Evidence of Iron Mineralization Channels in the Messondo Area (Centre-Cameroon) Using Geoelectrical (DC &IP) Methods: A Case Study

A geophysical survey was conducted in the Kelle-Bidjocka village, Messondo subdivision, in the Centre Region, Cameroon. The data acquisition was made by combining Schlumberger profiling and electrical soundings along six (06) profiles of 1500 m in length for a total of 64 geoelectrical stations’ survey conducted through a variable mesh 100 m × 200 m, or 100 m × 300 m. The equipment used is the DC resistivimeter Syscal Junior 48 (Iris Instrument). Processing and modelling of field data are made by using the Res2Dinv, Qwseln and Surfer software. The investigation methods used are electrical resistivity (DC) and induced polarization (IP) methods. The analyses and interpretations have helped to highlight areas of weakness or conductive discontinuities (fractures, faults, shear zones, etc.) in Precambrian gneiss formations, sometimes undergoing weathering processes. They identify the weathering or mineralogical accumulation horizons, the most promising is a mineralization channel identified in the NE-SW direction. The highlighted mineralization is characterized by strong gradients of chargeability or polarization. Samples and other geological evidences observed in the area are used to associate the most polarizable structures with ferriferous formations. Weakly polarizable and particularly conductive backgrounds identified by the inverse pseudo-sections are thought to be sulphate minerals or groundwater targets for future hydrogeological studies.

A preliminary study on ore-forming environments of Xianglushan-type iron deposit and the weathering mineralization of Emeishan basalt in Guizhou Province, China

Xianglushan-type iron deposits are one of the new types of iron deposits found in the Weining Area of Western Guizhou. The iron-bearing rock system is a paleo-weathered crustal sedimentary(or accumulating) stratum between the top of the Middle-Late Permian Emeishan basalt formation and the Late Permian Xuanwei formation. Iron ore is hosted in the Lower-Middle part of the rock system. In terms of the genesis of mineral deposit, this type of deposit should be a basalt paleo-weathering crustal redeposit type, very different from marine sedimentary iron deposits or continental weathering crust iron deposits. Based on field work and the analytical results of XRD Powder Diffraction, Electron Probe, Scanner Electron Microscope, etc., the geological setting of the ore-forming processes and the deposit features are illustrated in this paper. The ore-forming environment of the deposit and the Emeishan basalt weathering mineralization are also discussed in order to enhance the knowledge of the universality and diversity of mineralization of the Emeishan Large Igneous Province(ELIP), which may be a considerable reference to further research for ELIP metallogenic theories, and geological research for iron deposits in the paleo-weathering crust areas of the Emeishan basalt,Southwestern, China.

Evidences by Multiscale Analysis and 2D3/4 Models from the Magnetic Anomalies and Iron Mineralization (BIF) over the DJADOM-ETA Area, Southeastern Cameroon

The Magnetic method is one of the best geophysical techniques used to delineate subsurface structures. This study was conducted to investigate the basement faulting and ore mineralization into the overlying geological cover. The GEOSOFT v8.4 software was used to process the data. Upward continuation of the residual magnetic intensity map at various altitudes and the maxima of their horizontal gradient magnetic were used to highlight faults from shallow to deep, as well as, their dips and mineralization zones. The faults with the directions E-W, ESE-WNW and ENE-WSW are identified confirming the result of [1]. This study also reveals that, the layer is affected by faults propagating from the basement upwards into the cover. Our results added additional information to the knowledge of the geological structure and the mineral resources potential in the study area. Based on the 2D3/4 modeling, the Dja Fault (DF) is revealed and highlighted sub-area marked by a magnetite/or hematite dolerite, schist and sandstone blocks, which show strong magnetization. Specifically, in this area, models are made of BIF (bounded iron formation) and BIQ (bounded iron quartzite) as dominant minerals.

