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钱会 《地球科学与环境学报》1987,(3)
本文在参阅Crerar D.A.等人的资料的基础上,比较系统地论述了水溶液中各种化学组分可能存在形式分配及Eh值的计算方法。文章从对施实计算所需的原始数据的说明开始,主要从以下几个方面说明了计算方法:1.热力学问题的数学描述;2.问题的数值解;3.活度系数的校正;4.迭代步骤;5.Eh值的计算。文中以华清池温泉水化学分析资料为例,分别给出了此资料在12℃和42℃时的计算结果。由于分析技术和计算方法的误差,Eh值的计算结果存在一定的偏离,这也可能是由于给定温度下水中某些组分间存在着非平衡而引起的。 相似文献
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早子沟金矿位于秦岭造山带西段夏河—合作断裂带上,矿区成矿作用与岩浆热液及断裂构造关系密切,矿区岩浆岩内石英中含有大量熔体包裹体及流体包裹体,显微测温结果显示,熔体包裹体均一温度范围为700℃-790℃,流体包裹体分为H2O-NaCl包裹体、NaCl-H2O-CO2包裹体、H2O-CO2包裹体3种类型,包裹体均一温度范围为195℃-360℃,本文通过对熔体包裹体的研究,采用“熔体包裹体＋流体包裹体”的方法 ,估算矿区岩浆岩成岩压力为275MPa,依据断裂带流体垂直分带规律,计算得到早子沟金矿成岩深度为13.96km,成矿深度为2.10-6.02km,平均成矿深度为4.06km。表明矿区深部成矿找矿尚有很大潜力。应用刘斌及Ryzhenko and Bryzgalin推导的计算流体包裹体pH值及Eh值的公式,对矿区不同体系（类型）流体包裹体的pH值及Eh值进行了估算,其结果表明：早子沟金矿包裹体的pH值为2.25-5.88,成矿溶液为酸性,在成矿阶段pH呈升高的趋势;包裹体的Eh值为0.409-0.139V,成矿溶液体系从早期到晚期Eh呈逐渐降低的趋势。pH值及Eh值的这种变化趋势,均有利于矿区Au元素的沉淀富集。 相似文献
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Physico-chemical parameters of the acidic mining lake (ML) 111 in the Lusatian region (Germany) were determined in April and August 1997 using a multiparameter probe for the water column and punch-in pH and Eh electrodes for the sediment, respectively. Samples of the sediment profile were taken by a gravity corer. Besides determination of the physico-chemical parameters, grain size and water contents were determined after sediment slicing.Differences in the redox state of the water body, deduced from oxygen saturation between April and August, could not be inferred. However, a shift in pH to lower values was apparent. Data support the conclusion that the enhanced oxygen content was consumed for oxidation of ferrous iron to ferric iron (oxides/hydroxides) coupled with the release of protons.In the sediment, different buffer systems of iron compounds could be detected within separate zones with values below and above pH 3. At higher pH values, the redox conditions are controlled and stabilized by the presence of Fe-oxide-hydroxides and possibly Fe-sulfates. 相似文献
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Sustainable land management often requires redevelopment of existing and often contaminated Brownfield sites over use of Greenfield or agricultural land. Stabilisation / solidification (S/S) offer a viable remediation option with particular suitability in treating heavy metal contaminants. However, uncertainties over long-term durability and previously cheap landfill disposal costs resulted in limited use in many countries. There is a need to characterise treated material and assess components containment and release, to improve S/S confidence and inform remedial design, using the evaluation of the leaching controlling mechanisms. To improve understanding of key features that will enable improvements to such designs, this paper presents an evaluation of leaching for CEM II stabilised kaolin, using the leaching behaviour of 4 main components—aluminium, silicon, calcium and sulphur. Results show no detrimental implications on chemical durability due to kaolin degradation with hydration under induced alkalinity, with increased formation of stable cementitious minerals. Availabilities for components show that aluminium and silicon had minimal leachability compared to total content, whilst calcium and sulphur show almost total leaching availability. Decreasing calcium and silicon leachability under natural chemical conditions with increased hydration duration supports the increased formation of stable cementitious products with time, using the products of kaolin dissociation. 相似文献
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伊犁盆地南缘侏罗系沉积微相及铀矿控矿条件研究 总被引：10，自引：0，他引：10
伊犁盆地是一个中生代陆相盆地，其南缘下－中侏罗统含煤地层十分发育。水西沟群划分为八道湾组、三工河组和西山窑组，沉积相分属于冲积扇相、三角洲相和湖泊相。可地浸砂岩型铀矿主要赋存于冲积扇扇中辫状河道微相和三角洲平原分流河道及泥炭沼泽微相。其铀矿床的主要控制因素是：盆地基底及周边地层含铀性；盆地周边构造发育条件；岩相古地理；沉积微相；成岩作用；地下水作用和氧化－还原地球化学分带。 相似文献
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G. M. Friedman P. K. Mukhopadhyay A. Moch M. Ahmed 《International Journal of Coal Geology》2000,43(1-4)
