Diatomaceous deposits of Fayium, Egypt; characterization and evaluation for industrial application

The Holocene lacustrine diatomaceous earth of Fayium,South West of Cairo,has been studied to define its minerals,chemistry,petrography and physical properties.Minerals were processed by way of calcination at 550℃ ,followed by acid leaching to reduce levels of mineral impurities.The diatomite is of biogenic opal A.with calcite as the main ganue mineral,quartz and clay minerals(smectite followed by kaolinite in abundance and a trace amount of illite).Silica in the diatomaceous earth accounts for about 63% on average.Positive correlation between CaO and CO2 indicates that Ca is present mainly as calcite.Al2O3,Fe2O3,MgO and K2O are attributed mainly to clay minerals.However,the physical properties of the diatomaceous earth as filter-aids and filler for paints and plastics are poor because of general high levels of impurities.The technological performances of the diatomaceous earth have been significantly improved owing to upgrading of diatoms through mineral processing trical.     

非金属矿物材料在环境保护中的应用

介绍了膨润土、沸石、硅藻土、海泡石、凹凸棒石等非金属矿物材料的结构和性质,对其在环境保护领域的应用现状进行了综述.提出应加强非金属矿物基础研究和应用研究,并加强开发生产非金属矿物环境材料.     

Geotechnical properties of stabilised Indian red earth

Locally available soils amended with sufficient bentonite are generally used for construction of liners for water and waste retention facilities. The amount of bentonite required to keep the hydraulic conductivity low varies with the nature of the local soil. Many studies have shown that bentonite content higher than 20% by weight is not usually required. This is also the case with Indian red earth containing predominantly quartz and kaolinite minerals. Incorporating bentonite, though keeps the hydraulic conductivity of soil low, increases the swelling and shrinkage potential; increases the loss of strength due to reduction in cohesion. This paper aims to improve the geotechnical properties of red earth and bentonite mixture with lime or cement. The studies reveal that the geotechnical properties of red earth with 20% by weight bentonite stabilised with 1% by weight of lime or cement are greatly enhanced, particularly after curing for 28 days. it has been shown that the early gain in strength is better with cement whereas its long-term strength gain is better with lime.     

纳米结构矿物的特殊结构和表-界面反应性

纳米矿物是纳米地球科学（Nanogeoscience）的核心研究对象之一.鉴于"纳米矿物"的概念在实际运用时较宽泛,有时与经典定义不符,建议用"纳米结构矿物"代替"纳米矿物",并简析了纳米结构矿物（Nanostructured Minerals）的概念.以管状纳米结构矿物（埃洛石和伊毛缟石）、球状纳米结构矿物（水铝英石）、层间纳米结构矿物（蒙脱石和伊/蒙混层矿物）和多孔纳米结构矿物（硅藻质蛋白石）为例,分析了纳米结构矿物的结构、表面基团的特殊性及其所衍生的特殊界面反应性,讨论了它们对矿物资源利用和油气生成等地球物质循环过程的重要意义.      

The Preparation and Adsorption Properties of Novel Ternary Composited Diatomaceous Earth

Xianfeng large-scale lignite mining area, symbiotic diatomaceous earth mining area is the second largest diatomaceous earth mining in China with high organic matter content. The Xianfeng diatomaceous earth mining is a difficult development and utilization of low-grade diatomaceous earth, which has not been effective utilized due to low economic value of traditional processes. The objectives of this paper are utilizing high organic matter content diatomite as waste resources and improving the comprehensive utilization ratio of mineral resources in Xianfeng coal mining areas. The high organic content diatomaceous earth was purified by the acid washing and then calcinations under N2 as a protective atmosphere and high temperature of 500 to 800 ℃. The organic matter was carbonized with the formation of amorphous complex of activated carbon and diatomaceous earth. The novel ternary composited diatomaceous earth was prepared by combining carbonation diatomaceous earth and magnetic nanomaterials. The absorption property of ternary composited diatomaceous earth was improved through the organosilane and polyacrylamide modification to meet the needs of practical application. Electron microscopy showed that magnetic precursor calcined under N2 as a protective atmosphere, the surface of the magnetic nanoparticles were coated with amorphous carbon, which improved chemical stability and compatibility with diatomaceous earth. The magnetic nanoparticles and amorphous activated carbon uniformly dispersed in a diatomaceous earth surface and within the pores, to form a stable magnetic nanoparticles - the amorphous active carbon - ternary complexes. The specific surface area and methylene blue adsorption test showed ternary composited diatomaceous earth performing much higher than conventional diatomite products, the novel diatomaceous earth with specific surface area of 55.79 m2/g, methylene blue adsorption capacity of 44.5 m2/g. MgFe2O4 and Co3O4-based superparamagnetic ternary composited diatomaceous earth as an unique adsorbent has great application potential in organic pollutants and heavy metals pollution treatment of water. In addition, the CoFe2O4 based soft magnetic ternary composited diatomaceous earth has potential applications in magnetic plastics, rubber functional filler fields. This study shows that the proposed technology is conducive to a substantial increasing economic value of the Xianfeng diatomaceous earth mining, has a broad industrial application prospects.     

