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Ikeda M.,Shikoku Research Institute | Kato S.,Shikoku Research Institute | Nishizaka N.,Shikoku Electrical Power Company Inc. | Ohno Y.,Shikoku Electrical Power Company Inc. | And 2 more authors.
Tectonophysics | Year: 2013

We carried out a magnetotelluric (MT) survey along a profile crossing the Median Tectonic Line (MTL) in western Shikoku, Japan. The MTL is a terrane boundary that formed during the Cretaceous between the Sanbagawa belt, consisting of high pressure/temperature (P/T) metamorphic rocks, and the Ryoke belt of granites and low P/T metamorphic rocks. The MT image shows a zone of remarkably low resistivity, dipping northward at 40°, at the surface coincides with the surface trace of the MTL. The low-resistivity zone probably corresponds to a fluid-filled damaged zone of porous media composed of clay minerals and cracked rocks, formed by repeated faulting of the MTL since Late Cretaceous time. The calculated maximum porosity of the damaged zone is 7.1%, which is clearly higher than that of the non-damaged crystalline rocks. © 2013 Elsevier B.V.


Groundwater flow exerts a crucial control on the boundary between the sea and freshwater and is thus a key factor for preserving groundwater resources and preventing seawater intrusion in coastal areas. Although it is highly probable that geological faults in coastal areas affect groundwater flow patterns, the effect has not been described yet in detail. This study is aimed at detecting and imaging groundwater flow and its temporal change around a fault in a coastal area through resistivity and chargeability distributions using electrical sounding. The Okoshiki area in central Kyushu, southwest Japan, was selected as a case study area, because of the presence of Kamiouda Fault. The measurements were conducted along six lines of both parallel and perpendicular orientations to the coastline. A feature suggesting a fault zone was evident on two lines. Through the temporal change of resistivity, movement and mixing processes of the seawater and freshwater during the ebb, low and flood tides were interpreted. A conceptual model of the processes was constructed in which a fault zone and the configuration of bedrock are dominant elements by acting as a selective path and a barrier to the groundwater flow, respectively. © 2013 Springer-Verlag Berlin Heidelberg.


Takayama J.,Nittetsu Mining Co. | Itoi R.,Kyushu University | Morita S.,Nittetsu Mining Co.
Transactions - Geothermal Resources Council | Year: 2014

The Ogiri geothermal power plant started its operation in March 1996 with installed capacity of 30MW. Since the beginning of operation, the plant has successfully maintained high utilization factor of over 90% in average. Timely change of well operations and developing a new area within Ogiri contributed to the long term high level productivity of the plant. Copyright © (2014) by the Geothermal Resources Council All right reserved.


Hayashi T.,Tohoku University | Baba Y.,Tohoku University | Taga T.,Tohoku University | Kishimoto A.,Nittetsu Mining Co. | And 2 more authors.
Fullerenes Nanotubes and Carbon Nanostructures | Year: 2011

To remove poly sulfide anions from basic solution, a fullerene/toluene solution was mixed with an aqueous solution containing S2 2- ions and agitated until the color of the aqueous phase changed from yellow to transparent. The treatment was repeated several times. During each treatment, white precipitates were produced in the aqueous phase and black crystals were formed after 4th treatment. XRD results indicated that former was elemental sulfur and the latter, fullerene-sulfur compounds. Thus, we succeed in extracting and separating poly sulfide ion from aqueous solution. By the fifth treatment, c.a. 675 S2 2- ions per one fullerene were successfully collected from the aqueous solution. This reaction can be applied to recovery of other anion species in basic solution. © Taylor & Francis Group, LLC.


Tateishi Y.,Kyushu University | Itoi R.,Kyushu University | Tanaka T.,Kyushu University | Hiraga N.,Nittetsu Mining Co. | Takayama J.,Nittetsu Mining Co.
Transactions - Geothermal Resources Council | Year: 2013

Numerical simulations of the Ogiri geothermal reservoir were conducted using a fractured reservoir model with particular focus on the periods of power plant maintenance when all production and reinjection wells are shut-in for a few weeks. The results show that the steam-water two-phase zone in the shallow reservoir shrinks somewhat and the single-phase water zone expands.


