• Title/Summary/Keyword: mineralogical characteristic

Search Result 67, Processing Time 0.027 seconds

Formation of Alunite and Schwertmannite under Oxidized Condition and Its Implication for Environmental Geochemistry at Dalseong mine (산화환경하에서 명반석, 슈베르트마나이트의 형성특징과 환경지구화학적 의미: 달성광산)

  • 추창오;이진국;조현구
    • Journal of the Mineralogical Society of Korea
    • /
    • v.17 no.1
    • /
    • pp.37-47
    • /
    • 2004
  • Sulfates such as alunite and schwertmannite formed under oxidation condition play a important role in geochemical processes taken place at waste dumps and a creek from Dalseong mine, Daegu. Water chemistry shows pH decreases from upstream toward downstream creek, mainly due to formation of schwertmannite that is the most abundant phase along the creek. The removal of Al from the creek is preferentially attributed to formation of Al-bearing minerals and Al-sulphates. Among them, alunite is the most important Al-sink phase that occurs at higher pH than $pK_1$, Al hydrolysis constant. With high saturation index, alunite formed at the creek has a spherical form, commonly associated with schwertmannite. Secondary minerals formed on the surface of altered or weathered surfaces of heavy metals from the wasted dump that underwent severe oxidation, where alunite has characteristic habits which are spheric, radiating, and botrytis-like aggregates. Natroalunite occurs in association with alunite, or as mixtures of both of them. Because the pH decreases with distance due to formation of schwertmannite, although total contents of dissolved ions slowly lessen at least in the AMD, it is expected that the minerals precipitated at the creek can be exposed to subsequent dissolution, which may induce possible environmental problems.

The Characteristic Dissolution of Valuable Metals from Mine-Waste Rock by Heap Bioleaching, and the Recovery of Metallic Copper Powder with Fe Removal and Electrowinning (더미 미생물용출에 의한 폐-광석으로부터 유용금속 용해 특성과 Fe 제거와 전기분해를 이용한 금속구리분말 회수)

  • Kim, Bong-JuK;Cho, Kang-Hee;Choi, Nag-Choul;Park, Cheon-Young
    • Journal of the Mineralogical Society of Korea
    • /
    • v.27 no.4
    • /
    • pp.207-222
    • /
    • 2014
  • In order to recover the metallic copper powder from the mine-waste rock, heap bioleaching, Fe removal and electrowinning experiments were carried out. The results of heap leaching with the mine-waste rock sample containing 0.034% Cu showed that, the leaching rate of Cu were 61% and 62% in the bacteria leaching and sulfuric acid leaching solution, respectively. Sodium hydroxide (NaOH), hydrogen peroxide ($H_2O_2$) and calcium hydroxide ($Ca(OH)_2$) were applied to effectively remov Fe from the heap leaching solution, and then $H_2O_2$ was selected for the most effective removing Fe agent. In order to prepare the electrolytic solution, $H_2O_2$ were again treated in the heap leaching, and Fe removal rates were 99% and 60%, whereas Cu removal rates were 5% and 7% in the bacteria and sulfuric acid leaching solutions, respectively. After electrowinning was examined in these leaching solution, the recovery rates of Cu were obtained 98% in bacteria and obtained 76% in the sulfuric leaching solution. The dendritic form of metallic copper powder was recovered in both leaching solutions.

Characterization and assessment of the dolomite powder for application as fillers in the marble-type ore (대리암형 백운석의 분체 특성과 충전재로서의 응용성 평가)

  • Noh, Jin-Hwan;Lee, Na-Kyoung
    • Journal of the Mineralogical Society of Korea
    • /
    • v.20 no.2 s.52
    • /
    • pp.71-81
    • /
    • 2007
  • The marble-type dolomite from the Jasung Mine, which was farmed by duplicated affects of contact metamorphism and subsequent hydrothermal alteration, corresponds to a high-purity dolomite ranging up to above 98wt.% in dolomite contents. The dolomite contain minor impurities such as quartz, muscovite, and pyrite. It is characteristic that the dolomite is fairy Fe-rich corresponding to 0.4 wt.% due to the presence of pyrite of possible hydrothermal origin. The dolomite is nearly white-colored and constituting with subhedral crystals ranging $0.35{\sim}0.46mm$M in size, forming equigranular texture. Compared to the typical high-Ca limestone from the Pungchon Formation, the powder characteristics of dolomite is rather superior in milling efficiency, yields of fine particles, and size distribution. In addition, except for iron contents, the dolomite powder is no less superior than the limestone in quality and characteristics as fillers with respects to not only whiteness, oil absorption, and specific surface area but also shape characters such as elongation ratio, aspect ratio, and sphericity. This good characteristics of dolomite powder seem to be originated basically from comparatively higher grade and crystallinity of dolomite. Higher iron contents and the presence of sulfides prevents the dolomite from application for uses by thermal treatment, except for metallic manufacture. However, if proper ore separation procedure is available, the dolomite can be sufficiently utilized as substitutes for high-Ca limestone in most fields of filler industries.

