共查询到18条相似文献，搜索用时 578 毫秒
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分别采用盐酸和草酸为浸出酸，对吉林省长白地区的瓷石进行了酸浸除铁漂白试验。对比了盐酸和草酸的酸浸除铁漂白的效果，结果发现用草酸比用盐酸除铁漂白效果好。草酸的浓度、矿浆浓度、浸出时间、浸出温度等因素对除铁漂白效果有一定影响。矿浆质量分数以15％为宜，随着草酸浓度的增加、浸出时间的延长、浸出温度的升高，瓷石的除铁漂白效果明显提高。最佳的除铁漂白方案为：草酸水溶液质量分数为l.00％，矿浆质量分数为15％，浸出反应时间为150min，浸出反应温度为60℃。经除铁漂白处理，使瓷石中铁的质量分数由原来的O．64％降为O．20％，瓷石白度由原来的68．2％提高到了83．7％，最高可达84％。 相似文献
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钾长石粉酸浸除铁废液资源化的实验研究 总被引：3，自引：0，他引：3
钾长石粉经过硫酸或盐酸酸浸除铁后, 废液中含有大量的金属离子和游离酸.对废硫酸进行循环利用实验, 钾长石粉铁的浸出率达到88.3%.对酸浸废液进行蒸发结晶, 分别制备得到了纯度为94.1%的绿钾铁矾和74%的三氯化铁.用硫酸酸浸废液蒸发结晶后, 铁的回收率为70.0%, 钾的回收率为96.5%, 整个工艺无需高温, 无需加压, 操作简单, 具有高效、低能耗、低污染的特点, 表明用本项技术处理酸浸废液行之有效.分析认为, 废液呈强酸性、溶液中存在大量Fe2+、碱金属离子含量偏低是蒸发结晶过程中形成绿钾铁矾而不是黄钾铁矾的主要原因. 相似文献
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利用钾长石粉水热合成13X沸石分子筛的实验研究 总被引：11，自引：0，他引：11
对综合利用钾长石提钾工艺中的重要高附加值副产品13X沸石分子筛的合成进行了实验研究。对福建沙县的钾长石粉加入配料NaCO3进行焙烧实验，确定培烧的最佳工艺参数为：钾长石粉：NaCO3=1：1．30(摩尔比)，焙烧温度为845℃，焙烧时间为150min；优化的水热合成条件为M2O／SiO2(mo1)=1．50，H2O／M2O(mo1)=40．0，合成时间为8h，晶种加入量为9．0％。对合成样品化学成分分析、X射线物相分析、红外光谱分析、扫描电镜分析表明，合成13X沸石分子筛结晶完好，性能优良．水热反应经由溶解水合反应和聚合浓缩反应两大阶段。 相似文献
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杂卤石矿地浸模拟实验研究 总被引：4，自引：0，他引：4
通过对难溶含钾矿物杂卤石的柱浸实验模拟石溶浸过程分析发现,采用CaCl2溶液作溶浸剂,其溶浸剂浓度、淋洗速度、矿石粒度、浸滤路径等因素对K溶浸率及溶浸速度均有影响,当矿石粒度为1 mm和5 mm时,钾浸出率分别可达到80%和70%以上,溶浸剂浓度增加,可提高钾的浸出率,但CaCl2浓度高于5%后,效果不明显。淋洗速度增大,虽可提高钾的浸出率,但同时浸出液中钾的富集程度有所降低,以4.5 ml/h～10 ml/h为佳;增加渗滤路径长度可同时提高钾的浸出率和富集程度。实验结果表明杂卤石溶解过程受固相层扩散控制,溶解反应过程较好地符合“收缩未反应核模型”的固相控制动力学方程1-(2/3)α(1-α)2/3=(2MD′c/bργ02)t。研究结果为地浸开采深埋藏杂卤石提供了一定的实验基础。 相似文献
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利用钾长石粉体水热合成13X沸石分子筛的晶化过程 总被引：2，自引：1，他引：1
实验研究了以钾长石粉体为原料水热合成13X沸石分子筛的晶化过程,确定了晶化过程的诱导期、晶化期和沸石晶体的平均生长速率。以钾长石焙烧熟料为前驱物合成13X沸石,反应混合物首先转变为铝硅酸钠（钾）凝胶,再逐步水热晶化为13X沸石;在反应物未完全转变为铝硅酸钠（钾）凝胶之前,13X沸石已开始结晶。13X沸石晶体的生成主要发生在凝胶相内部,是凝胶结构逐步趋于有序化的过程。13X沸石晶体生成是由凝胶相内的[TO4]四面体相互连接,互套构成笼状结构。推测13X沸石形成机理为：硅酸根离子和铝酸根（+铁酸根）离子发生聚合反应,生成次级结构单元双六元环;双六元环进一步缩合,生成方钠石型笼;最后,方钠石型笼进一步相互联结,生成13X型沸石分子筛的硅铝骨架结构。 相似文献
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地浸过程中铀迁移特征研究 总被引：1，自引：1，他引：1
通过室内溶质迁移试验，对地浸过程中铀迁移的规律进行了研究。结果表明：地浸过程中溶质铀主要以铀酰、硫酸铀酰为主要存在形式；铀迁移经历了溶解迁移、沉淀、再溶解迁移的多次旋回；浸出铀浓度最大值和浸出速度与浸出距离和浸出时间密切相关。 相似文献
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Harald Puchelt Hans Hartmut Schock Erich Schroll Helmut Hanert 《International Journal of Earth Sciences》1973,62(3):786-812
Recent iron sediments forming at present in a bay of the volcanic island Palaea Kameni within the caldera of Santorini, Aegean Sea, have been investigated for their mineralogy and geochemistry. For the first time siderite has been found in a marine environment to be major constituent of a recent sediment. Further main constituents are opal, ferric hydroxide, vivianite, ferrous hydroxide, and possibly ferrous silicate. The chemical composition both of the solid