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

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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

---

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

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

---

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.

著者

花野 峰行

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.214-222, 2017-09-01 (Released:2017-09-08)

参考文献数

24

被引用文献数

1

---

The Matsukawa geothermal power station has been in commercial operation since 1966. Its geothermal reservoir was discovered by chance, by drilling of hot spring wells by the local administration in 1952. Japan Metals & Chemicals (JMC) noticed this phenomenon and started exploration for a geothermal power development in 1956. Then, JMC and Geological Survey of Japan (GSJ) started collaborative study in 1958. The biggest technical challenge for success in Matsukawa was a decision of drilling target depth for steam production and a casing shoe depth to stop in-flow of shallow cold water. It was examined through measurements of water levels in three exploration wells, borehole temperature profiles and flow rates of rivers. Geological and geophysical studies by GSJ helped this study. Owing to this study, the 1st production well succeeded to produce dry steam in 1964 and led to a success in the first commercial scale geothermal power development in Japan.

著者

佐々木 順悠 村上 進亮

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.8, pp.207-213, 2017-08-01 (Released:2017-08-31)

参考文献数

8

---

Mineral prices hit their ceilings and started fluctuating. It forced resource-related companies to reassess their assets. In order to secure the stable supply of resources, it is important for Japan, which is a resource-importing country, to keep an eye on the changes in strategies of resource-related companies, especially mining giants that dominate the global production of various minerals. There are some studies focusing only on risk management at an individual mine level and fluctuation in mineral prices, but few studies focus on asset management of the mining giants as an entity. The purpose of this paper is to analyze and understand the asset management strategies of the mining giants. All assets of the giants, such as mines, smelters and refineries are considered as risky assets, calculating the optimal portfolio under the “Modern Portfolio Theory”. By comparing the derived optimal portfolio with the actual one, we conclude that the mining giants' asset management strategies are almost optimal. We also found out which asset will be on sale from each company, which can be useful for Japanese companies increasing the share in overseas mines.

著者

早野 明 板倉 賢一

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ

巻号頁・発行日

vol.133, no.4, pp.76-86, 2017

---

<p>Fracture mapping conducted during gallery excavation on construction projects of a large-scale underground facility is based on traditional geological techniques such as visible observations and simple measurements of fracture orientation using a clinometer. Therefore, some difficulties persist, such as securing data quality and worker safety. Three-dimensional (3D) laser scanning, which can instantly acquire point clouds representing the 3D shape of an object surface, is can be effective for resolving these difficulties. In order to confirm the applicability of the three-dimensional laser scanning to the fracture mapping on a gallery wall, this study proposes the method for obtaining attribute information from a point cloud, such as trace length and orientation, associated with the spatial distribution of fractures. In the proposed method, the two-dimensional image is generated from the point cloud to obtain the trace map. After the proposed method was applied to an approximately 50-m-long horizontal gallery excavated into the granitic rock, the reproducibility of the attribute information of fractures obtained solely from the point cloud was examined. Results show that the number of fractures extracted from the point cloud is approximately 80% of those extracted by traditional geological techniques. Although the trace length reproducibility ratio of fractures is approximately 70%, fracture orientations calculated from the point cloud compare favorably with those measured by an on-site researcher. Most fractures that were not extracted from the point cloud do not act as water-conducting fractures because they had short lengths and because they were bonded tightly. Even if the fracture data obtained from the point cloud were applied to modelling for hydrogeological analysis, the results would probably not be influenced strongly. Results of this study indicate the possibility of applying 3D laser scanning to fracture mapping.</p>

著者

小林 幹男

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.133, no.8, pp.193-206, 2017-08-25 (Released:2017-08-26)

参考文献数

53

被引用文献数

4

---

Recently the treatment of mine drainage, especially acid mine drainage (AMD) is attracting a lot of attention, including the passive treatment that is a cost-effective and energy efficient process. In such a process, the natural geochemical reaction, gravitational flow, bacteria metabolism, etc, are utilized for the active treatment, enabling continuous addition of chemical reagents and maintenance of mechanical facilities, and so on. For a long time, the development of the passive treatment was mainly carried out in North America and Europa, thus, much useful knowledge is cultivated and many experimental and actual sites are operated in these area. In this paper, the useful knowledge, information and instances related to the passive treatment are reviewed. The performance of sulfate reducing bacteria (SRB) is very important for the treatment of the mine drainage from non-ferrous mine sites. Thus, the matters related with SRB, that is, the reaction, the reactor and the operation are also described in detail.