江苏优势矿产开发前景与对策

江苏优质矿产主要有五大类：即粘土类矿产，建材类矿产，化工原料矿产，冶金辅助原料矿产，特种用途矿产。江苏矿产资源的开发应注重开源，开优，开新和开外相结合的原则。适当加大地质工作投入，实施好全省矿产资源勘查工程，力争实现矿产资源的重大突破。大力开发优势矿产资源，提高全省非金属矿开发利用水平，形成一批非金属矿产原材料基地。依靠科技进步，开发新产品，新矿种，振兴矿业经济。     

Characterization of the Lebanese Jurassic–Cretaceous carbonate stratigraphic sequence: a geochemical approach

The Lebanese crustal segment is part of a much larger carbonate platform deposited along the northwestern margin of the Arabian Plate, in the eastern Mediterranean region. It is made up mainly of Jurassic–Cretaceous carbonate rocks. Most of this stratigraphic sequence is exposed in the Nahr Ibrahim canyon and surrounding areas in central Lebanon. The various formations, from the oldest unit (the Lower Jurassic Kesrouane Formation) to the Upper Cretaceous Chekka Formation, are made up of different types of carbonate rocks including micritic limestone, medium‐ to coarse‐grained dolostone, biomicritic (chalk), biosparrudite limestone, micritic dolostone, pelmicrite, marl and marly limestone. Results of this first chemical investigation on the Lebanese carbonate platform show that the micritic limestone of the Kesrouane Formation is relatively enriched in Ca, Na and Sc, and has low rare‐earth element (REE) contents. The marl units of the Hammana Formation are enriched in Al, Fe, K, Ti, Rb, Ga, Nb, U, Th and REE. The chalk of the Chekka Formation shows the highest phosphorus content. A significant increase in P and Sr contents with time (from the Lower Jurassic to the Upper Cretaceous carbonate units) characterizes the Lebanese sequence; this is interpreted to be related to a possible increase in continental weathering rates during the Mesozoic. Enrichment in Ni, Ti and Nb in some formations is interpreted to be linked to Mesozoic volcanism in central Lebanon. The Cretaceous formations are subdivided according to their REE patterns into two distinct groups: limestones (Mdairej, Sannine and Maameltain formations) which are depleted in REE; and marl/chalk (Hammana and Chekka formations) which are significantly enriched in REE. On several geochemical variation diagrams, such as the K–Ti–P triangular plot, the Lebanese Mesozoic carbonate formations are found to occupy distinct compositional fields. Thus, carbonate geochemistry could prove to be a powerful tool (especially when combined with petrographic data) in characterizing and correlating carbonate formations (chemical stratigraphy), particularly in regions where field evidence may be limited. Results of this study have significant implications for the entire carbonate platform that covers a large part of the eastern Mediterranean region. Copyright © 2002 John Wiley & Sons, Ltd.     

REE Compositions of Lower Ordovician Dolomites in Central and North Tarim Basin, NW China: A Potential REE Proxy for Ancient Seawater

Rare earth dement compositions of Lower Ordovician dolomites in the Central and Northern Tarim Basin are studied. Most dolomite samples are more or less contaminated by clay minerals. Their rare earth element compositions have been consequently changed, showing both seawater-like and non-seawater-like features. The clay contamination should be disposed before the REE data are used. Through ICP-MS and ICP-AES analyses, the REE features are well documented. The clay contamination is quantitatively determined by microscopic investigation, trace elements and REE contents. The dolomites, at least in the Tarim Basin, are thought to be pure when their total LREE contents are less than 3x10-6. Through comparison, the pure dolomites show similarities in REE patterns but differences in REE contents with co-existing pure limestone, which indicates that dolomitization may slightly change the REE compositions. Nevertheless, whatever the change is, the pure dolomites may act as a potential REE proxy for Ordovician seawater, which would be significant for ancient massive dolomite strata that lack limestone.     