material of the sediment cores and of their pore solution indicate that the ore forming solutions have originated from the leaching of volcanic kalk-alcaline rocks by hot acid solutions. This is in agreement with experimental leaching of these rock types. No enrichment of lead, copper, zinc etc. was found in the sediments. Iron oxidizing bacteria in the reddish-brown ferric hydroxide sediments now forming in bays of the Kameni Islands have been studied by light and electron microscopic investigations. Samples from the uppermost parts of the sediment consist mainly of the ferric hydroxide stalks of the iron bacteriumGallionella ferruginea. The stalks showing their morphological characteristics occur in such masses that there is no doubt concerning the presence, activity and share of these bacteria in the process of iron sedimentation. Phases of sedimentation process and kinetics of ferric hydroxide stalk formation have been determined qualitatively and quantitatively by in-situ-experiments using artificial growing surfaces (underwater “Aufwuchs” on glass slides). The results obtained are compared to similar iron sedimentation in fresh water habitats and iron rich carbonate springs discussed in literature in connection with the problem of submarine exhalative sedimentary iron ore formation. 相似文献
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Thomas D. Brock Susan Cook Sandra Petersen J.L. Mosser 《Geochimica et cosmochimica acta》1976,40(5):493-500
A survey of hot, acid springs in Yellowstone Park has shown that high concentrations of ferrous and ferric iron are often present. Total ionic iron concentrations in different springs ranged from less than 1 ppm to greater than 200 ppm, and up to 50% of the ionic iron was in the ferrous form. Some of these springs also have high concentrations of reduced sulfur species (S2? and S0). Significant populations of the bacterium Sulfolobus, acidocaldarius, an autotrophic organism able to live and oxidize sulfur compounds at low pH and high temperature, were present in most of these springs. The role of this organism in the oxidation of ferrous iron was investigated by incubating natural samples of water and assaying for disappearance of ferrous iron. Controls in which bacterial activity was inhibited by addition of 10% NaCl were also run. Bacterial oxidation of ferrous iron occurred in most but not all of the spring waters. The temperature optimum for oxidation varied from spring to spring, but significant oxidation occurred at temperatures of 80–85°C, but not at 90°C. Thus, 85–90°C is the upper temperature at which bacterial iron oxidation occurs; a similar upper limit has previously been reported for sulfur oxidation in the same kinds of springs. The steady-state concentrations of ferrous and ferric iron are determined by