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推荐ＸＲＦ粉末法直接测定硅线选矿流程试样中铝、铁、钛、钾、钠。以不同矿区的选矿流程试样作为标准，试样研磨至所需粒度。用经验系数校正法克服矿物效应，颗粒度效应和共存元素间的影响，与化学分析法相比，本法快速，简便，成本低，测定结果满足选矿要求。 相似文献
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滑石的颗粒粒径、形貌、晶型等对其应用的实效性、终端产品的性能产生极大影响,目前主要研究其表面改性,而有关微观形貌及晶体结构研究较少。本文利用X射线荧光光谱、X射线衍射分析、红外光谱、粒度分析仪结合高分辨场发射扫描电镜(FE-SEM)技术对辽宁滑石粉在高强度机械力研磨作用下的微形貌和晶体结构变化特征进行系统研究。结果表明滑石粉原矿混合物中MgO与SiO2的分子个数比约为0.45,该数值明显低于纯滑石粉晶体中MgO与SiO2的分子个数比0.75。此类滑石为典型的单斜晶系,研磨作用使滑石粉由晶态转变为非晶态结构,其层状结构的有序化和键合作用发生了明显的变化。滑石粒度随研磨时间变化呈现减小-增大-减小的循环过程。研磨后粉体形貌存在差异,细化的小颗粒粉体因团聚而呈"准球体",且随着研磨的进行出现细化-团聚-细化的反复过程。此结论对于滑石的深加工与应用及其相关矿物粉体的研究具有一定的参考价值。 相似文献
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《矿物学报》2017,(6)
综合多种测试方法,考察了研磨对茂名高岭石粒径、形貌与微结构等理化性质的影响。重点采用~(29)Si、~(27)Al MAS NMR光谱考察了研磨过程中结构脱羟、Si、Al配位环境变化、新活性位点形成等微结构演变等。结果表明:研磨初期,高岭石六方片层遭到破碎,颗粒粒径逐渐减小,比表面积在研磨1 h达到最大(43.8 m~2/g);此后,颗粒发生团聚,比表面积减小,样品脱羟量和表面吸附水含量均逐渐增加。核磁Si谱和Al谱分别在化学位移-100.5和14.8处出现新的信号,归属于四面体Si与八面体Al相连顶氧质子化作用而产生的Q~3 Si-OH~+-Al结构。研磨导致高岭石脱羟,Al配位状态从AlⅥ经由AlⅤ逐渐向AlⅣ转变。 相似文献
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凹凸棒石-TiO2-磁性颗粒纳米复合材料的制备 总被引：3，自引：0，他引：3
为制备具有高效吸附、光催化性能,可磁分离回收催化剂的凹凸棒石-TiO2-磁颗粒纳米复合材料,本文研究了不同反应温度、不同量的氧化剂加量、不同的碱加入量对复合材料磁化率的影响,并利用透射电镜、X射线粉末衍射对制备的复合材料结构和微形貌进行了表征。实验结果表明,在70℃下,Fe2 ∶OH-∶NO3-质量比为1∶0.6∶0.056时,反应生成的产物再经500℃煅烧,获得的凹凸棒石-TiO2-磁性颗粒纳米复合材料的磁化率最高。高分辨透射电镜表征结果显示,经500℃煅烧获得的凹凸棒石-TiO2-磁性颗粒复合材料,其TiO2和磁性颗粒非常均匀地吸附在凹凸棒石表面。 相似文献
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矿物颜料是传统绘画的物质基础,青金石颜料的应用历史源远流长。为研究高能球磨对青金石结构和颜料性能的影响,使用行星式球磨机处理原料,通过扫描电镜测试、透射电镜测试、激光粒度分析、BET分析、X射线衍射测试、X射线光电子能谱测试对样品进行分析和表征,以硅橡胶基底法制备颜料样品并使用分光色度计进行色差分析。研究结果表明,球磨后,颗粒的物质组成不变,表面的层状沟纹形貌被破坏,粒度和孔径减小,粒径分布变窄,比表面积和孔容增加,结晶度降低。球磨后颜料的亮度和反射率上升,粒度变化是其主要影响因素。在一定研磨时间内粒度变小使处在长波段的红光的反射受到干扰,颗粒在a*轴色品上产生由红色向绿色漂移的呈色效果;在一定研磨时间后颗粒结晶度变小使蓝紫波段可见光的反射受到削弱,颗粒在b*轴色品上产生由蓝色向黄色漂移的呈色效果。 相似文献
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研究了钠基蒙脱石吸附Ni^2+后以及产物经过500℃热处理后的结构变化,采用了X射线荧光光谱术(XRF)、粉末X射线衍射术(XRD)、电子顺磁共振谱术(ESR)、傅里叶变换红外吸收光谱术(FTIR)以及拓展X射线吸收精细结构谱术(EXAFS)等分析手段测试了固体产物的特征,并利用电感耦合等离子体原子发射光谱术(ICP-AES)分析了吸附残余液的化学组成。吸附残余液的化学分析结果表明,溶液中Ni^2+的量显著降低,同时又检测到一定量的Na^+、Mg^2+等离子,且XRD结果也证实蒙脱石层间域发生Ni^2+的交换吸附。EXAFS和ESR的结果进一步表明吸附反应后Ni^2+以[Ni(H2O)6]^2+的形式存在于蒙脱石的层间域,样品经过500℃加热后产物的XRD和FTIR结果均显示出现类滑石相产物。 相似文献
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动态光散射技术原位表征天然有机质存在下纳米零价铁的团聚效应 总被引：1，自引：1，他引：0
纳米零价铁原位修复地下水污染是近年发展起来的新技术,通过改性合成不同种类纳米零价铁可以克服其易团聚易氧化的问题,水体中存在的天然有机质也会对纳米铁的分散性和反应活性产生影响,因此开展原位测试并研究不同种类纳米铁在水中的团聚效应具有重要意义。本文对实验合成的纳米零价铁、羧甲基纤维素包覆纳米零价铁、膨润土负载纳米零价铁以及商用纳米零价铁,基于动态光散射技术(DLS),运用纳米粒度/Zeta电位分析仪,结合透射电子显微镜(TEM)和沉降光谱曲线等手段,对比研究了天然有机质(腐植酸HA)对纳米铁团聚效应的影响。结果表明,羧甲基纤维素包覆或膨润土负载改性提高了纳米零价铁颗粒的分散稳定性,有效抑制了团聚沉降,团聚体粒径分布在1000 nm以下。HA会吸附在纳米铁颗粒表面,从而增加静电排斥力,进一步减缓了团聚效应,尤其是对膨润土负载纳米零价铁的影响最为显著,其团聚体粒径能降至100 nm以下,沉降速率也极大减缓,分散稳定性表现最佳。本研究表明DLS结合TEM表征纳米颗粒是获得更加丰富的微观粒子信息的一种非常重要的手段。 相似文献
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水悬浮体系中凹凸棒石与Cu2+作用机理 总被引：12，自引：0，他引：12
