著者

荒牧 憲隆 A.K.M. Badrul Alam 玉村 修司 上野 晃生 村上 拓馬 金子 勝比古

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.132, no.12, pp.190-198, 2016-12-01 (Released:2016-12-16)

参考文献数

23

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Recently, the possibility of realizing a subsurface bio-reactor has been realized since microbial methanogenesis has been confirmed in diverse subsurface environments such as coalbeds or petroleum reservoirs. We propose a new gasification method for use in subsurface environments, known as the Subsurface Cultivation and Gasification (SCG). SCG was devised based on the production of biogenic methane gas in subsurface environments. This approach employed hydrogen peroxide to decompose organic matter rapidly. Conversion of organic matter from source rocks into biomethane with the help of microorganisms is expected to be highly profitable. In this study, a series of batch tests using a hydrogen peroxide (H2O2) solution were performed on lignite to estimate the potential of low-molecular-weight organic acid production. The effects of several factors on the production of low-molecular-weight organic acids have been considered, such as, concentration of H2O2, temperature, liquid-solid ratio, and specific subsurface area of lignite. It was found that the quantity of low-molecular-weight organic acids depended on temperature, liquid-solid ratio, and specific subsurface area of lignite; however, there isn't a unique relationship between them and the H2O2 concentration. Moreover, the mass of lignite reduced remarkably when batch tests were performed with a high concentration of H2O2. If H2O2 is to be injected into a target seam with the SCG method, we should estimate the optimum H2O2 concentration to produce low-molecular-weight organic acids with taking into consideration the mechanical stability of the target seam as well as the subsurface environmental chemical reaction with a geological improvement.

著者

森 勇人 高橋 弘 加来 伸夫 西村 宏之

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.132, no.12, pp.182-189, 2016-12-01 (Released:2016-12-15)

参考文献数

14

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It is difficult to reuse the construction sludge directly because the water content of it is extremely high. Therefore, it has been disposed as industrial waste in the final disposal site. In order to reduce the construction cost and environmental load, the effective reuse of construction sludge has been an important problem. In order to increase the recycling rate of construction sludge and to solve the above mentioned problem, the authors have already developed a new recycling method for construction sludge by using paper debris and cement. As this method can improve the high water content sludge into high quality ground materials on sites, this method has already been utilized in over 400 construction sites in Japan.On the other hand, the biodegradation of fibrous materials is not made clear as yet. It is considered qualitatively that fibrous materials used in this method is hard to be biodegraded by soil microbes, because fibrous materials still remains in the soil which was improved by this method 10 years ago. However, the degradation by soil microbes is not confirmed quantitatively.Therefore, the biodegradability of fibrous materials was investigated experimentally through a culture test and a soil buried test. As a result, it was found that paper fragments were degraded in the solution of pH7.0, but were not degraded in the solution of pH9.5. Furthermore, it was confirmed through soil buried test that paper fragments buried in the normal mud were degraded significantly, but those buried in Fiber-Cement-Stabilized soils were not degraded and fibrous materials remained. Therefore, it was concluded that the fibrous materials in Fiber-Cement-Stabilized soil are not degraded by soil microbes when pH of Fiber-Cement-Stabilized soil is over 9.5, and they remains in the modified soils for a long time.

著者

濱井 昂弥 小寺 拓也 小林 幹男 増田 信行 酒田 剛

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.132, no.11, pp.175-181, 2016-11-01 (Released:2016-11-25)

参考文献数

17

被引用文献数

3

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In order to prevent the mine pollution caused by the acid mine drainage (AMD) from abandoned metal mines in Japan, the treatment of AMD has been conducted with neutralization using a significant number of reagents. Passive treatment processes are attractive as an alternative because of an energy and cost saving one. Although the passive treatment processes using sulfate-reducing bacteria (SRB) have been investigated widely in the United States and Europe, many of those processes require a huge area that is necessary for a long hydraulic retention time (HRT). So, in this research, the mechanism, influential factors and performance of metal removal using SRB have been investigated in the column test to develop it as a prospective, effective and compact process. The results showed that sulfate reduction by SRB had continued for 140 days under the condition of a 50-hour HRT, and that metals had been removed as sulfides in a column. In addition, it is apparent that the positions where each metal sulfide was precipitated were different. This means that the quality of AMD is an important factor when the treatment facility is designed.

