旋流微泡浮选柱在涡北选煤厂的应用

分析了涡北选煤厂煤泥粒度组成,发现煤样矸石存在泥化现象,高灰细泥含量较高,对浮选不利。进行了浮选机的单因素浮选试验、两因素三水平正交试验以及最优药剂条件下的分步释放试验,同时进行了浮选柱的煤泥浮选试验。结果表明,当煤泥矿浆质量浓度为45 g/L,复合药剂为1.10 kg/t时,精煤灰分为10.97%,精煤产率为72.62%,浮选完善指标最高为53.43%,浮选机煤泥浮选效果最好;浮选柱可以分选出各种质量的精煤,精煤灰分可调性大,可以适应市场变化。最后进行了浮选机和浮选柱的综合对比试验,在精煤灰分相近的情况下,浮选柱不同程度地提高了精煤回收率和浮选完善指标,具有明显优势。     

Comparative study of the performance of conventional and column flotation when treating coking coal fines

Investigations were carried out on coking coal fines by conventional cell and column flotation techniques. The effects of different operating parameters were evaluated for both conventional and column flotation. The coal fines were collected from Bhojudih washery, India. These coal fines averaged 24.4% ash, 19.8% volatile matter and 53.8% fixed carbon on a dry basis. A commercial grade sodium silicate, light diesel oil and pine oil were used as depressant, collector and frother respectively. The flotation performance was compared with release analysis. The conventional flotation results indicated that a clean coal with 14.4% ash could be obtained at 78.0% yield with 88.4% combustible recovery. The ash of the clean coal could be further reduced to 10.1% at 72.0% yield with 85.6% combustible recovery by using column flotation. The column flotation results were close to those obtained by release analysis.     

Performance,mixing and kinetics study in the flotation column reactor using coal

ABSTRACT

A flotation column has been designed and characterized with respect to gas velocity, slurry velocity, frother concentration, gas holdup, bubble surface area flux for the study of the mixing property, liquid phase residence time distribution, flotation recovery and rate constant. The study was performed using coal as solid. A strategy of integrating chemical kinetics into the flotation process to test the floatability behaviour of coal and to estimate floatability parameter of coal has been developed. The results indicate that the coal floatability parameter is 3.05 × 10^?4. A relationship between gas holdup and bubble surface area flux was developed.     

泉店选煤厂浮选系统改造

通过分析泉店选煤厂原浮选系统工艺流程,提出了选煤厂主要存在浮选尾煤灰分低,浮选药耗高,浮选系统处理能力偏低,浮选床效率低,浮选精矿池泡沫量大等问题。针对选煤厂存在的问题,提出2种改造方案,并最终确定采用新建浮选车间并安装2台浮选机替换原有浮选床的改造方案。改造完成后,泉店选煤厂浮选尾煤灰分、精煤产率和可燃体回收率分别提高了55.61%,43.86%和44.51%,精煤灰分降低了0.29%,药剂用量减少了0.22 kg/t;浮选精矿池泡沫量明显降低,加压过滤机上料情况明显好转,处理量增大,且减少了1台空压机的使用;选煤厂每年增加精煤收益,节省电费和药剂费用总计12770.74万元。     

Characterization of the coal fly ash for the purpose of improvement of industrial on-line measurement of unburned carbon content

The influence of selected properties of fly ash on the measurements of an on-line analyser was described. Fly ash studied in the research originated from the pulverized coal fired boiler. The samples were taken using an inspection method within a period of 3 months. Systematic observation of the properties of the ash allowed monitoring of the work of the industrial analyzer during a relatively long period of the power plant work. Samples of coal fly ash were examined for their chemical and physical properties. Morphology was analysed by scanning electron microscopy. Unburned carbon content in fly ash was determined by using loss-on-ignition (LOI) and thermogravimetry analysis (TGA). The particle size distribution of fly ash was examined. Correlation between laboratory and on-line industrial measurements of the unburned carbon content of ash was discussed.     

Optimization of some parameters in column flotation and a comparison of conventional cell and column cell in terms of flotation performance

In this study, a comparative evaluation was made between column and mechanical flotation cells for fine coal cleaning. In addition, the optimum values of operating parameters were examined, which are important to achieve a desired separation performance in column flotation, such as the frother concentration, the collector dosage, the froth thickness, the wash water rate, the air rate and the feeding rate. The coal sample was collected from a classifying cyclone overflow stream consisting of nominally −130 μm material. Ash, volatile mater, fixed carbon and total sulfur contents of the sample were found to be 47.50%, 20.80%, 31.70% and 0.75%, respectively. Comparison of the column and mechanical flotation results indicated that column flotation was considerably more efficient than mechanical flotation for fine coal cleaning. High froth thickness and wash water addition during column flotation made it possible to obtain cleaner coals. The column flotation produced a 15.60% product ash with a 50.92% clean coal yield and 81.85% combustible recovery.     