Ponou J.,University of Tokyo | Wang L.P.,University of Tokyo | Dodbiba G.,University of Tokyo | Okaya K.,University of Tokyo | And 5 more authors.
Journal of Environmental Chemical Engineering | Year: 2014

The ongoing development of new advanced technologies, created increasing demands for rare earth elements (REEs) in the international market. The available conventional technologies for concentration and recovery of REEs are expensive making biosorption an efficient and low-cost technology for the recovery of REEs from aqueous solution. Thus, the biosorption and desorption of multi-component solution containing Y(III), La(III), Sm(III), Dy(III), Pr(III), Nd(III), Gd(III) were investigated using dried or 250 °C and 350°C carbonized parachlorella. Evaluating the effect of pH with respect to contact time indicated a dependency of the system with those parameters. The optimum pH for dried and 250°C carbonized parachlorella was 7 whereas 350°C reaches it maximum uptake at pH 4. Rapid adsorption within the first 5 min of contact followed by a slight variation in the following 20 min characterized the sorption processes onto parachlorella by-products. The mechanism of the biosorption is explained by a combination of complex reactions occurring simultaneously in the biosorption process. In addition, desorption process has been investigated using various concentrations of HCl, HNO3, and H2SO4 at different temperatures. It was found that the reversible process is rapid, less temperature and pH dependent with high desorption percentage. Moreover, only light REEs were desorbed regardless of the kind of acid and the solution temperature. Parachlorella is found to be good and low-cost biosorbent for the recovery of above REEs from aqueous solutions. © 2014 Elsevier Ltd.


Kim J.-A.,University of Tokyo | Dodbiba G.,University of Tokyo | Tanimura Y.,Nittetsu Mining Co. | Mitsuhashi K.,Nittetsu Mining Co. | And 4 more authors.
Materials Transactions | Year: 2011

In the present study, REEs were leached from a Vietnamese ore, by using (NH4)2SO4 and REEs were adsorbed from this leachate by blue- green algae (phormidium). In addition, the biosorption characteristics of phormidium for the adsorption of Nd has been studied. When the concentration of ammonium sulfide was 1%, leaching time was 3h, and S/L ratio was 0.09, the leaching ratio of Nd was 67.3%. In the adsorption process, when dosage of phormidium was 0.2 kg/L, the contact time was 30 min, and the temperature was 298 K, while pH was kept at the initial value (i.e. pH 5.6), the adsorption density of Nd was 182 mg/kg. These results were similar with the adsorption density of other absorbents, such as: activated carbon, Fe-based absorbent, and calcinated dolomite. Moreover, the equilibrium sorption isotherm of Nd onto phormidium was described by the Langmuir isotherm equation and the pseudo-second-order kinetic model fits the experimental data well. © 2011 The Japan Institute of Metals.


Nishiyama E.,Nittetsu Mining Co. | Miyamoto T.,Komatsu Ltd. | Kodama J.,Hokkaido University | Kawasaki S.,Hokkaido University | And 2 more authors.
Rock Mechanics in Civil and Environmental Engineering - Proceedings of the European Rock Mechanics Symposium, EUROCK 2010 | Year: 2010

A method to evaluate regional stress state and Young's modulus by analyzing mining induced deformation of ground is proposed. Mining induced deformation is interpreted as the deformation due to the geometrical change of ground surface caused by mine activity and it is classified into two types, i.e., the displacement increment induced by the gravity and that by the horizontal regional strain. It is pointed out that both regional strain andYoung's modulus can be estimated by analyzing the mining induced deformation, because the displacement induced by the regional strain is independent of the Young's modulus and the displacement induced by the gravity is in inversely proportional to the Young's modulus. The relative displacement arising from mine excavation in Torigatayama limestone mine, Japan have been measured by GPS. Both the stress state andYoung's modulus of the regional field including the limestone mine were estimated by back-analysis using three dimensional finite element method. It is shown that the maximum principal direction of the regional stress is almost NE-SW andYoung's modulus of the ground is between 3 and 6 GPa. © 2010 Taylor & Francis Group.


Patent
Nittetsu Mining Co., Sumitomo Corporation and Toyo Engineering Corporation | Date: 2012-11-29

The present invention relates to a method for producing lithium carbonate, which is important as a raw material of a lithium ion battery and the like, from brine resources. More specifically, the invention relates to a method for producing lithium carbonate, in which carbon dioxide gas obtained by calcining limestone is introduced, in the presence of ammonia, into a concentrated brine, which is prepared from a lithium-containing brine as a raw material through an evaporative concentrating step, a desulfurizing step and an electrodialysis step, thereby depositing lithium carbonate crystals, and the crystals thus deposited are recovered through solid-liquid separation.


Patent
Sumitomo Corporation and Nittetsu Mining Co. | Date: 2012-05-29

The present invention relates to a method for producing lithium carbonate, the method including: mixing ammonia and carbon dioxide gas (carbonate gas) with an aqueous solution containing lithium chloride to conduct a carbonation reaction; and thereafter, recovering a produced solid by solid-liquid separation, and also relates to a method for producing high purity lithium carbonate.

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