一种低温无硼无铅生料乳浊釉的研究

研究了一种无硼无铅生料乳浊釉,并讨论了影响乳浊度的一些因素。     

无硼铅复合生料乳浊釉

本文就在料的充分利用，节约能源这两个方面来展开探讨。第一：以生料釉代替熔块釉节约能源；第二：以长石、方解石、萤石、滑石作为助熔剂代替价格昂贵的硼砂，以锆英石代替二氧化锡作为乳浊剂，从而节约成本；第三：研制良好的乳浊剂来遮普劣质素烧坯体，以充分利用自然资源，改变工艺流程来提高经济效益。     

高温钛乳浊生料釉的研究

本文对钛釉用于卫生瓷生产进行了研究，讨论了ＴｉＯ２外加加量以及长石，石灰石含量对釉面色泽，白度的影响，利用Ｘ射线衍射的偏光显微镜，对析出晶相的种类和分类进行了分析，在此基础上对钛釉的乳浊机理进行了探讨。     

无锆生料乳浊釉的研制

通过合理设计釉组成,研制出了一种不含锆英石微粉的生料乳浊釉,应用X-ray衍射法及相图理论,初步探讨了实验释的物相组成及乳浊机理,同时分析了影响釉面质量的其他因素。     

高温钛乳浊生料釉的研究

本文对钛釉用于卫生瓷生产进行了研究．讨论了ＴｉＯ２外加量以及长石，石灰石含量对釉面色泽，白度的影响．利用Ｘ射线衍射和偏光显微镜，对析出晶相的种类和分布进行了分析，在此基础上对钛釉的乳浊机理进行了探讨．     

新型生料乳浊釉的研制

通过引入合成硼酸锌及活化处理锆英石粉制备了烧成温度低、乳浊度高的生料乳浊釉,并讨论了硼酸锌及锆英石粉活化处理对乳浊釉性能的影响。     

氧化钛乳浊生料釉的研制

利用高岭土、钾长石、石英、烧滑石、石灰石、ZnO、TiO2等常用原料,通过单因素实验法、正交实验法研究了工艺参数和备原料用量对钛乳浊生料釉的影响。实验结果表明,采用适量的CaO、MgO、ZnO等助熔剂和一定量的TiO2作为乳浊剂,通过调整高岭土、钾长石和石英的量,控制适当的SiO2／Al2O3比,在合适的温度下烧成,可以制备出釉面白度高、光泽度高且性能稳定的钛乳浊生料釉。     

无铅低温乳浊釉研究现状与展望

近年来,由于国家绿色环保政策的日益严苛,陶瓷行业的节能减排成为重要的研究课题.可用于建筑卫生陶瓷及低品位原料日用陶瓷坯体的乳浊釉,尤其是无铅低温乳浊釉的研究越来越受到重视,同时也取得了一些研究结果.本文综述了无铅低温乳浊釉乳浊机理,介绍了其分类和研究现状,并分析了当前无铅低温乳浊釉存在的问题,指出其未来的主要研究方向.     

锆磷复合乳浊生料釉的研究

本文对锆磷复合乳浊生料釉的乳浊机理及基釉组成、添加物的影响进行了分析研究。并获得了效果理想的复合乳浊釉。     

低温快烧自微晶乳浊釉的研究

采用ＳＥＭ、ＥＤＸ、ＸＲＤ等手段,了ＫＮａＯ－ＭｇＯ－Ａｌ２Ｏ－Ｂ２Ｏ３－ＳｉＯ２系全熔块乳浊釉的形成规律,指出釉层中均匀分布的大量ＭｇＳｉＯ３微晶是釉面乳浊的原因。组成中Ｂ２Ｏ３含量愈高,釉熔体的析晶倾向愈大。少量Ａｌ２Ｏ３则可以降低釉熔体高温粘度,抑制析晶,改善釉面面白我泽度。在釉烧过程中,析晶继续进行,Ｂ２Ｏ３含量的增加使基质釉玻璃的成熟温度降低。设计合理组成有快烧工艺,可得到釉面综合质量良     

低温快烧自生微晶乳浊釉的研究

采用SEM、EDX、XRD等手段,研究了KNaO-MgO-Al2O3-B2O3-SiO2系全熔块乳浊釉的形成规律,指出釉层中均匀分布的大量MgSiO3微晶是釉面乳浊的原因.组成中B2O3含量愈高,釉熔体的析晶倾向愈大.少量Al2O3则可以降低釉熔体高温粘度,抑制析晶,改善釉面白度和光泽度.在釉烧过程中,析晶继续进行,B2O3含量的增加使基质釉玻璃的成熟温度降低.设计合理组成及快烧工艺,可得到釉面综合质量良好的微晶乳浊釉.     