REE Compositions of Lower Ordovician Dolomites in Central and North Tarim Basin, NW China： A Potential REE Proxy for Ancient Seawater

Rare earth element compositions of Lower Ordovician dolomites in the Central and Northern Tarim Basin are studied. Most dolomite samples are more or less contaminated by clay minerals. Their rare earth element compositions have been consequently changed, showing both seawater-like and non-seawater-like features. The clay contamination should be disposed before the REE data are used. Through ICP-MS and ICP-AES analyses, the REE features are well documented. The clay contamination is quantitatively determined by microscopic investigation, trace elements and REE contents. The dolomites, at least in the Tarim Basin, are thought to be pure when their total LREE contents are less than 3×10^-6. Through comparison, the pure dolomites show similarities in REE patterns but differences in REE contents with co-existing pure limestone, which indicates that dolomitization may slightly change the REE compositions. Nevertheless, whatever the change is, the pure dolomites may act as a potential REE proxy for Ordovician seawater, which would be significant for ancient massive dolomite strata that lack limestone.     

松散干容重对黏土质硅藻土矿床的评价作用

吉林省敦化市高松树硅藻土矿为含黏土矿物及碎屑较多的劣质硅藻土.在对本矿区样品分析结果对比中发现,由于围岩及夹层的化学组分与矿层相同,常规的工业指标不能区分矿石与岩石.为了能够对矿床做出正确评价,在测试样品基本分析项目外又增加了松散干容重一项.经反复测试研究,确定了以松散干容重≤0.95 g/cm³作为指标之一,与其他工业指标一起圈定矿层,成功地解决了矿体圈定及矿石质量评价问题.     

21世纪初期化工矿产资源形势及对策研究

我国的钾、磷、硫、硼以及天然碱、金红石、砷、钠硝石、石盐、芒硝、重晶石、萤石、天青石、明矾石、化工灰岩、硅藻土、膨润土等化工矿产资源 ,与世界相比 ,在资源量、生产能力、消费水平等方面的地位各不相同。面对未来 ,宜根据各矿种的实际情况 ,在地质找矿、开发利用、对外贸易等分别有所侧重 ,以保证市场之需求。     

浅议长春市矿业产业结构存在的问题及调整目标与优化

长春市查明可利用的矿产资源种类（含石油）４８种,保有储量达１２３。９３纱计探明储量１２５．０１亿吨。目前,已开发利用的矿种２１种,其中石油、天然气、煤炭、砖瓦用粘土占有优势。依据矿业产业结构存在的主要问题,建议调整目标;建立能源（石油、天然气、煤、油页岩）为龙头,非金属（三矿种：石灰石、膨润土、建筑石材;二石;沸石、伊利石;二岩：珍珠岩、陶粒页岩）为骨干,以贵金属（金）和矿泉水、二氧化碳气、沁 为     

巴颜喀拉盆地长石头山二叠纪—三叠纪碳酸盐岩丘的沉积岩石学和地球化学特征

青海巴颜喀拉盆地长石头山二叠纪—三叠纪碳酸盐岩丘是由罕见的块状纯灰岩组成,灰岩具团块结构,由泥微晶方解石团块和栉状生长的泥微晶方解石胶结物组成,部分泥微晶方解石发生了重结晶作用。灰岩的矿物组成主要为方解石,平均含量达97%,化学成分除CaO外,其余均低于5‰。灰岩的5%HNO3可溶相（碳酸盐矿物）稀土元素页岩配分模式具...     