the rate at which these ions move into the spring pools with the ground water (flow rate), by the rate at which ferric iron is reduced to the ferrous state by sulfide, and by the rate of bacterial oxidation. The bacterial oxidation rate is faster than the flow rate, so that the rate of reduction of ferric iron is probably the rate-controlling reaction. In several springs, no decrease in ferrous iron occurred, even though high bacterial populations were present. It was shown that in these springs, ferrous iron oxidation occurred but the ferric iron formed was reduced back to the ferrous state again. These springs were all high in suspended sediment and the reductant was shown to be present in the sediment. X-ray diffraction revealed that the sediment contained three major ingredients, elemental sulfur, natroalunite, and quartz. Chemical analyses showed a small amount of sulfide, too little to reduce the ferric iron. Elemental sulfur itself did not reduce ferric iron but when elemental sulfur was removed from the sediment by CS2 extraction, the activity of the sediment was abolished. It is hypothesized that the sulfide present in the sediment (possibly bound to natroalunite) reacts with elemental sulfur to form a reductant for ferric iron. The results show that bacteria can have a profound influence on the ferrous/ferric ratios of geothermal systems, but that temperature and mineral composition of the water may significantly influence the overall result. 相似文献
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酸性矿山废水中生物成因次生高铁矿物的形成及环境工程意义 总被引：10，自引：1，他引：9
酸性矿山废水(acid mine drainage,AMD)是一类pH低并含有大量有毒金属元素的废水。AMD及受其影响的环境中次生高铁矿物类型主要包括羟基硫酸高铁矿物(如黄铁矾和施威特曼石等)和一些含水氧化铁矿物(如针铁矿和水铁矿等),而且这些矿物在不同条件下会发生相转变,如施氏矿物向针铁矿或黄铁矾矿物相转化。基于酸性环境中生物成因次生矿物的形成会"自然钝化"或"清除"废水中铁和有毒金属这一现象所获得的启示,提出利用这些矿物作为环境吸附材料去除地下水中砷,不但吸附量大(如施氏矿物对As的吸附可高达120mg/g),而且可直接吸附As(III),还几乎不受地下水中其他元素影响。利用AMD环境中羟基硫酸高铁矿物形成的原理,可将其应用于AMD石灰中和主动处理系统中,构成"强化微生物氧化诱导成矿-石灰中和"的联合主动处理系统,以提高AMD处理效果和降低石灰用量。利用微生物强化氧化与次生矿物晶体不断生长的原理构筑生物渗透性反应墙(PRB)并和石灰石渗透沟渠耦联,形成新型的AMD联合被动处理系统,这将有助于大幅度增加处理系统的寿命和处理效率。此外,文中还探讨了上述生物成因矿物形成在AMD和地下水处理方面应用的优点以及今后需要继续研究的问题。 相似文献
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安徽宁国钾长石共烧结工艺研究 总被引：7，自引：0，他引：7
以宁国钾长石矿为主要原料，采用共烧结工艺，研究了用CaCl2做添加剂与钾长石共烧结温度、温度、CaCl2用量对溶出率的影响，确定了共烧结最佳参数，同时，通过XRD表征方法，对原矿物相及水浸潭物相进行了研究，探讨了共烧结反应机理，实验结果表明，钾长石中K2O溶出率可达95％。 相似文献
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Redox reactions in seafloor basalts: possible insights into silicic hydrothermal systems 总被引：1，自引：0，他引：1
John R. Holloway 《Chemical Geology》2004,210(1-4):225-230