著者

高野 雅俊 尾崎 佳智 浅野 聡 馬場 雄三 久保田 富生子 後藤 雅宏

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.8, pp.188-192, 2017-08-25 (Released:2017-08-19)

参考文献数

9

---

Extraction behavior of cobalt from sulfate media containing excess manganese by mixtures LIX63 and several amines was investigated. The addition of amines shifted cobalt extraction isotherm to higher pH region in all case. The degree of the pH isotherm shifts depended on the basicity of each amine in the case of manganese however did not depend on it in the case of cobalt. The separation ability of cobalt from manganese was highest in case of LIX63 and primary amine system.

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.133, no.7, pp.173-181, 2017-07-01 (Released:2017-07-28)

参考文献数

33

---

Peat from highly organic soil is abundant in Northern Hokkaido, Japan. In the past, peat was used in various applications in Japan, such as an artificial culture of soil, as a fertilizer for gardening, and as an energy resource. However, peat is not used by the modern energy and manufacturing sectors in Japan because it has a high moisture content and low calorific value, which lowers its value as a resource considering its material characteristics and handling difficulties. Furthermore, large amounts of peat are generated at the construction sites in this area, and they are difficult to be reused at their generation sites because peat is a very soft soil and not suitable for construction work. Recently, many Japanese research institutions have been carrying out research and development on renewable energy resources including biomass energy. In Hokkaido, there are many biogas plants for methanizing biomass derived from livestock excrement or food waste. Thus, peat which is high in organic matter could potentially be used as an energy resource. In this study, we investigated the potential of utilizing peat as an energy resource for biogenic methane production in regional cities of Northern Hokkaido, while considering both its material characteristics and resource circulation. Batch tests using a hydrogen peroxide solution were performed on peat and silty soil to estimate the quantity of low-molecular-weight organic acids and the producing potential for biogenic methane gas. The oxidative decomposition of the peat produced a high yield of low-molecular-weight organic acids that were used as substrates for methanogenic microorganisms. In addition, a novel resource circulation method was proposed for peat in order to use it as an energy resource. Moreover, the energy resources problem in Northern Hokkaido was discussed in association with geographical parameters and the construction recycling system in Japan.

著者

徳重 晃大 森 康平 大上 悟 松島 寛 鈴木 一成 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.7, pp.165-172, 2017-07-01 (Released:2017-07-21)

参考文献数

15

被引用文献数

5

---

Cu electrolysis was performed using low-grade copper anode with purity 78.7 mass% at a anode current density of 200 A・m-2 in an unagitated sulfate solution containing 0.596 mol・dm-3 of Ni2+ ions as impurity at 60 ℃, and the structure of anode slime before and after passivation was analyzed. The highly-concentrated Sb, Pb and Ag were dispersed in copper anode before electrolysis. The passivation occurred at short time of 17.7 hours in the case of low-grade copper anode, and it occurred at shorter time of 11.4 hours in the solution containing Ni2+ ions as impurity. At normal dissolution of copper anode, copper parent phase dissolved in the form of dendrite and the framework of anode slime was composed of remained Cu-Ni-Sb-Sn-As compound. Cu2S and single phase of Ag and Pb were observed around this framework. At passivation, Cu, Ni and Sn dissolved from the slime framework composed of Cu-Ni-Sb-Sn-As compound, resulting in formation of Sb condensed phase. These Cu-Ni-Sb-Sn-As compound, Sb condensed phase, Cu2S compound around the slime framework, Ag and needle-shaped PbO dotted in the whole slime suppressed the diffusion of Cu2+ ions, as a result, CuSO4 was formed at interface between the slime and copper substrate. The passivation occurred at slime thickness of approximately 500μm in Ni2+-free solution, while it occurred at slime thickness of approximately 300μm in solution containing Ni2+ ions. This indicates that the passivation do not depend on only the thickness of slime. The thickness of CuSO4 formed at passivation in Ni2+-free solution was almost identical with that from the solution containing Ni2+ ions. In solution containing Ni2+ ions, the passivation occurred at less thickness of slime, showing that CuSO4 is easy to be formed in the vicinity of copper substrate due to decrease in solubility of CuSO4 and diffusion coefficient of Cu2+ ions.

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.133, no.7, pp.157-164, 2017-07-19 (Released:2017-07-19)

参考文献数

8

被引用文献数

2

---

The flow through annuli is encountered in drilling operation, in which drilling mud flows between the borehole wall and the drilling pipe. Some drilling muds, depending on their prepared materials, exhibit nonNewtonian characteristics and in many cases may be regarded as pseudoplastic fluids. This study examines the dimensionless flow rate defined by Fredrickson and Bird (Fredrickson and Bird, 1958) on pseudoplastic fluid laminar flow in concentric annuli. A new approximation function is derived to evaluate the viscosity factor, also easy to use without numerical procedures. The function is more precise than the one, which was previously shown by the authors (Masuyama and Hatakeyama, 2003). Further, a new scheme is proposed to evaluate the characterizing coefficients, such as the pseudoplastic viscosity and the rheology constant using flow data. Furthermore, generalized formulas of the Reynolds number and the pipe friction coefficient for pseudoplastic fluid are shown for concentric annuli in order to calculate the pressure drop. They are extendable in the case of circular pipes, also parallel plates.