研究矿物吸附重金属性能和机理,对正确认识矿物吸附性质、环境矿物材料应用研究以及重金属环境化学行为具有重要理论和实际意义。凹凸棒石是重要粘土矿物之一,也是重要的环境矿物材料,其吸附净化功能潜在应用受到广泛关注。在制备凹凸棒石纯样基础上,进行了凹凸棒石吸附Cu^2 单因素实验,吸附前后溶液pH值变化观测和吸附Cu^2 后凹凸棒石表面结构高分辨透射电镜调查。结果表明,从表面来看,凹凸棒石对Cu^2 的吸附性能主要受振荡速度、吸附时间、初始溶液pH值、吸附剂用量等因素影响,但实际上,凹凸棒石对Cu^2 的吸附作用主要是凹凸棒石诱导的Cu^2 水解沉淀作用以及凹凸棒石(带负电荷)与氢氧化铜(带正电荷)正负电荷胶体颗粒的互相作用,这有别于严格意义的矿物界面吸附作用。产生这种作用的机制在于凹凸棒石属于天然纳米矿物材料,具有较高的表面化学活性,凹凸棒石一水悬浮体系中凹凸棒石表面水解呈现出碱性,结果导致吸附平衡水溶液pH值较初始水溶液有较大程度的升高,达到Cu^2 水解基本完全的pH条件. 相似文献
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陕北晋西砂黄土的胶结物与胶结作用研究 总被引：26，自引：9，他引：17
在野外调查的基础上,采用SEM、XRD、土壤物理和土壤化学等方法,对陕北晋西12个县市的48个马兰黄土样品进 行了全分散法粒度组成测定、聚集体分析以及黄土胶结物组成的测试分析。结果表明,砂黄土中的粘土矿物和超细碳酸盐、 游离氧化物和有机质等胶结物质主要是以聚集体包膜的形式存在于碎屑颗粒表面,并构成砂黄土骨架间的结构联结,具有弱 胶结特性。砂黄土中粘土矿物和有机质为非水稳性胶结物质,仅在干燥状态具有较弱的胶结作用;黄土中的CaCO3呈粗颗粒 骨架和细分散超细碳酸钙两种形式存在,并分别起着骨架作用和胶结作用,超细碳酸钙为不可逆的胶结材料,在聚集体形成、 保存以及聚集体与碎屑颗粒之间的联结方面发挥着重要作用;非晶质游离氧化物(SiO2、Fe2O3、Al2O3)含量虽低,但由于他们 是以薄膜形式分布在颗粒表面,在黄土胶结作用中也是不可忽视的,并与上述各种胶结物共同起作用。通过统计分析认为, 凝聚系数可以较好地反映黄土的胶结程度,成为联系黄土胶结特性与黄土物理力学性质之间的桥梁。黄土胶结物组成及其 胶结机理的研究不仅有助于深化砂黄土工程特性的认识,而且对揭示黄土高原表生地球化学环境具有重要意义。 相似文献
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It has been widely accepted that a chemically altered, protective surface layer regulates the dissolution, and hence the weathering, of plagioclase feldspars under Earth's surface conditions. In this study, we examine this hypothesis in detail with the aid of scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Using these techniques, we have been unable to find any direct evidence suggesting the presence of a chemically altered coating on feldspar surfaces which have been weathered in the lab. Instead, our results suggest that the mechanism controlling feldspar weathering is a surface controlled reaction.Based on SEM observations and measurements of rate of release of silica, we postulate that the process of feldspar dissolution proceeds in two stages in the lab. Initially, one observes the dissolution of ultrafine (? 1 μm diameter) particles which are produced during grinding of the sample, and which adhere tenaciously to the surfaces of larger grains. This is the stage which results in the non-linear rates of dissolution which are commonly observed in the lab (parabolic kinetics). Secondly, the dissolution occurs at sites of excess surface energy such as at dislocations or similar crystal defects. This process yields linear rates of dissolution, and it dominates the weathering of feldspars in the field. 相似文献
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《矿物学报》2013,(Z1)
An attempt was made to prepare carbon coated tourmaline by mixing tourmaline powders and polyvinyl alcohol (PVA), followed by heat treatment in argon atmosphere. All samples were characterized by powder X-ray diffraction, high-resolution transmission electron microscopy, UV diffuse reflectance spectroscopy. Results showed that the residual carbon content was influenced by heat treatment temperature and the amount of PVA. The degradation of methylene blue by Carbon-coated tourmaline was also studied. The experiments pointed out that the carbon coated effects are best when the heating temperature was 900℃ and the weight content of PVA was 70%. And the tourmaline prepared under 900℃ in the oxidation atmosphere has the best degrade efficiency. The results also proved that the infrared radiation of tourmaline is not effect in the degrade progress. 相似文献
