多波长分光光度法同时测定钴精矿中钴和镍

探讨了在pH 7.8时,Co(和Ni(与二甲酚橙(XO)显色的反应条件,建立了K-矩阵分光光度法同时测定钴和镍的分析方法。钴和镍的络合物表观摩尔吸光系数分别为2.42×106L.mol-1.cm-1,1.63×105L.mol-1.cm-1;方法相对标准偏差分别为4.8%,3.9%;平均加标回收率分别为110.0%,94.1%。方法已用于不同比例合成样品和钴精矿中钴和镍的定量分析。     

快速比浊法测定氧化钴和碳酸钴中微量氯

试验了用硝酸 ( 1 +1 )浸取试样中微量氯离子 ,共存的大量钴用氢氧化钠沉淀分离 ,方法用于生产获得满意结果     

铁氰化钾电位滴定法测定粗制氢氧化钴中钴

锰会干扰电位滴定法对钴的测定,而粗制氢氧化钴中锰含量较高(质量分数达8%),因此,将电位滴定法应用于测定粗制氢氧化钴中钴时,需要考虑锰的干扰。实验通过对HG/T4506—2013工业氢氧化钴中钴标准检测方法的前处理阶段做出改进,用盐酸溶解样品后,在含磷酸的溶液中用高氯酸将锰(II)氧化为锰(III),再用氟化氢铵络合掩蔽锰(III)从而消除了锰的干扰。在氨性环境中,用过量的铁氰化钾将钴(II)铵络离子氧化成钴(III)铵络离子,再用钴标准滴定溶液返滴定过量的铁氰化钾,最终建立了电位滴定法测定粗制氢氧化钴中钴的方法。参照粗制氢氧化钴中锰与钴的质量比,配制锰与钴的质量比在13.7%~52.0%范围内的粗制氢氧化钴模拟样品,按照实验方法进行测定,钴的回收率在99%~101%之间,这说明锰对钴测定的干扰可忽略。将方法应用于粗制氢氧化钴的检测,相对标准偏差(RSD,n=15)为0.19%~0.26%,加标回收率为99%~104%。采用实验方法测定粗制氢氧化钴实际样品,测得结果与电位滴定法-电感耦合等离子原子发射光谱法相结合所测得的结果基本一致。     

Reaction mechanism of cobalt cementation from high cobalt zinc sulphate solution by zinc dust

Abstract

The experiments in this paper were performed to research the mechanism of cobalt cementation from high cobalt zinc sulphate solution by zinc dust. The reduction potential of zinc during cementation was determined to investigate the morphology of products. Residues after the cementation process from zinc sulphate solution were analyzed by SEM and EPMA to investigate the morphology of products. Different temperature will cause different structure of particles. The reaction mechanism of cobalt removal by zinc dust is thought to be as follows: first, the Co2+ forms Co–Zn alloy with zinc particles, and the reaction reaches equilibrium quickly; second, the Co–Zn alloy continues reacting to Co with Co2+, which is the control process of the whole reaction.     

Formation of silicon carbide from microsilica waste by means of lignite semicoke

The formation of silicon carbide from briquetted batch consisting of microsilica waste from silicon and silicon-alloy production is investigated. The batch is treated at 1873, 1923, and 1973 K, for 5–30 min, with various reducing agents: lignite semicoke, coal semicoke, coke breeze, and coke dust. The best results are obtained when using lignite semicoke from the Berezovsk deposit in Kansko-Achinsk Basin: the yield of silicon carbide is 97.00–97.62%; it constitutes 82.52–84.90% of the products obtained. The optimal treatment temperature and time are determined: 1923–1973 K for 15–20 min. The products consist predominantly of cubic silicon carbide (β SiC). Chemical enrichment increases the SiC content in the products to 90–91%; this is higher than in abrasive micropowder of grain size 1–2 μm. The effectiveness of enrichment in terms of oxide and iron impurities is high: 87–95%. The silicon carbide is characterized by a high silica content: more than 7%. Accordingly, it may be regarded as a promising material for the production of siliconcarbide refractories used in silica binder. Silicon carbide is obtained as micropowder with irregular particles in the size range 0.2–1.0 μm.     