著者

中村 大樹 山本 英和 田中舘 悠登 羽原 俊祐 小山田 哲也

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.7, pp.151-156, 2017-07-01 (Released:2017-07-08)

参考文献数

6

---

The effect of fine sand of blast-furnace slag (SBFS) on freeze-thaw resistance, sulfate resistance, and sulfuric acid resistance in mortar whose aggregate is replaced in part or in full with blast furnace slag (SBFS) was investigated. Evaluation carried out on small test specimens confirmed that freeze-thaw resistance, sulfate resistance, and sulfuric acid resistance all improve as the SBFS substitution rate increases. However, increased porosity with a larger proportion of pores sized 50 nm or larger was also observed. In the case of the use of molten slag from municipal solid waste (SMSW), no improvement in freeze-thaw resistance was observed with increases in SBFS substitution rate.

著者

川﨑 了

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.131, no.5, pp.155-163, 2015-05-01 (Released:2016-01-01)

参考文献数

84

被引用文献数

3

---

New ground improvement technologies using microbial functions have attracted attention recently both within and outside Japan. In this review paper, an outline of the present status of ground improvement technologies using microbial functions is presented. First, the advantages of ground improvement technologies using microorganisms are described. Second, previous studies on ground cementing technologies using calcium carbonate, silica, or calcium phosphate compounds, which are biominerals and representative eco-friendly cement materials in nature, are explained after being classified into three chapters. The main conclusions of the present review are as follows: most of the previous studies used calcium carbonate as the cement material; the studies were conducted mainly in the laboratory; the techniques fall one-step short of practical use stages. Finally, studies related to the usage of waste and applied to natural beachrock formations are presented as future prospects; similar to the ground improvement technologies mentioned above, these studies may lead to unprecedented new understanding, discoveries, and development through cooperation between microbiology and geotechnical engineering fields in the future.

著者

Le Trung TUYEN 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.133, no.6, pp.140-150, 2017-06-01 (Released:2017-06-29)

参考文献数

17

被引用文献数

2

---

2004 年5 月にホンタイ炭鉱で自然発火が発生して以降,ベトナムの四カ所の無煙炭炭鉱と一カ所の亜瀝青炭炭鉱で自然発火が続発している。これらに対処するため,筆者等は断熱環境下で石炭の酸化発熱試験ができる装置を使用して,各炭鉱の石炭試料について酸化発熱特性の試験を行っている。これらのデータについて実際に自然発火を発生している炭鉱の試料に注目してみると,150 ℃以下の低温領域の酸化反応速度が他の自然発火を発生していない炭鉱の石炭試料に比較して大きいことを見出した。即ち,低温域における石炭の酸化反応速度が自然発火の発生と深い関係があるという結論を得た。既存の自然発火性評価方法との比較も試みた。

著者

木下 尚樹 氏家 勲 河合 慶有 川口 隆 安原 英明 長江 俊勝

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.6, pp.132-139, 2017-06-01 (Released:2017-06-23)

参考文献数

13

被引用文献数

12

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Industrial waste generated in the domestic paper industry in Japan was 5.1 million tons in 2015, and after reduction and recycling, 152 thousand tons of the waste was consequently disposed. Organic sludge (paper sludge), which occupies two-thirds of the industrial waste generated in the paper industry, is incinerated for the purpose of volume reduction and thermal recycling, and then it becomes paper sludge ash (PS ash). PS ash is recycled as aggregate, roadbed material in the civil engineering field and cement raw material, but it is necessary to further expand the application and reduce the final disposal amount. From the above background, in this research, the strength characteristics, the durability performance and the environmental impact of low carbon concrete produced by reducing cement usage to 45% by using PS ash as admixture in addition to fly ash and blast furnace slag fine powder, were investigated. Experimental results show that the low carbon concrete produced in this research has long term strength development, and that PS ash does not contribute to long term strength. Moreover, the clay mineral contained in the PS ash has an effect of reducing drying shrinkage by water retention and expansion. With respect to durability performance, neutralization is promoted by decreasing the total cement amount, while salt tolerance resistance is improved. Frost damage resistance tends to decrease. The elution amount of toxic substances is less than the soil environmental standard value.