Geological Features,Mineralization Types and Metallogenic Setting of the Phlaythong Large Iron Deposit,Southern Laos

The Phlaythong large iron deposit in Shampasak of southern Laos,is located in the Kon Tum microblock （Fig.1A）,central-southern part of the Indo-China block,and the geographic coordinate of the central mining area is 14°43′04″ N and 106°07′02″ E.

Enrichment and separation of iron minerals in gibbsitic bauxite residue based on reductive Bayer digestion

The mineralogical characteristics of three kinds of gibbsitic high-iron bauxite and the effects of various digestion conditions on the enrichment and separation of iron minerals were investigated. The results show that adding an appropriate organic reductant such as glycerol can promote the digestion of concomitant diaspore, boehmite and alumogoethite as well as the conversion of goethite to hematite in the reductive Bayer digestion. Processing Bauxite A with A/S of 25.41 can directly produce qualified iron concentrates(TFe>56%) by the reductive Bayer digestion, and thus realize the zero red mud discharge. For Bauxite B and Bauxite C with A/S of 7.82 and 3.35, the iron recoveries of 65.13% and 79.13% can be achieved with the corresponding TFe of 52.05% and 50.16% in the iron concentrates by gravity separation, respectively, resulting in the red mud discharge reduction of ~50% or above.

Mineral processing plant location using the analytic hierarchy process——a case study:the Sangan iron ore mine(phase 1)

Locating the mineral processing plant near a mine is the most important parameter that affects the whole process.Many factors,and their preferences,should be considered in this stage.The factors include economical,geological,technical,environmental and tectonic parameters.A multi-criteria decision making method is necessary to rank the alternatives.In this paper we describe how plant location is selected by using the Analytic Hierarchy Process(AHP).This method,with eight criteria,was used to select a location for the mineral processing plant at the Sangan iron ore mine(phase 1).Three alternatives for the processing plant were evaluated.The main criteria were distance from the mine,access to heavy machinery transport,the amount of excavation required for grading,bed mixture capacity,belt conveyor length,distance from the tailing dam,distance from the waste dumps and surface water diversion requirements.Finally,the alternatives were ranked and the best location was proposed.

The Experimental Study of Iron Sulfide Mineral Evolution Under Thermal Sulfurization Condition

Iron sulfide minerals are widely distributed, of which characteristics had the identification significance of formation environment. Previously, there were more research on iron sulfide minerals under hydrothermal condition, and few studies under volcanism formation condition. To simulate volcanic mineralization, the study of different temperature from 250 to 410℃ , different iron sulfur ratio from Fe:S=2∶1 to 1∶8, and two different sources of iron, reduced iron powder (Fe) and ferrous sulfide (FeS), on iron sulfide mineral evolution was investigated under thermal sulfurization condition. By using scanning electron microscopy (SEM), X-ray diffraction (XRD) and other methods, the morphology, composition and structural characteristics of the products were observed and analyzed.

Chemical Forms of Heavy Metals in Carbonate-Derived Laterite and Enrichment of Its Iron Oxide Minerals

In this paper the seven-step continuous extracting method was employed in the studyof chemical forms of the six heavy metals Co, Zn, Pb, Cu, Cr and Mn. The result shows thatthe metals in the laterite are present in the chemical form of crystalline iron oxides andresidues, and they are transformed toward organic and exchangeable forms in the surface soil.Linear regression analysis indicates that the above heavy metals have a positive correlation withthe crystalline iron oxide minerals. The crystalline iron oxide minerals have a very importantrole to play in the enrichment of heavy metals, especially the solid components in the laterite.

