual projects. Little attention has been paid to the role of LR in Japanese urban growth and urban planning at a city or regional scale, although such an examination is necessary to understanding LR in Japan, and Japanese urbanisation and urban planning more generally. The present research examines the role of LR in shaping patterns of urban development in the rapidly growing northern suburbs of Tokyo in Saitama prefecture. In particular, the claim commonly made by Japanese writers that LR prevents urban sprawl is examined. Sprawl and its prevention have long been a preoccupation of both Western and Japanese urban planners for aesthetic and efficiency reasons. However, it has recently gained importance as the critical interconnections between urban form and urban travel patterns, and greenhouse gas emissions and global warming have become more widely recognised. The case studies examine the role of LR in land development and urban growth at the regional scale (Saitama prefecture) and at the local scale (Urawa, Omiya and Ageo cities). GIS mapping and analysis of the case study areas, and interviews with planners and participants are used to examine the role and impacts of LR projects in suburban land development in Japan. The research suggests that while there are various impacts of LR projects because they are so widely used, in a range of different contexts, it is fair to say that LR projects contribute to increased sprawl at the regional scale, while largely failing to prevent it at the local scale.

Dynamic recrystallization behavior during compressive deformation in Mg–Al–Ca–RE alloy

Mg alloys have a high potential for reduction in CO2 emission because of their high specific strength and stiffness [1]. For more applications of Mg alloys, it is desirable to improve creep resistance because Mg alloys often show poor creep resistance. It has been reported that Mg alloys containing Ca showed high creep resistance and elevated temperature strength [2, 3]. Recently, Bohlen et al. [4] suggested that dynamic recrystallization (DRX) occurred due to particle-stimulated nucleation (PSN). Recrystallization due to PSN tends to occur in metals containing large-sized particles more than 1 lm [5]. Insoluble second phases such as Al2Ca and Mg2Ca are present in Mg–Al–Ca system alloys, so that DRX is expected to be enhanced due to the PSN mechanism in Mg–Al–Ca system alloys. Several studies [6–8] showed that DRX occurs during hot deformation in Mg–Al–Ca system alloys. However, DRX in Mg–Ca alloys has not been understood sufficiently. In the present paper, compression tests are conducted on Mg–6Al–2Ca–2RE (in mass%) alloy at 523–573 K with 10–1 s and its DRX behavior is investigated. A Mg–6Al–2Ca–2RE (in mass%) alloy ingot was prepared by die-casting (Mitsui Mining & Smelting Co., Ltd.). The chemical composition of the alloy is listed in Table 1. Annealing was carried out at 683 K for 108 h for homogenization. Microstructure of the annealed alloy is shown in Fig. 1. The grain size of the alloy was approximately 20 lm. The second-phase particles were observed at the grain boundaries. Energy-dispersive X-ray spectroscopy in a transmission electron microscope showed that the precipitates were (Al, Ca, RE) compounds. The cylindrical specimens with 10-mm diameter and 12-mm height were cut from the ingot after homogenization. Compression tests were carried out at 523 and 573 K with constant true strain rates of 10–1 s. Microstructure of the specimens after the compression tests was observed with an optical microscope. It took less than 5 seconds for the specimens to cool off to room temperature after stopping the test. The grain size was measured by the line intercept method (d = 1.74L, where d and L are the grain size and the line intercept length, respectively). Microstructures of the specimens deforming to e = 1.6 at 573 K with 10 1 s are shown in Fig. 2. DRX was completed throughout the specimen and the grains were almost equiaxed in these specimens. The average grain sizes were 8.8, 6.7, 7.1, and 7.1 lm at the true strain rates of 10, 10, 10, and 1 s, respectively. In Mg–Zn– Y–Zr alloy [9], the DRX grain size depended on the strain rate. In the Mg–Al–Ca–RE alloy, however, effect of strain rate on the DRX grain size was small. It appears that the distribution and size of the particles did not depend on the strain rate. Microstructure of the specimen deforming to e = 1.6 at 523 K with 10 s is shown in Fig. 3. DRX occurred at 523 K as well as 573 K, but non-recrystallized regions were partially observed at 523 K. The grain size of the recrystallized regions was 5.5 lm, which was a little lower than the grain sizes at 573 K. Some studies [10, 11] showed that the DRX grain size of Mg alloys is governed by the Z-parameter (=_ eexp(Q/RT)), where _ e is the strain rate, Q is the activation energy for M. Hakamada (&) A. Watazu N. Saito Materials Research Institute for Sustainable Development, National Institute of Advanced Industrial Science and Technology, 2266-98 Anagahora, Shimo-shidami, Moriyama-ku, Nagoya 463-8560, Japan e-mail: masataka-hakamada@aist.go.jp

