著者

覺本 真代 坂本 靖英 宮崎 晋行 青木 一男 瀧口 晃 安井 彩 森 二郎

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.9, pp.117-130, 2018-09-30 (Released:2018-09-12)

参考文献数

37

---

Depressurization process is regarded as the most effective process for gas recovery method from the viewpoints of gas productivity and economic efficiency among in-situ dissociation processes of Methane Hydrate (MH) existing in marine sediments. However, it is supposed that consolidation and deformation of the stratum occurs due to MH dissociation and increase of effective stress in the stratum during operation of depressurization. Consolidation and deformation wreak negative friction on the production well. As a result, the production well may suffer large compressive or tensile stress. In the worst case, it may cause shear failure, tension failure and crushing. Therefore, in order to improve the accuracy for evaluation of stress distribution occurring on production well during depressurization, it is necessary to construct the numerical model enable to reproduce unsteady change of the relationship between shear stress and strain occurring on the contact surface between well and layer and introduce into geo-mechanical simulator. In this study, targeting three contact surface locating above depressurization interval such as 1) casing-cement, 2) casing-layer and 3) cement-layer consisting of different material, we conducted push-out test in laboratory in order to evaluate the frictional behavior at these contact surface based on the relationship between displacement and axial load. From experimental observation, it was found that shear stress occurring on the contact surface linearly increased at the initial stage in the case of steel-cement specimen. On the other hand, for specimens consisting steel-clay and cement-clay, non-linear increase of shear stress was confirmed in the process leading to the shear strength. In addition, shear strength τmax for each contact surface increased depending on effective stress σ ', effective friction angle δ' and effective cohesion c' as failure criteria was estimated based on τmax and σ '. Then, constitutive equation of variable compliance type was applied for reproduction of the relationship between displacement and shear stress observed in a series of push-out test. Through numerical simulation by introduction of this constitutive equation, we confirmed the validity of modeling of the frictional behavior.

著者

船津 貴弘 平島 美和 笹木 圭子

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.8, pp.110-116, 2018-08-31 (Released:2018-08-28)

参考文献数

2

---

An Advanced Graduate Program in Global Strategy for Green Asia (GA) is a component project of the "Program for Leading Graduate Schools" which is supported by the Japan Society for the Promotion of Science (JSPS) and started in 2013. The concept of a “Green Asia” is a bold ideal. Some of the most challenging global environmental conditions now exist in Asia. Many developing countries face the difficult task of raising millions of citizens from poverty. Consequently, environmental concerns are often overlooked. The key to this complex issue is scientific innovation and a transfer of knowledge from technologically advanced to less advanced nations. This educational program aims to cultivate leaders in science and technology who are able to contribute to the realization of an Asia where ecology and economic growth can coexist. Only 20 exceptional students including 10 Japanese and 10 international are allowed to enroll in the GA program each year. This elite group are taught in a bespoke educational environment, also benefitting from the vast collective resources and shared facilities of KU. The students are offered a financial support in order attract the premium candidates and to maximize the available study time by avoiding the need for part time jobs. The students of the Green Asia Education Program follow a stage gate system. This system comprises of six stages, Research Laboratory Rotation, Practice School, Coursework, International Seminar, Internship and the Green Asia Seminar. All activities described above are carried out in English in order to educate international and multicultural sense. Through these program, the students acquire five abilities, which are research, global perspective, leadership, practice and system landscape. In addition, applied skills such as expansion, analysis and upstream thinking skill are also trained by various activities, especially, practice school and international internship. As first batch students had finished this program in March 2017, we introduce the GA program and how the program is managed and carried out in order to make this program better.

著者

高野 雅俊 浅野 聡

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.8, pp.105-109, 2018-08-31 (Released:2018-08-22)

参考文献数

12

---

Gallium is used as a raw material for a CIGS solar cell. In the manufacturing process of CIGS solar cells, only 30% of the target material is used, and the rest is not used and becomes a spent target scrap. In order to recover gallium from spent target scrap, we investigated the process composed of hydrometallurgical treatment only which does not require pyrometallurgical treatment. We describe the details of the developed process in this report.

