中等品位铝土矿纯碱烧结法烧结条件及硫影响研究

对纯碱烧结法烧结条件进行了研究,考查碱比、烧结温度、烧结时间等对氧化铝溶出率的影响。并在较适宜烧结条件下,对铝土矿中不同硫含量对氧化铝溶出率的影响进行研究。实验结果表明,较适宜烧结条件为碱比1.3,烧结温度1 100℃和烧结时间40 min;铝土矿中硫含量的增加导致氧化铝溶出率降低。     

茉莉花茶中铅镉元素的含量测定

本文比较了样品前处理微波消解法和干灰化法,优化了微波消解条件和石墨炉原子吸收光谱仪的各项技术参数,建立了同时测定茶叶中重金属Pb和Cd的新方法。测定12批茉莉花茶及茶渣中Pb、Cd两种重金属元素含量,计算了常规泡制条件下,该二元素的溶出率。结果表明：用微波消解-石墨炉原子吸收法测定Pb和Cd方法,铅、镉金属元素检出限分别为0.03μg/L和0.004μg/L,加标回收率在93.6%～97.2%之间。方法简便、可靠,能满足茉莉花茶中Pb、Cd分析检测的要求。检测的12批广西生产的茉莉花茶Pb含量均未超标,沸水泡制后Pb的溶出率为10.5%～18.6%,Cd的溶出率约为12.0%～34.7%。     

电感耦合等离子体质谱法测定柴油车用SCR催化器中钒

首先采用6种不同酸配比的酸溶法对选择性催化还原(SCR)催化剂进行前处理,采用电感耦合等离子体质谱法测定样品中钒元素的含量。结果显示:在添加盐酸的基础上添加氢氟酸或过氧化氢,对钒的溶出都有增益。考虑氢氟酸的毒性及腐蚀性,选取盐酸和过氧化氢酸配比进行研究。通过对酸添加量、微波消解温度和微波消解时间的考察,进一步优化酸溶法,并以电感耦合等离子体质谱法测定样品中钒元素含量。结果显示:采用6 mL盐酸、2 mL过氧化氢,在180℃下微波消解30 min,为最佳消解SCR催化剂的前处理方案,钒的回收率为99.3%,相对标准偏差为1.5%,结果满意。     

应用PDA法和PIMS法测定钢中酸溶铝方法研究

本文应用脉冲高度分布分析方法（ＰＤＡ）和峰值分析法（ＰＩＭＳ），进行了碳素钢和低合金钢中铝（ＡｌＴ）和酸溶铝（Ａｌｓ）的分析方法试验研究，试验部分叙述了基本分析条件选择试验，分析了共存元素干扰影响，叙述了测定条件和方法以及精密和准确度试验。试验表明两种方法的一铝和酸溶铝分析操作简便，准确可靠，分析速度快，满足连铸工艺对全铝，酸溶铝，酸不溶铝在线分析的要求。     

固溶温度和时间对ZL114A合金组织的影响

通过金相分析、动力学分析等方法,研究了固溶温度和固溶时间对ZL114A合金共晶硅形态的影响。结果表明：固溶温度对共晶硅的粒化过程有很大的影响,在不产生过烧时,温度越高共晶硅的粒化速率越快、粒化程度越彻底;固溶时共晶分枝和凹槽处首先熔断,并且端部钝化逐渐圆整;ZL114A合金在550℃×10h固溶时的硅相形态最为理想。     

对溶出压煮器料浆温度测量偏低问题的分析

在氧化铝拜尔法溶出生产中．温度是十分重要的工艺参数。在溶出工艺流程中．采用常规自控仪表300余套．而温度测量仪表就有130余套．它们分别对流程中各物料温度进行测量和联锁控制。     

车用陶瓷催化剂酸溶后残渣成分的研究

采用酸溶法消解车用陶瓷催化剂后都会残留残渣,对残渣的成分进行分析并对其中的贵金属含量进行检测。采用半定量分析发现,残渣成分是氟化铝。将残渣用碱熔融法进行溶解,并用电感耦合等离子体质谱仪对其进行定量分析发现残渣中贵金属元素含量低于定量下限,可忽略不计。结果表明:采用酸溶法对车用陶瓷催化剂溶解后有残渣不能表明贵金属不完全溶出。     

