著者

近藤 敏 武山 眞 大藏 隆彦

出版者

一般社団法人 資源・素材学会

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.122, no.8, pp.386-395, 2006-08-25

参考文献数

2

被引用文献数

4 7

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Some 400 tons of platinum group metals (PGM) are yearly produced and used mainly for auto-catalyst, jewelries and electric appliances. The annual growth rate is currently more than 4%. Main resources for PGM exist predominantly in South Africa, Russia and North America, showing that they co-exist with Ni-Cu sulphide in the range of 5-10 ppm in their ores.<BR>Meanwhile, technological developments for fuel cells are being promoted, in which PEMFC (proton exchange membrane fuel cell) should be used for vehicles and stationary power. The PEMFC needs platinum as a catalyst due to the lower reaction temperature. The imbalance between supply and demand of Pt should become one of critical paths for the PEMFC promotion, if Japanese Government target is realized.<BR>This paper describes the forecast of supply & demand of Platinum based on various researches and investigations, and self-constructed model. Supply of platinum will be short in 2030's on schedule of the Japanese Government's scenario. Political countermeasure should be applied together with resources developments in order to secure the Pt resource.

著者

角谷 博樹 立田 則男 工藤 万雄

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.113, no.6, pp.440-445, 1997-06

被引用文献数

2

著者

佐々木 久郎 ディンディウェ チャールズ 安達 毅

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.117, no.7, pp.604-612, 2001-07-25

参考文献数

17

被引用文献数

1

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In this paper, a new concept for final pit shape in open pit design, Best Positive Inverted Truncated Cone (BPITC) algorithm, is presented for feasibility study and basic scheduling. Five mineral deposit models were used for eventual surface mine design optimization. Initially, geological reserve models were simulated by the utilization of GSLIB using randomly and regularly spaced drill hole data. Effects of varying anisotropy on the obtained metal quantities in reserves were also investigated. The BPITC was successfully applied to 100-times simulated deposit data set using Geostatistical simulation code GSLIB. The optimization results by BPITC were compared with those obtained by Positive Moving Cone (PMC) and Dynamic Cone (DC) based algorithms for the same mineral deposit models. The obtained results indicate that BPITC is superior to all the other optimizers. Concequently, the frequency distribution curves of profits and pit incremental feature by BPITC give effective information on mineral project decision-making and mining sequencing respectively.<BR>The conclusions from this study are summarized as follows:<BR>1. It was proved that for any type of deposit, the usage of correct anisotropic factors used in GSLIB lead to correct evaluation of reserves.<BR>2. All the profits / benefits computed for all the five model deposits show that a newly developed scheme named as BPITC can always indicate optimal solutions for final pit designs.<BR>3. Conclusively, the frequency distribution curves of profits and pit incremental feature by BPITC give effective information on mineral project decision-making and mining sequencing, respectively.

著者

荒井 健男 咲間 修平 佐藤 義倫 篠田 弘造 JEYADEVAN Balachandran 田路 和幸

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.119, no.12, pp.713-720, 2003-12-25

被引用文献数

1 2

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Stratified materials are defined as materials with nano-sized stratification that have been artificially controlled and designed. They are exemplified as a thin layer or stacked layers formed on surface of semiconductors. The present research is aiming at formation of controlled and designed stratification on surface of fine particles, leading to improvement of properties of fine particles which has been difficult to accomplish through the conventional particles engineering, and to development of novel properties created by the stratification.<BR>Here, we describe the method of the development of the nano-size CdS catalyst with stratified structure that efficiently separates electron and hole during photolysis, especially, to produce hydrogen gas from hydrogen sulfide, H₂S. Furthermore, as an approach for the development of the practical use photocatalyst, ZnS-carbon nanotube complex was also made and examined. In a way, the stratified structure is considered to enable the production of a reaction system which simulates function in biological cells. Using this catalyst in the solution mixed with various materials such as, calcium hydroxide, seawater and H₂S, we succeeded in producing about 7.5l/h m² of hydrogen gas under the sunlight.