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研究了电气石微粉吸附水中Cu2＋、Pb2＋、Zn2＋的过程,讨论了吸附时间、粒度、用量和pH值等因素对吸附效果的影响,分析了电气石对含Cu2＋、Pb2＋、Zn2＋废水的吸附机理。电气石加工成超细粉体时,表面产生大量的不饱和键,在溶液中与水配位,使水发生解离生成羟基化表面,将重金属离子吸附到晶体负极,使局部金属离子浓度增高与电气石表面羟基离解而产生的氢氧根离子发生反应,形成各种沉淀或碱式盐析出,直到溶液中各种离子浓度达到平衡时为止。提出了凡是氢氧化物难溶于水的金属离子,理论上都可以使用电气石微粉进行吸附净化处理的观点。研究结果表明,电气石微粉对Cu2＋、Pb2＋、Zn2＋有较好的吸附效果。 相似文献
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《International Journal of Mineral Processing》2005,76(4):244-259
The effect of carbon or graphite coating on the adsorption of gold cyanide on pyrite was investigated with pure pyrite and a pyrite concentrate. In the carbon or graphite contaminated pyrite systems carbon and graphite not only acted as gold sorbents, but also enhanced gold adsorption on pyrite. The carbon coating enhanced gold adsorption on pyrite to a larger extent, in comparison with the graphite coating. The carbon or graphite coating on pyrite reduced the negativity of the pyrite surfaces, and hence improved the physical adsorption of gold cyanide on pyrite. In addition, the highly conductive coating of carbon or graphite on pyrite could enhance electron transfer in the electrochemical reactions occurring in the chemical adsorption of gold and gold reduction on pyrite. The preg-robbing by pyrite or the graphite-coated pyrite was reduced and further eliminated at higher cyanide concentrations. However, gold adsorption on the carbon-coated pyrite could not be prevented even at higher cyanide concentrations due to gold adsorption on the carbon coating. In comparison with pure pyrite, the pyrite concentrate had a higher capacity adsorbing gold, due to the presence of carbonaceous matter in the pyrite concentrate. Fine grinding intensified the smearing of carbon or graphite on the mineral particles, resulting in a larger extent of enhancement in the preg-robbing of the concentrate by the carbon or graphite coating.A diagnostic elution of the preg-robbing pyrite samples indicated that the reduction of gold at the pyrite surfaces was the dominant mechanism for gold adsorption on pyrite, followed by physical and chemical adsorption. Surface topological studies by SEM/EDX showed that gold adsorbed at defect sites on pyrite surfaces. For the pyrite with a 5% carbon coating, gold was observed to adsorb not only at the defect sites, but also at the smooth surfaces with carbon present. For the pyrite with a 5% graphite coating, carbon was also found at the pyrite surfaces, but gold was only detected at the defect sites. XPS studies revealed that part of the gold physically and chemically adsorbed on pyrite or pyrite coated with carbon or graphite. Some gold cyanide was reduced at the pyrite surfaces, with the sulphide ions of pyrite being oxidised to elemental sulphur. 相似文献
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《International Journal of Mineral Processing》2005,77(3):123-138