非鉄金属製錬プロセスと操業 神岡鉱業（株）における亜鉛・鉛製錬

Kamioka Mining and Smelting Co., Ltd. became independent of Mitsui Mining and Smelting Co., Ltd. in 1986. Kamioka’s metallurgical operation consists of zinc electrolytic winning, lead smelting and lead electrolytic refining. The company’s main products are electrolytic zinc, electrolytic lead, zinc alloy, silver, cadmium, bismuth and sulfuric acid. Our metallurgical operation developed together with the mining operation at Kamioka mine, but the raw materials at zinc plant and lead plant were changed due to the reducing of the mine products. The new technologies that we developed to change the raw materials and the power that is supplied from the hydropower plants are our advantages. We will make effort to survive in Japan with these advantages.

非鉄金属製錬技術を活用した溶融飛灰処理技術の開発

The Metal Mining Agency of Japan has carried out a four-year Technical Development project on Disposal Free Treatment of Secondary Fly Ashes from Municipal Waste Incineration. We have attempted to apply the MF (Mitsui-type blast Furnace) process, which is employed to treat electric arc furnace dust, to recover heavy metals contained in the fly ashes along with decomposing dioxins to produce a slag which could be used for cement production. The main results of our experiments are as follows;1) Approximately 90% of heavy metals (mainly zinc and lead) contained in the secondary fly ashes can be recovered as raw materials, thereby contributing to non-ferrous metals production,2) The slag generated from the secondary fly ash treatment using the MF process can be used as a raw material for cement production, thereby utilizing decontamination technology without landfill,3) Two stages of alkaline washing will be needed to avoid equipment erosion caused by chlorine contained in the fly ashes, and4) The ratio of decomposition of dioxins is above 99%.Since 2003, based on the results of this project, Miike Smelter Co., Ltd., subsidiary of Mitsui Mining & Smelting Co., Ltd. has been treating fly ashes from municipal waste incineration at the MF plant in Omuta city, Fukuoka prefecture, Japan.

Mitsui Mining &amp; Smelting expanding mc catalysts

Mitsui Mining &amp; Smelting expanding mc catalysts

On Stock Investment of Aso &amp; Co. after Transferring Hondo and Fujitana Coal Mine to Mitsui Mining Company (1907-1919)

On Stock Investment of Aso &amp; Co. after Transferring Hondo and Fujitana Coal Mine to Mitsui Mining Company (1907-1919)

The reduction of gas phase air toxics from combustion and incineration sources using the MET–Mitsui–BF activated coke process

The dry desulfurization, denitrification and air toxics removal process using activated coke (AC) was originally researched and developed during the 1960s by Bergbau Forschung (BF) [Knoblaugh, E. Richter, H. Juntgen, Application of active coke in processes of SO x and NO x removal from flue gases, Fuel 60, September 1981, p. 832.], now called Deutsche Montan Technologies. Mitsui Mining (MMC) signed a licensing agreement with BF in 1982 to investigate, test and adapt the system to facilities in Japan. Japanese regulations are stricter than in the United States toward SO x /NO x pollutants, as well as flyash emissions from the utility industry, oil refineries and other industries. This process is installed on four coal-fired boilers and Fluidized Catalytic Cracker (FCC) units. These plants were constructed by MMC in Japan and Uhde in Germany. Two additional plants on a utility boiler and cement kiln are scheduled to start operation in 1999 and 2000. MMC provided design, equipment supply and installation. Marsulex Environmental Technologies (MET) formerly General Electric Environmental Services (GEESI) signed a license agreement in 1992 with MMC and Mitsui of Tokyo. Under this agreement, MET will market, design, fabricate and install the Mitsui–BF process for flue gas cleaning applications in North America. MMC also developed a technology to produce AC used in the dry DeSO x /DeNO x /Air Toxics removal process based on their own metallurgical coke manufacturing technology. This paper provides information on the details of MMC's AC used in the dry DeSO x /DeNO x /Air Toxics removal process and of the DeSO x /DeNO x /Air Toxics removal process itself.

