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LiCl-NaF-Na2WO4熔盐体系中电沉积钨的研究 总被引:6,自引:0,他引:6
本文用循环伏安法研究了钨酸钠在LiCl-NaF(80-20mol%)熔盐体系中的电化学还原过程, 并用X射线衍射法检测了由恒电位电解得以的阴极产物。结果表明, 钨酸钠的还原分两步进行, W(VI)首先经二电子还原成W(IV), 再经四电子还原成W(0)。 相似文献
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NdCl3-LiCl及NdCl3-LiCl-NaCl体系相图的研究 总被引:1,自引:0,他引:1
利用DTA和X射线结构分析研究了NdCl3-LiCl二元体系相图和NdCl3-LiCl-NaCl三元体系液相限. 发现NdCl3-LiCl体系相图属于简单低共熔型, 低共熔点e3为28.5(wt%)LiCl, 452℃. 在低共熔温度以下有一固相下生成的介稳化合物, 在443℃分解, 组成为2NdCl3.LiCl. 经长时间退火, 该化合物消失. NdCl3-LiCl-NaCl体系有对应NdCl3、LiCl、NaCl、2NaCl.LiCl、NaCl.LiCl的五个液相面, 七条两次结晶线, 一个三元低共熔点E[69.0(wt%)NdCl3, 13.5(wt%)NaCl, 374℃], 两个三元转熔点P1[69.5(wt%)NdCl3, 14.5(wt%)NaCl, 380℃], P2[70.0(wt%)NdCl3,15.5(wt%)NaCl, 385℃]. 相似文献
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锂 - 氧化铜电池及其反应机理 总被引:3,自引:0,他引:3
本文研究了Li/CuO电池和Li/CuO电池的一般放电行为,着重探讨了它们的反应机理。X射线衍射分析、ESR分析、XPS分析和循环伏安试验等结果表明,电池反应的实质是锂在正极内进行电化学嵌入反应,并在一定嵌入度后因Cu—O键断裂而析出金属铜。其化学反应式可表达为: xLi+CuO(Cu_2O)→Li_xCuO(Li_xCu_2O)(a) x_1Li+Li_xCuO(Li_xCu_2O)→ Li_(x+x_1)Cu_(1-y)O(Li_(x+x_1)CU_(2-y)O)+yCu (b) 用电化学暂态方法测得嵌入锂离子在正极内部的化学扩散系数约为2×10~(-12)cm~2·s~(-1)(室温),该值与在Li_xWO_3和Li_xTiO_2中的相近,与实际电池的放电速率是一致的。 相似文献
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The synergistic extractic extraction of lithium with a solution of o-phenylazophenols (HAX) and trioctylphosphine oxide (TOPO) or other trialkylphosphine oxide (TRPO, R = C8-10) in o-dichlorobenzene from aqueous solution of lithium hydroxide was reported. The structural effect of o-phenylazophenols on extraction of lithium has been examined. In the case of 1-(p-X-phenylazo)-2-naphthols, the HMO calculation shows that the charge density of azo nitrogen atom(the donor atom, denote azo N) and hydroxyl oxygen atom does not very apparently, so that the stability of their chelates with lithium has no obvious variations as well. In this case their ability to extract lithium is chiefly governed by the pKa. of the compound. The results of extraction prove that there is a linear correlation between the extraction constant Kex and pKa. However, for the second group of chelating agents, the change of their structure leads to the change of the change of both pKa and stability of chelates. The results of extraction and HMO calculation show that the stability of chelates is mainly influenced by the strength of the coordination bond, i.e. the larger the charge density of azo N (qN), the more stable the chelate will be. Therefore, their ability to extract lithium is roughly directly proportional to the stability of chelates and inversely to the pKa. the strength of coordination bond for the chelates can be experimentally measured by means of the strength of intramolecular hydrogen bond of chelating agent, ΔδOH (the diference of chemical shift of hydroxyl proton in free and bonded state). Therefore, the ratio, ΔδOH/pKa, can be used to evaluate the extraction ability of chelating agents to lithium. We find that it is approximately proportional to the distribution ratio (D). 相似文献
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研究了铌掺杂的Li/MgO甲烷氧化偶联催化剂的反应性质及铌的助剂作用。铌的引入使得该催化剂上甲烷氧化偶联反应的活化温度降低50℃以上, 使此温度降到了催化剂中碳酸锂的熔点附近。试验观察到部分催化剂上甲烷氧化偶联反应的活性曲线在碳酸锂的熔点附近有一转折, 这一转折现象的出现与否及程度取决于制备条件。在碳酸锂的熔点附近, 含有铌的催化剂得到活化, 观察到无稀释气体时的反应引燃现象, 即温度增加几度活性便达到最大值。当在比碳酸锂熔点稍高的温度下且不稀释时反应, 含铌催化剂活性很高但很快失活, 在稍低于此熔点下则不失活, 但活性较低。这些试验结果表明, 含铌催化剂的活化与失活均与催化剂中的碳酸锂的相变化有关。试验还观察到了在稍高于碳酸锂的熔点下做寿命试验时, 甲烷氧化偶联反应的振荡现象。 相似文献