Northern Greece's industrial minerals: production and environmental technology developments

This paper reviews the use of Greek industrial minerals into developing low-cost, high-tech solutions to remediate parts of the chemical pollution environmental problem. The remediation strategy, based on the application and implementation of the Greek industrial minerals potential, became a major line of investigation in projects to develop new environmental technologies. Although past and current experiments have been successful on a lab scale in a number of applications, the results have not always been implemented on industrial scales. Greek olivine has been successfully tested as neutralizing agent for acid wastes, co-producing exploitable amounts of silica gel, magnesium sulphate and magnetite. Vermiculite is currently tested as an environmental ‘cleanser' in a variety of applications, i.e. metalliferous mine seepage and processing waters, organically contaminated waste water from the textile/dye industry and absorption material for oil spills. Wollastonite will be applied as long-term fertiliser and dolomite, as a substitute of asbestos in brake linings, as pollution controller of heavy metal concentrations in waste waters and as a binder to stabilize waste solids. Magnesite has been successfully applied for neutralization of acid mine wastes produced from active sulphide deposits. Zeolites (fly ash and perlite converted to zeolites were also considered) is an objective for several environmental applications, i.e. as floating absorbent for waste water ponds, as drinking water purificator or as smell abatement.     

Natural and artificial minerals as matrices for immobilization of actinides

The possibility of insulation of long-lived actinides for the entire period of their potential hazard, i.e., over a virtually infinite time, is the crucial problem in safe disposal of high-level radioactive wastes (HLW). The reality of such a possibility is corroborated by the study of natural radioactive minerals that firmly retain U, Th, and REE, which are close in geochemical properties to transuranic actinides, for millions of years despite the effects of groundwater. The natural analogues of actinide HLW matrices are minerals where U, Th, and REE are contained as major elements or isomorphic admixtures. The study of these minerals is helpful for synthesis of durable artificial forms of wastes that ensure reliable insulation of HLW up to the complete decay of actinides independently of such engineering barriers of underground repositories as containers and bentonite buffers. The main requirements on confinement matrices include a high isomorphic capacity with respect to actinides and other HLW components, chemical and radiation stability, and technological feasibility of their industrial production. The natural and artificial minerals—uraninite, monazite, zirconolite, pyrochlore, britholite, garnet, and murataite—characterized in this paper may serve as a basis for efficient matrices for immobilization of actinide wastes.     

Modelling the interaction of bentonite with hyperalkaline fluids

Many designs for geological disposal facilities for radioactive and toxic wastes envisage the use of cement together with bentonite clay as engineered barriers. However, there are concerns that the mineralogical composition of the bentonite will not be stable under the hyperalkaline pore fluid conditions (pH > 12) typical of cement and its properties will degrade over long time periods. The possible extent of reaction between bentonite and cement pore fluids was simulated using the reaction-transport model, PRECIP. Key minerals in the bentonite (Na-montmorillonite, analcite, chalcedony, quartz, calcite) were allowed to dissolve and precipitate using kinetic (time-dependent) reaction mechanisms. Simulations were carried out with different model variants investigating the effects of: temperature (25 and 70 °C); cement pore fluid composition; dissolution mechanism of montmorillonite; rates of growth of product minerals; solubilities of product minerals; and aqueous speciation of Si at high pH. Simulations were run for a maximum of 3.2 ka. The results of all simulations showed complex fronts of mineral dissolution and growth, driven by the relative rates of these processes for different minerals. Calcium silicate hydrate (CSH) minerals formed closest to the cement-bentonite boundary, whereas zeolites and sheet silicates formed further away. Some growth of primary bentonite minerals (analcite, chalcedony, calcite and montmorillonite) was observed under certain conditions. Most alteration was associated with the fluid of highest pH, which showed total removal of primary bentonite minerals up to 60 cm from the contact with cement after ∼1 ka. The maximum porosity increase observed was up to 80–90% over a narrow zone 1–2 cm wide, close to the cement pore fluid- bentonite contact. All simulations (except that with alternative aqueous speciation data for Si) showed total filling of porosity a few cms beyond this interface with the cement, which occurred after a maximum of 3.2 ka. Porosity occlusion was principally a function of the growth of CSH minerals such as tobermorite. There was very little difference in the alteration attained using different model variants, suggesting that bentonite alteration was not sensitive to the changes in parameters under the conditions studied, so that transport of pore fluid through the bentonite governed the amount of alteration predicted. Principal remaining uncertainties associated with the modelling relate to assumptions concerning the evolution of surface areas of minerals with time, and the synergy between changing porosity and fluid flow/diffusion.     