Zircon U-Pb-Hf isotopes and mineral chemistry of Early Cretaceous granodiorite in the Lunggar iron deposit in central Lhasa, Tibet Y, China

The Lunggar iron deposit belongs to the Bangong-Nujiang metallogenic belt and is located in central Lhasa on the Tibetan Plateau.In the Lunggar deposit,iron mineralization formed in the skarnization contact zone between the Early Cretaceous granodiorite and the late Permian Xiala Formation limestone.In this study,we achieved detailed zircon U-Pb-Hf isotopes and mineral chemistry for the Early Cretaceous granodiorite.Zircon U-Pb dating results indicate that the Early Cretaceous granodiorite emplaced at ca.119 Ma.Based on the trace elements in zircons and the mineral chemical composition of amphibole and biotite,the Early Cretaceous granodiorite was believed to form under condition of high temperature(>700°C),low pressure(100400 MPa),and relatively high oxygen fugacity(lgfO2)(13.6 to 13.9)and H2O content(4%8%).Zircon trace elements,Hf isotope and biotite chemistry collectively reveal that significant juvenile mantle-derived magmas contributed to the source of the granodiorite.The relatively high logfO2 and shallow magma chamber are beneficial for skarn iron mineralization,implying remarkable potential for further prospecting in the Lunggar iron deposit.

Magnetic Mineralogical Characteristics of Hamersley Iron Ores in Western Australia

This paper presents the research outcomes of a magnetic mineralogical study on Hamersley iron ores. Thermal magnetic analysis shows that typical high-grade martite-microplaty hematite or M- (mpl H) and martite-microplaty hematite-goethite or M-(mpl H)-g ores contain a small amount of original magnetite. A small amount of magnetite/maghemite and pyrite/pyrrhotite/siderite may exist in typical martite-goethite (M-G) and martite-ochreous goethite (M-oG) ores. In “the hardcap zone”, M-(H)-g ores contain a small amount of magnetite and maghemite. Compared with XRD, thermal magnetic analysis is not only more sensitive in identifying trace of magnetite contained in high-grade hematite ores, but also more diagnostic in identifying other unstable magnetic minerals like maghemite and pyrite/pyrrhotite/siderite co-existed in the ores.

Effect of Foliar Application of Iron on Seasonal Changes of Minerals Composition in Petioles and Berries of Halwani Lebanon and Kamali Grape Cultivars （Vitis vinifera L,）

A field experiment was conducted in 2009 and 2010 growing seasons, to study the effect of foliar application of iron-chelated ＂Fe-EDTA＂ at concentration 0, 100 and 200 mg/L on the seasonal dynamic of mineral composition of N, P, K, Fe and Zn in petioles and berries of Halwani Lebanon and Kamali grape cultivars, grown on a calcareous soil in Mosul region, Iraq. The results revealed that the foliar application of 200 mg Fe/L caused a significant increase of N, P, K, Fe and Zn concentrations in petioles and berries compared with the control for both seasons. Additionally, the N, P, K, Fe and Zn concentration in petioles were high at the beginning of the growth season, whereas, decrease towards in the end of the growth season in both cultivars and seasons. While the N, P, K, Fe and Zn in berry content was increased towards from berry set to veraison and ripening stage in both cultivars and seasons. So there are various element contents in the cultivars.

Development and Testing of a Method to Estimate the Mineral Composition of Ore from Chemical Assays with a View toward Geometallurgy: Application to an Iron Ore Concentrator

For complex orebodies in which the valuable metal is carried by several minerals that respond differently to the concentration process, an ore block model should not be characterized solely with elemental assays, as this information is not sufficient to anticipate the mill performances. Data from an iron ore concentrator is used to demonstrate the idea. A method is then proposed to estimate the mineral contents of ore samples from elemental assays. The method can readily be extended to combine the estimation of the mineral contents in the feed of the mill with an estimation of the recovery of these minerals into the products of the concentrator. These mineral recoveries can subsequently be incorporated into a block model to predict the concentrator response to the processing of an ore block.