著者

児玉 淳一 立川 多久登 中 良介 濱中 晃弘 板倉 賢一 出口 剛太 福田 大祐 藤井 義明

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.7, pp.91-98, 2018-07-31 (Released:2018-07-31)

参考文献数

24

---

Small-scale underground coal gasification (UCG) model tests with a linking hole were carried out using two types of specimens made of either block coal or crushed coal to clarify their characteristics of combustion and gasification. Many similar characteristics were found between both specimens in terms of temperature change and its spatial distribution as well as concentration and heating value of each gas product as long as the crushed coal specimen was sufficiently consolidated. The shape and dimension of the cavity formed in the both specimens were also similar. Texture of the both specimens was changed after the combustion and gasification. Initiation of radial cracks from the linking hole was found in the both specimens. Within the zone with the radial cracks initiation, grains in the crushed coal were bonded whereas cleats in the block coal were healed. The grain bonding and the cleavage healing can be explained by melting and expansion of coal due to temperature increase. The radial cracks are likely initiated after the grain bonding or the cleavage healing due to tensile thermal stress induced by temperature gradient in the coal specimens. It can be concluded that the characteristics of combustion and gasification of the crushed coal and the block coal are similar because both types of coals become similar in texture through combustion and gasification. These results indicate that characteristics of combustion and gasification of coal seam can be mostly estimated from a model test with artificial coal seam made of crushed coal.

著者

濵中 晃弘 蘇 発強 板倉 賢一 髙橋 一弘 佐藤 孝紀 児玉 淳一 出口 剛太

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.7, pp.81-90, 2018-07-31 (Released:2018-07-31)

参考文献数

24

---

Underground coal gasification (UCG), a technique used to recover coal energy by the in-situ conversion of coal into gaseous products, enables recovery of coal energy from the potential coal resources abandoned under the ground for either technical or economic reasons. However, it might be difficult to adopt conventional UCG systems in Japan because of geological conditions that are complicated by the existence of faults and folds. Additionally, it is difficult to control the combustion/gasification area during UCG process because the process is invisible. Therefore, a co-axial UCG system that is compact, safe, and flexible to adopt is suggested with monitoring system by means of acoustic emission as an alternative UCG system. This UCG system has superiority in terms of applicability compared to the conventional one, but the recovered energy from the coal is relatively low because the gasification area in a co-axial system is limited around a well. In order to develop co-axial UCG system with high efficiency, the model UCG experiment with a large-scale simulated coal seam were conducted. It has been shown that 1) the gasification period can be extended by adopting proper oxygen inflow, 2) it is possible to control the combustion/gasification area and the product gas quality by controlling the position of oxygen inflow, 3) acoustic emission monitoring is an effective technique to evaluate the combustion/gasification area.

著者

矢岡 隆 西嶋 章

出版者

The Mining and Materials Processing Institute of Japan

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.123, no.12, pp.657-660, 2007-12-25 (Released:2010-12-17)

参考文献数

2

被引用文献数

1

---

Hikoshima Smelting Co., Ltd. is located at the western end of Honsyu. The plant switched from a horizontal retort process to an electrolytic zinc process in 1970. Hikoshima Co., Ltd. had made various improvements to reduce the operating costs about roasting, leaching, purification, electrolysis, casting, labor-saving and so on. In addition, the annual capacity extended from 55,000 tons to 74,000 tons during several expansion stages.Main products are zinc alloys for hot galvanizing and zinc anodes for plating.This paper describes these recent improvements and operations.

著者

山口 梅太郎

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.6, pp.67-73, 2018-06-30 (Released:2018-06-30)