Synthesis of hexagonal and cubic mesoporous silica using power plant bottom ash

An alkali fusion method was adopted to extract silicate species from coal bottom ash in a power plant and the supernatant solution was used for the synthesis of MCM-41, SBA-15, and SBA-16 mesoporous silica materials. The minor impurities present in the bottom ash were not found to be detrimental to the successful formation of mesoporous silica phases. Additional silica from sodium metasilicate was introduced to improve the textural properties for SBA-15 and SBA-16. According to SEM analyses, particle morphology of the samples gradually approaches those prepared using pure chemical as the amount of external silica source increases. XRD analyses confirmed well-ordered mesostructures in all of these silica materials. N₂ adsorption–desorption isotherms of MCM-41 prepared using bottom ash showed a type IV isotherm with a region of steep increase due to capillary condensation, whilst SBA-15 and SBA-16 showed type IV isotherm with H1 and H2 hysteresis loops, respectively. ²⁷Al MAS NMR analysis of MCM-41 synthesized from the supernatant solution reveals that the extracted Al species from bottom ash were tetrahedrally incorporated in the framework. TEM clearly showed the uniform pore structure of the materials prepared using the industrial waste.     

Direct liquefaction of vitrinite concentrates obtained by column flotation

In this paper, direct liquefaction of vitrinite maceral concentrates was studied. Coals from Cerrejon and Jagua collieries (Colombia, South America) were used. Vitrinite concentrates were obtained by column flotation at pH 7, air velocity of 1.4 cm/s and frother concentration of 4 ml of frother/kg of coal. Digestion runs were made at 380, 400 and 420 °C and ratios tetraline/coal (S/C) of 2/1, 2.5/1 and 3/1. Liquefaction time was 30 min. For all runs, tetraline was the hydrogen donor solvent. Feed and vitrinite concentrates were liquefied in order to compare their conversion, product distribution and oils selectivity. It was observed that, in general, conversion rates obtained from vitrinite concentrates were higher than those obtained from feed coal. The results showed that conversion tend to increase with temperature as well as the S/C ratio. Product distribution showed that both oils and gas fractions tend to increase with temperature and S/C ratio, whereas residues have a contrary behaviour.     

华恒选煤厂煤泥浮选的可行性研究

针对华恒选煤厂选煤方式单一、煤泥回收困难等问题,通过筛分试验、标准分步释放试验和煤泥浮选试验验证煤泥浮选的可行性。结果表明:煤泥中+0.5 mm产率较低,为0.18%,-0.25 mm产率为99.23%,符合煤泥浮选入料粒度要求;轻柴油和GF质量比9∶1,药剂用量为1000 g/t时,煤泥浮选效果最好,此时精煤产率为46.28%,精煤灰分为11.76%,可燃体回收率最高为73.99%,煤泥浮选可行。结合选煤厂实际情况分析了煤泥浮选的必要性,预测了增设煤泥浮选的经济效益,说明增设煤泥浮选系统在施工空间和工艺布置方面完全可行,增设煤泥浮选系统可优化选煤工艺,适应市场变化。浮选精煤可与精煤掺配销售,保持精煤水分稳定,减少因水分损失带来的亏吨现象,减少煤泥积压,缓解企业压力,增加销售收入1530.9万元/a。     

应用射流浮选柱分选微细煤泥的试验研究

介绍了细粒煤分选技术的发展现状和射流浮选柱具有的浮选速度快、分选精度高、综合性能显著优于传统机械搅拌式浮选机的特点。试验表明 ,在精煤灰分相近的情况下 ,射流浮选柱浮选微细煤泥的精煤产率明显高于机械搅拌式浮选机 ;在精煤产率相近的情况下 ,前者的精煤灰分比后者的低 2 0 %～ 3 0 %。     

充填浮选柱分选胶磷矿的工艺研究

充填浮选柱是一个复杂的气液固三相体系。本文考查了用充填浮选柱分选胶磷矿的主要操作参数的影响，讨论了Ｐ２Ｏ５的品位的沿柱高的分布，证实了充填浮选柱具有优良的分选性能，并为寻求缩短胶磷矿浮选工艺流程的途径提供了依据。     

FCMC-3000型旋流微泡浮选柱的应用分析

介绍了浮选柱的结构、特点及其工业应用的效果。分析了浮选柱利用微泡浮选、逆流浮选及旋流离心力场强化分选的机理。分析了入料、操作及环境因素对浮选柱分选系统的影响。工业应用表明,FCMC-3000型旋流微泡浮选柱能在保证精煤质量条件下,提高精煤回收率。     

难浮煤泥浮选工艺研究

阐述了难浮煤泥的特点及改善浮选效果的主要方法。以庞庞塔5号煤泥为浮选试样,研究了一次浮选、精煤再选、分支浮选3种不同浮选流程对难浮煤泥浮选效果的影响,从而找到了适合难浮煤泥浮选的工艺流程。结果表明,分支浮选流程可以在满足精煤灰分的要求下,提高精煤产率。     

The influence of carbon particle type in fly ashes on mercury adsorption

Recent research has shown that certain fly ash materials produced in coal combustion for power generation have an affinity for the mercury compounds present in flue gases. However, the exact nature of Hg-fly ash interactions is still unknown and the different variables that influence mercury adsorption need to be identified. In this work the microscopic components of fly ashes derived from the combustion of different types of feed blends of different coal rank and mercury adsorption were investigated. The aim of this research was to establish relationships between Hg retention and the type of unburned carbons present in various fly ashes. The fly ashes and fly ash fractions studied were used as sorbent beds for high mercury concentrations, conditions in which mercury retention is highly favored. From the results obtained it was confirmed that the role of the unburned carbon components in mercury capture may depend, among other factors, on the type of unburned carbon. Fly ashes capture different species of mercury depending on their nature and the type of anisotropic particles.     