The New York Bight is a sector of the Middle Atlantic continental shelf. The Bight consists of a part of the Atlantic Ocean offshore of the New York and New Jersey metropolitan area. This area includes the most populated coastal setting in North America. The Atlantic shelf and its estuaries are used for waste disposal, dredging, commercial fishing, and recreation; activities that contribute to the contamination of associated bottom sediments. Existing data for toxicants are still inadequate. Improvements in sediment and water quality will require a more detailed knowledge and understanding of sediments and water in the Bight. Eleven coring stations were established in New York Bight. Decreases in pH and Eh both above and below the water/sediment interface are attributed to the activity of anaerobic bacteria. Sulfate reduction is one of the important processes in lowering pH. Low Eh values of up to −443 can be related to sulfate-reducing bacteria. The highest negative Eh generally occurs with the highest organic carbon concentration. Core samples yielded up to 4.00% organic carbon compared to 0.8 to 1.2% in sediments of the natural nearshore environment. Twenty-seven different aliphatic hydrocarbons, fourteen PAHs, five cyclic hydrocarbons, and eight dicarboxylic acids were identified in the Bight pore waters. Sediment located deeper in the Hudson Shelf Valley has a greater abundance of aliphatic hydrocarbons as adsorbed pollution on clay and silt. The presence of dicarboxylic acids leached from plastic came from anthropogenic activities (mostly sewage). PAHs have two sources: coal ash (observed in sediments) and petroleum (part of the sewage, run-offs, and oil spills). The rest of the hydrocarbons have a petroleum or biogenic origin. The high amount of organic carbon may be the result of sewage sludge or originated from natural sources. The main sources of contaminants are dumpsites, emergency releases after heavy rainstorms from sewage-treatment plants, tanker washing, storage transfer spills, run-off, and air-borne pollution. The relatively high accumulation of organic matter causes oxygen depletion, which creates anaerobic conditions. The presence of hydrogen sulfide makes the environment toxic for most of the biota. Detected hydrocarbons, especially PAHs easily enter the food chain and may cause cancer and mutagenic reactions of biota and humans. Organic petrology of six organic-rich sediments from New York Harbor illustrates a diverse population of anthropogenic and natural organic components. Three core samples (V-2, AC-4, and HV-3) contain coarse-textured organic matter. A slim majority of those components are anthropogenic. They are derived mainly from coal combustion by-products. The other two core samples (AC-6 and T-1) contain mainly very fine-grained organic matter. A majority of them are amorphous organic matter (AOM) that is derived from bacterial degradation of modern organic matter. Radionuclide dating (137Cs, K-40, Pb-210) shows post-1950 components for the shallowest intervals in the cores (<30 cm). The post-1950 sediment, distributed in the tops of core, is recycled material from the dumpsites. The underlying sediment has isotopic signatures that suggest dates before active dumping. 相似文献
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Chemical parameters characterizing the sedimentary environment in a NW Adriatic coastal area (Italy)
Organic matter constituents (C, N, P) have been measured in surficial sediment samples from a coastal area often subjected to eutrophication phenomena. Chemical and physico-chemical parameters are substantially homogeneous throughout the area investigated, indicating a mainly autochthonous origin of the sedimented organic matter and allowing some considerations on the diagenetic processes possibly occurring at the sediment-water interface in relation to nutrient release. 相似文献
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To accurately measure the pH, Eh, EC and temperature of groundwater retrieved from boreholes, a deep groundwater sampling
apparatus was developed which provided sensory measurements both in situ and in a flow-through cell at ground level. Under
a pressure of 1×106 Pa the in situ accuracy of the apparatus sensor was within the following limits: pH ±0.2, temperature ±0.1°C, Eh ±10 mV,
and EC ±2.4%. The measuring and sampling of deep groundwater from a borehole of more than 1000 m in depth was performed continuously
for 30 days. Values of pH were the same for the in situ sensor, the flow-through cell sensor and the laboratory measurements
of the sampled water. At the beginning of the sampling period, Eh values of the in situ sensor indicated deep groundwater
conditions. The apparatus is particularly useful for Eh measurement. Chemical composition and stable isotope ratios indicated
that the groundwater sampled from more than 1000 m depth was a connate water with a chemical composition slightly different
from seawater of the present time, and the groundwater retrieved from 800 m depth was a meteoric water. Natural radioactive
elements are thought to be the origin of the tritium in the groundwater retrieved from the 1000 m depth.
Received: 6 August 1996 / Accepted: 22 October 1996 相似文献