A coupled non-isothermal reactive transport model for long-term geochemical evolution of a HLW repository in clay

A numerical model of coupled saturated/unsaturated water flow, heat transfer and multi-component reactive solute transport is presented to evaluate the long-term geochemical evolution in bentonite, concrete and clay formation for a potential geological radioactive waste repository. Changes in formation porosity caused by mineral dissolution/precipitation reactions are taken into account. Simulations were carried out with a general-purpose multicomponent reactive transport code, CORE^2D V4. Numerical results show that pH in the bentonite porewater can vary from neutral to up to 13 over a time scale of 1 Ma although dissolution of silica minerals and precipitation of secondary calcium silicate hydrate (CSH) minerals in bentonite buffer the effect of the hyperalkaline plume. Mineral precipitation reduces the volume of pore space in bentonite close to the bentonite–concrete interface due to the precipitation of CSH minerals. Model results indicate that bentonite porosity decreases less than 25%. The hyperalkaline plume from the concrete only extends to a distance of 0.7 m in the clay formation over the time range of 1 Ma.     

南岭钨锡稀土成矿带资源特征与潜力分析

南岭钨锡稀土成矿带跨越湖南、广东、广西、江西四省(区),其钨、锡、铋、铅锌、稀土等产量位居全国前列,是我国重要的有色金属资源基地和生产加工基地。该成矿带横跨扬子、华夏两个板块,位于中生代欧亚大陆板块构造岩浆活动带的华南陆块中部,区域成矿地质条件优越,是中国有色、稀有、稀土、放射性矿产的重要成矿远景区带。通过研究成矿带的成矿特征,划分了成矿系列,建立了成矿谱系,确定了区带的主攻矿种为钨、锡、锰、铅锌,并对其资源潜力进行了评价,预计可新增钨475万吨、锡375万吨、锰2.6亿吨、铅锌6084万吨。在此基础上,部署了江西省于都-银坑重点远景区、江西大余-上犹重点远景区、广东韶关地区铅锌、银、钨矿重点远景区、广东大宝山-连平地区铁、铜、铅锌、钨矿重点远景区、湖南郴州地区钨、锡、钼、铅锌、铜、萤石矿重点远景区5个重点远景区和湖南常宁地区铅锌、金、银、萤石、硼矿一般远景区等8个一般远景区,为指导本区勘查工作提供了依据。     

Characterization by electrical and electromagnetic geophysical methods of the shallow hydrogeological system at Hebron (West Bank,Palestine) in a semi-arid zone

Multi-electrode geo-electrical and transient electromagnetic surveys were carried out to characterize the nature of the subsurface infiltration zones (5 to 20 m) related to a series of groundwater outlets, and to reveal the geometry of the different aquifers at Bani-Naim, in the south-eastern foothills of the Hebron area, West Bank, Palestine. The purpose of the surveys was to understand the link between water storage/transfer and the characteristics of the geological formations. The strata in this semi-arid region are composed of alternate layers of chalky limestone, hard limestone, marl and chalk. A total of 30 ERT and 15 TDEM were conducted at Bani Naim-Jahir and Bani Naim-Birein. A correlation between the results indicates various infiltration pathways: fractures, feature heterogeneities, and porous chalk. The local heterogeneity on the eastern side were the major pathways for the water infiltration, whereas the thick marl layer underneath acts as a natural impermeable barrier preventing water from infiltrating deeper. A combination of the different geophysical results identified conductive features that correspond to the infiltration zones supplying the dug wells with water. Furthermore, it was established that the fractured chalk and porous chalky limestone act as an aquifer. A three-dimensional visualization of the resistivity allowed a useful reconstruction of the shallow hydrogeological system. Consequently, these studies contribute to regional sustainable development projects in this semi-arid region.     

Mahafir: A water harvesting system in the Eastern Jordan (Badia) Eesert

There are many different water harvesting systems in the Middle East and the operation of one type, the mahafir, was investigated in the Badia Region of Jordan. Mahafir are crescent and rectangular shaped excavations dug into the playa surface, now filled with sediment. Their previous volumes were estimated through topographical survey of the surrounding earth mounds. The average depth of the mahafir was found to be 3.2 m; storing a total water volume of 111,619 m³ at Maharouta and 55,005 m³ at Anka. The mahafir only occupy 4% of the playa surface and their source of water is primarily direct rainfall onto the playa surface augmented by runoff from adjacent slopes. Taking annual rainfalls as an input from 1963 to 1992 and even assuming rainfall harvesting is only 10% effective it appears that the full water storage potential of the mahafir could be met in most years.