著者

李 成五 呉 鍾基 申 芳燮

出版者

一般社団法人 資源・素材学会

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.115, no.11, pp.815-819, 1999-11-25

参考文献数

17

被引用文献数

1 5

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鉄酸化物の溶解は,金属表面の洗浄および産業鉱物から鉄分の除去などにおいて非常に重要な湿式製錬工程である。本研究ではしゅう酸を使用して各々の初期pH,反応温度,濃度の変化によって天然の鉄鉱石であるヘマタイト(赤鉄鉱)の溶解度を調査した。酸化鉄の溶解は反応温度25~60℃においてゆっきり進行したが,90℃以上では溶解度が急激に増加した。また0.048~0.476mol/lではしゅう酸濃度の増加によって溶解度が増加した。さらにpHの変化においても,pH1.5~2.5の増加により,溶解度は急激に増加したが、pH2.5以上では溶解度が鈍化するという現象を示した。以上の方法によって鉄酸化物であるiron rust(Fe_xO_y・xH₂O)に存在するgoethite(針鉄鉱α-FeOOH)とlepidocrocite(リン鉄鉱γ-FeOOH)と水酸化鉄(Fe(OH)₃)がヘマタイトより早く溶解するという特性を示した。

著者

島内 洋志 氏平 増之 鍵和田 忠男 菅原 隆之 石島 洋二 関 忠郎

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.122, no.3, pp.119-128, 2006-03-25

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In the transportation system using a large scaled dump truck, it is important to replace a wheel safely, quickly and easily when a wheel is burst or too much abraded partially. Conventionally, wheel replacement work has been depended on the replacement machinery for exclusive use. Considerable amount of expenditure was necessary to purchase the replacement machinery for exclusive use. Because of this reason, development of wheel replacing unit (handler unit ) has been expected for holding down the production cost.<BR>In this study, motion of a wheel replacement handler was analyzed both theoretically and experimentally, then handler unit was developed and wheel replacement test was carried out. Results obtained from the study are as follows; 1) Optional height of the axis of the large diameter wheel which is to be replaced can be adjusted easily, applying the analyzed equation obtained from theoretical study on the link motion. 2) It was found that a large scale wheel supported by a pair of steel pipes of which diameter and weight were 3.6 m and 5.2 t respectively could be rolled for setting the bolt holes to the bolt positions, when the pipe diameter was larger than 4 in. 3) As a result of rolling test for a large scale wheel using a pair of steel pipes of which diameter were 7in, it was proved that setting work of bolt holes to the bolt positions could be done within the time of 14-20 min. 4) Conclusively, it can be said that the handler unit newly developed in this study has the wide applicability, simplicity and cost performance comparing with conventional wheel replacing machinery.

著者

板垣 乙未生 ROGHANI Ghasem FONT Jonkion M.

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.115, no.4, pp.203-211, 1999-04-25

被引用文献数

1

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For thermodynamically understanding copper or nickel smelting processes using oxygen or oxygen-enriched air as a blowing gas, a series of the authors' experimental studies of the phase equilibrium and distribution of minor elements between the copper matte or the nickel matte and the FeOX-SiO2 base slag under the SO2 partial pressures of 0.1, 0.5 and 1 atm at 1,300 °C are reviewed in this paper. The solubility of copper was found to be independent of pSO2 when the matte grade was specified and it was considered that this behavior was ascribable to the constancy of (pO2 /pS2 ) against pSO2 . On the other hand, it was clarified that the solubility of nickel in the slag increased with increasing pSO2 at a given matte grade. The difference in the dissolution behavior between copper and nickel was considered to be ascribable to the difference in the chemical formulas of the mono-metallic sulfides in which one copper atom combines with 1/2 sulfur atom while one nickel atom with 2/3 sulfur atom. When the distribution ratio of a minor element, X, between the slag and matte phases was defined as LXs/m = (mass % X in slag)/{mass % X in matte}, LXs/m for arsenic, antimony and bismuth at a given matte grade increased with increasing pSO2. This behavior was explained reasonabley by assuming a mutual reaction between a metallic species in the matte and an oxidic species in the slag. On the other hand, the distribution ratio of silver at a given matte grade was almost constant against pSO2. This was considered to be ascribed to the sulfidic species of AgS0.5 prevailing in the matte phase as well as the constancy of (pO2 /pS2 ) against pSO2.