著者

Le Trung TUYEN Nhu Viet TUAN 大賀 光太郎 井清 武弘

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.132, no.11, pp.167-174, 2016-11-01 (Released:2016-11-21)

参考文献数

13

被引用文献数

5

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無煙炭は自然発火し難いと一般的に言われてきたが,ベトナムの無煙炭炭鉱においては2004 年以降,幾つかの炭鉱において自然発火が多発するようになってきている。筆者等は,これら全ての自然発火事象の調査と対策に関わってきている。また,亜瀝青炭を採掘する一炭鉱における数回の自然発火事象についても調査を行った。本論文では無煙炭の自然発火の特性を中心に検討を行う。この中で,無煙炭の自然発火の指標ガスとして,瀝青炭などに見られる炭化水素系ガスは発生せず,一酸化炭素と水素の二種類のガスに限定されることを明らかにするとともに,自然発火防止の観点から現場の採掘条件の問題点などについても検討する。

著者

五十嵐 敏文 上田 貴宏 洞 秀幸 城 まゆみ 加藤 欣也 三代 雅崇 工藤 元

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.130, no.2_3, pp.60-64, 2014-02-01 (Released:2015-02-01)

参考文献数

11

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Horonobe Underground Research Center, located in northern Hokkaido, Japan, has been excavating shafts of underground research laboratory for R&D of radioactive waste disposal. In this site, the groundwater seepage from the shafts and leachate from the waste rock storage site contain high concentrations of total nitrogen. Ammoniumnitrogen, the major chemical species of nitrogen in the seepage and leachate, has been treated by the effluent treatment facility. However, the ammonium-nitrogen is transformed to nitrite- and nitrate-nitrogen (nitrification products) by nitrification. As a result, the concentrations of total nitrogen increase to the effluent guideline due to nitrification. Therefore, column experiments were carried out to understand the phenomena and the factors affecting the leaching behavior of nitrification products. The result showed that the nitrification was inhibited when the column layer was almost saturated, and that the nitrification occurred near the surface of waste rocks, in particular, at 25℃. These results indicate that nitrification can be mitigated by controlling the hydrological conditions in the waste rock storage site.

著者

SU Faqiang ITAKURA Ken-ichi DEGUCHI Gota OHGA Kotaro KAIHO Mamoru

出版者

資源・素材学会

雑誌

Journal of MMIJ : journal of the Mining and Materials Processing Institute of Japan (ISSN:18816118)

巻号頁・発行日

vol.131, pp.203-218, 2015

被引用文献数

14

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Cavity growth occurring with crack extension and coal consumption during UCG processes directly influences the gasification efficiency and the estimated subsidence and gas leakage to the surface. This report presents an evaluation of the gas energy recovery, coal consumption, and gasification cavity estimation using a proposed stoichiometric method to analyze the coal gasification reaction process. We defined the evaluation parameters of rate of energy recovery and investigated the effects of different parameters using UCG trials conducted with coal blocks and coal seams, adopting different Linking-hole methods and operational parameters. Analyses of results obtained from laboratory experiments and small-scale field trials using V-shaped and L-shaped linking holes, and Coaxial-hole UCG models show that the gasification of Linking-hole models yielded average calorific values of product gas as high as 10.26, 11.11 MJ/m3 (lab.), and 14.39 MJ/m3 (field.). In contrast, the Coaxial-hole models under experimental conditions yielded average calorific values of product gas as: 7.38, 4.70 MJ/m3 (lab.) and 6.66 MJ/m3 (field.). The cavity volume obtained with Coaxial models was about half of the volume obtained from Linking-hole models. Results obtained for these UCG systems show that the feed gas and linking-hole types can influence coal consumption and product gas energy. Fissure ratios were also investigated. Results confirmed major factors underpinning gasification efficiency. Linking-hole types strongly influenced the development of the oxidization surface and fracture cracks for subsequent combustion in the gasification zone. Estimated gas energy recovery results support experimental observations within an acceptable error range of about 10%. Moreover, this stoichiometric approach is simple and useful for evaluating the underground cavity during UCG. Based on these results, we proposed a definition of the energy recovery rate, combined with the obtained volumes of gasification cavities that provide a definition of energy recovery and UCG effects. UCGにおいては,炭層内のき裂進展に伴う燃焼空洞の拡大と石炭の消費が重要であり,これがガス化効率や安全性 (地盤沈下,ガス漏洩等) に大きく影響する。本研究では,ガス化効率,回収エネルギーとガス化空洞の評価方法として,化学量論および化学平衡に基づく評価手法を検討した。生成ガス組成と求めたガス化反応式から,石炭の消費量,ガス生産量等を推定する方法である。また,エネルギー回収率を定義し,UCG室内モデル実験及び露天炭鉱の炭層で行った小規模現場実験の結果を評価し,リンキングの方式や注入ガス等のパラメータがガス化効率やガス化空洞の成長に与える影響を検討した。リンキングの方式として,L字,V字,同軸型のUCG実験を行い,ガス化効率の違いと,その原因を明らかにした。すなわち,リンキング型と同軸型モデルを比較すると,リンキング型UCGモデルの方が発熱量が高く,平均発熱量では,前者が10.26/11.11 MJ/m3 (室内) ,14.39 MJ/m3 (現場) であった。一方,同軸型モデル試験では,7.38/4.70 MJ/m3 (室内) と6.66 MJ/m3 (現場) と低い値であった。実験後の空洞体積の直接評価結果でも,リンキング型の方がガス化領域が拡大していることを確認した。リンキング方式の方が,炭層内にき裂を連続的に進展させやすいためと考えられる。また,エネルギー回収率の評価では,実験前後の供試体質量差から求めたエネルギー回収率と比較検討を行った。その結果,両者の誤差は約10%で,検討した手法によりエネルギー回収率や燃焼ガス化領域の石炭消費量を推定できることがわかった。以上の結果より,検討した化学量論法よる回収エネルギー評価手法は簡便で,実用的であることが明らかになった。

