地下水污染修复技术的研究综述

该文在大量搜集国内外地下水污染修复技术研究资料的基础上,阐释了各种方法的优缺点和适用范围。并探索性的将各种修复技术划归为四大类,即物理法修复技术、化学法修复技术、生物法修复技术和复合修复技术,以期能对我国地下水污染修复技术的研究、选用、命名和管理有所帮助。     

多因素对稀土电解槽电解效率影响研究

为解决稀土电解槽生产过程中电解效率不高的问题,以10kA稀土电解槽为研究对象,根据实际生产情况,确定了对电解效率影响较大的4个因素:阴极直径、阴极插入深度、纵向极间距、横向极间距。通过正交试验找出最佳因素组合。在阴极直径为70mm、阴极插入深度为370mm、纵向极间距为95mm、横向极间距为75mm条件下电解效率最高。实践验证结果表明,最佳因素组合条件下生产时电解槽电解产率最高。     

The use of thermomechanical analysis to characterise Söderberg electrode paste raw materials

Continuous self-baking electrodes, i.e. Söderberg electrodes, are commonly employed in the industrial operation of submerged arc furnaces to conduct electrical energy from a transformer(s) to the smelting zone inside the furnace. Söderberg electrodes are formed from Söderberg electrode paste consisting of two components, i.e. a binder that is mostly a coal tar pitch and a solid filler that can be either coke or calcined anthracite. In this paper it is demonstrated how thermomechanical analysis can be used to characterise the thermal dimensional behaviours of Söderberg electrode paste raw materials. Two case study coal tar pitches, three anthracites and a pre-baked graphite electrode sample were characterised. Results indicated that the method applied can be used to determine the baking isotherm temperature more accurately than previously. Enhanced knowledge of the baking isotherm temperature is critical to ensure safe, profitable and continues furnace operation. The results also indicated that the coal tar pitches shrunk approximately 12% if exposed to temperatures above the baking isotherm temperature up to 1300 °C, while the anthracites calcined at 1400 °C expanded 0.6–1.0% in the same temperature range. The magnitude differences in thermal dimensional behaviour and difference in motion (shrinkage vs. expansion) indicates the vulnerability of a Söderberg electrode baked for the first time at temperatures exceeding the baking isotherm temperature. In contrast to the calcined anthracites, the uncalcined anthracite samples shrunk 6–8% if exposed to temperatures up to 1300 °C. This stresses the importance of the efficiency of the calcination process of the anthracite prior to Söderberg electrode paste production to enhance dimensional stability of the Söderberg electrode paste. The results also indicated that the method detailed in this paper can be used by Söderberg electrode paste producers to optimise the selection of raw materials and to do quality control on calcined anthracite.     

氧化硫硫杆菌对电动修复铀污染土壤的强化作用

先构建一电动修复单元,研究了修复时长、电解液及电压梯度对电动修复铀污染土壤的影响.结果表明,在修复时长为7 d、电解液为0.1 mol/L柠檬酸与0.03 mol/L氯化铁混合液、电压梯度为1 V/cm及电极为石墨电极的条件下,该电动修复单元的修复效果达到最优;再在此基础上,向此电动修复单元接种氧化硫硫杆菌,构建一微生...     

高压电选机内电晕电流和电场的分布规律

在电选过程中，分选带较短，物料参选时间短，在这很短的时间内完成荷电、放电、最终分离，分选带内滚筒表面附近的电晕电流和电场分布情况就起着直接的决定作用。对电选机内电晕电流和电场分布规律进行了较深入的理论和试验研究，并以此为依据，对电选实践中如何通过调节操作参数、结构参数来改善分选效果进行了分析。研究结果表明：（1）电晕电极的主要作用是产生电晕电流，同时也产生静电场；电晕电流和场强随极间电压升高或极距减小而增强；（2）电晕电流和场强沿接地滚筒表面呈正态分布；（3）静电极主要产生强静电场，静电极对电晕电极的电晕放电有屏蔽作用；（4）在分选过程中应采用高电压、大极距的操作制度和电晕－静电复合电极结构。     