著者

島田 荘平

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.117, no.12, pp.923-930, 2001-12-25

被引用文献数

4 6

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There are many types of geological formations used for CO₂ sequestration. Coal seam is one of them. The characteristics of the coal seam used for CO₂ sequestration are the methane recovery when CO₂ is sequestrated. CO₂ is injected into coal seam not only for the CO₂ sequestration but also for CH₄ recovery (ECBMR).<BR>This paper reports the sequestration mechanism of CO₂ in the coal seam and the world R&D status in this field.<BR>The adsorption is a main sequestration mechanism of CO₂ in the coal seam. In the field scale sequestration, pressure of CO₂ is super-critical. The adsorption volume of CO₂ in coal in that condition is not yet clarified. This adsorption volume is very important for the prediction of sequestrable CO₂ volume.<BR>The present activities on this subject in the United States, Canada, Australia, Netherlands and Japan were reported. For the further studies, the international cooperative R&Ds are necessary. Items for the further R&Ds are summarized.

著者

黒川 晴正 家守 伸正

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.119, no.2, pp.55-60, 2003-02-25

被引用文献数

1 3

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Oxygen probes were applied to a PS converter in copper-making operation, and the oxygen pressures of white metal and blister copper in the converter were measured through the converter's mouth and through a tuyere, respectively. Based on the obtained results, the following reaction mechanism has been deduced.<BR>(1) The copper-making stage of a PS converter may be classified into three stages, i.e. the early substage where the tuyeres are completely in white metal, the intermediate substage where both phases of white metal and blister copper coexist in the converter and the tuyeres are in the blister copper, and the final substage where the white metal has disappeared from the converter.<BR>(2) In the early stage, direct oxidation of white metal by oxygen gas contained in the reaction air progresses in the vicinity of the tuyeres.<BR>Cu₂S(<i>l</i>) + O₂(<i>g</i>) = 2Cu(<i>l</i>) + SO₂(<i>g</i>) …………… (1)<BR>(3) In the intermediate substage, the following three reactions proceed near the tuyeres, at the interface of blister copper and white metal phases, and in the bulk of the blister copper, respectively.<BR>O₂(<i>g</i>) = 2<u>O</u>(<i>l</i>) …………… (2)<BR>Cu₂S(<i>l</i>) = 2Cu(<i>l</i>) + <u>S</u>(<i>l</i>) …………… (3)<BR><u>S</u>(<i>l</i>) + 2<u>O</u>(<i>l</i>) = SO₂(<i>g</i>) …………… (4)<BR>Here the most important factor is that reaction(4) progresses under the condition of <i>P</i>_SO₂=1atm. It is not dependent on how high the SO₂ pressure of the waste gas from the converter is. Because the condense phases, i.e. the white metal and blister copper phases, are not in equilibrium with the gas phase.<BR>(4) In the final substage, reactions(2) and (4) only proceed because the white metal is no longer in the converter. Some of the blister copper can be excessively oxidized to the extent that Cu₂O(<i>s</i>) is formed according to equation(5). However the final degree of oxidation of the whole blister copper does not reach this level.<BR>2Cu(<i>l</i>) + 1 / 2 O₂(<i>g</i>) = Cu₂O(<i>s</i>) …………… (5)

著者

古賀 誠 島田 英樹 松井 紀久男

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.118, no.1, pp.29-35, 2002-01-25

被引用文献数

4 7

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A bleeding examination and a flow characteristic examination of grout materials were performed to understand the fundamental characteristic of grout materials. Moreover, an injection experiment of grout materials which used a decomposed granite was conducted to understand the applicability of the analysis technique which introduced filtration theory. The results are as follows:<BR>1) When cement water ratio is large, a bleeding speed becomes slow, but the bleeding ratio becomes small.<BR>2) Plastic viscosity and yield stress become large with increase of cement water ratio. Particularly, plastic viscosity change greatly on <i>C</i> / <i>W</i> = 1 / 1.6. And as compared with yield stress, it is larger about influence on the discharge.<BR>3) Where a cement water ratio does not exceed <i>C</i> / <i>W</i> = 1 / 5, the clogging of the voids was done by a suspension custody. And where <i>C</i> / <i>W</i> = 1 / 3.5, that was done by a surface filter layer.<BR>4) The plastic viscosity measured using Brookfield viscometer is a result when some cement particles aggregate, and shows big value as compared with the theoretical relative viscosity.<BR>5) The result of injection analysis using the theoretical relative viscosity assumed that the cement particle is distributing completely is well as an experiment result in agreement. In the grout materials which flow the inside of the voids, it cleared that plastic viscosity follows the theoretical relative viscosity which the cement particles distributed.

