粉煤灰的矿物组成(中)

首先分析玻璃体的结构特征 ,然后介绍有关粉煤灰中玻璃体变异特性的研究结果 ,最后叙述粉煤灰中可能存在的玻璃体类型 ,并就粉煤灰中氧化物以玻璃体形式出现的顺序进行了分析。     

改性粉煤灰矿物组成变化特性试验研究

以低硫兖州煤为试验煤种,开展了低硫煤增钙粉煤灰矿物组成特性试验研究。试验结果表明：改性粉煤灰矿物组成接近贝利特水泥熟料矿物组成,但矿物组成中没有硅酸盐水泥熟料矿物3CaO·SiO2。     

粉煤灰的矿物学性质研究

为了拓展粉煤灰综合利用途径,提高粉煤灰产品的附加值,采用X射线衍射(XRD)分析方法,研究神华电厂粉煤灰的矿物相组成及其晶相结构。研究表明:神华电厂粉煤灰由非晶质玻璃体和晶质矿物相组成,通过结晶度模拟计算可知非晶质玻璃体含量在35%~70%,进一步分析发现其矿物相以莫来石相(7%~52%)、石英相(0~22%)为主,还包括石灰相、磁铁矿相、赤铁矿相、硬石膏相、钙长石相和钙铝黄长石相等。此外,进一步分析了燃煤组成及燃烧方式对矿物组成差异的影响,从而为了解粉煤灰的特性及其高附加值利用提供理论基础。     

燃煤电厂脱硫粉煤灰单颗粒研究及元素组成

研究电厂脱硫粉煤灰以粒径在3～45μm的颗粒为主,数量占80%以上,并多是表面光滑的球形微珠,主要的矿物成分是莫来石和石英,它的排放因子达到了2.45 kg/t。脱硫粉煤灰的元素组成选取了Mn、Zn、Cr、Cu、Pb、Ni、Cd七种元素,其中Mn在脱硫粉煤灰中的含量最高,但Mn元素的相对富集因子则小于Zn元素的相对富集因子,说明元素含量高其相对富集因子不一定大,还需要考虑电厂燃烧的煤种中的元素含量,从而来确定元素的富集行为。     

粉煤灰的矿物组成(上)

首先分析煤中可能存在的无机矿物在高温条件下的转化过程 ,然后介绍粉煤灰中晶体矿物的形成过程与类型     

粉煤灰的矿物组成(下)

粉煤灰矿物组成中 ,既有晶体矿物 ,又有非晶态矿物 ,其中铝硅玻璃体占 70 %左右 ,对粉煤灰玻璃体特性的认识有利于粉煤灰的充分利用。本文介绍采用一些常用手段与方法对粉煤灰玻璃体的研究结果     

粉煤灰微珠焙烧过程晶型结构变化的研究

通过X衍射图谱分析,讨论了粉煤灰在焙烧过程中主要晶相和次要晶相的变化;通过扫描电镜观察分析了粉煤灰微珠焙烧过程的微观形貌变化。     

钢渣配料硅酸盐水泥熟料的矿物组成和微观结构

实验室和工业生产一致表明,采用钢渣配料可烧制和生产优质硅酸盐熟料.为探究钢渣配料影响水泥熟料性能的机理,在实验室对比铁粉配料和钢渣配料生料易烧性、熟料强度基础上,采用XRD和岩相分析研究了实验室及工业生产钢渣配料熟料的矿物组成和微观结构.结果表明:和铁粉配料相比,钢渣配料没有改变烧成熟料的主要矿物组成,而且A矿(C3S)矿物晶粒发育更加完整、颗粒平均尺寸增大、分布更加均匀;钢渣在高温下的低粘度对离子迁移的促进及其所含熟料矿物的品种效应,共同促进熟料矿物的发育;钢渣配料熟料C3S晶型为M1+ M3型.     

不同燃煤电厂粉煤灰的特性及影响因素分析

研究了我国不同地域9个燃煤电厂的粉煤灰的化学组成、颗粒组成与矿物组成。     

调控熟料矿物组成优化强度的研究应用

对A公司熟料矿物组成跟踪研究，分析矿物组成情况与熟料强度的相关性，得出有效调控熟料矿物组成优化熟料强度的方案。结果表明：通过调整KH由0.920±0.01至0.895±0.01、保持窑皮长度在24 m以下、二次风温控制在1 150 ℃左右，熟料强度由59.5 MPa提升至65.3 MPa，水泥中熟料掺比平均降低3.48%，吨水泥材料成本下降约7.31元，能够有效降低生产成本。     