微波组件激光封焊的温度场仿真

基于高斯面热源加三维锥体热源的组合热源模型和ANSYS有限元软件,建立了高硅铝合金微波组件壳体的激光焊接数值分析模型。使用三角周期函数实现热源功率的循环加载。通过激光焊接过程的热仿真,分析了密封焊接过程中,微波壳体四条边的温度分布规律以及温度变化趋势。仿真结果表明,焊缝中心的温度随着焊接过程的持续进行而不断升高,焊接速度的提高也导致焊缝中心温度增加。此外,焊接过程中,铝硅壳体温度也持续上升,第4道焊缝收弧时,该点附近底板温度已经达到210 ℃,会损害底板上电子元器件的性能。     

汽油样品预处理方法的探讨：汽油中痕量铅的测定

本文研究测定汽油中痕量铅时两种预处理测定方法：（１）碘－正辛醇萃取－硝酸反萃取－离子交换、洗脱后用阳极溶出法测定；（２）微波提取－原子吸收测定。对两种方法的最佳条件进行了讨论。     

电感耦合等离子体发射光谱法测定面制食品中的铝

建立了利用电感耦合等离子体发射光谱法(ICP-AES)测定面制食品中铝的方法.采用微波消解法、HNO3,-HCIO4湿消解法及干灰化法对样品进行前处理,选用波长为396.152nm的铝发射线进行测定,工作曲线法定量.仪器检出限为0.02mg/L,回收率为91.7%-102.5%,测定的相对标准偏差均小于4%.实验表明本法操作简便、快速、准确等特点.     

改善大掺量粉煤灰水泥石抗碳化性能的试验

采取高温养护、粉煤灰磨细和水泥石内部补足碱3种方法,对大掺量粉煤灰水泥石的抗碳化性能进行改善,利用碳酸盐定量分析法对改善后水泥石的抗碳化性能进行测试,结果表明：高温养护和粉煤灰的磨细对大掺量粉煤灰水泥石的抗碳化性能有较好的改善效果;补足碱对大掺量粉煤灰水泥石抗碳化性能的改善作用不大。     

基于ANSYS的微波加热再生沥青路面温度控制仿真与试验

基于麦克斯韦热传导方程建立了微波加热温度理论模型;并采用ANSYS分析软件对沥青混合料微波加热进行仿真,得出了不同加热时间下的温度分布;进行了现场温度测试.实验结果表明:现场实测的温度数据与理论分析值基本吻合,说明用ANSYS仿真是可行的,并证明利用微波来加热沥青路面是可行的.     

Quantification of fly ash in hydrated,blended Portland cement pastes by backscattered electron imaging

An automated image analysis procedure for the segmentation of anhydrous fly ash from backscattered electron images of hydrated, fly ash blended Portland cement paste is presented. A total of six hundred backscattered electron images per sample are acquired at a magnification of 2000. Characteristic features of fly ash particles concerning grey level, shape and texture were used to segment anhydrous fly ash by a combination of grey level filtering, grey level segmentation and morphological filtering techniques. The thresholds for the grey level segmentation are determined for each sample by semiautomatic histogram analysis of the full image stack of each sample. The analysis of the presented dataset reveals a standard deviation of the reaction degree of fly ash of up to 4.3%. The results agree with a selective dissolution method to quantify the reaction degree of fly ash showing the potential of the presented image analysis procedure.     

Study on the Preparation and Tribological Properties of Fly Ash as Lubricant Additive for Steel/Steel Pair

Fly ash, generated during the combustion of coal for energy production, has been regarded as an environmental pollutant if not properly disposed of. Many aggressive efforts have been evaluated to recycle the fly ash. In this paper, a new approach was developed to prepare lubricant additive based on fly ash and the tribological properties were investigated in detail. The results show that fly ash modified with oleic acid not only performs favorable dispersive ability, but also significantly improves the friction-reducing and anti-wear abilities for steel/steel contact. Based on the characterization of the wear scars by scanning electron microscopy, Raman spectroscopy and energy-dispersive X-ray spectroscopy, the excellent tribological properties are attributed to the synergies of fly ash and oleic acid because fly ash can act as spacer and bearing and deposit on the worn surfaces to significantly improve the friction-reducing and anti-wear abilities, and the introduction of strong polar groups can make fly ash easily form a stable and successive tribofilm on the rubbing surfaces throughout the sliding process.     

