Synthesis and characterization of zeolites NaA and NaX from coal gangue

Journal of Material Cycles and Waste Management - Zeolites NaA and NaX were synthesized from initial coal gangue (milled sample) and pretreated coal gangue (calcinated and acid immersed sample) by...     

煤矸石中铅、铬、镉的溶出性能

以滕南煤田某煤矿风化煤矸石为研究对象,应用主成分分析法分析了煤矸石粒径对Pb,Cr,Cd溶出浓度的影响,应用回归分析法分析了浸溶时间与Pb,Cr,Cd溶出浓度的关系特征。实验结果表明：模拟湿地浸溶条件下,煤矸石中Pb,Cd,Cr溶出浓度均超出或接近Ⅲ类水体水质标准,对水环境存在污染风险;煤矸石粒径对Pb,Cd,Cr溶出浓度存在影响,粒径越小则Pb、Cr、Cd溶出浓度越大,粒径小于8.0 cm的煤矸石浸溶贡献较大。建立了表征Pb,Cr,Cd溶出浓度与浸溶时间对数（以10为底）关系的一元三次多项式回归方程,经检验均具有显著性。     

煤及煤矸石中砷的释放

研究了煤及煤矸石中砷的释放特征。采用XRD技术对煤样中的主要矿物成分进行了分析。表征结果显示,煤样中的主要矿物组成为碳酸盐矿物、硅酸盐矿物,以及一定量的SiO2、TiO2、硫化物矿物和硫酸盐矿物。实验结果表明：煤中砷的赋存形态主要以残渣态和硫化物结合态为主;在煤燃烧过程中,当燃烧温度为1 000 ℃时,1号矿井的煤样燃烧后灰渣中的砷含量为1.385 μg/g,砷的释放率为40.10%,2号矿井的煤样燃烧后灰渣中的砷含量为1.531 μg/g,砷的释放率为56.04%;在煤矸石的淋溶过程中,在淋溶液体积为100 mL的条件下,当淋溶液pH为5时淋出液中的ρ（砷）为19.27 μg/L,当淋溶液pH为7时淋出液中的ρ（砷）为7.78 μg/L。     

煤矸石的改性及其对稀土生产废水中氨氮的吸附

采用热改性、盐酸改性、硫酸改性、碱改性的方法分别制备了4种改性煤矸石吸附剂,研究了吸附工艺条件对4种改性煤矸石吸附剂对稀土生产废水中氨氮去除效果的影响以及吸附机理.实验结果表明:4种改性煤矸石吸附剂吸附氨氮的最佳工艺条件为:吸附剂加入量0.02 g/mL,振荡时间2.5 h,废水pH 7～8;4种吸附剂氨氮去除率大小顺序为:碱改性煤矸石＞硫酸改性煤矸石＞盐酸改性煤矸石＞热改性煤矸石;碱改性煤矸石的氨氮去除率最高,为59.19％;碱改性煤矸石吸附剂对含氨废水中氨氮的吸附较好地符合Langmuir方程和Freundlich方程,在一定程度上符合Temkin方程.     

Utilization of coal gangue for the production of brick

Journal of Material Cycles and Waste Management - Coal gangue, an industrial solid waste discarded from coal mining and processing, was used as the sole raw material to prepare brick. The coal...     

Low-carbon utilization of coal gangue under the carbon neutralization strategy: a short review

Journal of Material Cycles and Waste Management - The treatment and utilization of coal gangue, one of the main solid wastes produced during coal mining, are of great significance in environmental...     

Reaction characteristics and kinetics of phosphogypsum decomposition via synergistic reduction effect of composite reducing agent

Journal of Material Cycles and Waste Management - Large-area stacking of solid waste phosphogypsum (PG) and coal gangue (CG) poses environmental contamination hazards. This work presents the...     

330MW循环流化床机组协调控制系统的特点分析与应用实例

循环流化床机组在动态特征上不同于煤粉炉,其燃料煤粒较粗,燃烧过程复杂,并且因为其燃烧室内的床料具有相当大的热惯性和蓄热能力,是以当给煤量改变后,主蒸汽压力的变化相应比煤粉锅炉的迟延和惯性要大得多,造成了循环流化床机组燃烧过程实现自动协调控制的困难。以京海煤矸石发电有限责任公司凤凰岭电厂新建工程2×330 MW循环流化床机组控制系统为例,从变参数的应用、前馈的应用、主压力与给水的解耦控制、煤质修正控制等多方面阐述了循环流化床机组的控制特点,分析探讨了应用中存在的问题并提出了解决方法。     

