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1.
深圳市线路板蚀刻废液中铜、砷、铅、汞、镉含量调查 总被引:2,自引:0,他引:2
吴小令 《中国资源综合利用》2005,(6):21-23,28
对深圳市60家线路板企业含铜蚀刻废液中铜、砷、铅、汞、镉含量的检测结果显示:酸、碱性蚀刻废液铜含量范围分别为38.6~167.9g/L、53.7~171.8g/L,,通过测量比重推算铜含量适用于碱性废液但不适合酸性废液.56个样品可检出砷(大于3mg/L).56个样品未检出铅(小于5mg/L),其余4个铅含量偏高.所有样品汞、镉均未检出,含量分别小于4mg/L、0.3 mg/L.将各样品砷、铅、汞、镉含量实测值换算为铜含量100ga.时的相对值后发现,上述四元素在蚀刻废液中的正常值分别为<12mgAs/L、<5 mg Pb/L、<4 mg Hg/L、<0.3 mg Cd/L. 相似文献
2.
黄埔发电厂#6发电机转冷水铜离子含量超标,通过对缺陷原因进行分析,针对二级水封的特性对溢出的转冷水进行回收并利用化学凝结水处理去除溶出的铜离子,通过控制转冷水的pH值最终减缓铜管的腐蚀. 相似文献
3.
90年代,与世界铜矿资源总量相比,我国铜资源是比较贫乏和短缺的,这种状况将延续到下一个世纪。本文对我国近五年的铜金属市场进行了跟踪分析,对进出口进行了统计和形势分析,并对铜产品的市场价格和产量进行预测,提出了研究对策和建议。 相似文献
4.
目前地表水受到严重氮污染,其中以离子态硝酸盐为主。实验利用线性扫描伏安法与恒电位电解法,研究了铜电极表面硝酸盐电化学还原产物与反应机理。结果表明,硝酸盐的还原产物取决于外加电位。铜电极上硝酸盐的吸附从-0.6 V(以汞/氧化汞电极为参比)开始,-0.8~-1.0 V之间硝酸盐还原为亚硝酸盐,该反应为整个硝酸盐还原过程的速控步骤;理想产物氮气主要在-1.0~-1.2 V之间生成;-1.2~-1.4 V之间主要还原产物为氨氮。随着电势降低,反应速率增大,对副产物氨氮的选择性也升高。 相似文献
5.
以活性炭为载体,采用沉淀法制备纳米铁/活性炭新型材料,对活性炭的结构变化进行BET和TEM表征分析,研究纳米铁负载前后活性炭对水中铜离子的吸附能力以及p H值、起始浓度、吸附时间等因素对吸附性能的影响,同时考察其再生性能。结果表明:纳米铁成功负载于活性炭上,随着p H值的增加,吸附容量逐渐增大,当p H=6时,纳米铁/活性炭的最大吸附量为18.73 mg/g,与活性炭相比提高了150%。新型材料对铜离子的吸附过程符合Langmuir和Freundlich吸附模型,对铜离子的吸附量随时间变化的规律符合准二级动力学模型,由于负载的纳米铁阻碍了铜离子向材料表面扩散,其吸附速率仅为0.002 g/(mg·min),与活性炭相比下降了60%左右。新型材料再生效率高,具有较好的应用前景。 相似文献
6.
面板是混凝土面板堆石坝安全稳定的重要部位,铜止水制作和安装是面板防渗关键环节。在泽城西安水电站大坝面板施工过程中,采用自行设计的铜止水加工模具,结构简单、操作方便,实现了铜止水的连续加工成型,最大限度地减少了铜止水的焊缝,节约了施工成本,加快了施工进度,并提高了铜止水的施工质量。 相似文献
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8.
Copper trade and production of copper,brass and bronze goods in the Oldenburg monarchy: copperworks and copper users in the eighteenth century 总被引:1,自引:0,他引:1
Kristin Ranestad 《The Scandinavian economic history review / [the Scandanavian Society for Economic and Social History and Historical Geography]》2019,67(2):190-209
This paper explores trade connections – or the lack of such – between copperworks and copper processing plants in the Oldenburg Monarchy in the eighteenth century. Domestic customs areas, high tariffs on raw material export and import bans sought to encourage domestic copper and brass goods production of Norwegian copper raw material, however this was only realised halfway. The raw material from Norway was largely exported, and copper and brass materials used to produce copper-, brass and bronze goods were imported from all over the world. The copperworks and processing plants in the Monarchy never became strongly integrated due to several reasons. First, shareholders of copperworks acquired favourable credit deals abroad, and preferred to export the copper, and second, copper materials had different features and processing plants used all sorts of copper inputs in the making of goods, not only copper raw material. Norway produced mostly gar copper, so copper plants and coppersmiths had to turn elsewhere for other types of copper. Production of copper and brass goods increased, but did not meet the domestic demand partly due to a strong foreign competition. The optimal goal of ‘mercantilist theory’ regarding copper and brass import substitution was not reached. 相似文献
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10.
The substrate of fluvial systems is regularly characterized as part of a larger physical habitat assessment. These measures are instrumental in meeting the regulatory responsibilities of bioassessment and monitoring programs, and essential to monitoring restoration and rehabilitation success. We describe and validate a commonly used technique for broadly categorizing, and thus characterizing, the substrate in non‐wadeable streams and rivers called the sounding rod method. In brief, a rod, often hollow, is used to probe the substrate of non‐wadeable systems to characterize the substrate. We tested the viability of this method on three different systems by comparing estimated particle class and direct particle measurements. Our results indicate that substrates can adequately be defined into six broad classes (fine‐particle sediment, sand, gravel, cobble, boulder and bedrock) based on size using the sounding rod. Estimated classes were significantly positively correlated to measured classes (τ = 0.83, p < 0.001), and estimates of size class and direct measurements of size were not from significantly different distributions (χ2 0.05,9 = 569.51, p < 0.001). Further, there were significant differences between each category (H = 243.5, 3 d.f., p < 0.001). Although our results affirm that actual substrate class size can be directly inferred from estimated data, it should be noted that soft sediments <200 mm were not always detected. This finding should be carefully considered with individual study objective. Overall, the sounding rod method can be learned quickly, and it is a low‐cost and time‐efficient method for substrate classification. Published 2013. This article is a U.S. Government work and is in the public domain in the USA. 相似文献