Treatment of Lignite Mine Water with Lignite Fly Ash and Its Zeolite

Mine Water and the Environment - As expected, a zeolite formed from lignite fly ash proved to be far more effective in treating the water from the Neyvelli lignite mines than the fly ash itself....     

A Novel Method of Using Iron Nanoparticles from Coal Fly Ash or Ferric Chloride for Acid Mine Drainage Remediation

Mine Water and the Environment - Iron nanoparticles (nano Fe) were extracted from coal fly ash (CFA) or ferric chloride (FeCl3) and used for acid mine drainage (AMD) remediation. Characterisation...     

Removal of Ions and Acidity from Acid Mine Water Using Transformed Fly Ash

Fly ash obtained from a coal combustion thermal electric power plant was reacted with NaOH at 100 °C for 24 h to synthesize zeolite. Shaker flasks experiments were conducted to assess whether fly ash or fly ash zeolite (FAZ) could be used to treat acidic mine water. The FAZ was used to treat the mine water at doses of 5–60 g/L; the FAZ increased pH from 2.76 to as high as 7.51 and removed most of the Ca and Mg hardness and acidity from the mine water, though it did not affect sulphate concentrations. The cation exchange capacity of the FAZ was regenerated using NaCl. After six regeneration/reuse cycles, the FAZ was less effective but still capable of increasing pH and removing substantial hardness. In contrast, fly ash was not effective in removing hardness or acidity, and instead released ions into the mine water.     

Injection of Fluidized Bed Combustion Ash into Mine Workings for Treatment of Acid Mine Drainage

Abstract  A demonstration project was conducted to investigate treating acid mine water by alkaline injection technology (AIT). A total of 379 t of alkaline coal combustion byproduct was injected into in an eastern Oklahoma drift coal mine. AIT increased the pH and alkalinity, and reduced acidity and metal loading. Although large improvements in water quality were only observed for 15 months before the effluent water chemistry appeared to approach pre-injection conditions, a review of the data four years after injection identified statistically significant changes in the mine discharge compared to pre-injection conditions. Decreases in acidity (23%), iron (18%), and aluminum (47%) were observed, while an increase in pH (0.35 units) was noted. Presumably, the mine environment reached quasi-equilibrium with the alkalinity introduced to the system.     

Using Acid Mine Drainage to Recover a Coagulant from Water Treatment Residuals

We evaluated the recovery of aluminum from water treatment residuals by acidification using acidic coal mine drainage as an extraction solution. The water treatment residuals had Al and total Fe concentrations of 1.2 and 1.3%, respectively, based on mass. The influence of contact time of the mine water with the water treatment residuals and the percent of excess sulfate were assessed. The results showed that 28 min of contact and 100% of excess sulfate allowed recovery of >90% of the Al. Color was reduced from 25.9 to 0.8 total color units (TCU) and turbidity was reduced from 6 to 0 nephelometric turbidity units (NTU). The recovered coagulant performed appropriately in water treatment tests, based on physical–chemical parameters. The only parameter that requires more attention is antimony, which was close to the maximum concentration limits for drinking water.     

离子液体处理煤矿酸性矿井水的新设想

离子液体作为一类新型的溶剂或功能材料,不仅具有许多的优良的性质,而且可以通过设计和改变阴阳离子的结构和组成来调节离子液体的性质以达到特定的应用目的。简述了煤矿酸性矿井水的形成机理及其危害,通过分析研究大量的关于离子液体处理金属离子的文献,提出了利用具有绿色溶剂之称的离子液体进行处理酸性矿井水的设想。     

Reducing the Hardness of Mine Water Using Transformed Fly Ash

In the Jharia Coalfields, Dhanbad, India, huge quantities of water are pumped out of underground mines to make mining possible. The water contains high concentrations of total hardness, which makes it unsuitable for domestic use. Waste fly ash generated nearby from burning the coal in thermal power plants can be converted into a zeolitic mineral, and used to treat the mine water. The fly ash zeolite was determined to be effective in removing total hardness from the mine water. At a 40 g/L dose of fly ash zeolite, approximately 72% of the hardness was removed from the mine water. However, the mine water still requires additional treatment to further reduce total dissolved solids to make the mine water potable.     

