粉煤灰脱炭的流态化实验研究

粉煤灰的利用价值与其残余炭含量密切有关 .在采用现代分析测试技术的基础上 ,提出了采用流态化干法脱炭技术降低粉煤灰中残余炭含量并提高粉煤灰活性的基本思路 .流态化分选实验表明 :这种干法脱炭的思路是有效的 ,这一思路将为解决我国粉煤灰的综合利用问题提供有益的借鉴     

粉煤灰的特性及其在水泥生产中的应用

1 化学成分 目前煤的燃烧一般采取喷燃炉或流态化沸腾炉。粉煤灰的质量取决于煤种、煤粉机的型号、锅炉燃烧形式、除尘设备等因素。粉煤灰的质量是一个综合性的指标，与其化学成分、物理性能、颗粒形貌等均有直接的关系。粉煤灰的主要成分是SiO2、Al2O3、Fe2O3，代表粉煤灰的化学活性，他们的含量直接影响到粉煤灰的性能。以上三种成分含量较高的粉煤灰，生成的水化物较多，强度贡献较大。     

细颗粒的团聚流态化及其判定

本文在考查了不同细颗粒的流态化过程及物料的气动特性与粘附力关系的基础上，提出了当量流态化的概念；实验发现聚团密度的减小是改善细颗粒流化性能的一种有效途径；根据气动情况下不同的成团结果，把细颗粒的聚团流态化分成了三类：沟流；似A类聚团流态化；似B／D类聚团流态化；同时，结合实验结果，给出了不同细颗粒聚团流态化类型的定量判据     

1992—1994年国内发表的流态化文献目录

１９９２～１９９４年国内发表的流态化文献目录黄水源，陈卫，俞芷青，金涌（清华大学化学工程系，北京１０００８４）１．前言从上次流态化文献调查（“１９８９－１９９１年国内流态化文献目录”，化学反应工程与工艺，１９９３，９［２］，２２０）以来，国内流态化研...     

散装水泥车进料口的设计改进

散装水泥车是一种在工业、建筑业等方面得到广泛应用的专用汽车，适用于水泥、石灰粉、粉煤灰等颗粒直径不大于0．1mm粉粒干燥物料的运输和气压卸料。主要由汽车底盘、罐体总成、管路系统及传动装置等组成。其中罐体总成由罐体、进料口、流态化床、出料管总成、进气管及其它附件组成。在罐     

上海市粉煤灰综合利用办公室工作报告

今天召开的上海市粉煤灰综合利用工作会议，是为了进一步贯彻落实市府89号令《上海市粉煤灰综合利用管理规定》和《上海市粉煤灰综合利用管理规定实施细则》，总结1997年的工作，明确1998年工作的思路和目标，解放思想、统一认识、抓住机遇、努力把本市粉煤灰综合利用工作推向新的高度。11997年工作的回顾上海市粉煤灰综合利用办公室的工作在上海市粉煤灰协调小组和上海市建材业管理办公室的领导下，基本完成了1997年年初提出的工作计划和目标，取得了一定的成绩。1．1粉煤灰的排放和利用1．1．1粉煤灰的排放情况1997年上海市各电厂粉煤灰的…     

鉴别流态化特性的两种控制算法

时间序列相关法和床层塌落法控制算法是两种在线鉴别气固流态化特性的控制算法在时间序列相关法中开发了监测床压降和表观气速的功能，建立了床层、压降和气速三个变量的相关关系，用来在线判断初始流态化、鼓泡流态化和完全流态化，计算无因次沉降时间，同时控制流化床的操作条件，改善气－固接触两种控制算法从不同角度鉴别混合物料的流态化性能，对它们所起的作用作了较详细的分析和比较     

非金属导体流态化电极的研究及应用

流态化电极是处理低浓度重金属离子废水的有效方法，本文地非金属导体流态化电极进行研究，并应用于处理含铜废水，可将铜离子浓度降到１ｐｐｍ以下。     

流态化工程研究的前沿课题

流态化工程在当前和今后的技术进步中已显示出了强大的生命力。本文介绍了流态化工程在国民经济中的作用、快速流态化与传统流态化的区别。讨论了气液固三相流态化行为。提出了流态化技术的发展前景。     