Anodic stripping voltammetric measurement of trace heavy metals at antimony film carbon paste electrode

The antimony film carbon paste electrode (SbF-CPE) was prepared in situ on the carbon paste substrate electrode as a “mercury-free” electrochemical sensor. Its aptitude for measuring some selected trace heavy metals has been demonstrated in combination with square-wave anodic stripping voltammetry in non-deaerated model solutions of 0.01 M hydrochloric acid with pH 2. Some important operational parameters, such as deposition potential, deposition time, and concentration of antimony ions were optimized, and the electroanalytical performance of the SbF-CPE was critically compared with both bismuth film carbon paste electrode (BiF-CPE) and mercury film carbon paste electrode (MF-CPE) using Cd(II) and Pb(II) as test metal ions. In comparison with BiF-CPE and MF-CPE, the SbF-CPE exhibited superior electroanalytical performance in more acidic medium (pH 2) associated with favorably low hydrogen evolution, improved stripping response for Cd(II), and moreover, stripping signals corresponding to Cd(II) and Pb(II) at the SbF-CPE were slightly narrower than those observed at bismuth and mercury counterparts. In addition, the comparison with antimony film electrode prepared at the glassy carbon substrate electrode displayed higher stripping current response recorded at the SbF-CPE. The newly developed sensor revealed highly linear behavior in the examined concentration range from 5 to 50 μg L⁻¹, with limits of detection (3σ) of 0.8 μg L⁻¹ for Cd(II), and 0.2 μg L⁻¹ for Pb(II) in connection with 120 s deposition step, offering good reproducibility of ±3.8% for Cd(II), and ±1.2% for Pb(II) (30 μg L⁻¹, n = 10). Preliminary experiments disclosed that SbF-CPE and MF-CPE exhibit comparable performance for measuring trace concentration levels of Zn(II) in acidic medium with pH 2, whereas its detection with BiF-CPE was practically impossible. Finally, the practical applicability of SbF-CPE was demonstrated via measuring Cd(II) and Pb(II) in a real water sample.     

Graphite-epoxy composite as an alternative material to design mercury free working electrodes for stripping voltammetry

The use of graphite-epoxy composite electrodes (GECE) as an alternative to mercury or modified electrodes for stripping voltammetry is presented. The effect of preconcentration time on the peak current was studied. It is shown, unlike traditional mercury electrodes, that the accumulation of lead using GECE does not yield a saturation current even at high preconcentration times of 30 min. A preconcentration time of 1 min was chosen as a compromise between analysis time and sensitivity. The peak current was increased by decreasing pH, the pH range 1-2 being the most sensitive. Concentrations as low as 1 ppb for lead and copper and 10 ppb for cadmium in standard solutions have been detected. Both analytical results and SEM characterisation confirm the behaviour of GECE as a complex microelectrode array at a rough surface.     

Novel electrode for electrochemical stripping analysis based on carbon paste modified with bismuth powder

Bismuth-powder modified carbon paste electrode (Bi-CPE) is presented as an attractive “mercury-free” sensor applicable in electrochemical striping analysis of selected heavy metals. The electrode paste was prepared as a mixture of finely powdered metallic bismuth together with graphite powder and silicon oil. The Bi-CPE was characterized in nondeaerated solutions containing Cd(II) and Pb(II) at the μg/L level in conjunction with square-wave anodic stripping voltammetry. The electrode exhibited well-defined and separated stripping signals for both metals accompanied with a low background contribution, and a reproducibility of 5.6 and 6.0% (n = 12) for 20 μg/L Cd(II) and Pb(II), respectively. The Bi-CPE exhibited superior performance in comparison to the bare carbon paste electrode (CPE) and the bismuth paste electrode (BiPE) and surprisingly, yielded a higher response than the in situ prepared bismuth-film carbon paste electrode. The electrode displayed excellent linear behavior in the examined concentration range from 10 to 100 μg/L Cd(II) + Pb(II) (R² = 0.998 for both), with limits of detection of 1.2 μg/L for Cd(II) and 0.9 μg/L for Pb(II). The electroanalytical performance of Bi-CPE was successfully tested in a real sample of tap water spiked with Cd(II) and Pb(II).     