用煤矸石和鼓风炉淤泥制备聚硅酸铁铝混凝剂

研究了以煤矸石和鼓风炉淤泥为原料，在常压条件下制备高效混凝剂凝剂聚硅酸铁铝的方法，确定了合理的生产工艺和操作条件，用该混凝剂处理实际废水，并与聚合硫酸铁的处理效果进行比较，结果表明，出水COD和色度去除率均提高约30%，SS去除率提高约10%，同时探讨了该混凝剂处理废水的反应机理。     

用聚硅酸铁铝混凝剂处理炼油厂废水

研究了以煤矸石和硫酸烧来主要原料研制的聚硅酸铁铝（ＰＳＦＡ）混凝剂对炼油厂废水的絮凝作用及混凝剂种类、用量和体系ＰＨ对混凝效果的影响,试验结果表明,在工ＰＨ范围内,ＰＳＦＡ对炼油废水具有良好的混凝处理效果。与传统混产剂相比,它具有破乳性能好、投量少、滤饼含水率低、上清液透光性好的特点。     

不同煤矸配比脱硫试验分析

以一台130t／h循环流化床锅炉为研究对象，采用不同煤矸配比，以当地工业废渣为固硫剂，在不增加任何试验设备的情况下，进行炉内脱硫试验。结果表明，锅炉脱硫效果明显，试验取得了一定的成功。     

The current situation of solid waste management in China

With economic development, the quantity of solid waste is increasing rapidly in China; the total quantities of municipal solid waste (MSW), industrial solid waste (ISW), and hazardous waste (HW) in 2002 were 136.5 million tons, 945 million tons, and 10 million tons, respectively. In 2002, the quantity of MSW disposed of was 74.04 million tons, 89.30% of which was landfilled, 3.72% was incinerated, and 6.98% was composted. There are currently 651 disposal facilities for MSW in China. Mining gangue is the largest component of ISW, making up 27.5% of the total. In the Chinese industrial sector, the coal mining and processing industry contributed most to the total quantity of ISW, with 16.0% of the total quantity of ISW generated by this sector. In total, 44% of HW was recycled, 27% was stored, 13.5% was disposed of, and 15.4% was discharged. Of the total HW generated, 40% was produced by the chemical materials and chemical products industry. Five categories of HW, i.e., waste alkali, waste acid, inorganic fluoride waste, copper waste, and inorganic cyanide waste, made up 57.8% of the total HW generated. Solid waste pollution has become a huge challenge faced by those involved in Chinese environmental management, but this can be seen as an opportunity to improve environmental quality. This article introduces the strategies taken to improve solid waste management in China.     

Combustion characteristics of coal and refuse from passenger trains

Refuse from passenger trains is becoming a significant issue with the development of the Chinese railway. Co-firing is regarded as a promising thermal technology, both environmentally and economically, in reducing the quantity of refuse. The co-firing property of passenger train refuse with coal, however, may differ due to the differences in the composition of the refuse. In the present study, combustion properties of refuse from passenger train samples and the mixture of refuse with coal were studied in a tube furnace. Thermo analysis methods, such as thermogravimetry (TG), differential scanning calorimetry (DSC), differential thermal analysis (DTA) and derivative thermogravimetry (DTG) analyses were employed to evaluate combustion performance. We found that the mixture of passenger train refuse and coal at a ratio of 1:1 has a lower ignition and burnout temperature than the coal-only sample. Moreover, refuse from railway passenger trains has more reactive combustion properties than the coal-only sample, and the addition of railway passenger train refuse to coal can promote the reactivity of coal.     

Application of magnetic separation technology for the recovery of colemanite from plant tailings

In this study, colemanite was recovered from tailings produced by the Kestelek (Turkey) Processing Plant by magnetic separation. Magnetic susceptibility measurements revealed that colemanite is diamagnetic in character whereas gangue minerals are weakly paramagnetic, apparently due to the presence of the iron-bearing silicates such as smectite and, to a less extent, illite. Three-stage magnetic separation tests were performed on the size fractions coarser than 75 microm produced from the tailings (31.52% B(2)O(3)) using a high-intensity permanent magnetic separator. Under the test conditions a colemanite concentrate with a B(2)O(3) content of 43.74% at 95.06% recovery was shown to be produced from the tailings. The mineralogical composition of the tailings appears to allow the removal of gangue minerals by magnetic separation and hence the production of a concentrate of commercial grade.     