氧化锌原矿流态化浸出工艺

本发明属于冶炼工艺方法，特别是氧化锌原矿的湿法冶炼技术。本发明的工艺步骤为：对原矿破碎、球磨、调浆，泵入锥形的流态化反应器的上部，而将酸液从流态化反应器底部泵入，进行浸出，浸出液流人中和器中和，又进入浓密机浓缩，上清液送去净化作业，底流进入另一组流态化反应器再次进行酸性流态化浸出，酸浸矿浆作全矿浆压滤，滤液送球磨作调浆，滤渣堆存。本工艺简单，减少了矿浆的在槽时间，减少了锌的金属损失，提高了锌浸出率，降低电锌生产成本。     

Durability of biomass fly ash concrete: Freezing and thawing and rapid chloride permeability tests

Strict interpretation of ASTM C 618 excludes non-coal fly ashes, such as biomass fly ashes from addition in concrete. Biomass fly ash in this investigation includes (1) cofired fly ash from burning biomass with coal; (2) wood fly ash and (3) blended fly ash (wood fly ash mixing with coal fly ash). A set of experiments conducted on concrete from pure cement and cement with fly ash provide basic data to assess the effects of several biomass fly ashes on the performances of freezing and thawing (F-T) and rapid chloride permeability test (RCPT). The F-T tests indicate that all fly ash concrete has statistically equal or less weight loss than the pure cement concrete (control). The RCPT illustrate that all kinds of fly ash concrete have lower chloride permeability than the pure cement control concrete.     

The influence of air content by assessing the pozzolanic activity of fly ash by strength testing

The pozzolanic activity of fly ash and natural pozzolans are generally assessed by a compressive strength test with Portland cement in a mortar. A test mix in which part of the Portland cement is replaced by fly ash is compared with a control mix with pure Portland cement. When testing cement according to such procedures the influence of varying air contents in the test mortars can be comparable to that of other factors, hence complicating the interpretation of results. Fly ash seems to affect the air void content in mortar in two ways: By a direct contribution from hollow or porous particles in the fly ash and by reducing the amount of entrained air, an effect which is apparently caused by the residual carbon present in the fly ash.These aspects are elucidated by examples from laboratory experiments with fly ash.     

回收粉煤灰中未燃炭和降低碳含量的浮选研究

针对粉煤灰中未燃炭含量过高不利于大规模综合利用的问题,从理论上分析了浮选回收粉煤灰中未燃炭的基本原理,采用全浮选流程对粉煤灰中未燃炭进行了浮选回收试验,探讨了影响粉煤灰中未燃炭浮选效果的主要因素,确定了适宜的工艺条件。试验结果表明,采用全浮选流程可以使粉煤灰中可燃物降至4.1%左右。     

回收粉煤灰中未燃炭和降低碳含量的选研究

针对粉煤灰中未燃炭含量过高不利于大规模综合利用的问题,从理论上分析了浮选回收粉煤灰中未燃炭的基本原理,采用全浮选流程对粉煤灰中未燃炭进行了浮选回收试验,探讨了影响粉煤灰中未燃炭浮选效果的主要因素,确定了适宜的工艺条件.试验结果表明,采用全浮选流程可以使粉煤灰中可燃物降至4.1%左右.     

冻融环境下钢筋与粉煤灰混凝土的粘结承载力

通过对粉煤灰混凝土试件的直接拔出试验,分析粉煤灰掺量与冻融作用对粘结试件的初始滑移粘结强度、劈裂强度、极限粘结强度及粘结强度-滑移曲线下的面积作为粘结试件韧性评价指标的变化规律.试验结果表明:钢筋与粉煤灰混凝土的粘结强度随粉煤灰掺量的增加而降低;试件粘结韧性随粉煤灰掺量的增加先降低后增强,粉煤灰掺量较大的试件在加载过程中表现出良好的韧性;冻融作用对试件极限粘结强度的影响程度随粉煤灰掺量增大而减小,40%粉煤灰试件在冻融环境下表现出较好的粘结韧性.掺入较多粉煤灰可以在一定程度上减缓粘结试件的冻融损伤.     