基于浮选原理制备低灰煤的研究进展

结合中国煤炭资源现状及国家产业政策,介绍了低灰煤在中国煤炭深加工利用方面的重要性。阐述了制备低灰煤的原料煤性质,即必须具有内在灰分低、质脆易磨、矿物易于单体解离、可选性好等特点,且原煤中含有灰分小于2%的低灰组分,要尽量选择丝质体含量少且可浮性好的中、高变质程度煤。详细介绍了目前制备低灰精煤的2种方法,即预处理+浮选工艺和浮选柱分选工艺,并对2种分选方法的基本分选原理和分选效果进行了分析。最后论述了制备低灰煤的发展趋势,强调了应注重低灰煤专用、低成本、高效率化学药剂的研发和现有设备脱硫降灰效率的提高,采用严格的质量控制和过程控制来保证精煤的稳定性。     

浮选柱在淮北选煤厂涡北分厂的适用性分析

淮北选煤厂涡北分厂浮选系统存在煤泥量大、设备腐蚀和磨损严重、处理能力不足等问题,通过分析浮选柱在细粒、高灰煤泥分选方面的适用性,提出采用FCMC-4000型微泡浮选柱代替传统的机械搅拌式浮选机的方案,改造后将提高浮选精煤产率,降低电耗。     

预浮选式浮选柱分选细粒粉煤的实验研究

分析了传统旋流微泡浮选柱的应用现状,阐述了浮选入料性质及条件特别是入料浓度对浮选柱分选效果的影响,提出了采用预浮选式旋流微泡浮选柱分选解决高浓度细粒煤浮选的新方法,并通过试验论证了该方法的可行性,对工业现场的浮选作业具有一定的指导意义。     

抑制剂降灰浮选试验研究

为降低浮选精煤灰分,研究了抑制剂种类和用量对煤泥浮选降灰效果的影响,并选出最佳抑制剂种类和用量。结果表明:抑制剂的加入对浮选精煤降灰效果显著,但同时会对精煤产率和浮选完善指标造成一定影响。玉米淀粉的精煤灰分降低最大,但精煤产率和浮选完善指标降低速度更快,因此玉米淀粉作为抑制剂时,选择性较差,严重抑制低灰精煤上浮;亚硫酸钠的精煤灰分降低较少,浮选完善指标降低较快;CMC的精煤灰分降低较多,但同时精煤产率和浮选完善指标总体小于丹宁;丹宁的精煤灰分普遍较低,且精煤产率和浮选完善指标较高。因此,对于试验煤泥,丹宁用量为300 g/t时,降灰效果明显,精煤灰分为10.09%,满足精煤灰分(10±0.1)%的要求,同时对精煤产率和浮选完善指标影响最小,对矿物的抑制效果最优。     

Mobilization of some trace elements from ashes of Turkish lignites in rain water

Short-term water solubility characteristics of bottom ashes and fly ashes from two important Turkish lignites were investigated in association with the concentrations of some heavy metals. For this, the alkaline ashes were interacted with acidic rain water and dilute acidic solutions for leaching times changing from 10 min to 2 days to assess the mobilization potential during ash–water interactions. The concentrations of leachable trace elements such as chromium, lead, cadmium, zinc, and nickel were determined in leachate using Atomic Absorption (AA) Spectrometry. Iron concentrations were also investigated since it plays a critical role on trace element enrichment mechanism. The mineralogical and structural identification of the parent ash samples were carried out by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) techniques. The extent of the mobility of the ashes was identified regarding the physical and chemical properties of the ashes. Concentrations of the trace elements in leachates were compared to the several guideline values regulating the maximum contaminant levels in drinking water and irrigation water as well as the regulatory threshold concentrations in leachate.     

Study of loss-on-ignition anomalies found in ashes from combustion of iron-rich coal

Samples of a fly and a bottom ash, each before and after ignition at 960 °C, have been studied by X-ray diffraction, Mössbauer spectroscopy, carbon analysis, and thermogravimetric analysis with the aim to explain an observed negative loss on ignition. Ashes after ignition contain more maghemite resulting from oxidation of newly formed magnetite. Moreover, the fly ash that already contained magnetite exhibited an increase of hematite after ignition. Hercynite present in both ashes transforms to hematite and magnetite after the ignition. All these oxidation processes are responsible for a weight gain which may compensate the loss due to the burning of the remaining carbon in the ashes. Also, α-Fe is formed after ignition which may have originated from wustite.