火焰原子吸收法测定不同产地香菇中4种微量元素

比较不同产地香菇中Fe、Mn、Zn、Cu 4种微量元素的含量。采用火焰原子吸收法测定不同产地香菇中Fe、Mn、Zn、Cu的含量。结果表明:产地不同的香菇中四种微量元素的含量各不相同,其中Fe和Zn的含量相对较高,Fe最高可达293.47 mg/kg,Zn最高可达69.691 mg/kg;而Cu和Mn的含量相对较低,Cu最高可达35.401 mg/kg,Mn最高可达16.507 mg/kg。不同香菇中对相同元素的富集能力差别较大,福建龙岩(武夷山野生红菇)中各种微量元素均为最高。     

燃煤电厂脱硫灰渣理化特性研究

以徐州2个不同工艺电厂脱硫灰渣为研究对象,分别从粒径分布、重金属含量、矿物组成和微观颗粒形态4个方面,对灰渣进行了研究。结果显示：2个电厂飞灰的粒径分布相似,粒径主要集中于5μm以下,粒径在20μm以下的颗粒占全部颗粒的98％以上;所测试的重金属元素中,除Cd外,其他元素含量都在1μg／g以上。Mn的测试含量最高,均在300μg／g以上。多数重金属元素更易富集在细灰上;2个电厂灰渣的矿物组成特性稍有不同,主要区别表现在莫来石和CaSO4的相对含量上,这主要与电厂工艺和燃烧的煤质有关。另外,2个电厂的飞灰微观颗粒形态存在明显差异。     

粉煤灰对水泥中重金属存在形式的影响

本文对添加不同含量的粉煤灰后，熟料水化过程中重金属元素（Cr、Mn、Cu、Pb、Zn）存在形式及其浸出毒性进行了实验和探讨。随着粉煤灰掺入量由0%提升至10%，水化产物形貌中微细孔增多，重金属元素在C-S-H中富集程度增加，熟料重金属元素浸出毒性呈现不同程度下降趋势，最大下降幅度达到56.1%，主要因为微细孔对重金属有较好的吸附作用，且重金属元素在水化产物周围的富集程度增加，有助于重金属离子以较为稳定的形态固化在水化产物中。     

西部煤中环境敏感性痕量元素的燃烧迁移行为

应用仪器中子活化( INAA)、电感耦合等离子体原子发射光谱( ICP- AES)和原子吸收光谱( AAS)对我国西北部五个电厂原煤、底灰和飞灰中环境敏感性痕量元素的含量进行了系统测定,通过不同电厂原煤与燃烧产物中痕量元素的含量变化特征,揭示了痕量元素在不同燃烧产物中的相对富集规律.以痕量元素在不同燃烧产物中的相对富集系数为评价标准,建立了燃烧产物中痕量元素的分配模型.结合痕量元素的原始赋存状态,总结了痕量元素燃烧的迁移富集机理和环境效应.     

南四湖沉积物重金属含量水平与生态风险

本论文研究了南四湖沉积物中重金属的含量及生态风险;结果表明沉积物重金属Cd、Cr、Cu、Pb、Zn、Ni、Co的含量为0.08~1.12、58.92~135.62、38.09~78.65、24.51~53.95、110.51~235.36、11.30~65.40、4.12~20.14 mg/kg,均值顺序Zn Cr Cu Pb Ni Co Cd;重金属生态风险评价结果表明,Cd和Zn的相对富集因子明显高于其它元素,且某些点这两种元素的富集程度较高。因此,在南四湖环境污染防控中,应该关注沉积物中的Cd、Zn的污染。     

长兴电厂粉煤灰的微量元素含量及其安全性评价——长兴电厂粉煤灰综合利用对策研究之二

利用VF-320型X射线荧光光谱仪(XRFS)对长兴电厂粉煤灰中有毒、有害微量元素及放射性元素含量进行了测试。结果表明,大部分微量元素及放射性元素都有在细粒径粉煤灰中富集的趋势。该电厂粉煤灰中有毒、有害元素的含量不高,只要施用量不超过8654kg/亩(129810kg/公顷),用作土壤改良剂或肥料,不会对农作物造成危害;若用于生产建材,只要将掺量控制在总量44%内,建材制品的放射性防护也是安全的。     

