共查询到19条相似文献,搜索用时 125 毫秒
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以碳酸氢铵为沉淀剂,从氯化钴溶液中沉淀制得棒状碱式碳酸钴。采用TG-DTG-DSC热分析技术对碱式碳酸钴的热离解过程进行研究,采用X射线衍射技术对碱式碳酸钴在不同煅烧温度下的热离解产物进行物相分析,采用扫描电镜观察碱式碳酸钴及其在700℃的煅烧产物Co3O4的形貌特征。结果表明,在此实验条件下,碱式碳酸钴在450℃煅烧以及保温3 h的热离解产物中CoO的质量分数依然高达50.5%,碱式碳酸钴完全离解为Co3O4的温度高于359.5~421.1℃的热分析测量值;700℃煅烧可得到单一相成分的Co3O4;850℃煅烧,Co3O4发生离解,热离解产物中CoO的质量分数高达47.93%,这一离解温度低于Co3O4热离解最低温度为910~920℃的热力学理论预测值。要制备单一相成分的Co3O4,必须严格控制其前躯体的煅烧离解条件。Co3O4产物对碱式碳酸钴具有良好的形貌继承性,因此通过控制Co3O4粉末前驱体的制备条件可以实现对Co3O4粉末形貌的有效控制。 相似文献
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提出了一种以硫酸钴、碳酸氢铵为原料,聚乙二醇为表面分散剂,采用钴盐沉淀—热分解法制备超细八面体Co3O4的方法。通过热重-差热分析仪、红外光谱分析仪、X射线衍射仪、场发射扫描电镜、激光粒度分析仪对前驱体碱式碳酸钴和产品Co3O4进行了分析和表征。结果表明:制备的Co3O4粉末呈八面体晶体形貌,粒度在亚微米至微米级,粒度分布均匀且范围窄,制备过程分散剂的添加消除了粉末的团聚现象。 相似文献
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液相法合成碳酸钴的过程控制 总被引:1,自引:0,他引:1
本文着重考查了碳酸钴合成过程中氯化钴的浓度、反应温度、加料速度及表面活性剂等因素对碳酸钴的成核、生长的影响,通过以上条件的优化选择,利用液相法合成理想的碳酸钴晶体。 相似文献
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研究了用碳铵直接沉淀氯化钴制备前躯体进而煅烧制备电池级Co3O4的工艺.主要考察了氯化钴溶液中钴离子浓度、溶液起始pH值、沉淀反应温度、沉淀反应时间等对前躯体粒度分布的影响,以及前躯体煅烧温度、煅烧时间对产物Co3O4颗粒形貌、粒度的影响.XRD研究表明,用该方法制备的前驱体粉末为无定形的碱式碳酸钴,经过煅烧后生成均匀分散的Co3O4粉末.XRD、SEM、粒度分布、振实密度等测试对煅烧产物进行了性能表证,结果显示产物具有标准Co3O4晶型结构,结晶良好,粉末具有规整的颗粒形貌,并且具有较好的分散性,平均粒径l~5 μm,振实密度2.1 g·cm-3,满足电池级Co3O4的要求. 相似文献
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本文阐述了在硫化物存在的条件下,用蒸馏法从碳酸铵溶液中提取铜、钻、镍的研究结果。首先提取的是硫化钢,接着是水合碳酸钴,最后是碳酸镍。 相似文献
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HB Schi?th A Fredriksson C Carlsson P Yook R Muceniece JE Wikberg 《Canadian Metallurgical Quarterly》1998,139(1-2):109-115
Inulin ethers carrying primary amino groups have many potential applications. O-(Aminopropyl)inulin is obtained from O-(cyanoethyl)inulin by reduction of the nitrile groups. Heterogeneously catalyzed hydrogenation using Raney-cobalt as the catalyst resulted in only partial conversion of the O-cyanoethyl into O-aminopropyl groups. Complete conversion of the nitriles to primary amines was achieved by a homogeneous reduction with an excess of sodium borohydride and cobaltous chloride or with metals in liquid ammonia-methanol. Optimal results were obtained with the latter method; 83% of the substituents were converted into primary amines and 17% were lost by dealkylation. 相似文献
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针对氯化钙氯化锶混合体系,探索出能够准确分析该体系中钙和锶含量的分析方法。首先,用碳酸盐重量法分别对氯化钙和氯化锶单盐溶液进行分析,能够获得比较准确的测定结果且确定了碳酸盐沉淀适宜的烘干温度和烘干时间分别为200 ℃和20 h。在此基础上,结合碳酸盐重量法和经典的氯化银重量法对氯化钙和氯化锶的混合溶液进行准确地分析,分别获得碳酸盐沉淀的总质量和总氯的物质的量,再通过联立方程组求解得到钙锶氯化物共存体系中各组分的含量。最后,将实验方法用于分析钙和锶物质的量之比YB(YB=nCa∶nSr)为49、9.4、0.98、0.10和0.030的氯化物体系中氯化钙和氯化锶的组分含量时,测定结果比较准确,绝对误差小于0.5%。 相似文献
