电感耦合等离子体原子发射光谱法测定铅酸蓄电池用PE型隔板中镍、钴元素的含量

PE隔板在高温下完全灼烧后用(1+4)稀硫酸溶液浸取残渣,采用电感耦合等离子体原子发射光谱法测定浸取液中Ni、Co元素含量。选择测定镍、钴的分析谱线分别为231.604、228.615 nm。按所选仪器工作条件进行光谱测定,并制作各元素的工作曲线。镍、钴的检出限(3 s)分别为0.004、0.002mg/L。对2个样品中的2种元素各测定6次,测定值的相对标准偏差在1.21%~5.86%之间。用标准加入法进行回收试验,测得回收率在96.1%~98.1%之间。     

废锂电池正极活性材料中钴锂的浸提研究

针对废锂电池中正极材料所富含的钴锂,选用H_2SO_4+H_2O_2和P_2O_4分别对其进行了浸出和除杂研究,考察了硫酸浓度、固液比、时间和温度对钴、锂浸提效率的影响。结果表明,在硫酸浓度为2 mol/L、浸提液温度为60℃,反应时间为1 h、固液比为1:15浸提条件下,钴锂的浸提率皆达到99%以上。在pH为2.58、相比为1:1时,锰、锌去除率均在95%以上,少部分镁进入萃余液中,去除率为80%以上。     

镍基合金在烟气脱硫技术中的应用

介绍在烟气脱硫（FGD）设备中常用的镍基合金，根据不同类型合金的适应能力选择能经受FGD环境条件的合金，重点是各类合金技术条件的化学成分以满足在低pH值下盐酸溶液中耐蚀性能的要求，同时简述FGD设备中几种有效的镍基合金结构型式和加工制造技术。     

超声波制取生物柴油工艺技术探讨

介绍了新兴的超声波制取生物柴油工艺技术,并与液体碱催化技术进行了比较。众多试验结果表明,超声波能加速酯交换反应,反应时间仅需5-30min,其催化剂消耗量仅为液体碱催化技术的30％-50％,甲酯转化率可达99％。但在工业化应用方面仍需要原料预处理、甲醇回收、甲酯洗涤以及甲酯干燥等工艺过程。据估算,商业规模生物柴油加工中超生波处理的成本在0．002～0．015欧元／L之间。     

小麦秸秆转化为可发酵糖的研究

对小麦秸秆水解转化为可发酵糖进行了研究，考察了小麦秸秆预处理方法以及温度、pH值、酶用量、底物浓度和反应时间等因素对小麦秸秆酶水解的影响。试验结果表明，汽蒸加蒽醌方法是较好的预处理方法。酶解最佳工艺为：温度48℃，pH值5．2，酶解时间24h，酶用量与底物的最佳配比0．160：1；底物浓度≥1％，以1．5％～2．5％为宜，此时还原糖得率达32．4％。     

镁、铜、镍在活塞合金中的强化作用

本文简要介绍了铝活塞的基本要求，重点论述了镁、铜、镍三元素在Al-Si活塞合金中的作用及它们对活塞性能的影响；为活塞生产厂家对提高铝活塞产品质量，充分发挥镁、铜、镍在合金中的强化作用提供了一些宝贵的经验和处理生产过程中相关问题的方法。     

太阳光-TiO2催化氧化法处理棉浆粕黑液

先用酸地对棉浆粕黑液进行预处理，然后用太阳光－TiO2法进行催化氧化。文章研究了催化剂的投加量，pH值，光照时间，光强及搅拌速度对光解作用的影响。结果表明，在适宜的条件下，废水的COD和色度去除率分别可达92．4％和99％，制得的负载型TiO2具有较高的机械强度和化学稳定性，可重复使用，出水用石灰乳中和后可直接排放。     

酸处理化学污泥溶出铝盐影响因素研究

用铝盐作为水处理絮凝剂所产生的化学污泥往往含有大量的铝，对其综合利用，既能节省资源，又能避免二次污染。pH值是从化学污泥中浸提铝的关键影响因素，铝只有在pH值〈1．7（酸浓度〉0．02mol／L）时才能溶出，当酸浓度增加到4．0mol／L（pH值=0．6）时，铝溶出率最大。在酸性环境中，铝溶出时间很短，一般在4min后就达到了溶解平衡。搅拌与提高温度都能提高铝的溶出率。污泥中含有或向其中加入不同官能团小分子化合物也是铝溶出的强化条件，特别是含有-OH或含-OH与-NH2有机物共存时对铝的增溶效果最明显，一般可增溶10％以上，并可使铝溶出的pH值〈1．7的上限延伸到3．0左右。     