Use of a Quantitative Risk-Based Approach for Deciding Upon Short-Term Remediation Methods of a Contaminated Site

Soil contamination is an important issue for European environmental policy, since it represents potential hazards for human health and the ecosystem. This paper presents a case study from Greece. A historic metallurgy complex will be re-used for establishing the Lavrion Technology and Cultural Park (LTCP). Intensive mining and metallurgical activities that took place in the broader area for the last 3000 years have caused soil pollution, particularly with metals and metalloids. Because remediation is presently prohibitively expensive, a risk assessment methodology based on U.S. EPA guidance [1–5] was used to quantify human health hazards, implement immediate cost-effective countermeasures to ensure protection of human health, and provide time and data needed for the final remediation scheme to commence. Results indicated an excessive risk with respect to arsenic, mainly through the ingestion route, meaning that covering the top soil with the appropriate materials (limed sand and gravel) will exclude the particular “pathway” and eliminate hazards for a considerable amount of time.     

基于EDEM的双齿辊破碎机破碎效率影响因素仿真分析

运用离散元软件EDEM对MMD1000系列双齿辊破碎机破碎效率进行仿真研究,考察物料性质、物料粒度分布、齿辊转速等变量对破碎机破碎效率的影响规律。结果表明,物料大块率的增加将降低破碎机的破碎效率;物料硬度的变化会引起破碎机破碎后物料出料粒度尺寸存在差异,即硬度越大的物料,破碎后Bonding键断裂数目越少,破碎机破碎效率越低;适当提高双齿辊破碎机齿辊转速能在一定程度上增大破碎机破碎效率,破碎机破碎软岩物料时提高齿辊转速较破碎硬岩物料时提高齿辊转速破碎机破碎效率提高幅度高。齿辊转速的变化还会造成破碎后物料的粒度发生改变:低齿辊转速下会使破碎机破碎后物料粒度分布较为均匀,强制排出大块较少;而高齿辊转速易造成强制排出大块物料,物料粒度分布不均。试验结果可以为提高双齿辊破碎机生产效能和破碎机的选型设计提供参考。     

印刷电路板酸性蚀刻废液回收工艺中电极反应过程动力学研究

在印刷电路板酸性蚀刻废液中选用Ir系和Ru系电极作阳极,通过稳态动电位扫描和循环伏安扫描,对电极表面发生析氯和电积铜反应过程动力学进行了研究.在0.5 mol/L H_2SO_4溶液中及20kA/m~2电流密度下,Ir系钛阳极的强化使用寿命为Ru系钛阳极的20倍.Ir系钛阳极的析氯电位比Ru系钛阳极高,两种电极的析氯反应都属于不可逆反应.     

Investigation of the micro contact profile weldingtechnics

1IntroductionAlong with the rapid development of electronic technology,micro composite electric contact profile isapplied widely to all kinds of electronic products such as relay switch,key press,digital switch,micro-switch,circuit recorder,controller,linker and so on[1].Micro composite electric contact profile is a newweak electricity contact material with several layers andtiny cross section area.Generally,the electric con-tact layer is made fromnoble metal materials.In a typical case,the co…     

Investigation of the micro contact profile welding technics

The cladding preparation technology for the micro contact profile is investigated through the way of seam welding. The effects of the seam welding on different conditions including welding electrical current, welding time, electrode force and electrode material were contrasted through the way of metallographic structure, electron scanning, experiments of rectification and twist fatigue.The parameters of welding several kinds of materials were obtained. As a result, the qualified contact profile can be produced by making a control of the technical conditions: welding current, welding time, electrode force and electrode material.     

Investigation of the micro contact profile welding technics

The cladding preparation technology for the micro contact profile is investigated through the way of seam welding. The effects of the seam welding on different conditions including welding electrical current, welding time, electrode force and electrode material were contrasted through the way of metallographic structure, electron scanning, experiments of rectification and twist fatigue.The parameters of welding several kinds of materials were obtained. As a result, the qualified contact profile can be produced by making a control of the technical conditions: welding current, welding time, electrode force and electrode material.     

