零价铁还原法脱除地下水中硝酸盐的研究

利用零价铁还原法脱除地下水中的硝酸盐,研究了各种因素对硝酸盐去除率的影响.结果表明:较低的初始pH、较高的铁粉用量、较高的反应温度对零价铁还原脱氮反应均有促进作用;反应环境对脱氮也有一定的影响,而搅拌转速对零价铁还原脱氮的影响不大;固体表面的化学反应是速率控制步骤,零价铁还原脱氮反应符合一级动力学模型,表观速率常数为0.016 min-1,铁表面的电子转移是主要的还原反应机理.     

生物除铁除锰在地下水处理厂的应用

黑龙江省兰西镇地下水处理厂采用生物除铁除锰技术取得了满意的铁、锰去除效果。尽管原水含铁量为10～14mg/L、含锰量为0．65～1．1mg/L，出厂水水质仍然优于国家饮用水标准，总铁＜0．05～0．1mg/L，总锰＜0．05mg/L，彻底解决了兰西镇居民的生产和生活用水问题。     

Degradation of soil-sorbed trichloroethylene by stabilized zero valent iron nanoparticles: effects of sorption, surfactants, and natural organic matter

Zero valent iron (ZVI) nanoparticles have been studied extensively for degradation of chlorinated solvents in the aqueous phase, and have been tested for in-situ remediation of contaminated soil and groundwater. However, little is known about its effectiveness for degrading soil-sorbed contaminants. This work studied reductive dechlorination of trichloroethylene (TCE) sorbed in two model soils (a potting soil and Smith Farm soil) using carboxymethyl cellulose (CMC) stabilized Fe-Pd bimetallic nanoparticles. Effects of sorption, surfactants and dissolved organic matter (DOC) were determined through batch kinetic experiments. While the nanoparticles can effectively degrade soil-sorbed TCE, the TCE degradation rate was strongly limited by desorption kinetics, especially for the potting soil which has a higher organic matter content of 8.2%. Under otherwise identical conditions, ∼44% of TCE sorbed in the potting soil was degraded in 30 h, compared to ∼82% for Smith Farm soil (organic matter content = 0.7%). DOC from the potting soil was found to inhibit TCE degradation. The presence of the extracted SOM at 40 ppm and 350 ppm as TOC reduced the degradation rate by 34% and 67%, respectively. Four prototype surfactants were tested for their effects on TCE desorption and degradation rates, including two anionic surfactants known as SDS (sodium dodecyl sulfate) and SDBS (sodium dodecyl benzene sulfonate), a cationic surfactant hexadecyltrimethylammonium (HDTMA) bromide, and a non-ionic surfactant Tween 80. All four surfactants were observed to enhance TCE desorption at concentrations below or above the critical micelle concentration (cmc), with the anionic surfactant SDS being most effective. Based on the pseudo-first-order reaction rate law, the presence of 1×cmc SDS increased the reaction rate by a factor of 2.5 when the nanoparticles were used for degrading TCE in a water solution. SDS was effective for enhancing degradation of TCE sorbed in Smith Farm soil, the presence of SDS at sub-cmc increased TCE degraded by ∼10%. However, effect of SDS on degradation of TCE in the potting soil was more complex. The presence of SDS at sub-cmc decreased TCE degradation by 5%, but increased degradation by 5% when SDS dosage was raised to 5×cmc. The opposing effects were attributed to combined effects of SDS on TCE desorption and degradation, release of soil organic matter and nanoparticle aggregation. The findings strongly suggest that effect of soil sorption on the effectiveness of Fe-Pd nanoparticles must be taken into account in process design, and soil organic content plays an important role in the overall degradation rate and in the effectiveness of surfactant uses.     

湖南水口山矿田与3号隐伏岩体有关的铁多金属矿床地质特征及找矿标志

在湖南常宁水口山矿田中部,新近发现了一个隐伏的夕卡岩型铁多金属矿床。该矿床产于3号隐伏花岗岩体接触变质交代蚀变破碎带中,受控于倒转背斜、花岗闪长岩体超覆体、栖霞组灰岩与当冲组砂页岩构成的接触带"三角地带",共伴生有铁、铜、铅、锌、银、金和铀。围岩蚀变组合复杂,其中石榴子石—透辉石—透闪石夕卡岩化、角岩化、硅化、大理岩化与成矿关系密切。矿床类型为接触交代成因的夕卡岩型。这一新类型矿体的发现,为水口山矿田隐伏矿体的找矿突破提供了新的方向与空间(隐伏岩体超覆体下接触变质交代带)。     

Electrochemical recovery of hydrogen from coal acid mine drainage for the enhancement of sulphate reduction using grass cellulose as carbon source

