共查询到19条相似文献,搜索用时 625 毫秒
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《有色金属(冶炼部分)》2018,(11)
采用生物聚合硫酸铁絮凝剂对低浓度含铀废水进行絮凝试验研究,考察U(Ⅵ)溶液pH、絮凝剂投加量以及U(Ⅵ)初始浓度对絮凝效果的影响。结果表明,反应最佳pH范围在5~7,反应平衡时间为5min,其絮凝过程符合Lagergren准二级反应动力学模型。含铀废水经生物聚合硫酸铁絮凝处理过后,残余铀浓度低于《铀加工与燃料制造设施辐射防护规定》(EJ 1056—2005)中的排放限值(0.05mg/L)。 相似文献
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为探究膨润土对含铀废水的吸附性能,对膨润土进行钠化预改性,然后用十八烷基三甲基氯化铵(STAC)对钠化膨润土进行有机改性,探究模拟含铀废水pH、固液比、反应时间、反应温度、初始浓度对STAC有机改性膨润土吸附U(Ⅵ)的影响,并探究了膨润土吸附动力学和吸附等温曲线。结果表明,当pH=7.04、固液比4.0 g/L、反应时间480 min、反应温度318.15 K、含铀废水初始浓度<10 mg/L时,该吸附材料处理含铀模拟废水的效果最佳,最高吸附率达到99.52%。准二级动力学方程和Langmuir等温吸附模型更适于阐明STAC有机改性膨润土吸附U(Ⅵ)的过程,反应主要是化学吸附和单层吸附。Langmuir拟合吸附容量最高为198.73 mg/g。 相似文献
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Fe2(SO4)3-壳聚糖絮凝剂的制备及絮凝性能的研究 总被引:1,自引:0,他引:1
本文以无机絮凝剂Fe2(SO4)3与壳聚糖复配进行絮凝性能研究,并对实际食品废水进行处理。实验表明,以高岭土悬浮液为絮凝对象,当pH值为7,温度为30℃,搅拌时间为5min时,Fe1(SO4)3-壳聚糖絮凝剂的絮凝效果为最佳而且优于单独使用无机絮凝剂Fe2(SO4)3和天然高分子絮凝剂壳聚糖。以实际食品废水为絮凝对象,Fe2(SO4)3-壳聚糖的絮凝效果优于Fe2(SO4)3-壳聚丙烯酰胺复配絮凝剂的絮凝效果。 相似文献
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以淀粉为原料,3-氯-2-羟丙基三甲基氯化铵为阳离子醚化剂,采用湿法制备阳离子淀粉.考察了pH、絮凝剂用量、絮凝时间和絮凝温度等因素对絮凝效果的影响.阳离子淀粉对含锰(Ⅶ)废水的絮凝工艺条件为:pH 5-6,絮凝剂用量0.4 g,絮凝时间2.0 h,絮凝温度40℃.在上述条件下,阳离子淀粉对含锰(Ⅶ)模拟废水的絮凝率可达90.2%. 相似文献
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重庆大学郑怀礼教授等系统地研究了中药制药废水絮凝处理方法及其机理。所选絮凝剂有聚合氯化铝 ( PAC)、聚合硫酸铁 ( PES)以及自制的聚合硅酸硫酸铁 ( PFSS)等 ,研究了 p H、温度对絮凝效果的影响以及与有机阳离子高分子絮凝剂配合使用时的絮凝效果等。结果表明 ,PES较 PAC有更好的絮凝效果 ,但 PFSS更适合于该类废水的处理 ;每种絮凝剂都存在一最佳投药量 :PAC、PFS为 80~ 1 0 0 mg/L,PFSS为 1 .0 mg/L;有机阳离子高分子絮凝剂可增强 PFS、PAC的絮凝效果 ,而对 PFSS则影响不明显 ;水温在 2 0~ 40℃时对絮凝效果影响… 相似文献
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酸性地浸矿山退役后,采区范围内地下水中依旧存在着少量铀的残留,需要清除以恢复地下水环境。使用一株新的普通脱硫弧菌Desulfovibrio vulgaris GnLF21,开展了影响其除铀能力的因素及对废水稀释液的处理研究。结果表明,初始U6+浓度为4 mg/L、pH=7.0、初始SO42-浓度为1.0 mg/L时,菌株去除铀能力最强,铀去除率分别为97.9%、96.8%、92.7%。在废水pH为4.5、SO42-浓度≤2 g/L、初始U6+浓度为1.87 mg/L、菌株GnLF21接种量20%时,在96 h和120 h时铀去除率分别为77.74%和80.73%。可应用异源性硫酸盐还原菌开展酸性含铀废水的生物修复。 相似文献
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研究了用改性膨润土吸附处理含铀(Ⅵ)废水,考察了废水pH、改性膨润土用量、溶液初始铀(Ⅵ)质量浓度、反应时间、温度对吸附反应的影响。结果表明:用NaCl和STAB(十八烷基三甲基溴化铵)改性的膨润土(Na-Bentonite,STAB-Bentonite)都可用于从废水中吸附铀(Ⅵ);溶液中铀初始质量浓度30 mg/L、温度25℃条件下,Na-Bentonite对铀的最大吸附容量为13.4 mg/g;在溶液pH=4、吸附时间120 min条件下,STAB-Bentonite对铀(Ⅵ)的吸附量为22.35mg/g,吸附过程符合准二级动力学模型,且受化学反应控制。 相似文献