镍正极中钴添加剂掺入方式的研究

以钴作为Ni(OH)₂活性物质的添加剂, 研究了化学共沉积-表面沉积-机械混合、化学共沉积、表面沉积、机械混合4种掺入方式对镍电极性能的影响。通过恒流充放电对比测试表明, 在钴添加剂掺杂量相同的前提下, 采用化学共沉积-表面沉积-机械混合分步复合掺入方式的镍电极其放电容量和放电平台得到明显改善和提高。X射线衍射(XRD)和循环伏安(CV)法对镍电极分析表明, 分步复合掺入方式的钴添加剂能够在镍电极中能够形成良好的导电网络, 充电过程中更能有效的抑制γ-NiOOH的生成, 提高了析氧过电位, 增强了镍电极氧化还原反应的可逆性, 提高了活性物质的利用率, 大大提高了钴添加剂对镍正极的优化作用。分步复合掺入方式弥补了单一掺入方式的不足, 使镍电极表现良好的电化学性能。     

地下矿山直眼掏槽爆破参数优化研究

针对凡口铅锌矿目前直眼掏槽钻孔数量多、凿岩效率低等问题,开展了直眼掏槽爆破参数优化研究。通过理论计算,确定了钻孔孔径以及装药孔与空孔间距的范围。运用LS-DYNA数值模拟软件对理论计算取值范围内不同孔径、装药孔与空孔间距等参数进行模拟研究,对各模拟方案下应力分布状态及关键单元的应力值进行分析。结果表明,空孔具有导向及应力集中作用,在装药孔及空孔孔径相同条件下,当孔径为0.051 m和0.058 m时,孔间距均应取0.30 m; 当孔径为0.064 m时,孔间距应取0.35 m。工程应用结果表明,这3种爆破参数方案均能达到预期爆破效果,综合爆破后矿石块度及凿岩效率,最终确定掏槽爆破参数为:孔径0.051 m,装药孔与空孔间距0.30 m。     

离子水生成器电解槽的研究开发

将国内外多种电极和离子隔膜用于离子水生成器电解槽进行试验，结果表明：RIT涂层钛电极与进口2号离子交换膜的综合性能最优，可满足离子水机所产水质的要求；离子水水质与电极面积、电解强度和出水流量密切相关．电极面积越大，电解强度越高，出水流量越小．所产离子水越优．     

Release of Contaminants from Uranium Mine Waste – Laboratory and Field Experiments

The K?nigstein Uranium Mine was closed in 1990, ending uranium production in the former GDR. As a result of the mining operation, a dump of about 4 × 10⁶ m³ was left at Schüsselgrund valley near K?nigstein. As part of the reclamation of the mine and the dump, abandoned equipment, radioactive soil, and building wastes will have to be disposed of. The aim of this investigation was to define the characteristics of the abandoned materials and mine wastes in order to identify a suitable remediation approach for these materials. It was important to evaluate their long-term behaviour in order to determine if it would be safe to dispose of the abandoned materials in the Schüsselgrund mine dump before closing and covering it. After in-situ remediation of the dump, groundwater will become the most important pathway for the migration of radioactive and toxic contaminants into the environment. If the disposal of the abandoned materials significantly increases the risk of contaminant potential or release, safer disposal strategies will have to be found. The investigation focused on the potential geochemical interactions, the mineralogical characteristics, and the time scales of fixation/release of contaminants from the wastes. To evaluate chemical interactions of contaminants and dump material, a total of 19 columns and 5 field tests were installed. Experiences from three years of experiments are reported.     