中国首个燃煤电厂二氧化碳捕集示范项目开工

我国首个“燃煤发电厂二氧化碳捕集示范工程项目”日前在华能北京热电厂开工建设。项目设计二氧化碳回收率大于85％，年回收二氧化碳能力为3000t，分离、提纯后的二氧化碳纯度达到99．5％以上，可用于食品行业。华能北京热电厂将成为我国第1家同时具有烟气脱硫、脱硝、二氧化碳捕集设施的高效、节能、环保燃煤电厂。     

聚丙烯装置尾气回收技术分析

对大连石化聚丙烯装置尾气排放和回收现状进行了分析,通过对全厂尾气排放管网进行优化设置,把全厂尾气中的可回收气体（主要是丙烯、丙烷等有机蒸气）和不可回收气体（主要是氮气、乙烷等不凝气）分开排放,可回收气体排人气柜。尾气升压冷凝回收后,有机蒸气回收率为89．73％,但升压冷凝后的排空气中仍含有58％左右的C3H6和C3H8,再利用膜分离技术对排空气中的有机蒸气进行回收,丙烯单体回收率达到96．21％。通过优化排空管网设置、升压冷凝回收和膜分离回收等3种技术手段的综合运用,聚丙烯装置尾气中有机蒸气的回收率达到了99．59％,避免了装置尾气排放造成的环境污染．同时优化了资源,降低了生产成本。     

Recovery of metal values from spent nickel–metal hydride rechargeable batteries

A hydrometallurgical process is developed for the separation and recovery of metal values such as nickel, cobalt and rare earths from spent nickel–metal hydride (Ni–MH) rechargeable batteries. After removal of the external case, the electrode materials are dissolved in 2 M sulfuric acid solution at 95°C. The resulting liquor contains typically (g l⁻¹), 10.6 Ni, 0.85 Co, 1.70 Fe, 0.36 Zn, 0.21 Al, 0.54 Mn, 1.73 La, 0.10 Ce, 0.33 Pr, 1.10 Nd and 0.032 Sm. The pH is around 0.4. The rare earth values are recovered from the liquor by means of a solvent extraction circuit with 25% bis(2-ethylhexyl) phosphoric acid (D2EHPA) in kerosene, followed by precipitation with oxalic acid. A mixed rare earth oxide of about 99.8% purity is obtained after calcination of the precipitate. The total yield of rare earths approaches 93.6%. The cobalt and nickel in the raffinate are effectively separated by solvent extraction with 20% bis(2,4,4-tri-methylpenthyl) phosphinic acid (Cyanex 272) in kerosene. The individual cobalt and nickel are then recovered as oxalates by the addition of oxalic acid. Cobalt and nickel oxalates with purities close to 99.6% and 99.8%, respectively, are obtained. The overall recoveries are over 96% for both cobalt and nickel. A total flowsheet of the process for recovery of rare earths, cobalt and nickel from spent Ni–MH batteries is proposed.     

On the preparation of amorphous Mg–Ni alloys by mechanical alloying

This paper deals with the preparation of the amorphous Mg–Ni alloys. By mechanical alloying (MA) the amorphous Mg–Ni alloys with different compositions have been prepared of pure elemental magnesium and nickel powder. The as-milled powder was characterized by X-ray diffraction analysis and transition electron microscope (TEM) observation. The results showed that the 30 < Ni < 70 at.% composition could be amorphized with a milling time strongly dependent on the starting chemical compositions. The investigation on the early stage of MA showed that the different compositions amorphized by two different paths. On the magnesium rich side of 30–70 at.% Ni, the as-milled powders first formed the intermetallic compound Mg₂Ni, which subsequently destabilized into the amorphous phase. For the nickel rich side, the amorphous was obtained directly from the mechanical blend of magnesium and nickel powder by the suppression of the formation of thermodynamic equilibrium phase MgNi₂. © 1999 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.     

