机械力化学效应对锅炉底渣理化特性的影响

为了考察机械力化学效应对锅炉底渣理化特性的影响,采用高能球磨机对锅炉底渣进行球磨,并使用粒度测试、密度测试、XRD、SEM、FI-IR及DSC检测手段,分析其粒度、密度、矿物性能、显微形貌及热力学性质在不同球磨时间下的变化.结果表明:随着球磨时间的增加,锅炉底渣的粒度减小,密度增加;形貌明显改变,颗粒趋于球形,且分布均匀;锅炉底渣中的莫来石、石英等晶相遭到破坏;Al—O—Si、Si—O—Si键断裂,非晶态Al2O3、SiO2增加,有利于提高锅炉灰渣的活性.并确定了在实验条件下最佳球磨时间为9 h.     

机械力化学效应在凹凸棒石/TiO_2复合颗粒制备中的应用研究

用高能行星磨对凹凸棒石进行机械力化学活化,采用中和水解法制备了凹凸棒石/TiO2复合颗粒,通过热重分析、SEM和TEM分析,研究了机械力化学活化的凹凸棒石及所制备复合颗粒的热稳定性、粒度和微观形貌的变化情况。结果表明:凹凸棒石经粉磨后颗粒表面活性极大增强,颗粒变得扁平和细小,所制备的复合颗粒包覆效果理想,分散性好。     

无机非金属材料粉磨中的机械力化学效应

机械力化学是研究有和化学之间的相互转化的一门学科,机械力化学效应被大量运用于材料制备中的非平衡过程,着重评述了机械力化学效应的产生机制,特点,影响因素等方面。     

机械研磨锰渣的物理与机械力化学现象研究

以锰渣为主要研究对象,对其机械研磨过程中的物理与机械力化学现象进行了研究.通过密度测定、比表面积测定和颗粒群特征分析对活化锰渣的物理性能进行了表征,采用X射线衍射分析(X-ray diffraction,XRD)和扫描电镜分析(Scanning electron microscopy,SEM)等现代测试方法对锰渣机械力活化过程的结构特征进行了分析,结果表明,锰渣经过高能机械研磨后其密度增大,比表面积增大,粒径趋于向粒径小的方向分布;随着机械研磨时间的延长,大颗粒减少,小颗粒增多,晶体结构发生了变化,SiO2由晶形向无定形的转变量增加.制备了锰渣一水泥复合体系,并测定了其力学强度,结果表明,随着锰渣细度的增大,体系强度不断增大.     

无机材料机械力化学研究进展

近年来,机械力化学的研究取得了很大进展,本文简要介绍了机械力化学效应,对机械力学化在粉体,硅酸盐材料及其在特种陶瓷中的应用进行了综述和展望。     

机械力化学效应对煤矸石物理性能的影响

用高能行星磨对煅烧后煤矸石进行机械力化学活化,通过XRD、SEM和FI-IR分析,研究了粉磨过程中煤矸石的粒度、密度、形貌和显微结构的变化情况.结果表明:煤矸石属于易磨性物质,极易细化,球磨处理后的煤矸石,颗粒表面光滑,高岭土晶相消失,α-石英结晶程度降低,Al-O键和Si-O键键能和键结构发生了明显的变化,煤矸石活性提高.     

无机材料机械力化学研究进展

近年来 ,机械力化学的研究取得了很大进展。本文简要介绍了机械力化学效应 ,对机械力化学在粉体、硅酸盐材料及其在特种陶瓷中的应用进行了综述和展望。     

湿法超细研磨中白云石机械力化学效应

通过对不同累积研磨时间白云石样品的粒度、浆料中离子浓度和物相分析,研究湿法研磨时白云石的机械力化学效应。结果表明:白云石在湿法超细研磨时,颗粒粒度随着研磨时间的延长而显著地减小;浆料中Mg2+和Ca2+的浓度则先是显著增大后趋于平稳增大,表明白云石超细粉碎过程可以使碳酸镁和碳酸钙在溶液中溶解度有所增大,直至达到溶解和结晶动态平衡;晶体的显微应变和晶粒尺寸都随着研磨时间的延长而先减小后增大,说明在湿法研磨的过程中,由于机械力的作用使得白云石的晶体发生了畸变。     

氧化铝高能球磨时机械力化学效应研究

研究了氧化铝在高能球磨过程中机械力化学效应的变化.机械力化学效应因子随球磨时间的变化可分为三个阶段:第一阶段主要是晶粒尺寸减小和显微应变增加同时进行;第二阶段主要是有效温度系数的增加;第三阶段主要是点阵膨胀至饱和.用溶解法比较了球磨前后氧化铝的活性,发现经球磨后,氧化铝在盐酸中的溶解活化能由18 kJ/mol降至4 kJ/mol,表面活化层增厚.     