第一次大戦後の北海道石炭業と三井財閥

The purpose of this paper is to analyze the development of Mitsui Zaibatsu's affiliated companies in the coal-mining industry in Hokkaido after World War I, and intercompany relations between the direct-line companies, Mitsui Bussan Kaisha and Mitsui Mining Company, and the collateral-line company, Hokkaido Coal & Steamship Company (HCSC).In the 1910s, Mitsui Zaibatsu entered the Hokkaido coal-mining industry since it controlled HCSC. In order to sell coal, these three companies (HCSC, Mitsui Bussan Kaisha, and Mitsui Mining Company) established a common sales organization named Sansha Baitanbu. At first, HCSC could not sell and transport the coal by itself, and Mitsui Bussan interfered in these duties because direct-line companies were concerned that HCSC would withdraw from Mitsui Zaibatsu. In the latter half of the 1910s, however, Mitsui Mining increased holding stocks in HCSC, and direct-line companies sent staff to the executive board and middle management of HCSC, thus giving Mitsui Zaibatsu stronger control over HCSC than before. Consequently, the concerns about HCSC decreased, and at the same time HCSC was able to carry out its duties autonomously.In the 1920s, when Sekitan Kogyo Rengokai tried to control the shipment of the coal, both HCSC and Mitsui Mining increased their market shares. Mitsui Mining increased its production because it actively invested its capital and often exceeded the quantity stipulated by Sekitan Kogyo Rengokai. On the other hand, HCSC almost always kept within the stipulated quantity, and Mitsui Zaibatsu regulated its capital investment. Its gradual growth of production controlled the shipment of the coal in Hokkaido and had supported the growth of Mitsui Mining in Hokkaido.Thus, HCSC was located within Mitsui Zaibatsu in the 1920s, though some restrictions still remained, and the relationship between HCSC and Mitsui Mining became more meaningful.

Itai-Itai disease and the countermeasures against cadmium pollution by the Kamioka mine

The Itai-Itai disease case is one of four major pollution-related lawsuits occurring in Japan after World War II. This paper, which is based on investigations of the pollution source, the Kamioka mine, considers (1) the history of the disturbances to the environment caused by the Kamioka mine; (2) the Itai-Itai disease suit; (3) the pollution-prevention measures and methods of the Kamioka mine and refinery; (4) the reduction of cadmium pollution in the Jinzu River; and (5) the actual application of the “polluter pays principle”. The authors conclude that the court decision and the agreements between the victims and Mitsui Mining made it possible to control and reduce the damage caused by cadmium pollution and four additional, contributory factors.

石炭技術 ウンバルート炭鉱の躍進

Embalut Coal Mine is located in the north of Samarinda City, East Kalimantan, Indonesia. The mine started coal production in 1983. Coal production consists of U/G and O/P. 5 longwall panels are working in 3 underground pits, and coal is transported to the surface using mine cars by winders, then is carried about 6 km by dump trucks to the washing plant whichi is located at the east riverside of Mahakam River. An adequate quality coal for market is made by mixing the high caloric coal from U/Gwith low caloric coal from O/C at the washing plant. Clean coal is shipped to barges (2, 500～8, 000) by the loading facility (500 tons/hr), coal for domestic users is derectly carried to destination by barge and coal for export istransshipped to adepot ship on the opensea or Balikpapan Coal Terminal. Mitsui Mining Engineering Co., Ltd., had dispatced 3 engineers as mine managers and 4 engineers as vice mine managers from 1990 to 1997, and after that Indonesian mine manager has been engaged in. The improvements of the mine furing our stay in the mine were made by as follows; (1) introduction of retreat longwall mining system using hydraulic props & link bars, (2) introduction of endlesse wired transportation system at a each level road. At some extraction panels where wood have to be used, room & pillar system shich was using a traditional wooden props was replaced by a longwall system using combination of relatively strong and weak wooden chock at the early stage, but finally all the panels were improved to hydraulic props & link bars system. Furthermore, for the purpose of smooth mine car transpotation, the road maintenance system was improved. The results of those improvements of the mine, mining recovery ratio increased drastically, and the double level of U/G production has been reached compared with the period before under control of Mitui Mining Engineering