酸性矿山废水的污染与治理技术研究

分析了酸性矿山废水的成分、危害、来源和排放特点,经试验研究,推荐以添加缓蚀剂中和为主的几种既又实用的酸性废水治理技术,以实现废水的循环利用和无害排放。     

粉煤灰水热法提硅合成沸石工艺研究

以粉煤灰为原料,研究了水热反应时间对粉煤灰转变产物、溶液中Si1-浓度和制备A型沸石的影响,结果表明:80℃、水热6天,合成了含P型沸石和X型沸石的粉煤灰沸石;水热36h时,溶液中Si1-浓度最大为0.51 mol/L;水热26h,合成的A型沸石结晶较好.对A型沸石、粉煤灰沸石、活性炭、天然沸石和粉煤灰的吸附性能进行了研究,结果表明:合成的A型沸石吸附能力最好,对Cd2-的吸附率达99.83%.     

邢台矿粉煤灰充填技术可行性研究

粉煤灰作为燃煤电厂的排放废弃物，对其处理一直是企业的难题，把粉煤灰充填到煤矿井下采空区，既能减少环境污染，又能有效控制地表沉陷，是一条废物资源化利用的绿色采矿新路。     

Application of a Peat-humic Agent for Treatment of Acid Mine Drainage

A peat-humic agent (PHA), derived by mechanical, chemical, and thermobaric treatment of peat from the Krugloe deposit (Novosibirsk region, Russia), is a good sorbent for potentially toxic elements, and can be used to neutralise acid mine drainage (AMD). A new AMD remediation method has been developed using this PHA with subsequent solid/liquid separation using haydite sand or activated carbon.     

Long-term Performance of Passive Acid Mine Drainage Treatment Systems

Abstract.   State and federal reclamation programs, mining operators, and citizen-based watershed organizations have constructed hundreds of passive systems in the eastern U. S. over the past 20 years to provide reliable, low cost, low maintenance mine water treatment in remote locations. While performance has been reported for individual systems, there has not been a comprehensive evaluation of the performance of each treatment type for a wide variety of conditions. We evaluated 83 systems; five types in eight states. Each system was monitored for influent and effluent flow, ph, net acidity, and metal concentrations. Performance was normalized among types by calclating acid loading reductions and removals, and by converting construction cost, projected service life, and metric tonnes of acid load treated into cost per tonne of acid treated. Of the 83 systems, 82 reduced acid load. Average acid load reductions were 9.9 t/yr for open limestone channels (OLC), 10.1 t/yr for vertical flow wetland (VFW), 11.9 t/yr for anaerobic wetlands (AnW), 16.6 t/yr for limestone leach beds (LSB), and 22.2 t/yr for anoxic limestone drains (ALD). Average costs for acid removal varied from $83/t/yr for ALDs to $527 for AnWs. Average acid removals were 25 g/m²/day for AnWs, 62 g/m²/day for VFWs, 22 g/day/t for OLCs, 28 g/day/t for LSBs, and 56 g/day/t for ALDs. It appears that the majority of passive systems are effective but there was wide variation within each system type, so improved reliability and efficiency are needed. This report is an initial step in determining passive treatment system performance; additional work is needed to refine system designs and monitoring.     

Cross-Layer Leaching of Coal Fly Ash and Mine Tailings to Control Acid Generation from Mine Wastes

Mine Water and the Environment - Coal fly ash can be used in in various configurations (e.g. as cap, bottom liner, or blending) at a mine site, but comparative studies investigating their capacity...     

Review of Passive Systems for Acid Mine Drainage Treatment

When appropriately designed and maintained, passive systems can provide long-term, efficient, and effective treatment for many acid mine drainage (AMD) sources. Passive AMD treatment relies on natural processes to neutralize acidity and to oxidize or reduce and precipitate metal contaminants. Passive treatment is most suitable for small to moderate AMD discharges of appropriate chemistry, but periodic inspection and maintenance plus eventual renovation are generally required. Passive treatment technologies can be separated into biological and geochemical types. Biological passive treatment technologies generally rely on bacterial activity, and may use organic matter to stimulate microbial sulfate reduction and to adsorb contaminants; constructed wetlands, vertical flow wetlands, and bioreactors are all examples. Geochemical systems place alkalinity-generating materials such as limestone in contact with AMD (direct treatment) or with fresh water up-gradient of the AMD. Most passive treatment systems employ multiple methods, often in series, to promote acid neutralization and oxidation and precipitation of the resulting metal flocs. Before selecting an appropriate treatment technology, the AMD conditions and chemistry must be characterized. Flow, acidity and alkalinity, metal, and dissolved oxygen concentrations are critical parameters. This paper reviews the current state of passive system technology development, provides results for various system types, and provides guidance for sizing and effective operation.     