Hydrogen generation by oxidation of “mechanical alloys” of magnesium with iron and copper in aqueous salt solutions

Oxidation processes of magnesium and magnesium “mechanical alloys” with iron and copper (1–15 wt%) in presence of aqueous solutions of sodium, cobalt, nickel and copper chlorides have been investigated. The rate of hydrogen generation increases with the increase of the transition metal content in the “alloys” and levels out for the Mg–Cu system. The overall hydrogen yield does not exceed 92% of theoretical one at the initial solution concentrations of 0.032 M and chloride/Mg molar ratios of 0.0075 (0.85 M and 0.20 for NaCl), but becomes close to 100% at double concentration of the transition metal salt solutions. The electrochemical corrosion mechanism of the magnesium oxidation process has been suggested.     

Nickel‒cobalt bimetallic catalysts prepared from hydrotalcite-like compounds for dry reforming of methane

Ni–Co/Mg(Al)O alloy catalysts with different Co/Ni molar ratios have been prepared from Ni- and Co-substituted Mg–Al hydrotalcite-like compounds (HTlcs) as precursors and tested for dry reforming of methane. The XRD characterization shows that Ni–Co–Mg–Al HTlcs are decomposed by calcination into Mg(Ni,Co,Al)O solid solution, and by reduction finely dispersed alloy particles are formed. H₂-TPR indicates a strong interaction between nickel/cobalt oxides and magnesia, and the presence of cobalt in Mg(Ni,Co,Al)O enhances the metal-support interaction. STEM-EDX analysis reveals that nickel and cobalt cations are homogeneously distributed in the HTlcs precursor and in the derived solid solution, and by reduction the resulting Ni–Co alloy particles are composition-uniform. The Ni–Co/Mg(Al)O alloy catalysts exhibit relatively high activity and stability at severe conditions, i.e., a medium temperature of 600 °C and a high space velocity of 120000 mL g^?1 h^?1. In comparison to monometallic Ni catalyst, Ni–Co alloying effectively inhibits methane decomposition and coke deposition, leading to a marked enhancement of catalytic stability. From CO₂-TPD and TPSR, it is suggested that alloying Ni with Co favors the CO₂ adsorption/activation and promotes the elimination of carbon species, thus improving the coke resistance. Furthermore, a high and stable activity with low coking is demonstrated at 750 °C. The hydrotalcite-derived Ni–Co/Mg(Al)O catalysts show better catalytic performance than many of the reported Ni–Co catalysts, which can be attributed to the formation of Ni–Co alloy with uniform composition, proper size, and strong metal-support interaction as well as the presence of basic Mg(Al)O as support.     

The effect of Co addition on the positive active material in Ni–Cd pocket-plate batteries

The nickel electrodes in Ni–Cd pocket-plate batteries have been cobalt-doped (0.8–5.0 wt.%) either by coprecipitation during Ni(OH)₂ fabrication or by addition of cobalt oxide. It was observed that both methods of doping significantly improved the initial performance and performance after accelerated testing. In general, the higher the cobalt content, the higher the degree of material utilisation.     

Hydrometallurgical separation of rare earth elements, cobalt and nickel from spent nickel-metal-hydride batteries

The separation of rare earth elements, cobalt and nickel from NiMH battery residues is evaluated in this paper. Analysis of the internal content of the NiMH batteries shows that nickel is the main metal present in the residue (around 50% in weight), as well as potassium (2.2-10.9%), cobalt (5.1-5.5%), rare earth elements (15.3-29.0%) and cadmium (2.8%). The presence of cadmium reveals that some Ni-Cd batteries are possibly labeled as NiMH ones. The leaching of nickel and cobalt from the NiMH battery powder with sulfuric acid is efficient; operating variables temperature and concentration of H₂O₂ has no significant effect for the conditions studied. A mixture of rare earth elements is separated by precipitation with NaOH. Finally, solvent extraction with D2EHPA (di-2-ethylhexyl phosphoric acid) followed by Cyanex 272 (bis-2,4,4-trimethylpentyl phosphinic acid) can separate cadmium, cobalt and nickel from the leach liquor. The effect of the main operating variables of both leaching and solvent extraction steps are discussed aiming to maximize metal separation for recycling purposes.     