Geochemical Reactive Experimental and Modeling Studies on Caprock in the Pohang Basin (포항분지 덮개암에 대한 지화학적 반응 실험 및 모델링 연구)

  • Kim, Seon-ok;Wang, Sookyun;Lee, Minhee
    • Economic and Environmental Geology
    • /
    • v.49 no.5
    • /
    • pp.371-380
    • /
    • 2016
  • This study aims to identify the mineraloical and petrographical characteristics of caprock from drilling cores of Pohang basin as a potential $CO_2$ storage site. Experiments and modeling were conducted in order to investigate the geochemical and mineralogical caprock effects of carbon dioxide. A series of autoclave experiments were conducted to simulate the interaction in the $scCO_2$-caprock-brine using a high pressure and temperature cell at $50^{\circ}C$ and 100 bar. Geochemical and mineralogical alterations after 15 days of $scCO_2$-caprock-brine sample reactions were quantitatively examined by XRD, XRF, ICP-OES investigation. Results of mineralogical studies, together with petrographic data of caprock and data on the physicochemical parameters of brine were used for geochemical modeling. Modelling was carried out using the The Geochemist's Workbench 11.0.4 geochemical simulator. Results from XRD analysis for caprock sample showed that major compositional minerals are quartz, plagioclase, and K-feldspar, and muscovite, pyrite, siderite, calcite, kaolinite and montnorillonite were included on a small scale. Results from ICP-OES analysis for brine showed that concentration of $Ca^{2+}$, $Na^+$, $K^+$ and $Mg^{2+}$ increased due to dissolution of plagioclase, K-feldspar and muscovite. Results of modeling for the period of 100 years showed that the recrystallization of kaolinite, dawsonite and beidellite, at the expense of plagioclase and K-feldspar is characteristic. Volumes of newly precipitation minerals and minerals passing into brine were balanced, so the porosity remained nearly unchanged. Experimental and modeling results indicate the interaction between caprock and $scCO_2$ during geologic carbon sequestration can exert significant impacts in brine pH and solubility/stability of minerals.

Environmental Geochemical Characteristics of the Acid Mine Drainage and Stream Sediments in the Abandoned Honam Coal Mine Area, Korea (호남탄전지역 폐탄광의 산성광산배수와 하상퇴적물의 환경지구화학적 특성)

  • Park, Young-Seog;Kim, Jong-Kyun;Kim, Jin;Jang, Woo-Seog;Lee, Ki-Hyung;Han, Min-Su
    • Economic and Environmental Geology
    • /
    • v.35 no.3
    • /
    • pp.241-255
    • /
    • 2002
  • The purpose of this study is to investigate environmental geochemical characteristics for the acid mine drainage and stream sediments in the abandoned Honam coal mine area. For the chemical analysis, stream winter samples were collected at 54 sites and for the mineralogical and chemical analysis, stream sediments samples were collected at 34 sites. Physical and chemical characteristics of stream water were measured at the site and chemical compositions were analyzed by ICP-AES, ICP-MS and IC. Mineralogical characteristics of stream sediments samples were determined using XRD, SEM and EDS. In physical and chemical properties, stream water shows thats pH 2.85~8.12, Eh -62~215 mV, EC 0.205~146 ms/m, ER 0.234~255 {$\Omega}{\cdot}$m, DO 0.03~1068 mg/L and TDS 10.96~1420mg/L. In chemical compositions, we obtain that K 0.118~3.184 mg/L, Mg 2.1~114.48 mg/L, Ca 2.59~l25.02 mg/L, Al 0.01~44.72 mg/L, Fe 0.108~89.49 mg/L and Na 5.45~125.41 mg/L. Stream sediments are commonly composed of quartz, illite and goethite in the result of x-ray diffraction. After heat treatment at 98$0^{\circ}C$, the hematite peaks are distinctly shown. In consideration of heavy metals (include Fe) for steam sediments, Fe ranges 22575~34713 ppm, Zn 41.66~970.3 ppm, Cd 0.52~52.07 ppm, Cu 1.25~198.5 ppm and Pb 0.43~77.35 ppm.