粉煤灰中重金属元素分布规律的研究

通过对几个电厂所排放粉煤灰不同粒径范围内铜、锌、铬、镉、铅五种微量金属元素的含量分析 ,得出粉煤灰中部分微量元素的富集程度不仅与粉煤灰的平均粒径有关 ,而且与所研究的元素性质有关 ,粉煤灰的环境影响尤以细粒径灰粒最大     

艾士卡法测定脱硫粉煤灰中SO3的含量

随着电厂干法脱硫技术的推广,作为脱硫副产物的脱硫粉煤灰的应用也受到水泥行业的广泛关注。使用脱硫灰后,最主要的问题是水泥的凝结时间显著延长。其原因主要是由于脱硫粉煤灰中含有大量的亚硫酸盐导致,而目前测定粉煤灰及水泥中SO3的方法主要为硫酸钡重量法及离子交换法,试验证实此两种方法在测定脱硫灰中的亚硫酸盐含量时均存在较大偏差。尤其是硫酸钡重量法,     

鸡枞菌的矿质元素分析

采用湿法消解方法处理样品,以电感耦合等离子体发射光谱仪(ICP-AES)检测云南野生鸡枞菌中Cu、Fe、Zn、Mn、Na、K、Ca、Mg、P等元素的含量,结果表明:鸡枞菌中含有丰富的K、Fe、Cu、Mg、Zn、Ca、P等矿质元素,其中Mg、K、Zn、P、S元素在鸡枞菌的盖中含量均高于柄中含量,K、P和S元素在菌盖中的含量是柄中的2倍。ICP-AES检测各元素校正曲线的相关系数在0.998 3以上,各元素的检出限均小于0.1μg/m L,相对标准偏差(RSD)在0.34~4.22%之间,回收率在93.60%~105.21%之间。     

ICP-OES法测定矮地茶中微量元素含量

为测定矮地茶中微量元素,采用湿法硝酸-高氯酸进行消解,用ICP-OES法测定了矮地茶中Cu、Pb、Zn、Mn、Cd、Ni、Fe、Ca、As等9种元素含量。结果表明:方法操作简单、快速、灵敏,分析结果的相对标准偏差为0.49%~4.34%,方法的加标回收率为95.0%~102.1%。矮地茶中含有丰富的对人体有益的Ca、Fe、Zn、Mn、Cu等元素,有害元素Pb在根茎和叶中的含量差异较大,根茎中Pb已超过限量标准。结果可为矮地茶的开发利用提供依据。     

Trace elements (Mn,Cr, Pb,Se, Zn,Cd and Hg) in emissions from a pulverized coal boiler

The concentrations of seven trace elements (Mn, Cr, Pb, Se, Zn, Cd, Hg) in raw coal, bottom ash and fly ash were measured quantitatively in a 220 tons/h pulverized coal boiler. Factors affecting distribution of trace elements were investigated, including fly ash diameter, furnace temperature, oxygen concentration and trace elements' characteristics. Modified enrichment factors show more directly element enrichment in combustion products. The studied elements may be classified into three groups according to their emission features: Group 1: Hg, which is very volatile. Group 2: Pb, Zn, Cd, which are partially volatile. Group 3: Mn, which is hardly volatile. Se may be located between groups 1 and 2. Cr has properties of both Groups 1 and 3. The smaller the diameter of fly ash, the higher is the relative enrichment of trace elements (except Mn). Fly ash shows different adsorption mechanisms of trace elements and the volatilization of trace elements rises with furnace temperature. Relative enrichments of trace elements (except Mn and Cr) in fly ash are larger than that in bottom ash. Low oxygen concentration will not always improve the volatilization of trace elements. Pb forms chloride more easily than Cd during coal combustion.     

