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461.
About 500 samples of coal, pyritic coal balls, pyritic gangue and coal seam gangue were collected from different coal basins and geologic periods of coal formation to determine the arsenic (As) content and distribution pattern in China. The Permian-Carboniferous and Jurassic coals in the North China Plate and Northwest China account for nearly 85% of total Chinese coal reserves and data showed that As content ranged from 0.1 to 94?mg?kg?1, with the majority between 1 and 14.9?mg?kg?1. The As content of some Late Permian coals in Southwest Guizhou Province and stone coal in the South Qinling Mountain area were exceedingly high (30–534?mg?kg?1), but the majority of coal in the Southwest Guizhou Province contained low to medium amounts. Only the coals, which are situated in or near igneous rocks and are not considered a part of Chinese coal reserves, possessed unusually high As content (>30?mg?kg?1). Arsenic was also concentrated in pyritic coal balls and the pyritic gangue of the coal seam with values ranging from 21.5 to 142.46?mg?kg?1 and an average of 69?mg?kg?1 in Shaanxi and 78?mg?kg?1 in Shandong. Arsenic contents in coal gangue in the Northwest and North China Plate is about 0.2–15?mg?kg?1, a little lower than coals in the same seam. Washing gangue (waste from coal washing) generally contained more As than coal, because the washed gangue has more pyrite than the natural gangue (black shale). Washing coal reduced the content of the pyritic sulfur, heavy metals and As. Based on amounts of coal used with different As content in Chinese coal reserves, the average As content of Chinese coals is about 4.5?mg?kg?1. 相似文献
462.
This article deals with the co-coagulation of dyeing wastewater by coal fly ash using FeSO4 as coagulant, Benzo Scarlet 4BS and Brilliant Acid Scarlet 3R as the testing dyes. The optimal concentration of FeSO4 for co-coagulation process is 0.6–0.8?g/L wastewater, and the concentration of fly ash 4–5?g/L. The experimental results show that the co-coagulation process by fly ash helps to improve the color reduction, greatly accelerate the formation and settling of the floc, and reduce the content of the floc. The mechanism for co-coagulation process is discussed and similar effect is obtained when the co-coagulation method is applied for the treatment of the real dyeing wastewater samples. 相似文献
463.
Valentin Amrhein Lars Erik Johannessen Lena Kristiansen Tore Slagsvold 《Behavioral ecology and sociobiology》2008,62(10):1633-1641
The costs and benefits of bird song are likely to vary among species, and different singing patterns may reflect differences
in reproductive strategies. We compared temporal patterns of singing activity in two songbird species, the blue tit (Cyanistes caeruleus) and the great tit (Parus major). The two species live side by side year round, and they have similar breeding ecology and similar rates of extra-pair paternity.
However, they differ in two aspects of reproductive strategy that may have an influence on song output: blue tits are facultatively
polygynous and have a fairly short breeding season with almost no second broods, whereas great tits are socially monogamous
but more commonly raise second broods. We found that great tit males continued singing at high levels during the egg-laying
and incubation periods, while monogamously paired blue tit males strongly reduced singing activity after the first days of
egg-laying by their female. Since males of both species sang much more intensely shortly before sunrise than after sunrise,
at midday or in the evening, this difference was most conspicuous at dawn. No differences in singing activity were found within
species when testing for male age. We suggest that in contrast to blue tits, great tit males continued singing after egg-laying
to defend the territory and to encourage the female for a possible second brood. 相似文献
464.
西部开发中的煤矿区生态环境保护与重建问题 总被引:4,自引:0,他引:4
分析了西部尤其是西北地区煤矿区生态环境坡坏的现状,确定了矿区重庆重建工程的目标,提出了矿区生态环境保护与重建的具体措施。 相似文献
465.
Flame propagation in hybrid mixture of coal dust and methane 总被引:1,自引:0,他引:1
Yi Liu Jinhua Sun Dongliang Chen 《Journal of Loss Prevention in the Process Industries》2007,20(4-6):691-697
To investigate the flame propagation through hybrid mixture of coal dust and methane in a combustion chamber, a high-speed video camera with a microscopic lens and a Schlieren optical system were used to record the flame propagation process and to obtain the direct light emission photographs. Flame temperature was detected by a fine thermocouple. The suspended coal dust in the mixture of methane and air was ignited by an electric spark. The flame propagation speeds and maximum flame temperatures of the mixture were analyzed. The results show that the co-presence of coal dust and methane improves the flame propagation speed and maximum flame temperature notably, which become much higher than that of the single-coal dust flame. The flame front temperature varies with the coal dust concentration. 相似文献
466.
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469.
以哈尔滨市区近年的大气监测为依据,剖析了市区大气污染物的分布特征,并探讨了市区内产生大气污染的主要原因。哈尔滨市大气污染特征表现为“煤烟型污染”。针对哈尔滨市大气污染现状,依据环境监测数据,制定出了相应的防治措施。 相似文献
470.
This work was conducted to evaluate whether Ca-bearing additives used during coal combustion can also help with the retention of some other elements. This work was focused on the evaluation of bottom ashes collected during four full-scale combustion tests at an operating thermal fluidized-bed power station. Bottom ashes were preferred to fly ashes for the study to avoid interference from condensation processes usually occurring in the post-combustion zone. This work focused on the behaviors of S, Cl, Br, As, Mn, V, Cr, Ni, Cu,Zn, W, and Pb. Strong positive correlations with CaO content in bottom ashes were observed(for all four combustion tests) for S, As, Cl and Br(R = 0.917-0.999). Strong inverse proportionality was calculated between the contents of Pb, Zn, Ni, Cr and Mn and CaO, so these elements showed association to materials other than Ca-bearing compounds(e.g., to aluminosilicates, organic matter, etc.). Somewhat unclear behaviors were observed for W, Cu, and V. Their correlation coefficients were evaluated as statistically "not significant", i.e., these elements were not thought to be significantly associated with CaO. It was also discovered that major enrichment of CaO in the finest bottom ash fractions could be advantageously used for simple separation of elements strongly associated with these fractions, mainly S and As, but also Cl or Br. Removal of5% of the finest ash particles brings about a decrease in As concentration down to 77%-80% of its original bulk ash content, which can be conveniently used e.g., when high As content complicates further ash utilization. 相似文献