著者

藤田 豊久 佐野 葉奈 武藤 一 柴山 敦 宮崎 敏夫 井上 千弘

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.117, no.1, pp.43-48, 2001-01-25

被引用文献数

1

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Bactrerium inhabiting in Amarume crude oil of Yamagata prefecture was identified as <i>Pseudomonas mendocina</i>. In the first step, biodegradation experiments were conducted by using the bacteria of 0.510⁶ cells / ml and 300 ppm of chlorobenzene in aqueous solution under aeration and irradiation. After 6 hours, chlorobenzene was perfectly decomposed. Next, the mixtures of synthesized polychlorinated dibenzo-<i>p</i>-dioxins (PCDDs) and dibenzofurans (PCDFs) were degraded with the bacteria of 0.510⁸ cells / ml, where the initial total concentrations of PCDDs and PCDFs were 1,400 ppm and 180 μg-TEQ / ml. After 24 hours, about 70 % of PCDDs and 60 % of PCDFs were biodegraded. The biodegradation rates of PCDD / Fs were much faster than those reported in literatures with other bacteria.<br>

著者

井上 誠 岩井 正雄 鎌土 重晴 小島 陽 井藤 忠男 菅間 光雄

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.115, no.3, pp.189-194, 1999-03-25

参考文献数

12

被引用文献数

1 2

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A newly recycling process for video camera components of AZ 91 D magnesium alloy used for professional market was developed by melting and casting processes in order to satisfy the JIS specifications for recycled AZ 91 D magnesium alloy ingot. Various quantities of Mn were added to the melt in order to avoid contamination by impurities such as Fe, Ni and Cr from paints. Composition analysis and mechanical properties and corrosion resistance of the recycled ingots were also examined. Recovery ratio of the recycled ingots is in the range of 60 % to 75 %. Chemical composition and tensile properties of the recycled ingot with Mn addition of more than 0.23 % is satisfied by JIS specification except for Cu content. Tensile strength and 0.2 % proof stress of the recycled ingots increase with increasing Mn content. The recycled specimens with Mn addition of more than 0.23 % almost exhibit the same level of corrosion resistance as the virgin ingot of AZ 91 D magnesium alloy.

著者

国吉 実 村上 次雄 溝田 忠人

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.118, no.7, pp.511-516, 2002-07-25

被引用文献数

2

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Sodium bicarbonate easily forms cakes during the storage and / or transport process after production, due to the influence of conditions such as humidity, temperature, compaction etc. Caking causes serious degradation of the material in the commercial value. To overcome the problem, the caking mechanism must be clarified first, and thereafter the effective treatment should be considered to avoid caking. Weak caking strength of sodium bicarbonate powder at the initial stage of caking was measured and evaluated in relation to amounts of various components and physical properties of the powder. Caking under the high humidity (RH80%) of sodium bicarbonate found to occur due to the bridging among particles during the process of changing of sodium carbonate to sodium sesquicarbonate. The caking under the conditions of low humidity (RH40%) and high temperature (40 ∼ 50 °C) however owes bridging accompanied by the change from sodium carbonate to Wegscheider's salt. Caking strengths measured for sodium bicarbonate samples with various particle sizes were correlated with contacting numbers among particles. The caking strength, <i>B_L</i>, was found to be expressed with the equation: <i>B_L</i> = <i>k</i>·<i>Sc</i>·<i>F</i>, where <i>Sc</i> is the contact area per unit surface area of sodium bicarbonate particles, and <i>F</i> is the formation quantity per the unit surface area, of the double salts such as sodium sesquicarbonate and Wegscheider's salt. We have found finally an effective method to avoid caking through the process of analyzing the caking mechanism of sodium bicarbonate.