The characteristics of inorganic elements in ashes from a 1 MW CFB biomass gasification power generation plant

This paper investigated the characteristics of inorganic elements in ashes from biomass gasification power generation (BGPG) plant. The ash samples of the gasifier ash, separator ash and wet scrubber ash were collected in a 1 MW circulating fluidized bed (CFB) wood gasification power generation plant. Particle size distribution of ashes was determined by gravimetric measurement and super probe analyzer. The concentrations of trace elements and major ash-forming elements, such as As, Al, Ca, Cd, Cr, Cu, K, Mg, Na, Ni, Pb, Ti in different ashes as a function of particle size were determined by Inductive Coupled Plasma Spectrometer. The concentrations and distribution coefficient and enrichment factors of the inorganic elements in ashes were studied. X-ray fluorescence spectrometer and X-ray powder diffraction were used to provide information on the characteristics of the ashes. The results showed that most of the trace elements had an enrichment tendency in the finer size particles. A considerable amount of the ashes was residual carbon. Most of the volatile e.g. halogen elements and alkali elements existed mainly in wet scrubber ash and enriched in fly ash. Most of the Si, Ni, Pb, Zn, Cr, Cd were found in separator ash, indicating an enrichment of heavy metal elements in separator ash. K, S, Mn, Cu mainly existed in gasifier ash.     

超低排放燃煤机组硒的迁移转化及飞灰对其富集特性

采用微波消解法和氢化物发生-原子荧光光谱法考察了9台超低排放在役机组硒迁移转化规律,探究了循环流化床（CFB）和煤粉炉（PC）机组飞灰特性差异对硒吸附能力的影响。燃烧后煤中硒几乎全部呈现挥发态,底渣中残留量极低。与浓度归一化和质量分布法相比较,相对富集系数法可以客观地评价燃煤副产物中硒的富集能力,两类机组中硒均主要富集于飞灰中。CFB较低炉膛温度和添加CaO可以降低入炉煤中硒释放比例并增强飞灰对硒的吸附能力,故其底渣和飞灰中硒的富集程度均高于PC,导致脱硫石膏中硒富集程度低于PC。飞灰对硒的吸附量随比表面积或孔容积增大而增大,但随粒径或孔径增大而减小。CFB飞灰中未燃尽碳含量高、形状不规则、表面粗糙且存在较多蜂窝状孔隙,导致其对硒的富集程度高于PC飞灰。     

煤灰基本特征及其微量元素的分布规律

对兖州矿区煤灰的化学成分、微量元素分布及灰的岩石学特征等方面进行了研究，并对灰产率与微量元素含量分布之间的关系进行了研究，同时对影响煤灰化学成分的因素方面进行了初步探讨。通过对兖州矿煤灰的采样分析可知,研究区煤灰由结晶物质、玻璃状物质和末燃尽有机质组成，其化学成分主要为SiO2,Al2O3,Fe2O3和CaO及少量的O3,P2O5,Na2O和TiO2,煤燃烧过程中微量元素发生了再分布，多数微量元素在煤灰中富集。同时它们在飞灰中富集的浓度明显高于底灰，即随着煤灰粒度的变小，它们在其中富集的浓度越高，其含量与煤灰的粒度成反比。微量元素Th,V,Zn,Cu,Pb与灰产率之间成正相关关系，而Cl与灰产率成负相关关系。     

The fate of trace elements and bulk minerals in pulverized coal combustion in a power station

The behaviour of 15 trace elements (As, Ba, Cr, Cu, Mn, Mo, Nb, Ni, Pb, Rb, Sr, V, Y, Zn and Zr) and 10 major and minor elements (Al, Ca, Fe, K, Mg, Na, P, S, Si and Ti) in coal during combustion in a power station has been studied. Synchronized sampling of pulverized coal, bottom ash and fly ash was undertaken over a limited time period. Fly ash morphology was studied by SEM and the mineral composition was studied by EDX and XRD. Major, minor and trace elements were determined by XRF and AAS. Differences between the composition of the ashes of pulverized coal, bottom ashes and fly ashes have been observed. As, Cu, Mo, Pb and Zn were concentrated in the fly ash. The relationship between the composition of the fly ashes and their particle size was studied. Enrichment factors were calculated for each element in different size fractions. As the particle sizes of fly ash decrease, the concentrations of As, Cu, Mo, Pb and Zn increase. From the different composition of bottom ashes and fly ashes (and relying on the results of the characterization of the feed coal carried out in previous work), it can be assumed that pyrite and carbonates make a greater contribution to the furnace bottom ashes. Quartz carries through into the fly ash. This mineral is almost absent in the finest fractions, reflecting the absence of small quartz particles in the feed coal.     