Biological Source Treatment of Acid Mine Drainage Using Microbial and Substrate Amendments: Microcosm Studies

Microcosm studies in the laboratory demonstrate that sufficient dosages of wastewater effluent (microbial inoculum) and returned milk (substrate) can effectively raise the pH of pyrite-amended acid mine drainage water to circumneutral levels under aerobic conditions in as little as 7 days, and the pH remains at these levels for >19 months. Microbial analysis indicates that a complex biofilm (>70 species) forms over the pyrite. The biofilm dominantly consists of facultative anaerobes, which potentially interact with obligate anaerobes, such as sulfate-reducing Desulfosporosinus sp., to maintain an oxygen-free micro-environment surrounding the pyrite, even though the overlying water remains aerobic. The biofilm became established in water samples with an initial pH as low as 2, and subsequently caused the water pH to increase to circumneutral levels. Concurrently, concentrations of Al, As, Cu, Fe, Pb, Ni, and Zn all decreased substantially compared to baseline concentrations in the control microcosms. An erratum to this article can be found at     

粉煤灰提铝后尾渣合成13X分子筛及其对Pb2+吸附性能的研究

利用循环流化床粉煤灰"一步酸溶法"提取氧化铝后的尾渣为原料,通过碱溶—水热法合成了13X分子筛,并对样品组成进行了XRD表征,颗粒尺寸进行激光粒度测试分析,热稳定性进行了TG-DSC技术表征,详细考察了其对Pb2+离子的吸附效果。结果表明:导向剂用量、老化温度、铝源等因素对分子筛合成影响显著。合成的分子筛颗粒尺寸约为2.8 μm,拥有较高的热稳定性。该分子筛对溶液中Pb2+离子饱和吸附量达到35.82 mg/g,具有较好的市场应用前景。      

粉煤灰在矿井中的综合利用

粉煤灰是燃煤电厂生产过程中的排放物 ,该排放物不仅对环境污染严重 ,而且处理该废物需占地及运输等综合处理费用较高。而在许厂煤矿通过对粉煤灰进行注浆防火、巷道支护、封堵采空区等综合利用的试验和探索。不仅将污染环境的废物变成了潜在的资源 ,同时节约了大量的人工及材料费 ,收到了良好的经济效益和社会效益     

用略阳电厂粉煤灰合成沸石的试验研究

以略阳电厂粉煤灰为原料,进行了用水热法和熔融水热法合成A型沸石和Y型沸石的试验研究。结果表明：粉煤灰在80 ℃和碱性条件下水热反应4 d,可获得含P型沸石和X型沸石的粉煤灰沸石;向粉煤灰中加入Al(OH)₃和NaOH固体,以800 ℃熔融1 h后,在80 ℃下水热反应12 h,可获得A型沸石;向粉煤灰中加入硅灰石和NaOH固体,以800 ℃熔融1 h后,在80 ℃下水热反应36 h,可获得Y型沸石。将3种合成沸石与天然沸石和粉煤灰进行吸附溶液中Cd²⁺的对比,吸附能力由强到弱的排序为Y型沸石＞A型沸石＞粉煤灰沸石＞天然沸石＞粉煤灰。     

粉煤灰处理矿井水重金属污染研究

通过静态浸泡实验和动态淋溶实验,研究了用粉煤灰处理矿井水重金属污染的可行性,结果表明:粉煤灰处理矿井水中高浓度的重金属时效果较好;对Cu,Zn,Pb和Cr的去除效果较好,去除Cd的效果较差;粉煤灰投加量和重金属的去除率成正相关性。     

酸活化粉煤灰处理焦化废水的研究

针对传统焦化厂废水生物脱酚存在的废水 COD值偏高的问题 ,采用粉煤灰、酸活化粉煤灰单独处理生化出口水和酸活化粉煤灰与生物联合处理焦化废水 ,结果表明 ,酸活化后粉煤灰的活性显著提高 ,酸活化粉煤灰和生物联合处理焦化废水是一种提高废水处理效果的有效方法