Effect of Bi(III) concentration on the stripping voltammetric response of in situ bismuth-coated carbon paste and gold electrodes

The effect of Bi(III) concentration (over the wide concentration range of 10⁻⁷ to 10⁻⁴ M) on the determination of Pb and Cd metal ions (in the 10⁻⁸ to 10⁻⁵ M range), by means of anodic stripping voltammetry (ASV) at in situ bismuth-coated carbon paste (CPE) and gold electrodes, has been studied. It is shown that in square wave anodic stripping voltammetry (SWASV) experiments the sensitivity of the technique generally depends on the Bi(III)-to-metal ion concentration ratio. It was found that, unlike the usually recommended at least 10-fold Hg(II) excess in anodic stripping experiments at in situ prepared mercury film electrodes, Bi(III)-to-metal ion ratios less than 10 are either optimal or equally effective at CPE and Au electrode substrates. Detection limits down to 0.1 μg L⁻¹ for Pb(II) and 0.15 μg L⁻¹ for Cd(II) were estimated at CPEs under conditions of small or moderate Bi(III) excess. Depending on Bi(III) concentration and deposition time, multiple stripping peaks attributed to Bi were recorded (especially in the case of Au substrates), indicating various forms of Bi deposits.     

分相-析晶乳浊釉的制备及其乳浊机理研究

采用天然矿物原料,通过四角配料法优化组成制备出了无锆的分相-析晶乳浊釉.借助X射线衍射仪、透射电镜等测试手段,对乳浊釉的晶相组成和显微结构进行了分析,探讨了其乳浊机理.结果表明:该乳浊釉中P2O5和B2O3促进釉分相,CaO和MgO促进釉析晶,分相与析晶结构并存,釉层中均匀分布着大量尺寸接近可见光波长的球形孤立液滴和细小的透辉石晶体,两者对可见光强的散射作用是釉面产生乳浊的根本原因,优化出的乳浊釉白度可达80.2％.     

Microscopic and electrochemical characterization of lead film electrode applied in adsorptive stripping analysis

Lead film electrodes (PbFEs) deposited in situ on glassy carbon or carbon paste supports have recently found application in adsorptive stripping voltammetric determination of inorganic ions and organic substances. In this work, the PbFE, prepared in ammonia buffer solutions, was investigated using scanning electron microscopy, atomic force microscopy and various voltammetric techniques. The microscopic images of the lead films deposited on the glassy carbon substrate showed a considerable variability in microstructure and compactness of the deposited layer depending on the selected experimental conditions, such as the concentration of Pb(II) species, the nucleation and deposition potential, and the time applied. The catalytic adsorptive systems of cobalt and nickel in a solution containing 0.1 ammonia buffer, 2.5 × 10⁻⁵ M nioxime and 0.25 M NaNO₂ were employed to investigate the electrochemical characteristics and utility of the in situ prepared lead films.The optimal parameters, i.e. the lead concentration in the solution, the procedure of film removal, and the time and potential of lead nucleation and film deposition for the adsorptive determination of metal traces, were selected, resulting in the very good reproducibility (RSD = 4.2% for 35 scans) of recorded signals. The voltammetric utility of the lead film electrode was compared to that of glassy carbon, mercury film and bismuth film electrodes, and was subsequently evaluated as superior.     

复合聚铝用于冬季太湖水的混凝脱浊研究

将特征黏度系列化的聚二甲基二烯丙基氯化铵(PDM)与聚合氯化铝(PAC)复合用于冬季低温太湖原水强化混凝脱浊处理。由混凝烧杯实验,考察了PAC/PDM复合比例、PDM特征黏度对脱浊效果及絮团沉淀性能的影响,并与经预加氯处理的太湖水的相应处理结果作对比。结果表明,对浊度在24~26 NTU,温度为5~9℃,藻含量为8.01×103个/mL的太湖水,在与某市某水厂混凝强度相近的搅拌强度下,要达到其2 NTU沉淀池出水的余浊标准,PAC投加量3.28 mg/L,而复合比例分别为20∶1、10∶1、5∶1的PAC/PDM复合混凝剂所需PAC投加量随PDM特征黏度0.55、1.53、2.47 dL/g的增加,分别为2.93~2.83,2.70~2.60,2.62~2.51 mg/L,相应的PAC投加量减少的幅度分别为10.67%~13.72%,17.68%~20.73%,20.12%~23.48%;当沉淀出水浊度要求提高至1 NTU时,PAC需4 mg/L的投加量,复合混凝剂需3.77~3.04 mg/L的投加量,相对于PAC可减少投加量5.75%~24.00%。可见PDM明显提高了PAC的混凝脱浊效果,且PAC/PDM复合配比越低,PDM特征黏度越高,复合混凝剂的脱浊效果与沉淀性能越好。此外,PAC/PDM复合混凝剂有可能通过减少预加氯的投加量,来减少卤代有机物的形成机会,增强供水水质安全性。