水淬渣-累托石颗粒吸附材料的制备及应用

研究了水淬渣-累托石颗粒吸附材料制备工艺条件、再生方法及其去除铜冶炼工业废水中重金属的条件.试验结果表明,累托石与水淬渣的比例为1∶1,另加入10%的添加剂(IS)和50%的水,焙烧温度为400℃时,制成的颗粒吸附材料体积密度为1.06kg/m3,显气孔率为62.29%,吸水率为58.82%,抗压强度为2.22Mpa,吸附效果好,散失率较低.在未调节铜冶炼工业废水pH值的条件下,颗粒吸附材料用量为0.05g/cm3,反应时间为40min,吸附温度为25℃(常温)时,Cu2 、Pb2 、Zn2 、Cd2 、Ni2 的去除率分别为98.2%、96.3%、78.6%、86.2%、64.2%,处理后的水符合国家污水综合排放标准(GB8978-1996)一级标准.颗粒吸附材料对Zn2 、Cu2 有很好的选择性.吸附饱和的颗粒吸附材料用1mol/L氯化钠溶液再生效果好.该颗粒吸附材料具有分离容易、可重复使用、处理效果好、应用前景广阔的优点.     

Source Apportionment for the Zinc—Containing Component of Air Particulate Matter using Automated Electron Probe Micro Analysis of Individual Particles

Abstract

A methodology is described for the apportionment of zinc-containing particulate matter sampled in the vicinity of a zinc smelter to their corresponding sources in the factory. Bulk samples of particulate matter from six potential emission sources were analysed by automated electron probe microanalysis (EPMA) in order to characterize the individual particles. Based on a data set of relative peak intensities and with the aid of a binary clustering method, the most important particle classes were identified. They were used as a basis for the development of a set of disjunct identification rules (decision rules), which were able to describe the classes in a unique manner. Applying these rules upon ambient particulate data enabled the estimation of relative contributions of different types of zinc-containing particles. Evidence was found that a large number of particles was modified by a soil component or by gas phase reactions.     

Studies of the naturally occurring biomethylation of selenium and the determination of the products

A systematic study of the biomethylation of selenium and the determination of the methylated species indicates preliminarily that selenium is susceptible to natural biomethylation under certain environmental conditions. Detectable levels of methylated selenium species, including dimethyl selenide [(CH₃)₂Se], dimethyl diselenide [(CH₃)₂Se₂] and dimethylselenone [(CH₃)₂SeO₂] have been detected by gas chromatography – graphite furnace atomic absorption spectrophotometry (GC – GF AA) from a variety of environmental samples. Findings of naturally methylated selenium species from both soil samples and related air samples suggest that there may exist a localized cycle of selenium between ground soil and the ambient air. Factors that influence the sensitivity and accuracy for the determination of alkyl selenide compounds by GC – GF AA have also been investigated. Flashlike injection mode and addition of about 10% of hydrogen gas to the argon carrier gas provide for highly sensitive detection. Reproducible determination can be obtained with a precision of about 6% and the detection limits are 0.3 ng Se m^?3.     

Determination of Thallium In Solid Environmental Samples By Electrothermal Atomic Absorption Spectrometry

Abstract

A method for the determination of thallium in solid environmental samples is developed. After destruction of the sample, TI(III) is extracted from 0.5 M hydrobromic acid solution into diisopropyl-ether. the organic phase is evaporated and the residue taken up in a mixture of sulfuric and nitric acids. Measurements are carried out with an atomic absorption spectrometer with Zeeman background corrector. the accuracy of the method is tested by analysis of certified reference materials and the method is applied to fly ash and emitted particulate matter from a municipal refuse incinerator and to soil samples.     

Flowability of various dusts collected from secondary copper smelter off-gas

Stable flow of off-gas dust from dust collector hoppers and storage silos is important for smooth operation. Flow properties of the collected off-gas dust are critical to achieve suitable flow. Various dust samples collected from secondary copper smelter off-gases were studied. The median diameter of the fine-grained dusts varied from 0.8 to 1.4 μm and the flowability ranged from “cohesive” to “very cohesive”. The flowability of shaft and anode furnace dust improved slightly with increasing consolidation stress and their wall friction angles decreased, which is a typical behavior. In contrast, the flowability of converter dust decreased with increasing consolidation stress and its wall friction angles increased. Pre-shear treatment of converter dust worsened its flowability, increased the wall friction angle, and improved the flowability with increasing consolidation stress. This is believed to occur because pre-shear treatment fragments small agglomerates in the dust that improve flowability. The presence of such agglomerates was confirmed by sieving tests. A diagrammatic representation of the flowability showing that the unconfined yield strength is dependent on consolidation stress can be improved by using logarithmically scaled axes.