改性粉煤灰对沙土物理特性改良效果研究

针对内蒙古锡盟地区粉煤灰堆存量大、利用率低以及当地土壤荒漠化严重等系列问题,本工作提出利用粉煤灰改良荒漠土壤的新思路。首先用硫酸对惰性的粉煤灰进行表面活化改性,采用SEM和XRD等分析测试手段研究粉煤灰结构变化,采用XPS和TG分析方法分别对粉煤灰表面羟基定性分析和定量计算,以期明晰粉煤灰表面羟基化效果;其次,使用改性前后粉煤灰分别作为土壤加固剂,以现场采集沙土为加固对象,研究改性粉煤灰对砂土稳定性的影响。结果表明,使用1.5 mol/L的硫酸溶液预改性后,颗粒表面羟基数量较原始粉煤灰增大4倍。按质量比1:9将酸改性前后的粉煤灰分别与沙土复配并静置15天后对复配土的力学强度进行测定,结果显示原始沙土间的黏聚力为0.29 kPa,改性前粉煤灰-沙土复配土的黏聚力为0.88 kPa,而改性后粉煤灰-沙土复配土的黏聚力提高到3.51 kPa。     

粉煤灰掺量对天然盐渍土强度和变形的影响

选取天然盐渍土在不同粉煤灰配合比条件下进行三轴试验、压缩试验和溶陷试验,研究粉煤灰对天然盐渍土的改良特性规律。试验结果表明:同种类盐渍土在一定条件下,盐渍土的抗剪强度随着粉煤灰配合比的增加逐渐增加;粉煤灰可改良盐渍土的压缩特性,压缩系数变化较大的垂直压力在400kPa之前,粉煤灰掺量越多,改良效果越好。氯渍土的压缩系数较硫酸盐渍土小,相应的压缩模量较大;粉煤灰对天然盐渍土溶陷特性的改良存在峰值压力为400kPa,对于粉煤灰的配合比也存在一界限值,氯盐渍土的粉煤灰最优配合比为15%,亚硫酸盐渍土的粉煤灰最优配合比为20%。     

Study on thermal,mechanical and morphological properties of recycled poly(vinyl chloride)/fly ash composites

The present study deals with the development of composite materials utilizing recycled poly(vinyl chloride) (r‐PVC) recovered from waste electrical and electronic materials and waste fly ash obtained from thermal power plants. The effect of the incorporation of fly ash on the mechanical, thermal and morphological properties of the r‐PVC matrix was studied. The primary characterization of r‐PVC and fly ash was done employing FTIR, EDX, particle size analysis and XRD analysis. Subsequently, fly ash with a particle size of approximately 9.29 μm was incorporated within the r‐PVC matrix. Composite sheets were prepared using a melt blending process followed by compression moulding. The mechanical test revealed an increase in the tensile strength and elongation at break of the r‐PVC/fly ash composite up to 30 wt% loading of fly ash beyond which there was a decrease in the tensile strength. The impact strength, however, decreased with increasing fly ash content in the r‐PVC matrix. The morphological properties of the composites showed a good distribution of the filler within the recycled matrix. The thermal properties of r‐PVC also improved with the incorporation of fly ash which was revealed from DSC and TGA studies. The water absorption test showed an increase in water uptake with the addition of fly ash in the r‐PVC matrix. © 2020 Society of Chemical Industry     

Effects of fly ash and bottom ash on the frictional behavior of composites

Immense quantities of coal combustion by-products are produced every year, and only a small fraction of them are currently utilized. Our recent work has focused on developing value-added products especially from fly ash, bottom ash, and flue gas desulfurization (FGD) scrubber sludge. We explored the potential utilization of fly ash, bottom ash, and sulfate-rich scrubber sludge as frictional modifiers and additives for automotive frictional composites. The surfaces of the frictional composites, fabricated from scrubber sludge and fly ash or bottom ash, were characterized with the help of scanning electron microscopy (SEM). The mechanical properties of by-products containing composites were evaluated using a dynamic mechanical analyzer (DMA). The frictional behavior of the composites was probed with the help of friction assessment and screening test (FAST). The frictional results suggested that fly ash or bottom ash had a profoundly different effect on the frictional coefficient (μ) and wear of the composite than those observed for scrubber sludge particles. It appeared that fly ash or bottom ash particles had abrasive characteristics and gave frictional composites a higher μ-value. The FAST test also revealed that the fluctuations in the μ-value were a minimum for composites that contained 20 vol% fly ash or bottom ash among the ash-derived composites. The composites that contained 30 vol% fly ash or bottom ash showed fade after approximately 60 min of continuous FAST test. We compared the frictional and wear performance of our composites with a commercial automotive brake, and it appeared that frictional composites could be formed which contained up to 20 vol% fly ash or bottom ash and 25 vol% scrubber sludge.