著者

朴 洗憲 山崎 哲生 島田 荘平 山本 恭久

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.118, no.10, pp.641-649, 2002-11-25

参考文献数

48

被引用文献数

3 3

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Cobalt-rich manganese crusts on seamounts and manganese nodules on deep ocean floor have both been received attention as future resources for Co, Ni, Cu, and Mn. Lack of information on cobalt-rich manganese crusts has precluded comparisons between the two sources in terms of their technical and economical advantages. In the past 15 years, Japan has surveyed the cobalt-rich manganese crusts; therefore, it seems the proper time to compare the two. In this paper, we consider distribution features and R&D results to develop a method for examining and comparing the economical potentials of manganese nodule and cobalt-rich manganese crust mining. Through the preliminary evaluation of the two, the effectiveness of the method is confirmed. <BR>Cobalt-rich manganese crust development seems a risky but high return venture because of its high sensitivity to cobalt prices. Manganese nodule development, on the other hand, is considered to be a stable and good for a long-term venture. One of the application fields will be the selection of suitable metallurgical processing. A lower substrate ratio in excavated ore is clearly required for the economy of the crust development. In order to improve the evaluation, detailed technical information for the recovery efficiencies in the subsystems and units is necessary.

著者

中野 正則

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.115, no.7, pp.498-504, 1999-07-25

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IBUKI Limestone Quarry started operation from 1952. In order to obtain limestone ore resources, the exploitation plot plan for the upper lever was first considered in early 1970's. This area is adjacent to the natural park and natural monument area where high mountain plants are growing in groups. Prior to making the plot plan, the exploitation concept was discussed with experts and local communities and determined with regard to the natural environment. According to this concept, the excavating system including restoration on the planting and transporting system of limestone ore were developed. In order to verify restoration by planting and also to confirm the coexistence with mining work, the planting work had been performed since 1971 at the already excavated area below 1,000 meter level. On the other hand, the facilities for ore transportation were installed underground so that it cannot affect the existing landscape. Although rock had enough strength, strength of rock mass was not high due to considerable cracks observed. When the vertical ore shaft was constructed in the cracked rock, the diameter of the shaft was designed as a small scale and the walls were reinforced with concrete and steel ringing. To avoid choking in the shaft, the rock size supplied to the shaft is made under 300 mm using a mobile crushing plant. The operations in the upper limestone quarry was started in 1978, then the restoration planting at the upper limestone quarry was started in 1979. At the beginning of operation, there are many unexpected troubles in operations. This paper describes a design of exploitation which agreed with the concept, countermeasure for the troubles in operations, additional construction work to improve the environment against dust emission and the restored results in the excavated area.

著者

作田 庸一 嶋影 和宜

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.120, no.2, pp.71-77, 2004-02-25

被引用文献数

1 2

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A large amount of marine organic residue is generated and wasted from scallop shell processing manufacture. Because the waste product of scallop, especially the mid-gut gland contains a large quantity of heavy metals such as cadmium and copper, it cannot be effectively used. Now, a large part of these wastes are treated in landfills. However, in recent, the landfill treatment runs into trouble because of an environmental pollution and a decrease in proposed landfill ground. Consequently, the development of a new treatment method of the scallop waste is really required. In order to recycle the organic residue of scallop mid-gut gland, a new technology has been developed for removing the harmful cadmium and using as fish meal and fertilizer.<BR>This treatment consists of a cadmium leaching process from the mid-gut gland in a sulfuric acid solution and a cadmium electro-deposition process. This new treatment technology corresponding to hydrometallurgical process can remove more than 95% of cadmium from the mid-gut gland. At first, influences of various factors on cadmium removal efficiency such as acid concentration, electrolytic voltage, anode materials and so on, were examined to decide the most suitable conditions of an electrochemical treatment method by using a small scale plant test.<BR>And secondarily, a demonstration plant to enable one batch treatment of about 100kg/day was designed on the basis of the results of a fundamental experiment, and a prototype plant was built. Finally, a demonstration test was conducted.<BR>The dried and crushed wastes products of scallop after the removal of cadmium were reused as a feed and fertilizer materials, and in the year 2000, two recycle plants of the scallop waste on the basis of this development research were constructed at Oshamanbe-cho and Sawara-cho in Hokkaido, and now under operating.