放射性核素及重金属污染土壤电动修复技术研究进展

工业、农业和核技术的快速发展不可避免的带来土壤放射性核素及重金属污染问题,对生态环境安全及人体健康造成威胁。因此,选择高效科学的修复技术对改善和解决土壤重金属及放射性核素污染问题至关重要。物理修复技术适用于大面积污染土壤,该技术具有处理速度快的优点,但存在修复不彻底的缺点;化学修复技术适用于有高渗透能力的污染土壤,该技术通过使用固化剂与污染物络合形成沉淀从而去除污染物,其优点是处理速度较快,但存在易产生二次污染的缺点;生物修复技术适用范围较广,在修复过程中对土壤结构没有影响、成本低,但修复周期长,且不适用高浓度污染土壤的修复。电动修复技术是新兴的修复技术,具有可有效处理低渗透性污染土壤、修复时间短等优点。同时,电动修复联合技术也表现出一定优势。近年来,研究者们在放射性核素及重金属污染土壤电动修复技术方面开展了大量研究,但是针对这方面的综述还鲜有报道。因此,本文综述了重金属及放射性核素污染土壤电动修复技术、电动增强修复技术及电动修复联合技术,展望了电动修复技术的发展趋势,以期为电动修复技术在土壤污染修复方面的发展提供参考。     

电极材质对泥岩电化学改性效果的影响

为阐明电化学作用下电极材质对泥岩物性变化的影响规律,以新生代煤系泥岩为对象,运用物理模拟方法,研究低压直流电场作用下电极为铜、铁和铝时的电极腐蚀特征与新生矿物表征,电流变化与电流降低率,模型不同区域岩样电阻率和强度特征,并探讨了电阻率与强度的内在联系。结果表明：不同材质电极阳极均在酸性环境下发生金属氧化反应,电极被腐蚀生成新矿物,铝电极阴极在碱性环境下生成大量三水铝石,铁、铜电极阴极则没有明显变化;通电初期不同材质电极模型电流均有一个陡降过程,然后缓降,降低模式和降低率存在明显差异;3种电极模型不同区域岩样的电阻率和单轴抗压强度均呈现阳极＞中间＞阴性的趋势,且电阻率和单轴抗压强度正相关。     

我国稀土矿选矿近十年研究现状及发展前景

为了提高选矿厂微细粉尘电凝并的除尘效率,提出一种颗粒电晕强化荷电装置。运用COMSOL软件开展颗粒荷电数值模拟计算,获得电晕过程中旋流空间电势、颗粒饱和荷电量及颗粒荷电速率的分布特征与规律,研究电晕对粉尘荷电的强化作用机理;以原煤胶带转载点粉尘为研究对象,开展粉尘荷电和电凝并除尘实验。研究结果表明,电晕强化荷电区电极间存在明显的电势差,电极尖端和壁面形成了高电势,电极电晕可以强化颗粒荷电效果,使颗粒电场荷电速率明显高于扩散荷电速率,有助于提高颗粒饱和荷电量。实验发现,电晕作用使粉尘颗粒荷质比增加了550 nC/g,提升了对粒径5.0 μm以下粉尘颗粒的脱除效果,粒径0.5~ < 1.0 μm的粉尘电凝并脱除效率最好,颗粒数量变化率达63.48%。

     

Effect of Energy Deposition on High-Voltage Electropulse Drilling Efficiency in Granite

The study shows that in electropulse drilling, an increment in energy deposition into the discharge channel results in the linear increase in the drilling rate that grows with the spacing of electrodes. The energy consumption due to energy deposition undergoes a minimal change, while the size of cuttings is conditioned by the energy deposition and spacing of electrodes.     

镍催化多孔掺硼金刚石薄膜电极的制备及其电化学氧化降解染料废水实验研究

采用化学气相沉积技术在铌基体上制备了BDD/Nb薄膜电极,并通过高温镍催化处理和电化学处理,获得了多孔BDD/Nb薄膜电极; 选用活性橙X-GN染料废水进行了模拟降解实验,探讨2种电极降解废水效果。结果表明：相比于BDD/Nb电极,多孔BDD/Nb电极的有效电极面积增加了2.8倍; 在活性橙X-GN染料废水降解实验中,多孔BDD/Nb电极的降解效率显著提高,相对于BDD/Nb电极,色度移除速度提高约4倍,COD移除速度提高约3倍,电流效率提高约15.92个百分点,能耗降低近75%。