Geochronology and Petrochemistry of Foliated Granites between Damyang and Jinan (담양(潭陽)-진안(鎭安)사이에 분포(分布)하는 엽리상화강암류(葉理狀花崗岩類)에 대(對)한 지질시대(地質時代)와 성인(成因)에 관(關)한 연구(硏究))

  • Kim, Cheong Bin;Kim, Yong Jun
    • Economic and Environmental Geology
    • /
    • v.23 no.2
    • /
    • pp.233-244
    • /
    • 1990
  • Plutons of Damyang-Jinan area consist of gray feldspar granite gneiss, biotite granite gneiss, foliated granites, Namweon granites, gabbro, biotite granite and Ogangri granite in term of mineralogical, texture and field evidence. From Isotope data of study area, chronological order of the Plutons are the Pre-cambrian gray feldspar granite gneiss(Ar39-Ar40, hornblende, $1998.4{\pm}8.3Ma$), middle to late Triassic Daegang foliated granite(Rb/Sr, whole rock, $288{\pm}4Ma$), foliated hornblende biotite granodiorite(K/Ar, hornblende, $198.7{\pm}9.9Ma$), Sunchang foliated granodiorite(Rb/Sr, whole rock, $222{\pm}4Ma$), foliated two mica granite, Samori foliated granite and Namweon granite(Rb/Sr, whole rock, $211{\pm}3Ma$: K/Ar, hornblende, $203{\pm}10.2Ma$), middle Jurassic Gabbro(K/Ar, hornblende, $180.7{\pm}9MA$) and biotite granite, and Cretaceous Ogangri granite. According to variations diagrams of $Al_2O_3$ versus normative PI(100 An)/(Ab+An), Daegang foliated granite is plotted on tholeiitic series, and other foliated granites on calc alkaline rock series which are consider to be formed by magmatism at continental margin and island arc region. And alkalinity versus $SiO_2$ shows that Daegang folited granite and Samori foliated granite are correspond to alkaline region, foliated hornblende biotite granodiorite and Sunchang foliated granodiorite to calc alkaline region, and foliated two mica granite to both regions. According to ACF diagrams, Daegang and Samori foliated granites are plotted on S-type. Foliated hornblende biotite granodiorite and Sunchang foliated granodiorite on I-type, and foliated two mica granite on both type. Foliated granites are a series of differentiated products from cogenetic magma, and effected under ductile sheared zone. Characteristic foliation of foliated granites are considered to be generated by dextral strike slip faulting and ductile shearing.

  • PDF

A Study on the Properties of Electric Arc-Furnace Steelmaking Dusts for Stabilization Processing (안정화 처리를 위한 전기로 제강분진의 물성)

  • 현종영;조동성
    • Resources Recycling
    • /
    • v.7 no.5
    • /
    • pp.13-18
    • /
    • 1998
  • This study was carried out to understand the properties of the E.A.F. steel-making dusts for stabilization processing. The properties are related to mincral composition, shape, particle size, magnetism, density, porosity and leaching characteristic. the dust particles, the size of which ranges from sub-micron to tens-micron, were mainly spherical like balls that were agglomerated each other: the large particles were generally Fe-rich and the small particles were spherical like balls that were agglomerated each other: the large particles were franklinite (ZnFe$_{2}O_{4}$), magnetite (Fe$_{3}O_{4}$) and zincite (ZnO) by XRD analysis. When the dusts were sieved by a wet process, the particle fraction over 200 mesh had 1.5 wt.% with magnetite and quartz. The particles in the size range of 200-500 mesh consisted of magnetite, franklinite. The 82 wt.% of the steel-making dusts were occupied by the particles finer than 500 mesh and contained franklinite and zincite as main mineralogical compositions. When the dusts of around 78% porosity compressed under the load of approximately 1 KPa, the porosity decreased to 68% and to 535 under around 13 KPa. When the E.A.F. dusts were leached according to the Korea standard leaching procedure on the waster, the heavy metals exceeding the leaching criteria were cadmium, lead and mercury.