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采用溶胶—凝胶法制备出钢渣负载羟基磷灰石复合材料,并通过静态试验方法探讨pH、复合材料投加量、反应时间及铀初始浓度对复合材料吸附水溶液中U(Ⅵ)的影响。结果表明,复合材料对U(Ⅵ)具有较好的去除性能,在pH=4、投加量0.4g、反应时间120min的条件下,对初始浓度5mg/L的水溶液中U(Ⅵ)的去除接近完全,对应吸附量为1.25mg/g。复合材料对U(Ⅵ)的吸附过程为化学吸附,符合准二级动力学模型(R~2=0.996 9);Langmuir吸附等温线模型拟合(R~2=0.999 1)表明,吸附过程为吸附剂表面上的单层吸附;且通过R_L(R_L 0.063)的计算表明,复合材料对U(Ⅵ)的吸附极其接近不可逆吸附。 相似文献
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Preliminary leaching studies were carried out to develop a suitable method for the recovery of uranium and the elimination of arsenic from a low grade carbonate/silicate ore containing 64 ppm U and 2446 ppm As, as well as some Cu, Pb, Ni and Zn. An examination of the mineralogy found mostly uranium(VI) minerals, such as uraninite, and various base metal sulfides and arsenates in veins and fissures. Roasting the ore at 500–800 °C to volatilize arsenic proved to be unsuitable. Therefore, the ground ore was subjected to direct leaching with sulfuric acid, sodium sulfide and ferric chloride at 80–90 °C with a liquid to solid ratio of 1:1. With sulfuric acid at a concentration of 180 kg/t ore, complete recovery of both uranium and arsenic was achieved giving undesirable arsenic in the leach liquor. The maximum recovery of uranium and arsenic by leaching with sodium sulfide was only 20% and 18%, respectively. However, 3 M ferric chloride leached approximately 92% U(VI) and precipitated arsenic as ferric arsenate. Therefore, maximum uranium can be extracted and arsenic eliminated as impurity by selective leaching with ferric chloride. 相似文献
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Yasuhiro Awakura Koji Sato Hiroshi Majima Shuichiro Hirono 《Metallurgical and Materials Transactions B》1987,18(1):19-23
The diffusion coefficients of U(VI) in aqueous uranyl solutions were determined between 293.5 and 311.0 K by comparing the
limiting current densities between the copper electrodeposition and the electrolytic reduction of uranyl sulfate under the
same hydrodynamic condition. The diffusion coefficients thus determined were almost constant despite the change in agitation
speed of electrolyte solutions, which suggests the appropriateness of the method employed in this study. On the other hand,
the diffusion coefficients of U(VI) showed a slightly decreasing trend with increase in uranyl sulfate concentration, but
when total uranium concentration was kept constant the diffusion coefficient appeared to be almost constant. The activation
energies of diffusion coefficients of U(VI) were found to be 21 to 22 kJ mol−1 for the solution studied.