Synthetical catalysis of nickel and graphene on enhanced hydrogen storage properties of magnesium

Reduced graphene-oxide-supported nickel (Ni@rGO) nanocomposite catalysts were synthesized, and incorporated into magnesium (Mg) hydrogen storage materials with the aim of improving the hydrogen storage properties of these materials. The experimental results revealed that the catalytic effect of the Ni@rGO nanocomposite on Mg was more effective than that of single nickel (Ni) nanoparticles or graphene. When heated at 100 °C, the Mg–Ni and Mg–Ni@rGO composites absorbed 4.70 wt% and 5.48 wt% of H₂, respectively, whereas the pure Mg and Mg@rGO composite absorbed almost no hydrogen. The addition of the Ni@rGO composite as a catalyst yielded significant improvement in the hydrogen storage property of the Mg hydrogen storage materials. The apparent activation energy of the pure Mg sample (i.e., 163.9 kJ mol⁻¹) decreased to 139.7 kJ mol⁻¹ and 123.4 kJ mol⁻¹, respectively, when the sample was modified with single rGO or Ni nanoparticles. Under the catalytic action of the Ni@rGO nanocomposites, the value decreased further to 103.5 kJ mol⁻¹. The excellent hydrogen storage properties of the Mg–Ni@rGO composite were attributed to the catalytic effects of the highly surface-active Ni nanoparticles and the unique structure of the composite nanosheets.     

Hydrogen storage behavior of magnesium catalyzed by nickel-graphene nanocomposites

In present study nanocomposites of Graphene Like Material (GLM) and nickel containing 5–60 wt % Ni were prepared by a co-reduction of graphite oxide and Ni²⁺ ions. These nanocomposites served as effective catalysts of hydrogenation-dehydrogenation of magnesium based materials and showed a high stability on cycling. Composites of magnesium hydride with Ni/GLM were prepared by high-energy ball milling in hydrogen. The microstructures and phase compositions of the studied materials were characterized by XRD, SEM and TEM showing that Ni nanoparticles have size of 2–5 nm and are uniformly distributed in the composites. The kinetic curves of hydrogen absorption and desorption by the composites were measured using a Sievert's type laboratory setup and were analyzed using the Avraami – Erofeev approach. The re-hydrogenation rate constants and the Avraami exponents fitting the kinetic equations for the Mg/MgH₂+Ni/GLM composites show significant changes as compared to the Mg/MgH₂ prepared at the same conditions and this difference has been assigned to the changes in the mechanism of nucleation and growth and alteration of the rate-limiting steps of the hydrogenation reaction. The composites of Mg with Ni/GLM have a high reversible hydrogen capacity exceeding 6.5 wt % H and also show high rates of hydrogen absorption and desorption and thus belong to the promising hydrogen storage materials.     

Aligned nickel–cobalt oxide nanosheet arrays for lithium ion battery applications

Aligned nickel–cobalt nanosheet arrays are deposited on nickel foam substrates by means of chemical bath deposition technique. The nanosheet arrays are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The electrochemical performances as anode materials of lithium ion batteries are investigated by galvanostatic charge–discharge cycle and cyclic voltammetry (CV) tests. The results show that the nickel–cobalt oxide film prepared from the solution in which Ni/Co = 3/1 has the best performance. Its initial charge capacity at 0.1 A g⁻¹ is 798 mAh g⁻¹. When cycled at higher current densities of 0.5 and 1.0 A g⁻¹, the initial charge capacities are 570 and 500 mAh g⁻¹, and 84% and 86% can be retained after 50 cycles, respectively. It is believed that the interconnected nanosheet-array structure and the nickel–cobalt binary composition play important roles in their electrochemical performances.     

Influence of Coal Ash and Slag Dumping on Dump Waste Waters of the Kostolac Power Plants (Serbia)

The content of selected trace and major elements in the river water used for transport, as well as in the subcategories of the waste waters (overflow and drainage) were analyzed in order to establish the influence of transport and dumping of coal ash and slag from the “Kostolac A” and “Kostolac B” power plants located 100 km from Belgrade (Serbia). It was found that during transport of coal ash and slag to the dump, the water used for transport becomes enriched with manganese, nickel, zinc, chromium, vanadium, titanium, cobalt, arsenic, aluminum, and silicon, while more calcium, iron, cadmium, and lead are adsorbed by the ash and slag than is released from them. There is also an equilibrium between the release and adsorption processes of copper and magnesium during transport. The vertical penetration of the water used for transport results in a release of calcium, magnesium, manganese, and cadmium to the environment, while iron, nickel, zinc, chromium, copper, lead, vanadium, titanium, cobalt, and arsenic are adsorbed by the fractions of coal ash and slag in the dump.