参考文献数

14

---

The Chichibu region located in Saitama Prefecture is a limestone mining area. Mt. Buko limestone deposit is located in the Chichibu region and is being collaboratively mined by Chichibu Taiheiyo Cement, Ryoko Lime Industry, and Buko Mining companies by bench-cut from the top of Mt. Buko. Since the start of mining from the top, Mt. Buko has produced about 260 million tonnes of limestone until the end of March 2017 and a large rock slope (over 400 m high, about 2 km wide, and with overall inclination of 45°) has formed. Currently, managing the stability of the rock slope is considered the most important and critical issue at Mt. Buko. The Task Group for Research on Rock Slope in Chichibu Area (Chichibu Zanken) was established before the start of the cooperative mining at Mt. Buko. The Chichibu Zanken is composed of engineers (especially younger engineers) from the three companies and its first meeting was held in November 1973. In the 45 years since then, the Chichibu Zanken has continued to meet and has held a total of 450 meetings. In the beginning, activities of the Chichibu Zanken were more fundamental, focusing on collecting information on slope stability and studying to design a stable rock slope. Since around 1994, monitoring and analysis of slope behaviors have actively intensified. After the typhoon in September 2007, a significant but short-term slope displacement was detected. From analysis of current and previous data, it was found that the rock slope was affected by heavy rainfall. Therefore, slope drainage, pavement to suppress water permeation, steel pipe piling, retailing rock piling on the rock slope, and their effects on slope stability are important discussion subjects for the Chichibu Zanken. Mining of Mt. Buko is ongoing and making the slope to extend further. The Chichibu Zanken is set to play a key role based on accumulated knowledge and cooperation to solve future unforeseen problems.

著者

永井 燈文 柴田 悦郎 中村 崇

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.129, no.12, pp.694-700, 2014-12-01 (Released:2014-12-01)

参考文献数

19

被引用文献数

2 2

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Platinum group metals(PGMs), such as rhodium(Rh) and ruthenium(Ru), are rare and unevenly distributed in the earth's crust. They are used in automobile catalytic converters and electronic equipment. The consumption of such rare resources is unsustainable; therefore, recycling technologies are needed. In this paper, the chemical properties and separation/recovery of Rh and Ru, and PGM smelting/refining technologies are reviewed. In PGM refining processes, Rh and Ru are converted into chloride complexes. To effectively separate each metal, operating conditions of the reaction have to be optimized. The valences of PGM chloro-complexes change with redox potential, and the distributions between chloro- and aquo- complexes vary with chloride ion concentration. The Ru and Os oxides are separated by distillation.

著者

幾尾 憲伍 蒋 飛 辻 健

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.5, pp.60-66, 2018-05-31 (Released:2018-05-31)

参考文献数

18

被引用文献数

1

---

Hydraulic properties of fracture are directly related to shale-gas production, oil/gas reservoir and geothermal reservoir distribution. The permeable fracture could work as fluid pathway, but the fracture sealed by minerals (i.e. less permeable fracture) could work as seal in reservoir. Thus, hydraulic properties of the fracture are important in reservoir fluid managements. Because fracture typically has heterogeneous geometry, it is difficult to model the fracture using analytical approaches (e.g., rock physics model). Permeability of fracture is often measured by laboratory experiments, however few studies have focused on calculating permeability by using fluid flow simulation on digital fracture models. Here we used Lattice Boltzmann Method (LBM) to calculate the fluid behavior in 3D digitalized fracture models. The permeability derived from LBM simulation agrees with the laboratory-derived results. We used two natural fracture models: before and after shear deformation. We observed large-scale fluid flow network in the sheared model. We further observed permeability anisotropy for the sheared model, although the anisotropy was not clear in the non-sheared model. The permeability normal to shear direction is larger than that parallel to the shear direction. We then discussed the Representative Elementary Volume (REV) of the hydraulic properties of these fracture models. We extracted several subdomains (i.e., small fracture models) from the whole model and estimated permeability of the subdomains. When the size of subdomain is small, the values of estimated permeability widely vary by the location of subdomain. Convergence of the permeability data is found when the model size is close to the whole model. The REV of the sheared model is larger than that of the non-sheared model. Because the hydraulic properties of fracture models smaller than REV are largely influenced by local heterogeneity, the estimation of REV using the proposed method is important to calculate meaningful hydraulic properties.

著者

片岡 みなみ 羽柴 公博 福井 勝則

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.3, pp.41-45, 2018-03-31 (Released:2018-03-30)

参考文献数

27

被引用文献数

2

---

It is known that the rock strength increases with an increase in loading rate. Many studies on the loadingrate dependence of rock strength have been performed under two environments, namely water-saturated and airdried conditions, and the loading-rate dependence has not been investigated well under the conditions of various water saturations observed in situ rock masses. In addition, the quantitative relation between the loading-rate dependence and water saturation has not been examined. In this study, the uniaxial compression test of Sanjome andesite under various water saturations was carried out and the dependence of the strength on the loading rate and water saturation was investigated. The test was performed with alternating two loading rates and the strength corresponding to each loading rate was determined from a single specimen. The test results show that the strength increase with a ten-fold increase in loading rate is almost the same under various water saturations and that the strength increases with a decrease in water saturation. Based on the test results, the theory to explain the dependence of the strength on the loading rate and water saturation was suggested. The variation in the strength was discussed to validate the theory.