KOJI SATO formerly Graduate Student, Department of Metallurgy, Kyoto University, Kyoto, Japan 相似文献
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深锥浓密机内底部料浆的屈服应力过高容易导致压耙,为此通过对不同絮凝沉降条件下获得的浓缩超细尾砂料浆的屈服应力进行原位测量,并通过对絮凝前后料浆总有机碳的测试来分析超细尾砂颗粒表面的絮凝剂吸附量,进而分析了絮凝沉降对浓缩超细尾砂料浆屈服应力的影响规律。研究发现,絮凝沉降对浓缩超细尾砂料浆的屈服应力有显著影响,pH和絮凝剂单耗通过影响尾砂颗粒表面的絮凝剂吸附量进而影响浓缩超细尾砂料浆的屈服应力,屈服应力随着pH和絮凝剂单耗的增大均不断增大。综合考虑尾砂料浆的絮凝沉降效果和所得浓缩超细尾砂料浆的屈服应力,最佳絮凝条件是pH值为11和絮凝剂单耗为15 g·t?1,在此最优条件下料浆固液界面的初始沉降速率为0.4565 mm·s?1,沉降后上清液浊度为143 NTU,底部沉积尾砂料浆的固相质量分数为51.56%、屈服应力为243.18 Pa。初步建立了适用于超细人造尾砂的基于絮凝剂吸附量的屈服应力模型,屈服应力随尾砂颗粒表面单位面积的絮凝剂吸附量的增大而增大,为实际生产中控制全尾砂絮凝沉降参数提供参考。 相似文献
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采用氢氧化铁吸附脱除硫酸盐溶液中的微量硅。结果表明,在下述优化条件下:反应温度60℃,终点pH=5.5,氧化剂双氧水用量2mL,反应时间60min,絮凝剂用量0.1g/L,溶液中锌、铁含量稳定,硅含量由10×10-6降至1×10-6左右。 相似文献
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采用液相还原法制备纳米零价镍,并用来去除溶液中的U(VI)。通过SEM、EDS技术表征反应前后材料的形貌,从微观角度分析纳米零价镍去除溶液中U(VI)的机理,并进行了热力学分析。结果表明,纳米零价镍对溶液中U(VI)有良好的去除效果,在室温下,pH=4.0、接触时间60min、固液比0.3g/L和初始浓度50mg/L时,U(VI)的去除率和去除量分别达到了98.44%和182.372mg/g。新制备的纳米零价镍呈明显的球状,颗粒较为分散且粒径较均匀,反应后,材料表面形貌发生变化,呈不规则碎片堆积、粒径变大,且材料中出现了铀元素。热力学研究结果表明,该反应是自发吸热反应,同时也是不可逆的熵增反应。 相似文献
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Experiments were conducted to determine the effect of solid levels on natural sedimentation of swine manure. Total solids (TS) levels of 0.5, 1.0, 2.0, 4.0, and 6.0% were evaluated. Natural sedimentation was impeded at higher than 2.0% and also at lower than 1.0% TS concentrations. Two flocculants (ferric chloride and aluminum sulfate) commonly used in the municipal wastewater treatment industry were then evaluated for their enhancement of natural sedimentation and concomitant removal of phosphorus from swine manure. Each flocculant was evaluated at five levels—0 (control), 500, 1,000, 1,500, and 2,000 mg∕L—on swine manure with an adjusted TS level of 1.0%. At dosage levels of 1,500 mg∕L (5.4 mM Fe+3), ferric chloride removed 76% suspended solids (SS) and 86% phosphorus, while aluminum sulfate at the same dosage level removed 96% SS and 78% phosphorus. Unaided natural sedimentation at this TS concentration removed 66% and 42% of the SS and phosphorus, respectively. Chemical flocculation can, therefore, be an effective method of removing solids and phosphorus in swine manure. 相似文献