著者

富山 眞吾 五十嵐 敏文 井伊 博行 髙野 日出男

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.132, no.5, pp.80-88, 2016-05-01 (Released:2016-05-14)

参考文献数

30

被引用文献数

6

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The understanding of source and flow path of the groundwater provides important strategy for the environmental management of mines. Thus, groundwater samples from the shaft and level in the Shimokawa mine and the surrounding river water samples were taken and the stable isotopes of hydrogen and oxygen and water quality of the samples were analyzed. The results indicate that shallow groundwater starts mainly from mountain-sides and passes through rocks above ore bodies. The simulation of groundwater flow was also conducted. The distribution of velocity vector of the simulated result showed that down streamlines which flows more than 2×10-3 m per day from mountain-sides to the ore bodies were observed. By considering the altitudes of mountain-sides range from 300 to 550 m, these results correspond well with the altitudes estimated from δD and δ18O values of samples.

著者

徐 維那 森本 慎一郎

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.132, no.4, pp.66-70, 2016-04-01 (Released:2016-04-29)

参考文献数

21

被引用文献数

3

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Cobalt tends to occur in the high risk regions of the world. Cobalt sources are typically concentrated in Congo, DRC, and there are concerns about supply security. Cobalt is used in the leading-edge industries including green technologies and aerospace industries. In terms of resource security, it is important to verify the domestic cobalt consumption trends. In order to resolve the domestic cobalt consumption trends in Japan in 2013, we tracked the cobalt consumption structure from material to end-uses by applying the bottom-up approach, and illustrated the recent domestic cobalt flow by using a substance flow analysis. Recent consumption in 2013 was driven primarily by the use of cobalt in Li ion batteries (7839 t) and nickel metal hydride batteries (1263 t). In total, 9413 t of cobalt was input to Japan in 2013. And also, we anticipated the future domestic cobalt demand up to 2020, based on the relationship between the historical consumption trends and GDP. It showed that cobalt demand would reach to 13162 t in 2020, that is, Li ion battery sector (11089 t) should hold the biggest demand in 2020, followed by NiMH battery sector (1004 t), carbide sector (320 t), magnet sector (360 t), etc.

著者

三宅 裕

出版者

The Mining and Materials Processing Institute of Japan

雑誌

Journal of MMIJ : journal of the Mining and Materials Processing Institute of Japan (ISSN:18816118)

巻号頁・発行日

vol.124, no.9, pp.554-561, 2008-09-25

被引用文献数

1

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The exploitation of copper in Ancient Western Asia has a long history. Already in the Neolithic period malachite was used as raw material for bead and pigment, and then native copper was shaped into small objects by hammering and annealing. Based on the evidence from copper objects and workshops found in Iran and Anatolia, smelting and casting were carried out in the 5<SUP>th</SUP> millennium B.C. In the early copper production it is likely that the oxide ores such as malachite were used as raw material which was smelted in the crucible set on the shallow pit furnace with the aid of blow pipes. The advent of alloy in the late 4<SUP>th</SUP> millennium B.C., another significant development in early metallurgy, might make casting easier and more successful. The first copper alloy was arsenical copper which continued to produce until the end of the Middle Bronze Age along with bronze, an alloy of copper and tin. By the second half of the 3<SUP>rd</SUP> millennium the copper production in the vicinity of the sources became prevailing. The Late Bronze Age shipwrecks in the Mediterranean provide good evidence for the long distance trade of copper and tin in the shape of ingot.