著者

澤山 兼吾 土屋 範芳

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.3, pp.46-52, 2018-03-31 (Released:2018-03-30)

参考文献数

21

被引用文献数

2

---

Environmental impact assessment was conducted at the Ohitachi Mine (Cu-Zn-Pb) located in Odate, Akita Prefecture, Japan. Zn concentration in river water exceeded the environmental standard (30 µg/L) even in the downstream of the Mine. Here, treatment facility for acid mine drainage had already constructed, however, the capacity of the facility was not enough to protect the environmental standard of Zn in the downstream. We calculated Zn load (mg/s) and concentration of Zn (µg/L) in individual watershed along the mainstream and branches. Several watersheds which emitted high concentration of Zn were recognized in the mining area. Particularly, discharge of Zn along the mainstream and watershed which includes open adit shows strong effects to concentration and load of Zn in river water. Based on concentration of Zn in river water and flow rate, we calculated mass balance of Zn load between sampling points. In order to protect environmental standard of Zn (30 µg/L) around village in downstream, we have to reduce 4.22 mg/s of Zn load. In that case, we have to reduce discharge of Zn along the mainstream and from open adit in the mining area. Based on the load and concentration of Zn in individual watershed around the mining area, quantitative evaluation is possible to estimate environmental risks of heavy metals in the river water caused by abundant mine.

著者

畠山 信夫 清水 賀之 益山 忠

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.2, pp.31-40, 2018-02-01 (Released:2018-02-27)

参考文献数

33

被引用文献数

1

---

One of the authors has developed a numerical simulator of airlift pump to solve governing equations represented by the drift flux model. The solver is based on the finite volume method which is known as SIMPLER algorithm for numerical scheme. The calculated results using the simulator were comparatively in good agreement with experimental ones by Weber et al. and Saito et al., despite lack of appropriate correlations used in the constitutive equations. In this study, the simulator is improved by a recent study (Ishii and Hibiki, 2011) on the constitutive equations of the drift flux model in the gas-liquid two-phase flow. The effect of newly incorporated correlations versus original ones in the constitutive equations is studied on the lifting characteristics such as relation between inputting air and lifted water. Also, flow characteristics along axial direction of pipes are examined to compare numerical results with experimental ones over wide range of pipe diameter and pipe length. Furthermore, pressure losses are grasped from the standpoint of the pump head, the relation between various pressure losses and lifting characteristics is discussed.

著者

岩野 圭太 永江 純一 福井 勝則 羽柴 公博

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.2, pp.22-30, 2018-02-01 (Released:2018-02-27)

参考文献数

14

---

Because blasting is a quite efficient and economical excavation method, it has been widely applied to tunnel excavation especially in hard rock. However, this method is rarely used to the tunnel site close to residential houses due to its environmental impact such as vibration and noise. Nowadays, the advanced electronic detonator, which was widely used in overseas mine site, was introduced to the tunnel site in Japan. This electronic detonator with accurate delay time (=ignition time difference between consecutive holes) has a potential to mitigate blasting vibration. In the past, many studies to lower the blasting vibration had been conducted and in some of them, several ways of simulation were implemented and the relations between vibration mitigation and arrangement of delay time were proposed. In this study, based on the past achievement and blasting test the authors had carried out, the appropriate method to determine the optimum delay time was proposed. In the case of electronic detonator in which each hole has different ignition time, the methods using autocorrelation and frequency analysis were found to be good expectation of delay time to lower the vibration. Also, in the case of conventional electric detonator in which ignition time has dispersion, the relation between vibration and ignition time dispersion was calculated, and the proper way to lower the vibration was proposed. This study gives practical method to set appropriate ignition time to lower blasting vibration.