Development of a leaching assessment framework for the utilization of coal ash at South Korean mine reclamation sites

Coal-based power generates large quantities of coal ash in South Korea. However, coal ash recycling is still inactive and most wasted coal ash is buried in landfills. Recently, beneficial uses of coal ash such as in mine reclamation sites has been increasingly considered; however, as a result of legal limitations due to environmental concerns, the utilization of coal ash at mine reclamation sites has procrastinated. Consequently, to resolve this issue, the relevant environmental impact of coal ash must be considered. Therefore, a leaching assessment framework to assess the environmental impact of coal ash utilization at South Korean mine reclamation sites is presented. The framework was used to identify leaching mechanisms and support an assessment of the environmental impact of coal ash usage at mine reclamation sites in South Korea. This framework could provide guidance with regard to designing more realistic leaching procedures appropriate for all mine conditions and could support the development of regulations and protocols for future environment-friendly coal ash usage.     

欧盟国家燃煤电厂环保政策及技术路线分析

温室气体的排放控制作为全球性的环境问题受到了广泛关注。中国是火力发电的大国,其燃煤机组的温室气体排放总量巨大。《火电厂大气污染物排放标准》（GB 13223-2011）提高了我国燃煤电厂的烟气污染物排放的要求,对火电厂烟气处理的技术选择和投资都会产生重大影响。针对中国燃煤电厂环保面临的新形势,阐述了欧盟国家的环保政策重点,并对欧盟国家燃煤电厂污染物控制的相关标准进行了分析,同时简要介绍了欧盟国家燃煤电厂环保的主要技术路线,在一定程度上可作为中国燃煤电厂污染物控制的借鉴和参考。     

改性活性焦及其脱硫性能的研究

以褐煤为主要原料,以煤焦油为粘结剂,加入一定量的金属氧化物制成的改性活性焦,具有良好的吸附能力和机械性能,脱硫效率高并易于再生,为烟气脱硫提供了一种新的吸附剂。     

Pyrolysis characteristics of the mixture of printed circuit board scraps and coal powder

Thermogravimetric (TG) analysis and infrared spectroscopy were used to analyze the pyrolysis characteristics of printed circuit board scraps (PCBs), coal powder and their mixtures under nitrogen atmosphere. The experimental results show that there is a large difference between waste PCBs and coal powder in pyrolysis processing. The pyrolysis properties of the mixing samples are the result of interaction of the PCBs and coal powder, which is influenced by the content of mixture. The degree of pyrolysis and pyrolysis properties of the mixture are much better than that of the single component. The TG and the differential thermogravimetric (DTG) curves of the PCBs mixed with coal powder move towards the high-temperature zone with increasing amount of coal powder and subsequently the DTG peak also becomes wider. The Coats–Redfern integral method was used to determine the kinetic parameters of pyrolysis reaction mechanism with the different proportion of mixture. The gas of pyrolysis mainly composes of CO₂, CO, H₂O and some hydrocarbon. The bromide characteristic absorption peak has been detected obviously in the pyrolysis gas of PCBs. On the contrary, the absorption peak of the bromide is not obvious in pyrolysis gas of the PCBs samples adding 40% coal powder.     

循环流化床锅炉采用两级脱硫实现SO_2超低排放的探讨

介绍了循环流化床锅炉炉内脱硫工艺,并以东北某煤矸石电厂为例,对该项目的脱硫方式选择进行了分析,论证了循环流化床锅炉采用两级脱硫方式实现SO2超低排放的合理性和可行性。     

Mercury Capture on Fly Ash and Sorbents: The Effects of Coal Properties and Combustion Conditions

The US fleet of coal-fired power plants, with generating capacity of just over 300 GW, is known to be a major source of domestic mercury (Hg) emissions. To address this, in March 2005, the Environmental Protection Agency (EPA) promulgated the Clean Air Mercury Rule (CAMR) to reduce emissions of mercury from these plants. It is generally believed that most of the initial (Phase I) mercury reductions will come as a co-benefit of existing controls used to remove particulate matter (PM), SO₂, and NO _X . Deeper reductions in emissions (as required in Phase II of CAMR) may require the installation of mercury-specific control technology. Duct injection of activated carbon sorbents is the mercury-specific control technology that has been most widely studied and has been demonstrated over a wide range of coal types and combustion conditions. The effectiveness of the mercury control options (both “co-benefit control” and “mercury-specific control”) is significantly impacted by site-specific characteristics such as the combustion conditions, the configuration of existing air pollution controls, and the type of coal burned. This paper identifies the role of coal properties and combustion conditions in the capture of mercury by fly ash and injected sorbents.