FURTHER STUDIES ON THE MALIGNANT TRANSFORMATION OF SYRIAN GOLDEN HAMSTER EMBRYO CELLS IN VITR0 BY THORIUM DIOXIDE AND RARE EARTH IRON MINERAL DUSTS

Malignant transformation of hamsterembryo cells was induced in vitro by rareearth iron mineral dusts(MP),naturalthorium(Th02) and MP plus Th02.Dusts of MP,MP plus Th02 or Th02 were added into themedium with the final concentration of 17.0,

中国铁矿石选矿技术发展与展望

铁矿石作为钢铁工业最为重要的原材料,是我国重要的战略性矿产资源之一。我国铁矿资源储量丰富,但97%以上属于贫矿,需要经过选矿富集后才能供给高炉炼铁。多年来,在我国选矿工作者的共同努力下,我国铁矿选矿技术得到长足进步和发展。通过回顾我国铁矿选矿技术的发展历程,综述单一弱磁选、单一浮选、重选—磁选—反浮选、磁化焙烧—磁选等主要选矿技术在我国铁矿选矿厂的应用,总结我国典型多金属共生型铁矿石如伴生稀土/萤石型铁矿石、伴生钛铁矿型铁矿石、伴生多金属硫化物型铁矿石和伴生硼铁矿型铁矿石的选矿现状,介绍影响我国铁矿选矿技术进步的关键设备如圆锥破碎机、高压辊磨机、半自磨机、立环脉动高梯度磁选机、高频振动细筛、搅拌磨机等,指出我国铁矿选矿未来要以“高效节能、低碳减排”为原则,以“优质优用、劣质能用”为战略,开发选冶联合工艺,研发大型高效设备,研制低温环保药剂,提高智能控制水平,加强资源综合利用。

Metallogeny and Emplacement Conditions of Continental Terminal 3 (Ct3) Iron Formations of the Niamey Region (Western Niger)

This study aims to characterize the different lithofacies of the Ct3 formation in the Niamey region, and to determine the distribution of major and trace elements, in order to highlight the conditions for the establishment of iron mineralization. A lithological column, synthesizing sections of selected outcrops in the vicinity of Niamey, was produced. The chemical compositions of the selected samples were determined by X-ray fluorescence (XRF) spectrometry. Microscopic analysis of the thin sections determined the gœthitic nature of the oolitic iron ore. The oolites show a quartz, limonitic or gœthitic nucleus. Sometimes the nucleus is absent. From a morphoscopic point of view, two types of oolites have been distinguished: spherical-shaped and ellipsoidal-shaped oolites. The oolites are either contiguous or disseminated, as the case may be, in a limonitic to goethitic cement or in a fine sandstone matrix. The larger oolites (pisolites) are relatively friable. They reflect the influence of a relatively turbulent to submerged environment. The hardground of the iron mineralized horizons are covered by quartz grains. They are indicative of a submerged or emergent environment. X-ray fluorescence analysis shows high Fe2O3 contents (50% to 80%) and variable contents of major elements SiO2, Al2O3, TiO2, MnO, MgO, CaO, K2O and P2O5 associated with certain trace elements such as Th, U, V, Y, Zn, Zr and As. The results of the study are an important tool for decision-makers to adopt effective prevention/remediation measures for groundwater contamination in the Continental terminal aquifer systems.

草酸与铁氧化物相互作用及光化学活化分子氧过程的研究进展

草酸与铁氧化物共存于自然环境中,二者之间的相互作用及光化学行为强烈影响着分子氧的活化.而分子氧活化影响共存体系中污染物的迁移与转化,是发展绿色污染控制氧化技术的关键.因此,探讨草酸与铁氧化物之间的相互作用与光化学活化分子氧是目前的研究热点之一.本文系统总结了近年来围绕草酸与铁氧化物相互作用以及草酸诱导铁氧化物活化分子氧的研究成果,论述了草酸在铁氧化表面的吸附与转化特性、草酸铁络合物光化学过程以及活性氧产生与转移途径,同时探讨了上述过程对环境污染物降解的影响,借此加深理解草酸诱导铁氧化物环境光化学行为与活化分子氧原理,并对今后的研究发展方向提出了展望,以期为利用天然铁氧化物和有机质发展原位环境修复技术提供依据.