著者

笹木 圭子 小林 弘幸 恒川 昌美

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.117, no.9, pp.747-752, 2001-09-25

被引用文献数

4

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Aragonite-type of light calcium carbonate was synthesized by the successive reaction using calcined-hydrous scallop shells and calcined lime stones in the aqueous system with Mg²⁺ ions under the CO₂ bubbling. In order to obtain the high aspect ratios of aragonite, the reaction temperature and concentrations of Ca²⁺ ions in the 2nd step were important. The aspect ratio of aragonite increased when the reaction temperature was higher in the 2nd step than in the 1st step of the successive reaction. When the smaller amounts of calcium source were added in the 2nd step than in the 1st step, and the reaction temperature was lower in the 2nd step than in the 1st step, large particles of aragonite were produced with no smooth surfaces. The successive reaction was useful to extend the variety of morphologies in aragonite.

著者

笹木 圭子 本郷 大 恒川 昌美

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.114, no.10, pp.709-713, 1998-09-25

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Aragonite-type calcium carbonate was synthesized from calcined scallop shell using carbonates of orthorohombic structure (such as SrCO3) as seeds, by bubbling CO2 at ambient temperature. The products were examined by FTIR, SEM, EPMA, and XRD. The addition of SrCO3 increased aragonite content in the products, but BaCO3 and PbCO3 did not play the role of seed crystals due to the difference of their lattice parameters to those of aragonite, whereas lattice parameters of SrCO3 are the most similar to them. With increasing SrCO3 -addition, formation of aragonite was accelerated to a limit in the amount. Light calcium carbonate rich in aragonite was formed in agglegates consisting of needle-like crystals with large specific surface areas.

著者

西須 佳宏 小林 幹男 竹内 理

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.119, no.9, pp.573-578, 2003-09-25

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The effect of regents concentrations for recovery and shape of precipitate on the liquid-phase synthesis of precursor particles of Y₂O₃ : Eu phosphor was studied. The amount of precipitant generated by hydrolysis of urea was remarkably changed by reaction temperature and initial concentration of urea. Therefore, the reaction rate of the precipitation reaction was controlled by reaction temperature and initial urea concentration. The recovery of precipitate was increased from < 10% to > 99% with the increase in urea concentration from 10 × 10^-3 to 30 × 10^-2 mol/dm³ in the synthesis at 92°C for 1 hour, when initial concentration of rare-earth ion was 10 mmol/dm³. On the other hand, the particle size was decreased with increase in urea concentration. The shape of particles was changed from uniform sphere to irregular aggregate with increase in initial concentration of rare-earth ion under the lower urea concentration condition. However, mono-dispersed spherical particles were formed even in that case, when the ratio of rare earth for the urea was higher. Though non-aggregated particles were amorphous basic carbonate; (Y, Eu)OHCO₃, the carbonate was crystallized in the aggregated particles. By the calcination at above about 600°C, both compositions converted to the oxide; (Y, Eu)₂O₃, but original shapes of precipitate particles were retained after that. Therefore, mono-dispersed spherical Y₂O₃ : Eu phosphor particles could be obtained from morphologically identical precursors. These results indicate the range of initial reagents concentrations in which mono-dispersed spherical Y₂O₃ : Eu phosphor is prepared.

著者

張 其武 齋藤 文良

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.114, no.4, pp.253-257, 1998-04-25

被引用文献数

11 30

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Leaching of fluorescent powder containing rare earths using 1N HCl solution at room temperature was conducted to extract the rare earths, followed by dry grinding of the powder using a planetary ball mill. The dry mechanochemical treatment of the powder causes the structural change of the crystals in the powder into a disordered system. This mechanochemical treatment leads to easy extraction of the rare earths. Only 3 minutes of grinding enables us to extract Y and Eu at above 70-80 % yield. More than 80 % of the other rare earths can be extracted from the powder ground for 2-hours. The mechanochemical treatment to the fluorescent powder before leaching would be an effective operation to be able to extract the rare earths at high yield in room temperature leaching even by low concentration HCl solution.