静电纺丝法制备氧化钴纳米纤维

采用硝酸钴与聚乙烯吡咯烷酮(polyvinylpyrrolidone, PVP)为原料制备纺丝液, 利用扫描电子显微镜、同步热分析仪、X-射线衍射仪以及透射电子显微镜对前驱体纤维及煅烧后纤维进行表征与分析, 研究静电纺丝技术制备氧化钴纳米纤维的可行性及最佳实验条件。结果表明: 在PVP(K30)质量分数为43%, 硝酸钴质量为2 g以及最佳设备参数条件下, 可以制备出直径约600 nm、均匀光滑的硝酸钴/PVP前驱体纤维, 经600℃高温煅烧后, 可得到直径约30 nm的氧化钴纳米纤维。     

Production of silicon carbide from microsilica waste by reduction with lignite semicoke

Silicon carbide may be produced from fine-grain batch consisting of two main components: microsilica waste; and semicoke obtained from Berezovsk lignite (Kansko-Achinsk Basin). The physicochemical properties of the silicon carbide are certified in the present work. Two forms of microsilica are considered: (1) microsilica formed in the production of silicon (containing 93.41–95.33% SiO₂; 1.96–3.28% C_free; 0.30–0.34% Si_free; and 1.25–1.45% CaO + Fe₂O₃ + MnO); (2) microsilica formed in the production of high-silica ferrosilicon: (containing 91.72–93.63% SiO₂; 0.56–1.18% C_free; 0.18–0.20% Si_free; and 1.38–2.32% CaO + Fe₂O₃ + MnO). Its specific surface is 21000–24000 m²/kg. The microsilica is inclined to form spherical aggregates measuring 200–800 nm. The aggregates consist of spherical particles ranging in size from 30 to 100 nm. The lignite semicoke contains 94.05% carbon, 9.2% ash, 0.2% sulfur, and 0.007% phosphorus; its specific surface is 264000 m²/kg. The composition of the silicon carbide is investigated, along with its specific surface; the size and shape of the carbide particles are determined. In both cases, the predominant phase is cubic silicon carbide (β-SiC), with an accompanying glassy phase consisting of silicates of calcium, magnesium, and iron. When the batch containing microsilica from ferrosilicon production, the silicon carbide is accompanied by α iron. In synthesis at 1923 and 1973 K for 50 and 90 min, respectively, polymorphic conversion of β-SiC to α-SiC_p is observed. The content of silicon carbide in the products is 82.52–84.90%. Chemical enrichment of silicon carbide proves expedient. The optimal enrichment conditions are as follows: the action of hydrochloric acid (concentration no less than 35%) at 353 K for 3 h, with a 1:2 solid/liquid ratio. The enrichment characteristics are as follows: the content of silicon carbide in the products is 90.42–91.10%; and 87–95% of the impurities (metal oxides and iron) are removed. The silicon carbide is obtained as micropowder consisting of irregular particles (size 0.2–1.0 μm) with specific surface 8000–9000 m²/kg.     

过硫酸铵氧化沉淀法富集净化钴渣中钴的试验研究

某公司生产初期采用α-亚硝基-β-萘酚除钴工艺回收湿法炼锌净化钴渣中的钴,存在药剂消耗量大、钴渣含钴低、生产亏损的问题,后采用过硫酸铵氧化沉淀法富集钴,形成了一种钴的富集倍数高,成本低、流程短、易操作、环保的净化渣回收钴的实用方法.该方法分三个阶段:酸浸阶段包括稀酸选择性浸出和逆流酸性浸出,在较优工艺参数下,钴的浸出率...     

Separation of cobalt and nickel by ozone oxidation

The utilization of ozone for the separation of cobalt from nickel sulfate was investigated by determining the oxidation rate for Co(II) and Ni(II) ions under various ozonation conditions at 60°C. The oxidation reaction was observed to follow a first order rate with respect to the ozone partial pressure of the O₃-O₂ mixture gas and to be promoted considerably by vigorous agitation. The oxidation rates were virtually constant down to a fairly low concentration of the oxidizable ions. Nickel ion was found to be oxidized more easily at lower pH in the mixed sulfate solutions than in solutions of a single sulfate. At pH 2.5–5.0, ozone oxidation seems to be effective to separate cobalt ions selectively from nickel sulfate solutions, due to the extremely slow oxidation of the nickel ion in comparison with cobalt.     

ICP-AES测定氧化钴中杂质

利用仪器所带软件 ,拟定了氧化钴中铅、锌、铁、镉、铜、锰的分析方法 ,试验选定了各元素的分析谱线及仪器的工作参数。氧化钴试样用盐酸分解 ,在体积分数为 5 %的盐酸介质中同时测定 ,结果满意。     