The effect of carbon or graphite coating on the adsorption of gold cyanide on pyrite was investigated with pure pyrite and a pyrite concentrate. In the carbon or graphite-contaminated pyrite systems carbon and graphite not only acted as gold sorbents, but also enhanced gold adsorption on pyrite. The carbon coating enhanced gold adsorption on pyrite to a larger extent, in comparison with the graphite coating. The carbon or graphite coating on pyrite reduced the negativity of the pyrite surfaces, and hence improved the physical adsorption of gold cyanide on pyrite. In addition, the highly conductive coating of carbon or graphite on pyrite could enhance electron transfer in the electrochemical reactions occurring in the chemical adsorption of gold and gold reduction on pyrite. The preg-robbing by pyrite or the graphite-coated pyrite was reduced and further eliminated at higher cyanide concentrations. However, gold adsorption on the carbon-coated pyrite could not be prevented even at higher cyanide concentrations due to gold adsorption on the carbon coating. In comparison with pure pyrite, the pyrite concentrate had a higher capacity adsorbing gold, due to the presence of carbonaceous matter in the pyrite concentrate. Fine grinding intensified the smearing of carbon or graphite on the mineral particles, resulting in a larger extent of enhancement in the preg-robbing of the concentrate by the carbon or graphite coating.A diagnostic elution of the preg-robbing pyrite samples indicated that the reduction of gold at the pyrite surfaces was the dominant mechanism for gold adsorption on pyrite, followed by physical and chemical adsorption. Surface topological studies by SEM/EDX showed that gold adsorbed at defect sites on pyrite surfaces. For the pyrite with a 5% carbon coating, gold was observed to adsorb not only at the defect sites, but also at the smooth surfaces with carbon present. For the pyrite with a 5% graphite coating, carbon was also found at the pyrite surfaces, but gold was only detected at the defect sites. XPS studies revealed that part of the gold physically and chemically adsorbed on pyrite or pyrite coated with carbon or graphite. Some gold cyanide was reduced at the pyrite surfaces, with the sulphide ions of pyrite being oxidised to elemental sulphur. 相似文献
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Mining and metallurgical processing of gold and base metal ores can lead to the release of arsenic into the aqueous environment as a result of the weathering and leaching of As-bearing minerals during processing and following disposal. Arsenic in process solutions and mine drainage can be effectively stabilized through the precipitation of ferrihydrite. However, under anaerobic conditions imposed by burial and waste cover systems, ferrihydrite is susceptible to microbial reduction. This research, stimulated by the paucity of information and limited understanding of the microbial reduction of arsenical ferrihydrite, was conducted on synthetic adsorbed and co-precipitated arsenical 6-line ferrihydrite (Fe/As molar