著者

中村 謙吾 桑谷 立 駒井 武 山崎 慎一

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.2, pp.13-21, 2018-02-01 (Released:2018-02-15)

参考文献数

36

被引用文献数

4

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Understanding the geochemical characteristics of various soils is significant for revealing the mechanisms occurring under natural conditions, assessing the environmental risks and managing the land use. However these various soils have complex forming mechanisms. This study examined geochemical characteristics of surface soils using statistical analysis. Principal component analysis (PCA), a very commonly used multivariate technique that can extract hidden structures and patterns from high-dimensional data, was applied to 633 classified soil samples. Soil samples collected in the Miyagi and Ibaraki prefectures were analyzed for major elements (Si, Ti, Al, Fe, Mg, Mn, Ca, Na and K) and heavy metals (Cr, Cu, Zn, As and Pb). Major elements showed most distinctive relationships with an inverse correlation between Si and Ti, Fe and Al. Heavy metals did not exhibit clear correlations with each other. However, background concentrations could be estimated using the frequency distribution and log-normal distribution curves. The background concentration of Cr, Cu, Zn, As and Pb were 50 ~150 mg/kg, 75 ~150 mg/kg, 200 ~300 mg/kg, 25 ~50 mg/kg and 30 ~60 mg/kg, respectively. Results of PCA clarified four common factors controlling major elements and heavy metals in the soil samples. They are ‘Physicochemical formation', ‘Soil components',‘ Vegetation effect' and ‘Adsorption and desorption'. Soils are formed by leaching reactions from rain and groundwater and mixed organic matter from different vegetation types. Therefore, major elements and heavy metals in soil are affected by these processes, which are common to most soil types.

著者

覺本 真代 坂本 靖英 米田 純 片桐 淳 青木 一男 瀧口 晃 安井 彩 森 二郎

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.1, pp.1-12, 2018-01-25 (Released:2018-01-24)

参考文献数

38

被引用文献数

1

---

Depressurization process is regarded as the most effective process for gas recovery method from the viewpoints of gas productivity and economic efficiency among in-situ dissociation processes of Methane Hydrate (MH) existing in marine sediments. However, it is supposed that consolidation and deformation of the stratum occurs due to MH dissociation and increase of effective stress in the stratum during operation of depressurization. Consolidation and deformation wreak negative friction on the production well. As a result, the production well may suffer large compressive or tensile stress. In the worst case, it may cause shear failure, tension failure and crushing. Therefore, for optimization of gas production process by depressurization, it is necessary to perform numerical simulation in consideration of a series of phenomenon during MH dissociation in porous media and evaluate the effect of consolidation deformation of the stratum on MH production well. In this study, using the geo-mechanical simulator named as COTHMA developed under MH21 research consortium, we carried out the field-scale numerical simulation for prediction of deformation and stress distribution around production well during depressurization. On the basis of field data for the Eastern Nankai Trough area and the structure of production well for the methane hydrate first offshore production test in 2013, the detailed model for reservoir and production well was constructed. In addition, we conducted push-out test to evaluate the frictional behavior at the interface between screen-gravel pack as the different materials constituting production well and introduced into numerical model for COTHMA. From calculation results, it was found that Mises stress occurring on base pipe installed into the interval of depressurization reached 420 MPa as yield point of steel due to the effect of friction. However, the original shape was maintained because the occurred equivalent plastic strain was about 2.95 % and this strain value was much smaller than 21 % as failure criterion. Furthermore, the effect of interface between casing and cementing was not large. This result suggested that the well structure above the interval of depressurization acted as unit and the interfacial frictional behavior between well and layer was the dominant factor on deformation behavior and stress distribution of casing and cementing.

著者

花野 峰行

出版者

資源・素材学会

雑誌

Journal of MMIJ = 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:18816118)

巻号頁・発行日

vol.133, no.7, pp.214-222, 2017-07

著者

八木 俊介 池野 豪一 山田 幾也

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.133, no.11, pp.264-269, 2017-11-01 (Released:2017-11-30)

参考文献数

49

被引用文献数

3

---

In recent years, the electrochemical water splitting using renewable energy has attracted considerable attention for the production and utilization of hydrogen gas as a fuel. However, the high overpotential for the oxygen evolution reaction increases the electrical power expense and induces degradation of the electrode materials. In order to promote the oxygen evolution reaction by lowering the overpotential and suppressing the side reactions, noble metals and their alloys or oxides have been typically employed as catalysts. Nevertheless, alternative catalysts have been sought in recent years in view of the high cost and limited resources of noble metals. In this review, the recently developed oxygen evolution reaction catalysts are presented, and the requirements for the development of such highly active catalysts have also been discussed.