循环流化床固硫灰复合胶凝材料的早期水化特点

研究了大掺量循环流化床固硫灰复合胶凝材料的物理力学性能,以及其早期水化放热特点和水化产物。研究结果表明:利用掺量为30%～60%固硫灰制备的复合胶凝材料满足32.5、42.5强度等级水泥标准;固硫灰复合胶凝材料的标准稠度比水泥的标准稠度大,且随着固硫灰用量的增加标准稠度增加,同时凝结时间变长;与P.O42.5水泥相比,循环流化床固硫灰复合胶凝材料水化的诱导期较长,水化放热速率明显变小,水化热较低。     

粉煤灰陶粒填料制备及用作曝气生物滤池填料的性能考察

以粉煤灰为主要原料,黏土、脱水污泥、脱硫石膏等为辅料,自制了粉煤灰陶粒。通过强度性能筛选出原料的最优配比为粉煤灰:脱水污泥:黏土:脱硫石膏= 85:10.5:0.5:4。研究对比了自制粉煤灰陶粒与市售的陶瓷陶粒和黏土陶粒的性能,如扫描电镜、孔隙率、盐酸可溶率、比表面积等,结果显示:粉煤灰陶粒的表面粗糙度最大,孔隙率最高,比表面积最大,密度最小。进一步比较了3种陶粒用作曝气生物滤池填料处理城市污水的效果。结果表明,粉煤灰陶粒填料对COD的去除率可达到80%以上,对NH₃-N的去除率可达到90%,对总磷(TP)的去除率高于80%,均明显优于其他两种市售陶粒填料。     

垃圾焚烧飞灰水洗脱氯及重金属浸出特性研究

系统研究了机械炉排炉垃圾焚烧飞灰水洗过程中氯化物和重金属的浸出特性,并采用Visual MINTEQ模拟分析水洗液中重金属的存在形态。结果表明：飞灰中的氯主要以可溶性氯化钠（NaCl）、氯化钾（KCl）、氯化钙（CaCl₂）、碱式氯化钙（CaClOH）的形式存在,飞灰水洗浸出成分97%以上为氯离子（Cl^-）、钠（Na）、钾（K）、钙（Ca）,其中氯离子占比高达60%;重金属及其他成分的浸出量很少,不足1%。水洗对氯离子的去除效果非常明显,可达92%以上,但是重金属的浸出量极低。飞灰单次水洗最佳条件：液固体积质量比为6 mL/g,洗涤时间为10 min。Visual MINTEQ模型分析表明,pH是控制飞灰水洗液中铅（Pb）、铜（Cu）、锌（Zn）、镉（Cd）形态的重要因素,氯离子（Cl^-）对镉的形态分布也有着重要的影响。飞灰水洗液电导率与氯离子质量浓度具有极好的线性相关性,其可作为监测滤液中氯离子质量浓度变化的有效间接指标。     

Analysis of fly ash heavy metal content and disposal in three thermal power plants in India

The study investigates the heavy metal content of fly ash and bottom ash from three major power plants in North India, using flame atomic absorption spectrometry. It also studies the prevalent disposal methods used at these sites. The ashes were analysed for the presence of Cr, Mn, Pb, Zn, Cu, Ni and Co and detectable levels of all were found in both fly ash and bottom ash. The concentrations of Cr and Zn were highest while Co concentration was less. The wet disposal method is used in two of the power plants (site 1 and site 3). Neither of the sites uses ash pond lining in the construction of the ash ponds, hence leaching of the heavy metals is possible. Site 2 has adopted 100% dry disposal system which allows better utilization but incurs additional costs. Better management practices, increased utilization and proper disposal practices need to be undertaken to minimize the adverse environmental impact.