ratio of 10/1) using Shewanella sp. ANA-3 and Shewanella putrefaciens CN32 in a chemically defined medium containing 0.045 mM phosphate concentration. Both bacteria were equally effective in their reducing abilities around pH 7, resulting in initial rates of formation of dissolved As(III) of 0.10 μM/h for the adsorbed, and 0.08 μM/h for the co-precipitated arsenical 6-line ferrihydrite samples. The solid phases in the post-reduction samples were characterized by powder X-ray diffraction (XRD), micro-XRD, scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron microprobe and X-ray absorption spectroscopy (XAS) techniques. The results indicate the formation of secondary phases such as a biogenic Fe(II)–As(III) compound, akaganeite, goethite, hematite and possibly magnetite during bacterial reduction experiments. Holes and bacterial imprints measuring about 1–2 μm were observed on the surfaces of the secondary phases formed after 1200 h of reduction. This study demonstrates the influence of Fe and As reducing bacteria on the release of significant concentrations of more mobile and toxic As(III) species from arsenical 6-line ferrihydrite, more readily from the adsorbed than from the co-precipitated ferrihydrite. 相似文献
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Iron sulfide was synthesized by reacting aqueous solutions of sodium sulfide and ferrous chloride for 3 days. By X-ray powder diffraction (XRPD), the resultant phase was determined to be primarily nanocrystalline mackinawite (space group: P4/ nmm) with unit cell parameters a = b = 3.67 Å and c = 5.20 Å. Iron K-edge XAS analysis also indicated the dominance of mackinawite. Lattice expansion of synthetic mackinawite was observed along the c-axis relative to well-crystalline mackinawite. Compared with relatively short-aged phase, the mackinawite prepared here was composed of larger crystallites with less elongated lattice spacings. The direct observation of lattice fringes by HR-TEM verified the applicability of Bragg diffraction in determining the lattice parameters of nanocrystalline mackinawite from XRPD patterns. Estimated particle size and external specific surface area (SSAext) of nanocrystalline mackinawite varied significantly with the methods used. The use of Scherrer equation for measuring crystallite size based on XRPD patterns is limited by uncertainty of the Scherrer constant (K) due to the presence of polydisperse particles. The presence of polycrystalline particles may also lead to inaccurate particle size estimation by Scherrer equation, given that crystallite and particle sizes are not equivalent. The TEM observation yielded the smallest SSAext of 103 m2/g. This measurement was not representative of dispersed particles due to particle aggregation from drying during sample preparation. In contrast, EGME method and PCS measurement yielded higher SSAext (276-345 m2/g by EGME and 424 ± 130 m2/g by PCS). These were in reasonable agreement with those previously measured by the methods insensitive to particle aggregation. 相似文献