氧化铝高能球磨时机构力化学效应研究

研究了氧化铝在高能球磨过程中机械力化学效应的变化,机械力化学效应因子随球磨时间的变化可分为三个阶段;第一阶段主要是晶粒尺寸减小和显微应变增加同时进行;第二阶段主要是有效温度系数的增加;第三阶段主要是点阵膨胀至饱和。用溶解法比较了球磨前后氧化铝的活性,发现经球磨后,氧化铝在盐酸中的溶解活化能由１８ｋＪ／ｍｏｌ降至４ｋＪ／ｍｏｌ,表面活化层增厚。     

碳酸化钢渣和矿渣作硅酸盐水泥混合材水化性能研究

通过对钢渣碳酸化前后的硅酸盐相提取及水化放热性能和将碳酸化钢渣和矿渣作为混合材的硅酸盐水泥的胶砂强度和水化产物种类的测定,以及对它们微观形貌的观察,研究了碳酸化钢渣对胶凝体系水化性能的影响.结果表明,碳酸化使钢渣中硅酸盐相的含量由47.06％下降至14.38％;碳酸化促进了钢渣的早期水化,抑制其后期水化;在配比相同的条件下,碳酸化钢渣-矿渣-硅酸盐熟料体系试样的3、28d抗压强度较未碳酸化钢渣-矿渣-硅酸盐熟料体系试样的高;碳酸化生成的CaCO3促进了熟料的水化;碳酸化钢渣促进了胶凝体系中AFt的生成,且生成水合碳铝酸钙.     

Stress and oxidation of nickel according to its purity

Abstract

The effect of impurities on the oxidation mechanism of nickel and on mechanical characteristics of the NiO scale was studied on two industrial grades and one pure nickel.

The oxidation mechanism at 800°C was clarified using kinetics approach, microstructure observations, EDX and XPS analyses, profilometry, oxygen isotopic exchange and SIMS.

The mechanical characteristics were determined mainly by three point bending tests performed in a scanning microscope.

Whatever the nickel grade, the oxide toughness varies with the scale thickness and tends towards the value of massive NiO. The main difference related to Ni purity consists in the fact that spalling occurs at an oxide/oxide interface for the industrial grades, while it appears at the metal/oxide interface for pure Ni.

Indeed, due to the presence of impurities, internal oxidation, extrusion of metallic nickel along grain boundaries of the substrate and formation of an inner equiaxed oxide film are observed in industrial grades. This induces mechanical keying of the oxide, and therefore crack propagation in a mixed mode is easier at the oxide/oxide interface.

With pure nickel, only a single oxide film is formed by outward diffusion of Ni and there is no internal oxidation. Thus crack propagation occurs along the metal/oxide interface.     

高温固相法制备钒掺杂含钛高炉渣光催化抗菌材料

采用高温固相法,掺杂不同质量分数的V2O5,在800℃煅烧2h合成了钒掺杂的含钛高炉渣催化剂(vanadium oxide modified titanium bearing blast furnace slag,VTBBFS)。用X射线衍射、扫描电子显微镜和紫外-可见漫反射光谱仪对钒掺杂的含钛高炉渣催化剂进行了表征,确定其具有钙钛矿结构;粉体的颗粒形态均为不规则块状,800℃煅烧后出现了团聚现象;在紫外区域具有强光吸收能力,并发生红移。以白色念珠菌为实验菌种考察钒掺杂的含钛高炉渣催化剂抗真菌能力。结果表明,V2O5掺杂量为10%时,催化剂具有较强的抗白色念珠菌能力,在普通光照下杀菌率可达到100%。     

The Soret effect in dilute aqueous alkaline earth and nickel chloride solutions at 25°C

The Soret effect in dilute aqueous solutions of alkaline earth and nickel chlorides at 25°C has been investigated by the potentiometric method. The molar entropies of transport have been obtained from the measurements of the initial (homoheneous) and final (Soret steady-state) thermoelectric powers. The Soret coefficients at 0.005 M (molarity) have been calculated. The variation of the conventional ionic entropies of transport with the ionic radii is investigated and its possible implications for ionic hydration phenomena are discussed.Paper presented at the Ninth Symposium on Thermophysical Properties, June 24–27, 1985. Boulder, Colorado, U.S.A.     