火力发电厂燃煤飞灰润湿性能

化学团聚是控制燃煤电厂细微颗粒排放最有效的方法之一。颗粒物被团聚剂润湿是化学团聚的首要步骤。以小龙潭电厂燃煤飞灰为对象,采用激光粒度仪研究了燃煤飞灰在十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(SDBS)和Triton X 100(TX100)三种润湿剂溶液中的润湿性能,考察了润湿剂浓度、温度对燃煤飞灰润湿性能的影响。结果表明：水仅能将飞灰颗粒中的PM^₁₀+部分全部润湿,0.25%的SDS溶液中PM_2.5⁺可全部润湿,1%的SDS及0.4%的SDBS溶液中PM₁⁺可全部润湿;TX100溶液在低浓度条件下具有较强的润湿飞灰颗粒的能力,且0.1%的TX100溶液对细微颗粒的润湿性能较好;温度从20℃上升到60℃,润湿剂溶液表面张力降低,飞灰的润湿性能增强。鉴于飞灰在三种润湿剂中良好的润湿性能,三种润湿剂均可作为团聚剂组分以促进燃煤飞灰中的细微颗粒润湿进而被团聚成为容易脱除的大颗粒。     

Characteristics and composition of fly ash from Canadian coal-fired power plants

Fly ashes were collected from the electrostatic precipitator (ESPs) and/or the baghouse of seven coal-fired power plants. The fly ashes were sampled from power plants that use pulverized subbituminous and bituminous feed coals. Fly ash from bituminous coals and limestone feed coals from fluidized-bed power plant were also sampled. The fly ashes were examined for their mineralogies and elemental compositions. The fly ashes from pulverized low sulfur coals are ferrocalsialic, those from high sulfur coals are ferrosialic and the fly ashes from the fluidized bed coals are ferrocalcic. The concentrations of As, Cd, Hg, Mo, Ni, and Pb in fly ash are related to the S content of the coal. Generally, those feed coals with a high S content contain higher concentrations of these elements. The concentrations of these elements are also greater for baghouse fly ash compared to ESP fly ash for the same station. The S content of fly ash from high S coal is 0.1% for pulverized ESP fly ash and 7% for baghouse fly ash from the fluidized bed, indicating that most of the S is captured by fly ash in the fluidized bed. The baghouse fly ash from the fluidized bed has the highest content of Cd, Hg, Mo, Pb, and Se, indicating that CaO, for the most part, captures them. Arsenic is captured by calcium-bearing minerals and hematite, and forms a stable complex of calcium or a transition metal of iron hydroxy arsenate hydrate [(M²⁺)₂Fe₃(AsO₄)₃(OH)₄·10H₂O] in the fly ash. Most elements in fly ash have enrichment indices of greater than 0.7 indicating that they are more enriched in the fly ash than in the feed coal, except for Hg in all ESP ashes. Mercury is an exception; it is more enriched in baghouse fly ash compared to ESP. Fly ash collected from a station equipped with hot side ESP has a lower concentration of Hg compared to stations equipped with cold side ESP using feed coals of similar rank and mercury content. Fly ash particles from fluidized bed coal are angular and subangular with cores of quartz and calcite. The quartz core is encased in layer(s) of calcium-rich aluminosilicates, and/or calcium/iron oxides. The calcite core is usually encased in an anhydrite shell.     

电厂粉煤灰活化工艺参数的研究

利用机械研磨-碳酸钠混合焙烧对粉煤灰进行活化,探讨了机械研磨时间对粒度和真密度的影响,研究了焙烧条件对铝浸出率的影响。结果表明,在机械研磨及碳酸钠混合焙烧联合作用下,粉煤灰中惰性硅铝组分可得到充分活化。最佳活化工艺参数为:球磨时间40 min,灰碱质量比1∶0.40,焙烧温度875℃,焙烧时间2 h。烧结熟料主要成分为霞石相(NaAlSiO_4)。     

电厂粉煤灰活化工艺参数的研究

利用机械研磨-碳酸钠混合焙烧对粉煤灰进行活化,探讨了机械研磨时间对粒度和真密度的影响,研究了焙烧条件对铝浸出率的影响。结果表明,在机械研磨及碳酸钠混合焙烧联合作用下,粉煤灰中惰性硅铝组分可得到充分活化。最佳活化工艺参数为:球磨时间40 min,灰碱质量比1∶0.40,焙烧温度875℃,焙烧时间2 h。烧结熟料主要成分为霞石相(NaAlSiO_4)。     