Neutron-irradiation effect on the mechanical properties of alumina fiber

This paper describes the neutron irradiation effects on the deterioration of alumina fiber (made by Mitsui Mining Material, Almax), a typical electrical insulation material. The material was irradiated at the research reactor at Kyoto University Research Reactor Institute with a maximum fluence of 5.6×10 23 n/m 2 (energy: E>0.1 MeV). Tensile strength and tensile modulus of the specimen scarcely changed. Observation with a scanning electron microscope (SEM) and a transmission electron microscope (TEM) did not indicate any changes in crystal or pore structure. However, the Weibull coefficient of tensile strength decreased as the irradiation dose increased. This suggests an increase in the defect size distribution.

97/03710 Operation of a CWM relay station in the CWM chain from China to Japanese users

Yanri CWM Co., Ltd. was established in 1990 as a joint venture company between Yanzhou Coal Mines Bureau (Shandong, China), Nissho Iwai Corporation of Japan and JGC Corporation (JGC) and thus, CWM manufactured in China began to be exported to Japanese users in 1992. Meanwhile, CWM West Japan Co., Ltd. was established in 1991 as a joint venture between Nissho Iwai, Mitsui Mining Co., JGC and Tsurumi Yuso Co., as a relay station to deliver CWM manufactured in China to Japanese users. This joint venture company constructed a 10,000-kl dome-roof CWM storage tank in Hibiki, Kita-Kyushu City and started the reception, storage and transshipment of CWM in March 1992. So far, there have been only two Japanese CWM users, that is, Tayca Corp. and the Mizushima Power Station of The Chugoku Electric Power Co., Ltd. which has been in operation since February 1995. CWM West Japan has to date suffered no trouble in the delivery of products to its users, thus functioning perfectly as a relay station.

電池材料の開発とその事業化

Since Leclanche invented the dry battery with manganese dioxide and zinc as active materials, batteries have yielded revolutionary improvement with the growth of industry. Today, the production of the chemical batteries in Japan has reached 6 billion units, corresponding to 656 billion in sale. Most recent remarkable development of electronic devices has made appliances cordless and small-sized so that high performance batteries have attracted growing interest as small size and high energy density. Nowaday, batteries have been recognized as one of three key devices in electronic industry. We, Mitsui Mining & Smelting Co., Ltd. started the commercial production of electrolytic manganese dioxide in 1949 and has produced variety of key materials for batteries, i. e., zinc alloy powders, lead alloys, cadmium oxide, lithium foils and hydrogen storage alloys. In this paper, high quality of electrolytic manganese dioxide and mercury-free zinc alloy powders will be introduced and Research Development activities for battery materials in Mitsui Mining & Smelting Co., Ltd. will be outlined as well.

三池炭鉱―技術の足跡

It has been described that coal was discovered at Miike, Japan in 1465.In Edo era, Miike mine had been operated systematically for 150 years.A westernized mining technology was introduced by the British in 1878. Mitsui Mining Company Limited succeeded the operation in 1889 and has continued it up to the present.In spite of huge amount of coal resources and thick seam, Miike mine had been trou-bled with a gush of water and faced with a severe condition of the mining under the bot-tom of the sea since 1910. However, Miike mine has defeated these disadvantages with the constant efforts and the employment of new technologies, and has built up the pre-sent status accumulating the valuable experiences.Miike mine has played an important roll of a leader in mining industries and has contributed to the society. Unfortunately, Miike mine has at last come to an end of the roll in 1997 for economical reason. In the history of 110 years, Mitsui mining company produced and supplied over 289 million tons of coal. Now we have a duty to look back the course Miike mine and Mitsui mining company have followed and achieved.

Neodymium iron boride compound prepared by mechanical alloying : T. Harada et al. (Mitsui Mining and Smelting Co, Ageo, Japan ). J. Japan Soc. PowderPowder Metall., vol 41, no 5. 1994, 554–559. (In Japanese.)

Neodymium iron boride compound prepared by mechanical alloying : T. Harada et al. (Mitsui Mining and Smelting Co, Ageo, Japan ). J. Japan Soc. PowderPowder Metall., vol 41, no 5. 1994, 554–559. (In Japanese.)