冀东地区尾矿资源调查及综合利用建议

河北省是我国矿产资源大省,尤其是冀东地区的矿产资源开发导致大量尾矿堆存,亟需开展尾矿资源调查和综合利用,实现尾矿的资源化、减量化和无害化。本文调查了冀东地区尾矿和废石的堆存情况,分析了冀东地区典型铁尾矿和金尾矿物理化学性质,提出了综合利用建议。研究结果表明,冀东地区尾矿和废石堆存量分别为33831万m3和108637万m3;尾矿以铁尾矿、金尾矿为主,堆存量分别为33079万m3和752万m3。冀东地区典型铁尾矿中,除水厂铁矿尾泥、司家营铁矿(2#尾矿库)尾矿和清河沿铁矿尾矿外,其他铁尾矿粒径较大,砂粒(2.00~0.05 mm)占比>89%。冀东地区铁尾矿属于高硅低铝型尾矿,除了清河沿铁矿尾矿和黄槐玉铁矿尾矿外,其他铁尾矿SiO2占比>70%。铁尾矿中矿物以石英为主(>43%),其次为黑云母、微斜长石、斜长石、角闪石、白云石和透辉石等。对于冀东地区金尾矿,三家金矿和金厂峪金矿以砂粒为主,均超过90%,其他金尾矿粒径相对较细。冀东地区金尾矿为长英岩型尾矿,SiO2含量明显较铁尾矿低(57.69%~68.65%),而Al2O3含量明显较铁尾矿高(9.32%~16.09%)。金尾矿中主要矿物为石英、斜长石、黑云母、绢云母等,其中,斜长石占比明显较铁尾矿高。根据冀东地区铁尾矿性质,建议将大粒径铁尾矿作为建筑砂,细粒尾矿作为建材原料实现综合利用,剩余尾矿可进行土地复垦。对于金尾矿,建议首先进行井下填充,其次作为建材原料实现综合利用。该研究对冀东地区尾矿资源综合利用具有一定的指导意义。

CO_(2)对A.ferrooxidans活性和次生铁矿物形成的影响

通过摇瓶试验模拟富铁富硫酸盐环境,研究了在0.03%(空气中CO_(2)含量),3%,6%,9%和12%浓度的CO_(2)条件下对Acidithiobacillus ferrooxidans活性及次生铁矿物形成的影响,并分析了pH值,Fe^(2+)氧化率及氧化速率,总Fe沉淀率以及次生铁矿物矿相等相关指标.结果表明,CO_(2)浓度为3%时,菌氧化Fe^(2+)能力最强,72h时Fe^(2+)氧化率达到100%,试验结束时总Fe沉淀率最高,为42.8%.随着CO_(2)浓度增加,各体系A.ferrooxidans活性受到抑制.不同CO_(2)浓度体系最终获得矿物均为黄铁矾类矿物混合少量施氏矿物.适当提高CO_(2)浓度,有助于提高A.ferrooxidans活性,并促进水解成矿增加矿物产量.本研究为酸性矿山废水的治理提供理论依据.

超高料层双层烧结富氧强化及烟气排放行为研究

针对超高料层双层烧结矿强度低的问题,采用富氧方法强化双层烧结。研究富氧浓度和燃料用量对烧结矿产质量的影响,分析普通双层烧结和富氧强化双层烧结的烧结矿主要矿物组成和微观结构,研究两者烧结烟气中O_(2)、CO_(2)和CO的排放行为。研究结果表明:富氧方法能明显强化超高料层双层烧结,大幅度提高烧结矿成品率和转鼓强度;二次点火后对料层进行富氧,氧气体积分数为25%,烧结矿成品率、转鼓强度、利用系数和固体燃耗分别为69.06%、66.40%、2.09t/(m^(2)∙h)和53.79kg/t,与普通双层烧结指标相比,成品率、转鼓强度和利用系数分别提高4.11%、7.73%、0.18t/(m^(2)∙h),固体燃耗降低3.23kg/t;富氧使烧结矿中磁铁矿氧化充分,铁酸钙大量生成,烧结矿结构均质、紧密;富氧增大烧结烟气O_(2)质量分数,可有效解决下部料层缺氧问题,提高燃料燃烧效率,减少CO排放量。