Thermal expansion of slag and fly ash from coal gasification in IGCC power plant

Integrated gasification in combined cycle (IGCC) is an electrical power generation system which is characterized to be a clean coal technology different than conventional process in combustible treatment. IGCC process gives rise to inorganic solid wastes in the form of vitreous slag and fly ashes with singular thermal properties. The gasification of the fuel takes place at high temperature and pressure in reducing atmosphere. Under that conditions, gases such as H₂, N₂ or CO, which are the main components of the gas mixture in the gasifier, show a high solubility in the melt and during the cooling remain enclosed in the vitreous slag. When these wastes are afterward thermal treated in oxidizing conditions, two phenomena occur. The development of a crystalline phase by devitrification of the glassy matrix and the releasing of the enclosed gas, which starts at temperatures nearly to the softening point. At higher temperatures the bubbles with increasing kinetic energy tend to ascent with difficult through the viscous liquid phase and promotes an expansive reaction, giving rise to a foam glass-ceramic product. This paper has been focused on the study of thermal expansion in slag and fly ash samples from the ELCOGAS IGCC power plant located in Puertollano (Spain).     

A comprehensive characterisation of fly ash from a thermal power plant in Eastern India

A comprehensive characterisation of fly ash from Bokaro Thermal Power Plant, Jharkhand, India has been carried out for creating utilisation potential of the ash. As received fly ash, was size fractionated and the fractions were characterised. The non-magnetic and magnetic fractions of ash have been analysed in terms of their morphological, mineralogical features and physico-chemical properties. The results of such analysis reveal that there is a striking difference in the features and properties of the coarser and finer particles. The coarser fractions of the non-magnetic component seem to contain high percentage of char and semicoked/coked carbonaceous particles. The percentage of char albeit the carbon content decreases with decrease in size of the particles. The particles of the finer fractions have more spheroidal character than the coarser ones. The non-magnetic components essentially contain quartz and mullite as the main mineral phases. The magnetic component differs from the non-magnetic ones in respect of shape, mineralogical composition and carbon content. These are much more spheroidal than the non-magnetic ones. The ferrospheres present in these components bear crystallites with different geometrical patterns clearly indicating a definite degree of variation in the crystallisation process. Such comprehensive characterisation leads to not only a definite direction about the uses of the various fractions of the ash, but also gives useful informations regarding the prevailing combustion process.     

粉煤灰的计量与控制

粉煤灰是以燃煤为燃料发电的火力发电厂排出的一种工业废渣,由于其自身具有一定的火山灰质特性,因此粉煤灰已作为活性混合材料广泛应用于水泥生产过程。由于粉煤灰是容重只有０７ｔ／ｍ３、水分＜１%的极细粉末,因而粉煤灰具有易流动的物理特性。在水泥生产过程中,对粉煤灰的计量与配比控制具有一定的难度。我厂在生料配料和水泥配料中均使用了粉煤灰,以下根据我厂的使用经验谈一谈水泥厂对粉煤灰的计量与配比控制。１粉煤灰固体流量计计量与控制系统简介我厂水泥工段有两个粉煤灰库,最初设计使用两台固体冲击流量计量机构,控制仪表共用一台…     

改性粉煤灰对燃煤电厂脱硫废水中氯离子的吸附性能

为了将"以废治废"的理念融入实际工业应用中,开展对燃煤电厂固体废弃物粉煤灰改性后在不同条件下进行脱硫废水的吸附实验研究.结果表明,改性粉煤灰的最佳投加量为25 g/L,此时对废水中Cl-的去除率最大,为56％;在45°C和pH为5的条件下,粉煤灰对Cl-的吸附量最大,在反应约280 min时达到吸附平衡.该吸附过程为吸...     

红外光谱分析淮南煤灰中矿物组成

选取淮南矿区HN115与HN119两种煤样,在氧化性气氛下,制成815℃煤灰。利用红外光谱研究了其矿物质组成以及煤中添加不同比例助熔剂CA后矿物组成的变化。结果表明:淮南煤灰中,矿物质组成为石英、硬石膏、方解石、高岭土和赤铁矿,其中硬石膏和方解石含量较低。煤中添加助熔剂CA后,煤灰中硬石膏含量增加,并且随着助熔剂CA量的不断增加,方解石含量在不断减少,硬石膏含量在不断增加。     

Mössbauer studies of iron in Lurgi gasification ashes and power plant fly and bottom ash

Iron Mössbauer spectroscopy and X-ray diffraction methods were applied to the study of a selection of ashes produced in a Lurgi gasification plant and fly ash from a pulverized coal combustion. The ashes contained hematite, magnetite, and goethite. Sixty percent or more of the iron in these ashes was in the oxide form, with the remainder present in mullite and other silicate phases. Iron was divalent in the latter, and present as both Fe⁺² and Fe⁺³ in mullite. Ratios of Fe⁺² and Fe⁺³ varied from 0.3 to 0.7. By comparison, a water-quenched molten bottom ash was free of iron oxides and contained only amorphous silicate phases with virtually all iron in the divalent state.