  • PDF

A Study of Weathering Characteristic of Baeknokdam Trachyte in Jeju Island (제주도 한라산조면암의 풍화특성에 관한 연구)

  • Lee, Chang-Sup;Cho, Tae-Chin;Lee, Sang-Bae;Won, Kyung-Sik
    • The Journal of Engineering Geology
    • /
    • v.17 no.2 s.52
    • /
    • pp.235-251
    • /
    • 2007
  • Baeknokdam rock mass at the crest of Halla mountain is composed of Baeknokdam trachybasalt in the eastern region and Hallasan trachyte in the western region. On-going weathering, rockfall and collapse of Baeknokdam wall rock are closely linked to the weathering of trachyte distributed in the western region of Baeknokdam, though within the restricted area of eastern region trachybasalt blocks has been naturally formed and may be rolled down neering properties have been conducted. Based on the results of these experiments variations of mineralogical-petrographical characteristics of trachyte together with chemical and physical properties with respect to the degree of weathering have been analyzed. Weathering mechanism of Baeknokdam trachyte has been delineated by investigating the environmental cause of weathering and the peculiar features of weathered rock mass.

Tunisian phosphogypsum tailings: Assessment of leaching behavior for an integrated management approach

  • Zmemla, Raja;Sdiri, Ali;Naifar, Ikram;Benjdidia, Mounir;Elleuch, Boubaker
    • Environmental Engineering Research
    • /
    • v.25 no.3
    • /
    • pp.345-355
    • /
    • 2020
  • This study has been carried out to evaluate the leaching behavior of Tunisian phosphogypsum (PG) tailings in Skhira city (southern Tunisia). Two PG samples, including old and freshly deposited samples, were characterized in terms of physical, geotechnical, mechanical, chemical and mineralogical properties. Special attention was paid to their leaching behavior when subjected to standard leaching tests. Our results indicated that both samples are mainly composed of more than 31.85% CaO and 31.4% SO3, indicating the predominance of gypsum. This was further confirmed by XRD patterns that revealed the presence of characteristic reflections of gypsum, brushite, quartz and Maladrite. Compressive strength after 90 d exceeded 769 kPa, but still lower than that of natural sand (1,800 kPa). Leaching test was proposed as an appropriate method to determine the released contaminants from PG. The obtained results showed that Fluorine and Phosphorus are the most released elements from PG with 40 and 30%, respectively. The released Se, Cd, and Zn were the only trace elements that exceeded the threshold limits. It seemed that leached element concentrations were independent aging or particle size of the PG. Based on the assessment of leaching behavior, an integrated management approach of the PG deposits was proposed.

Quantum Chemical Calculations of the Effect of Si-O Bond Length on X-ray Raman Scattering Features for MgSiO3 Perovskite (양자화학계산을 이용한 Si-O 결합길이가 MgSiO3 페로브스카이트의 X-선 Raman 산란 스펙트럼에 미치는 영향에 대한 연구)

  • Yi, Yoo Soo;Lee, Sung Keun
    • Journal of the Mineralogical Society of Korea
    • /
    • v.27 no.1
    • /
    • pp.1-15
    • /
    • 2014
  • Probing the electronic structures of crystalline Mg-silicates at high pressure is essential for understanding the various macroscopic properties of mantle materials in Earth's interior. Quantum chemical calculations based on the density functional theory are used to explore the atomic configuration and electronic structures of Earth materials at high pressure. Here, we calculate the partial density of states (PDOS) and O K-edge energy-loss near-edge structure (ELNES) spectra for $MgSiO_3$ perovskite at 25 GPa and 120 GPa using the WIEN2k program based on the full-potential linearized projected augmented wave (FP-LPAW) method. The calculated PDOS and O K-edge ELNES spectra for $MgSiO_3$ Pv show significant pressure-induced changes in their characteristic spectral features and relative peak intensity. These changes in spectral features of $MgSiO_3$ Pv indicate that the pressure-induced changes in local atomic configuration around O atoms such as Si-O, O-O, and Mg-O length can induce the significant changes on the local electronic structures around O atoms. The result also indicates that the significant changes in O K-edge features can results from the topological densification at constant Si coordination number. This study can provide a unique opportunity to understand the atomistic origins of pressure-induced changes in local electronic structures of crystalline and amorphous $MgSiO_3$ at high pressure more systematically.