Many features of the magma-hydrothermal interface are directly observable in, near seafloor hydrothermal systems at mid-ocean ridges. A striking aspect observed at that interface is the spontaneous redox reaction that occurs during rapid crystallization of basaltic magma, which results in generation of highly reducing hydrothermal fluids. A consequence of the reaction is that the ferric/ferrous ratio observed in the resulting crystalline basalt is much higher than it was in the basaltic magma, the redox state of the magma inferred from the ferric/ferrous ratio in the crystalline rock is considerably higher than it was in the magma [Earth Planet. Sci. Lett. 79 (1986) 397]. Magnetite-ulvöspinel is the only ferric iron-containing phase observed in the crystalline portion of the basalt. This suggests that the driving force for that reaction is related to the stability of magnetite relative to the FeO component in the basaltic liquid (or glass), resulting in the oxidation of ferrous iron by H2O dissolved in the melt, yielding magnetite, releasing H2 from the system. This is an auto-oxidation reaction in which all reactants are present internally in the basalt magma prior to crystallization. H2O is the limiting reagent for magnetite formation in the case of MORB magma. If a similar auto-oxidation occurs in the more silicic magmas commonly associated with terrestrial hydrothermal ore deposits, it would have important consequences for the interpretation of the redox condition existing at terrestrial magma-hydrothermal interfaces. Glassy I-type dacites extruded on the seafloor in the Manus Basin have ferric/ferrous ratios that are significantly lower than in I-type plutons, terrestrial volcanics. The ferric/ferrous ratios in the Manus Basin dacites yield oxygen fugacities from about one to more than two log units below that of nickel–nickel oxide. Oxidation of ferrous iron in these silicic magmas is predicted to generate an amount of H2 that is proportional to the amount of ferrous iron present, rather than the amount of H2O (as in the case of MORB) due to the high ratio of H2O to ferrous iron in silicic magmas. These relatively reduced dacitic magmas would yield significant quantities of H2 on crystallization, which would make hydrothermal fluids at the interface strongly reducing, thus affect the speciation in fluids at the magma-hydrothermal interface. 相似文献
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BIF在全球广泛分布,BIF型铁矿是铁的重要来源。根据产出的构造背景将其分为阿尔戈玛型（Algoma-type）和苏必利尔湖型（Lake Superior-type）。BIF主要产出于前寒武纪的古老克拉通和/或年轻地体,形成时代集中在3.0～2.0 Ga,峰期为2.5 Ga左右。前人对BIF型铁矿的成因研究着重于BIF的物质来源和Fe2+ 氧化沉淀机制两个方面,但都尚未达成共识。物质来源的观点主要有大陆风化剥蚀、海底热液、海底热液和海水的混合物、热液淋滤洋壳、既有大陆物质来源又有热液来源,沉淀机制主要有生物沉淀和非生物沉淀两种认识,前者是指Fe2+ 利用微生物（如蓝藻）光合作用产生的O2氧化成Fe3+,或Fe2+ 直接被微生物代谢氧化,后者主要包括热液与海水混合、密度流作用、相分离、紫外线引起Fe2+ 氧化沉淀等。 相似文献
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含金黄铁矿氧化过程中金溶解机理的探讨——与王恩德、关广岳先生商榷 总被引：2，自引：0，他引：2
含金黄铁矿在细菌氧化、化学氧化过程中,除生成高铁的硫酸盐和硫酸外,还生成了亚铁的硫酸盐及硫的低价氧化物,体系中的电位较低,距溶解自然金呈Au(SO_4)_2~-所需电位甚远,实验表明,金不溶于硫酸铁溶液中。当氧化程度加深,介质pH>4,黄铁矿氧化产生的硫代硫酸根可稳定存在时,自然金呈稳定的硫代硫酸盐配合物溶解。 相似文献