基于飞灰比电阻检测的烟尘治理管理手段

介绍了某电厂通过飞灰比电阻检测手段加强烟尘治理的经验,提供了国内十多种典型煤种燃烧后的飞灰比电阻检测数据。提出了避免采购高飞灰比电阻煤炭、高飞灰比电阻煤与低飞灰比电阻煤掺烧、利用飞灰比电阻检测手段综合诊断除尘设备缺陷等烟尘治理的精细化管理手段。     

Multi-response optimisation of sintering parameters of Al–Si alloy/fly ash composite using Taguchi method and grey relational analysis

In this paper, an attempt has been made to optimise the sintering process parameters of Al–Si (12%) alloy/fly ash composite using grey relational analysis. Al–Si alloy/fly ash composite was produced using powder metallurgy technique. Al–Si alloy powder was homogenously mixed with various weight percentages of fly ash (5–15 wt.%) and compacted at a pressure ranging from 307 to 512 MPa. The green compacts were sintered at temperatures between 575 and 625°C. Experiments have been performed under different conditions of temperature, fly ash content, and compacting pressure. Taguchi’s L₉ orthogonal array was used to investigate the sintering process parameters. Optimal levels of parameters were identified using grey relational analysis, and significant parameter was determined by analysis of variance. Experimental results indicate that multi-response characteristics such as density and hardness can be improved effectively through grey relational analysis.     

改性粉煤灰结构与吸附性能及其在废水处理中的应用研究

采用碳酸钙、碳酸钠、硫酸及碳酸钠处理后再加硫酸等改性剂对粉煤灰进行改性处理;通过X-射线衍射分析研究其改性后的物相结构,并对几种废水进行吸附试验.研究探索出了粉煤灰及其改性后的吸附机理.并将其应用到了废水处理中,收到了较好的效果.     

Effect of ash fraction and particle size on ash deposition during pulverized coal combustion

Coal is an important energy source to increase consumption continuously. However, the ash residues from coal combustion have produced ash deposition that causes slagging and fouling in boilers. The goal of this study is to examine the characteristics of ash deposits (i.e., the effects of the ash fraction and particle size) in pulverized coal combustion. For this study, five coals (Suek, Macqurie, Berau, Lanna and Vitol) are used, which have similar chemical components in the ash but differences in the ash fraction. A Thermomechanical analysis technique (TMA) and Drop tube furnace (DTF) are used to analyze the tendencies in the ash fusibility and deposition with temperature, respectively. Moreover, the size and morphology of the fly ash are analyzed for physical changes by using a particle-sizedistribution analyzer and Scanning electron microscopy (SEM), respectively. In the TMA results, all coal types have a similar fusibility because of the similar chemical components in the ash. The order of the deposited mass is Suek, Macqurie, Berau, Vitol and Lanna in accordance with the ash fraction in the DTF. The ash fraction in coal is a major factor in the ash deposit according to these results. The size of the fly ash changed compared to that of the raw coal according to the results of a particle-size analysis and SEM owing to physical processes such as fragmentation, shedding and coalescence during coal burning. On this basis, a deposition model is developed with the ash fraction and particle size. The model results are in good agreement with the measurements. The results demonstrate that the particle size and ash fraction influence the deposit.

     

粉煤灰超细磨的开发与应用

资源综合利用是我国经济建设中的一项重大技术经济政策,粉煤灰是可利用资源,国家积极支持和鼓励粉煤灰的综合利用,先后制定了一系列的政策和标准。在目前国家环保要求不断提高,灰场占地日益紧张的客观条件下,对分选后粗灰进行磨细,使其达到符合国家标准的Ⅰ级、Ⅱ级灰,提高其附加值,从而实现粉煤灰零排放的已成为势在必行的趋势。论述了磨细后粉煤灰的利用价值及粉煤灰超细磨系统的设计。     

Lubricant Additives Based on Carbon Nanotubes Produced from Carbon-Rich Fly Ash

Carbon-rich fly ash has been reported to be a suitable precursor and catalyst for carbon nanotube (CNT) growth. In this work, CNTs grown from carbon-rich fly ash were evaluated as a lubricant oil additive to reduce the friction coefficient of metallic surfaces using a ball-on-disk tribometer. Different concentrations of the as-grown CNTs in the range 0.005–0.5 wt% were dispersed in a base sunflower oil. The value of the friction coefficient was also investigated as a function of load. Excellent results were obtained for the value of the friction coefficient, where it drastically decreased to around 58% of its original value without additives. This was achieved at a very low concentration of CNTs; that is, 0.1 wt%. The obtained result was compared with that of a commercial multiwalled CNT at the same concentration and found to be superior. This superiority of CNTs produced from fly ash could be attributed to the existence of active radical sites on their side wall. Moreover, the friction coefficient value was observed to decrease with increasing load, which might be due to the formation of protective graphitic carbon layers on antagonist surfaces. The viscosity of pure and 0.1 wt% CNTs-impregnated base oil was also studied in the 25–100°C temperature range. No significant changes are observed in the viscosity of the CNTs-impregnated base oil. These results suggest that the low-cost CNTs produced from fly ash are excellent nanomaterials as additives for lubricant oil.