著者

名木 稔

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.123, no.12, pp.779-783, 2007-12-25 (Released:2010-12-17)

参考文献数

11

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In Japan, the domestic recycling system of the nonferrous metal is formed with two businesses. One is many collecting & sorting enterprises and processing & wholesale enterprises, which are usually small and medium-sized business. The other is nonferrous metal smelting & refining enterprises, which are usually big business. Recently legislative resource recycling system, which consists of Home Appliance Recycling Law, End-of-Life Vehicles Recycling Law, Law for Promotion of Effective Utilization of Resource and so on, has been also developed. But, in spite even in these circumstances, considerable amount of domestic occurrence scraps of copper has been exported to China, and a lot of used home appliances and used personal computers have been exported to foreign countries. Namely, it has become clear that the present resource recycling system could not circulate the resources sufficiently inside Japan.These problems were caused by rapidly increasing resource consumption of the world in these several years, which was originated by quick economic development of the Asian region, in especial in China. Tightness of worldwide resource demand has requested the advancement of creating new countermeasures and/or corresponding methods under the slogan of “conservation and effective utilization of resources” for a long time.This manuscript intoroduces these circumstances and suggested some solutions to the problems.

著者

田村 智樹 太田 光浩 児玉 淳一 吉田 豊

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.128, no.2, pp.65-71, 2012-01-25 (Released:2013-06-26)

参考文献数

14

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Recently, old narrow tunnels are reused by widening their sections for economic efficiency. New design concept will be required in their construction because excavation damaged zone (EDZ) might be already formed around old tunnels. Especially, estimation of EDZ extent is necessary for safe construction and stability assessment of a widening tunnel. In this study, EDZ around an old tunnel constructed in the Neogene soft rock seventy years ago was estimated based on P-wave velocity and observation of the face during widening. Deformation caused by widening the old tunnel was also measured. It was found that EDZ estimated by reduction in P-wave velocity was in good agreement with that estimated by observation of the face. It was also found that deformation of the widening tunnel was much less than that of either the old tunnel or a new tunnel constructed near the widening tunnel. In the widening tunnel, most of EDZ had been excavated and non-damaged zone outer side of the EDZ had been little excavated. It can be expected that deformation of a widening tunnel is little when the section size of that is almost equal to extent of EDZ.

著者

松木 浩二 狩野 祐一 坂口 清敏 木崎 彰久

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.126, no.12, pp.668-678, 2010-11-25 (Released:2011-11-25)

参考文献数

26

被引用文献数

1 1

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Using joint elements for a mechanical model of grain boundaries, we performed a preliminary 3D finite element analysis of uniaxial tensile fracture for specimen models of monomineral polycrystalline rock under the assumption that fracturing occurs only at the grain boundaries. The specimen models were created on a computer by the method previously proposed by the authors, and the constitutive law of the grain boundaries was derived by applying the associated flow rule in the plastic theory and a tension-shear-softening curve to an extended Coulomb criterion. Tensile fracturing initiates at grain boundaries with a small angle of the normal direction relative to the loading axis, which are followed by grain boundaries with a larger angle of the normal direction. Unloading of intergranular cracks occurs before the peak strength when the intergranular cracks do not compose the final failure plane that is completely formed near the inflection point of the axial stress-axial strain curve after the peak. During the completion of the final failure plane, the conversion of failure mode from tension to shear occurs at intergranular cracks that have a large angle of the normal direction relative to the loading axis. For these intergranular cracks, the axial displacement given at an end of the specimen is converted to a shear displacement, rather than an opening displacement, and the normal stress becomes to be compressive due to shear dilation. Furthermore, the number of tensile intergranular fracturing at the peak strength increases with a decrease in the constant α that characterizes the rate of decrease in the tensile strength in the tension-shear-softening curve of the grain boundaries, and as a result, the tensile strength of the rock specimen increases with a decrease in the constant α. However, the effect of the residual frictional coefficient is small and limited to the stage after the final failure plane is completely formed, since the residual friction coefficient affects the mechanical behavior of the grain boundaries only after the failure plane is completely formed.

著者

高階 浩二 中尾山 利行

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.751-753, 2007-12-25 (Released:2010-12-17)

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The Ikuno tin smelter has started its operation in 1913, followed by tin refinery in 1916. Originally, the reverberatory furnace had been used for smelting, but later it was replaced by the present electric furnace in order to improve productivity and increase tin recovery. The refinery was relocated from Ikuno to Osaka in 1920, and then again relocated to Naoshima in 1960.The present refinery in Ikuno has started operation in 1991. After Akenobe mine was closed in 1987 due to low tin price and its poor mining condition, domestic secondary materials from the market has been purchased and treated. At present, Ikuno plant is the only producer of electro-refining tin in Japan and 65t/month of electric-tin has been produced.