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Silver chloride is exceptionally soluble in dimethylsulfoxide saturated with calcium chloride at 25°C. Solutions containing up to 196 gl?1 silver as Ca(AgCl2)2 have been prepared. If 30–40% by volume of water is added to such solutions, then pure silver chloride is precipitated almost quantitatively. The silver chloride can be easily converted to pure (99.99%) silver metal either by melting at 1100°C with excess sodium carbonate as flux, or by reducing with hydrogen at 300–400°C, or by reducing an aqueous suspension with zinc dust. The water added to the DMSO solution can be recovered by distillation and both it and the CaCl2-DMSO bottoms are recycled for further leaching. This leads to a fast and cheap process for obtaining silver from crude silver chloride, or from materials containing silver in a form that can be converted to silver chloride. Applications to an anode slimes leach residue, a silver halide teaching laboratory residue, and the silver chloride cake from a gold refinery are demonstrated. 相似文献
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以工业生产氯化钴溶液为钴源,碳酸氢铵为沉淀剂,采用液相法制备碳酸钴。系统研究了沉淀过程碳酸氢铵用量、碳酸氢铵浓度、保温时间、陈化时间和反应温度对母液钴浓度和钴沉淀率的影响,得到优化沉淀工艺条件:碳酸氢铵单耗3.173g/g、碳酸氢铵浓度250g/L、保温时间10min、陈化时间30min、反应温度33℃,在优化条件下,母液钴浓度为0.045g/L,钴沉淀率达99.92%。碳酸钴粒度分布均匀且范围窄,D50=1.428-1.488μm,形貌为小颗粒球形团聚体,物相纯度高。 相似文献
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以含银的废弃YBaCuO化合物为原料,对其中所含的贵金属银进行了回收,并对实验过程中的影响因素进行了分析。银回收的具体方法为:用硝酸法溶解YBaCuO粉末样品,生成硝酸盐溶液,再加入盐酸使生成氯化银沉淀,之后氯化银与Na2CO3在1000℃共熔得到金属银。分析结果证明,过滤得到的氯化银较为纯净,银的纯度为95.86%,银回收率可达92.56%。 相似文献
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研究不同前驱体对氧化稀土的影响,以碳酸氢钠、碳酸氢铵、草酸为沉淀剂,氯化镧为镧源,制备了相应的前驱体,并焙烧获得了氧化镧.以TG、XRD、FT-IR、粒度分析、SEM和ICP为分析表征手段,探究前驱体对氧化镧形貌结构的影响.结果表明:前驱体焙烧时,均存在3个失重阶段,分别对应水(结晶水和吸附水)的脱离,部分CO2的脱离... 相似文献
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The official final action method for sodium chloride in cereal foods, 14.129, was found to give erroneously low results because of loss of chloride during ashing. Comparison of the data with values obtained by the official first action potentiometric method, 32.A01-32.A06, which does not require ashing, showed that large and variable losses of chloride occurred. Official ashing methods for other foods specify addition of sodium carbonate to prevent conversion of chloride to volatile forms, but this was not specified in 14.129. In the present study it was found that sodium carbonate did not completely prevent loss of chloride. The official first action potentiometric method, 32.A01-32.A06, has been adopted as official first action for the determination of chloride in cereal foods to replace 14.129, which was repealed, official first action. A cross-reference to 32.A01-32.A06 has been added to 14.096. 相似文献