含锗褐煤的利用现状

概述了我国含锗褐煤的资源状况，分析了我国从含锗褐煤中提取锗的方法和特点，对国外含锗煤的利用现状进行了评述，提出了含锗褐煤利用的发展方向。     

褐煤的气相色谱/串联三重四极杆质谱鉴别检测方法

基于传统褐煤鉴别方法操作复杂、定性结果主观影响较大等特点,探索并建立了褐煤的气相色谱/串联三重四极杆质谱鉴别方法(GC-MS/MS)。对煤炭样品采用丙酮溶液提取,提取液用气相色谱/串联三重四极杆质谱仪进行全扫描总离子流色谱和选择离子扫描及多反应监测扫描质谱(色谱和质谱)的采集分析。从总离子流图检测出褐煤的特征峰,结合特征峰的质荷比394.8/187、394.8/95、394.8/161、394.8/159.1对褐煤样品进行多反应监测模式(MRM)分析,使得定性分析更准确可靠。实验方法可广泛应用于煤炭中褐煤与其他种类煤炭区分的定性检测。     

分光比浊法测定氯化钴中硫酸根

基于在酸性溶液中、有保护剂存在的条件下,SO₄^2-与Ba²⁺形成细微均匀的BaSO₄悬浮微粒使溶液浑浊,其浊度与试样中硫酸根(SO₄^2-)含量呈正比关系的原理,建立了以丙三醇为稳定剂测定氯化钴中硫酸根(SO₄^2-)含量的分光光度比浊法。考察了超声振荡、丙三醇浓度、稳定时间等因素对检测结果的影响,并对各条件进行了优化。钴背景对测定有影响,但这种影响可以通过在标准比对液中加入不含硫酸根的氯化钴溶液,使标准比对液中钴浓度与样品中钴浓度一致而消除。该方法对氯化钴中硫酸根的检测范围为0%～0.1%,相对标准偏差为0.84%～3.4%,回收率为98%～101%。方法用于氯化钴产品中硫酸根的检测已近两年,效果较好,适于推广。     

含锗褐煤的利用现状

概述了我国含锗褐煤的资源状况,分析了我国从含锗褐煤中提取锗的方法和特点,对国外含锗煤的利用现状进行了评述,提出了含锗褐煤利用的发展方向。     

Adsorption of 1,1,1,2-Tetrafluoroethane by Various Adsorbents

Experiments have been conducted to investigate gas-phase adsorption characteristics of 1,1,1,2-tetrafluoroethane (HFC-134a) by activated carbon fiber, extruded activated carbon, granular activated carbon, activated alumina, and molecular sieve. HFC-134a is currently regarded as an excellent replacement for chlorofluorocarbon-12, a refrigerating and cooling agent extensively used previously in all automobiles and many cooling systems. Performances of HFC-134a adsorption were characterized by the equilibrium adsorption capacity, time to reach equilibrium, and desorption efficiency of exhausted adsorbent. A simple thermal treatment process with proper operating temperature and treatment duration was found to be effective for the regeneration of exhausted adsorbents. Adsorption isotherms of the empirical Freundlich and Jossens types were observed to adequately represent the equilibrium adsorption data. A mass transfer model based on the pseudo steady state squared driving force was adopted to describe the mass transfer process of HFC-134a adsorption.     

吸光比浊法测定硝酸钴溶液中硫酸根

研究了用吸光比浊法检测硫酸根的最佳实验条件并建立了硝酸钴溶液中硫酸根的测定方法。在稀盐酸介质中,当温度为50℃时,SO₄^2-与Ba²⁺反应生成BaSO₄的细微颗粒,有保护剂(OP乳化剂-乙醇溶液)存在时,这种细微颗粒能均匀悬浮在溶液中,并且在390nm波长处硫酸根浓度与吸光度成良好的线性关系。实验表明,稳定剂的最佳加入量为5mL,温度在50～60℃时溶液浊度值在40min之内保持稳定,硫酸根的测定范围为1～8μg/mL,样品的加标回收率在95%～105%之间。方法应用于硝酸钴溶液的分析,SO₄^2-的测定值与离子色谱法的测定值相符。     

铜汞合金电极吸附伏安法测定痕量钴

提出了利用铜汞合金电极吸附伏安法测定钴的新方法。采用铜粉与汞混合制成的汞合金糊涂布在固体石蜡碳糊电极表面,固化后制得铜汞合金电极。在pH 9.0的NH3.H2O-NH4Cl缓冲溶液中,Co(Ⅱ)与丁二酮肟形成络合物在该电极上产生灵敏催化波,用线性扫描伏安法在-0.80~-1.30 V范围内进行扫描,于-1.05V出现灵敏还原峰,峰电流与Co2+的浓度在0.02~3μg/mL范围内呈线性关系,Co2+的检出限为0.01μg/mL。该法已用于水样中Co2+含量的测定,结果与原子吸收光谱法或认定值相符。该电极保留了汞电极由于有较高的氢过电位而应用电位范围广的特点,又避免了汞电极有毒、使用不方便的缺点。