著者

渡 健太 金子 祐輔 大上 悟 大原 秀樹 竹田 賢二 中野 博昭

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.133, no.10, pp.250-255, 2017-10-01 (Released:2017-10-31)

参考文献数

17

被引用文献数

1

---

To elucidate the effect of solution composition on the passivation of anode in Cu electrorefining, the potentiodynamic polarization curves were measured by polarizing from -0.2 V versus NHE to 1.0 V using the potential sweep method at 1.0 mV·s−1. The diffusion coefficient was measured by rotating disc electrode method under the conditions of 50, 100, 150, 200, 250 and 300 revolutions per minute of disc electrode and polarizing from 0.34 V to -0.40 V at 10.0 mV·s−1. The critical current density for passivation and the passive current density decreased linearly with total concentration of SO4 in solution regardless of solution composition and the presence of impurities such as As3+,Sb3+ and Bi3+, showing the good correlation between the current density for passivation and the total concentration of SO4. The diffusion coefficient of Cu2+ ions decreased with total concentration of SO4 in solution. The increase in passivation with the total concentration of SO4 is attributed to both decreases in solubility of CuSO4 in electrolyte and the diffusion coefficient of Cu2+ ions. On the other hand, focusing on the effect of kinds of cation on the passivation, the harmful effect on the passivation was largest with Cu2+ ions, and was larger in the order with Li+,Ni2+ and Na+ ions, and was smallest with H+ ions. The diffusion coefficient of Cu2+ ions decreased most with Ni2+ ions, and decreased secondly with Li+ and Na+, and decreased least with H+ ions. The diffusion coefficient of Cu2+ ions decreased with increasing the viscosity of solution.

著者

井上 聡大 羅 武輝 森山 紗好 平島 剛 島田 英樹 笹木 圭子

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.133, no.10, pp.235-240, 2017-10-01 (Released:2017-10-14)

参考文献数

28

---

Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident produced much amount of radioactively contaminated water at the Great East Japan Earthquake. 137Cs and 90Sr have been focused to remove from the contaminated water using zeolite types of adsorbents. Other radionuclides have been treated and removed separately by Advanced Liquid Processing System (ALPS), where resin is used to immobilize anions. However, these kinds of spent-adsorbents are not suitable for long-terms burying because of its instability, and the representative anionic radionuclides (129I, 36Cl, 99mTc and 79Se) have quite long half-life (105-107 years). Montmorillonite (Mt) is an useful adsorbent because of its high chemical stability and large cationic exchange capacity. In the present work, surfactant modified Mt (OMt) has been developed using hexadecylpyridium chloride for adsorption of ClO4-, which is a surrogate of 99mTcO4-. For stabilization of spent-OMt, cement solidification was examined with varying the ratio of spent-OMt content. To evaluate its chemical and physical stability, soaking and compressive strength tests were conducted. As a result, it was revealed by FTIR and 29Si-NMR that with increase in OMt contents, the linkage of calcium silicate hydrate was more developed.

著者

羽柴 公博 福井 勝則 小泉 匡弘

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.133, no.9, pp.223-229, 2017-09-25 (Released:2017-09-27)

参考文献数

92

被引用文献数

2

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Rock drills were developed about two hundred years ago, and hydraulic percussion rock drills are about half-century old. Performance and efficiency of rock drills have been increased by a number of researchers and engineers. Percussion energy was dramatically increased with changing the power source from pneumatic to hydraulic pressures; rods and rod joints were improved to endure the high percussion energy; carbide button bits were developed for hard rock drilling. This paper reviewed the previous studies and future issues on the drilling processes with hydraulic percussion rock drills. Studies on the stress wave propagation in rods and rod joints were based on theoretical and graphical methods and recently on numerical simulation. Studies on the interaction between a button bit and rock included crack propagation in rock, force-penetration relationship during drilling, and bit wear. Studies on the factors affecting drilling efficiency and drilling rate made a transition from simple to precise numerical simulations. Finally, important future issues were presented for the further progress of hydraulic percussion rock drills.