共查询到20条相似文献,搜索用时 126 毫秒
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裂解汽油一段加氢Pd系和新型Ni系催化剂加氢性能对比及影响因素浅析 总被引:6,自引:0,他引:6
对裂解汽油一段加氢Pd系和新型Ni系催化剂,通过工业应用情况分析和实验室加氢性能评价,催化剂物性分析表征和热重分析认为:新型Ni系催化剂加氢和抗结炭性能优异,此优良的性能在于新型Ni系催化剂的载体结构和活性相结构特征。改进载体孔结构可借助大孔容焦作用提高Pd系催化剂的抗积炭性能,但不能实现长周期运转。对杂质含量较高的原料,新型Ni系催化剂适应性良好。 相似文献
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以聚乙二醇(PEG)200作溶剂,合成了花状Ni和NiS纳米结构。用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对产物进行了表征。实验结果表明:产物形貌均为由交织的纳米片组成的花状Ni和NiS结构,其中纳米片的厚度分别为约10nm和20nm。对溶剂和有机表面活性剂对NiS纳米结构形貌的影响也进行了研究。实验结果表明PEG200在合成花状Ni和NiS纳米结构起着关键性作用。 相似文献
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以实际富镍电镀废液为研究对象,使用沉淀回收得到的Ni(OH)2为镍源制备次磷酸镍(Ni(H2PO2)2·6H2O)。主要考察反应pH值和温度对金属沉淀效率的影响、反应P/Ni物质的量比和温度对Ni(H2PO2)2·6H2O合成反应速率、产率和纯度的影响。试验结果表明:金属离子沉淀效率随反应pH值和温度的升高而增大,在pH值为3.6,反应温度为85℃的条件下,以1 mol/L的NaOH溶液作沉淀剂,Fe、Al、Cr的沉淀率和Ni损失率分别达到98.7%,95.6%,96.2%和3.47%。在pH值为8.2,反应温度为85℃的条件下,Ni的沉淀率为97.5%;XRD物相分析表明,P/Ni物质的量比是影响Ni(H2PO2)2·6H2O合成反应速率、产率和纯度的重要因素。在P/Ni物质的量比为2.4,反应温度为6... 相似文献
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通过电镀、化学镀及复合镀的方法,制备了Ni—S、Ni—P、Ni—Mo、Ni—W、Ni—Co、Ni—WC及Ni—ZrO2等一系列二元镍基合金镀层及复合镀层,并通过阴极极化曲线测试,比较了它们的析氢性能。从元素电子结构及元素电负性方面对合金元素的作用进行理论分析,初步探讨了镍基合金镀层的电催化机理。 相似文献
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铝和铝合金化学镀镍工艺 总被引:3,自引:0,他引:3
阐述了铝和铝合金化学镀镍工艺的流程、各道工序的操作要点。注意事项以及工艺参数。结合作者实际工作体会,综述了国外近期文献关于铝和铝合金化学镀镍的报道,可供从事铝和铝合金表面处理的同行参考。 相似文献
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硬铝合金化学镀镍耐蚀机理 总被引:4,自引:0,他引:4
通过对铝合金组织,化学镀镍各溶液成分,化学镀镍镀层性质,铝合金化学镀镍工艺的分析,找出了影响铝合金化学镀镍耐蚀性的关键因素是镀层厚度和孔隙率,铝合金基体状态,前处理工艺,化学镀镍工艺参数,溶液成分,镀后处理等均会影响镀层的孔隙率,所以对铝合金化学镀镍耐蚀性等级要求高的行业在使用该工艺时要控制全过程工艺要点,否则就达不到预期的目的。 相似文献
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S. Kelebek P. A. Distin 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1989,44(4):309-326
Nickel extraction from an uncrushed spent nickel-tungsten catalyst was studied using sulphuric acid leaching in a column. The effects of flowrate, temperature and acid concentration on the cumulative nickel recovery was investigated using a three-variable, two-level factorial design. Statistical analysis indicated that among these variables only acid concentration was significant (at the 95% confidence level) in the ranges investigated. The catalyst can be leached either by a two-step process or in a single step following catalyst preoxidation. In either case extractions exceeding 95% can be obtained. With oxidized samples, single-step acid leaching at 82°C yielded significantly better nickel extraction than at 95°C. This was attributed mainly to tungstic acid precipitation in the catalyst pellets, an effect which occurs rapidly at 95°C and retards the leaching of nickel. Nickel extraction was also suppressed following preoxidation at over 300°C. This was thought to be due to formation of slow-leaching nickel oxide-tungstate. Following preoxidation at the optimum of 300°C, 97% of the nickel could be leached in 4 h at 82°C using (by volume) 3% sulphuric acid and 0.6% nitric acid flowing at 1.5 litres/h. About 70% of the nickel could be extracted from preoxidized catalyst using only water for 40 h at room temperature. These findings are incorporated in a simple proposed flowsheet. 相似文献
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氢氧化镍电极的修饰及电化学性能的研究 总被引:1,自引:0,他引:1
镍系列二次电池的正极活性物质Ni(OH)2的晶型和镍电极的制备工艺对电池的性能具有较大的影响。文章以镍-氢电池作为对象,着重研究作为电池正极的氢氧化镍电极。通过不同的方法制备电极的活性物质Ni(OH)2,以Co、Zn和稀土作为掺杂剂对电极进行修饰,并对不同掺杂方式构成的电池进行了测试。用金相显微镜来观察Ni(OH)2的外观、颗粒大小;通过恒电流放电曲线比较各电极的放电性能,并通过XRD谱图了解样品的晶型结构。电池性能测试结果表明:采用配位沉淀法制备的Ni(OH)2晶体为最佳;在添加剂方面,Zn、Co、Sm均对镍电极的电化学性能影响较大。 相似文献
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研究了以从工厂含镍废液中回收的硫化镍为原料,试验从酸浸出,除杂净化和沉镍等方面制取镍盐的工艺过程和最佳条件。由本工艺可以生产出高含量镍的镍盐,其品位符合国家或企业标准,废镍的回收率达91%以上。 相似文献
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《分离科学与技术》2012,47(11):1602-1608
A method of recovering nickel from spent electroless nickel-plating solutions has been investigated through the electrowinning method, following the precipitation of nickel by adding alkali and then dissolving this nickel precipitate with sulfuric acid. When sufficient caustic soda was added to a spent electroless nickel-plating solution to increase the pH to higher than 13, fine nickel particles, below 4 microns in size, along with nickel hydroxide were formed. After filtering the nickel precipitate, it was dissolved with a sulfuric acid solution of over 2 vol%, with which more than 95% of the nickel precipitate could be dissolved. For nickel recovery by electrowinning, the pH of the nickel solution required an adjustment of nearly 2.0. 相似文献