This paper investigates the generation of hydrogen at the cathode in an electrolytic cell treating acid mine drainage (AMD) and the effect of the generated hydrogen on the biological removal of sulphate using grass cellulose. The performance of the bioreactors was assessed by means of sulphate reduction, chemical oxygen demand (COD), and volatile fatty acid (VFA) utilization. To this end, two batch reactors, A, B were operated similarly with the exception of the addition of hydrogen. Reactor A received no hydrogen to act as a control, while reactor B received hydrogen for the experimental duration. Further experiments were conducted to investigate the feasibility of sulphide oxidation to elemental sulphur using air. The results show that during sulphide oxidation, the sulphate concentration decreased from 364 to 183 mg/L, a decrease of 50% and the concentration of sulphide decreased from 163 to 70 mg/L, a decrease of 57%.     

新型混杂纤维水泥砂浆抗冻性试验研究

抗冻耐久性是混凝土结构性能重要的指标之一。近几十年来,纤维混凝土迅速发展,且大都集中在其力学性能的研究,文中从抗冻耐久性着手,采用钢纤维(SF)、聚乙烯醇纤维(PVA)、碳酸钙晶须(CW)三种纤维混杂体系增强的水泥砂浆进行抗冻性试验研究。结果表明,这种新型的混杂纤维能够提升水泥基复合材料的抗冻耐久性,为工程应用提供依据。     

CMIT-MIT活化铁尾矿粉体系对混凝土性能影响的研究

针对铁尾矿活化效率低的问题,采用机械力-化学耦合活化工艺有效地激发铁尾矿粉潜在火山灰活性,为铁尾矿的大规模绿色资源化利用提供了基础。活化铁尾矿粉复合胶凝体系的实验结果表明,与纯水泥相比,活化铁尾矿粉混凝土具有高的坍落度和扩展度,混凝土工作性良好。CMIT活化铁尾矿粉-水泥体系中,反应初期活性降低,形成少量的水化产物,导致其孔隙率增大,抗压强度较低;随着反应的进行,大量的Ca(OH)2与水化凝胶的产生导致混凝土孔隙率降低,结构更加致密,其力学性能显著增加。     

高精度磁法测量在棒槌崖矽卡岩型磁铁矿勘查中的应用

通过棒槌崖地区开展高精度磁法测量,对磁测数据进行光滑、化极、频率域向上延拓处理,划分断层位置、圈定磁异常形态,总体查明了该区磁异常特征。依据磁异常特征,结合地质、物性资料,对异常进行定性和半定量正反演计算,完成了该区地质物探综合解释推断。通过对综合信息的比较分析,进行成矿靶区预测,并开展潜力评价。最终通过钻孔验证,找到了矽卡岩型磁铁矿体。本次实践应用充分说明高精度磁测在棒槌崖地区寻找矽卡岩型磁铁矿效果显著。     

地面高精度磁法在青海大沙龙铁矿勘查中的应用

大沙龙铁矿区位于北祁连洋壳沉积带西段,走廊南山复背斜轴部南翼。属北祁连Cu-Pb-Zn-Fe-Cr-Au-Ag硫铁矿—石棉成矿带。区内广泛分布有奥陶纪火山沉积岩,岩层褶皱紧密,断裂发育,其西南侧为柴达诺山花岗岩体,矿区内有较多脉岩分布。据钻孔资料,深部见隐伏超基性岩体。根据大沙龙铁矿床特征及矿石中有用组分和伴生元素的特点,在前人工作成果的基础上,以地质工作与物探工作相结合的勘查手段,配以山地工程及各项分析测试手段,较全面系统地评价大沙龙矿床。地磁异常反演解释及钻探深部验证是找矿发现的关键。     

添加钛、铌、锰、硫及镁对亚共晶灰铸铁初生奥氏体形核及生长的影响

共晶铸铁在共晶凝固时,熔体中碳的状态,即“C的微小集合体”已经被深入研究.然而时于与初生奥氏体密切相关的铁原子的状态,即“铁的微小集合体”却缺乏研究.本文作者提出,在亚共晶灰铸铁熔体中,初晶γ的形核受“Fe的富集部”的影响,而“Fe的富集部”的形成及消失与“C的微小集合体”有关.研究表明,初生奥氏体的形核过冷度、形核数和晶核生长形貌随工艺条件如过热度、保温时间和冷却速率而变化.本文讨论了在熔体的过热度、保温时间和冷却速率固定的条件下,钛、铌、锰、硫和镁这五种添加元素对亚共晶灰铸铁初晶γ的凝固过程的影响.