Investigation on the effect of MgO content on the crystallization behavior of synthetic BF slag

The crystallization of molten blast furnace (BF) slag can increase its viscosity and reduce its liquidity; it can also affect the quality of slag fibers following their manufacture. The crystallization behavior of BF slag is influenced by its chemical composition. In this study, four synthetic BF slags with various MgO contents, ranging from 6 to 12%, were investigated. FactSage simulations were performed to predict the types of crystallized phases as well as their mass fractions that are developed within the synthetic BF slags during the cooling process. To verify the validity of FactSage simulation, X-ray diffraction and scanning electron microscope–backscattered electron imaging, where the equipment was coupled to an energy-dispersive spectrometer, were performed to explore the mineralogical compositions and morphologies of the synthetic BF slags. Experiments using the hot thermocouple technique were performed to identify the initial crystallization temperatures of the synthetic BF slags. The results indicate that the observed phases of the synthetic BF slags were primarily composed of akermanite (2CaO?·?MgO?·?2SiO₂) and gehlenite (2CaO?·?Al₂O₃?·?SiO₂), which could form a solid solution, melilite, and control the initial crystallization temperature. The initial crystallization temperature increased as the MgO content of the slag increased. A low initial crystallization temperature was achieved in the cases of the synthetic BF slag samples with MgO contents of 6–8%; these slags were considered suitable for the manufacture of slag fiber.     

硅钙渣对水泥熟料易烧性的影响

为使高铝粉煤灰提氧化铝后产生的二次固废硅钙渣能够在水泥行业中被大量地消纳,以熟料中的f-Ca O含量为指标,对不同配比硅钙渣水泥熟料的易烧性进行了研究,并采用XRD和ESEM对其进行分析.结果表明:硅钙渣能显著增加熟料烧成时的液相量,促进矿物晶体生成与长大,改善生料的易烧性;但当硅钙渣掺入量高于40%时,由于铝率的升高,使生料的易烧性下降.     

铈元素对镍电极性能的影响

研究了Ce元素作为添加剂，通过外掺和共沉积的方式加到Ni(OH)2时对镍电极性能的影响，并用循环伏安法对结果进行分析，结果表明外掺法极大地提高了电极的性能，而共沉积加入Ce元素却不能有效地改善电极的性能，循环伏安实验结果表明，外掺法加入Ce元素时能够很好地改善电极的可逆性，改善了电极反应中电子的传输能力，因而很好地改善了电极的性能。     

纳米级氢氧化镍和钴对镍电极性能的影响

通过充放电曲线和交流阻抗谱的测定探讨了纳米级氢氧化镍和氢氧化镍表面包复CoOOH以及镍箔上电镀钴层对氢氧化镍粉末压制的镍电极性能的影响。结果表明．纳米级氢氧化镍有较快的活化能力，CoOOH包Ni(OH)2则有较高的放电容量，而比例适当的纳米复合镍电极才有更好的电化学性能。氢氧化镍表面包复CoOOH可改善镍电极的充放电性能；镍箔上镀钴可大大降低电极过程的电荷转移电阻；钴含量大于3％后．虽然活化速度有所下降，但是大电流充放电时，镍电极活性物的利用率更高，放电容量更大。纳米级Ni(OH)2含量大于30%后，镍电极的活化速度不仅未能加快，反而略有减慢，而且容量也降低。     

高岭土和氢氧化铝共司粉磨时的机械力化学效应研究

本文通过SEM、XRD、DTA、FT-IR等测试手段对高岭土和氢氧化铝的高能球磨过程进行了研究。结果表明，高能球磨可以使该混合物发生明显的机械力化学变化，粉磨后颗粒形貌改变，粒径变小，晶体变成无定形态，部分化学键出现断裂。这为莫来石的低温煅烧提供了理论基础。