火电厂管道清灰装置的液压系统的设计

针对化学清洗的成本高、污染大和物理清洗的除垢率低的特点，为解决火电厂输灰管道除垢问题提出了一种新式的机械清洗方法，该方法可实现灰垢的在线清洗，降低灰垢清洗的成本，延长管道的使用寿命，清洁无污染，并且可以达到满意的除垢率。本文主要介绍了机械清洗液压部分的工作原理，并对液压部分的设计计算及零件的选取做了详细的叙述。     

基于介电泳效应的高速抛光电极分布仿真研究与实验验证

目的解决传统平面环抛过程中存在的两种问题:(1)抛光液受抛光盘和工件旋转离心力作用而抛光液在加工区域分布不均,导致加工工件高平面度差;(2)抛光液受到的离心力作用限制了抛光盘转速,导致抛光效率低。方法提出一种基于介电泳效应的平面抛光方法(DEPP),在抛光区域增加一个非均匀电场,利用中性粒子在非均匀电场中极化后受介电泳力的作用,使其具有向电极和抛光区域中心运动的现象,降低旋转离心力对抛光液的甩出作用,实现对平面工件的高速、高精度抛光。采用有限元分析软件数值模拟极化后磨粒所受介电泳力对离心力的抑制作用,优化产生非均匀电场的不同电极宽度,得到最优非均匀电场电极分布参数,实际测量优化电极后抛光液所受介电泳力的大小和方向,最后搭建试验平台验证介电泳效应高速抛光平面工件的有效性。结果提高抛光盘转速,进行抛光磨砂玻璃对比实验,加工1 h以后,采用介电泳效应抛光能完全去除玻璃磨砂层,工件平整度好,最终RMS值为0.276λ;无介电泳效应抛光后,工件中心部分磨砂层仍有存在,工件平整度相对较差,最终RMS值为0.694λ。通过测量加工去除量,介电泳效应抛光比无介电泳效应抛光的去除率提升了18%结论通过仿真模拟和实验验证,证明了调整电极布置形式以及优化电极分布参数后,介电泳效应高速平面抛光的方法能够有效提升抛光效率和抛光后工件表面平面度。     

Effects of blasting parameters on removability of residual grit

This article shows the quantitative evaluation of the residual grit on a blasted substrate, and the removability of the residual grit is examined. Carbon steel plates were blasted by white alumina grit with mean diameters of 338 to 1106 μm. The velocity and the number of grit particles were measured during blasting. The residual grit was removed from a substrate surface by the dissolution of the blasted substrate surface. A mixed acid solution was used as the dissolution solution. The residual grit weight was 7 to 17 g/m². The amount of the residual grit and the penetration depth of the embedded grit increased with increasing grit size. The penetration depth was 5 to 9% of the mean diameter of the grit. The residual grit weight and the penetration depth increased with the increase of the momentum of the grit particle. This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials Park, OH, 2006.     

长余辉发光粒子与光催化剂在SiC晶圆化学机械抛光中的协同作用

目的 获得一种可改善单晶SiC晶圆化学机械抛光(CMP)效率的复合增效技术，实现单晶SiC晶圆高效率和低成本的加工要求，并对其增效机理进行深入研究。方法 通过抛光实验和原子力显微镜测试，探究长余辉发光粒子(LPPs)与不同光催化剂的协同作用对SiC–CMP的材料去除速率和表面粗糙度的影响。结合扫描电子显微镜(SEM)、紫外–可见漫反射光谱仪(UV–vis)、光致发光光谱仪(PL)和X射线光电子能谱仪(XPS)等仪器的测试结果，研究LPPs与光催化剂的协同增效机理。结果 与传统CMP的条件相比，在光催化条件下采用LPPs(质量分数0.5%)+TiO2(质量分数0.5%)+ H2O2(质量分数1.5%)+Al2O3(质量分数2%)的抛光液时，SiC的材料去除速率(MRR)由294 nm/h提高到605 nm/h，同时获得的晶圆表面粗糙度(Ra)为0.477 nm。然而，采用含有LPPs和ZrO2的抛光液抛光SiC时，其材料去除速率和表面粗糙度都未得到明显改善。XPS测试结果表明，LPPs与光催化剂的协同作用增强了抛光液对SiC的氧化作用。UV–vis和PL测试结果显示，LPPs与不同光催化剂协同效果的差异主要与其光学性能有关。结论 在光催化条件下，LPPs和TiO2对单晶SiC–CMP具有协同增效的作用，然而LPPs和ZrO2没有展现出协同增效的作用，即LPPs与光催化剂的协同作用可以改善SiC–CMP的性能，但是光催化剂的选择需要考虑LPPs的发光特性。     

Dearsenification of gold concentrates via microwave roasting

ABSTRACT

Arsenic can cause environmental pollution and also affect mineral processing efficiency. To determine the mechanism of separating arsenic from minerals, microwave roasting tests were conducted using Hunan arsenic sulfide gold concentrate as a raw material. The heating behaviour of gold concentrates under microwave irradiation was analysed. The effects of roasting temperature, reaction time, and oxygen content on arsenic removal were investigated. Temperature has the greatest effect on arsenic removal, followed by reaction time and oxygen content. The optimum parameters were determined experimentally. The removal rate of arsenic was 93.16% (gas supply: 4?L min^?1, reaction temperature: 650°C, duration: 15?min). Scanning electron microscopy analysis of the minerals after microwave roasting and conventional roasting showed that there are more cracks on the surface of minerals after microwave roasting, and the specific surface area is larger. The reaction mechanism of arsenic separation from gold concentrate during microwave roasting is discussed.     

挥发除硼-硫酸锂重量法测定锂硼合金中锂

锂硼合金中锂元素的含量对电池的电化学性能起着决定性作用。而使用重量法测定锂时,流程较长,且大量共存的硼干扰锂的测定。试验探究了先使用甲醇除硼再采用硫酸锂重量法测定锂硼合金中锂的方法。样品经稀硝酸溶解后,加入2.0mL无水甲醇,于90℃左右恒温水浴锅中挥发除硼,然后加入2.0mL硫酸(1+1)和少量水溶解盐类,转移至铂坩埚中,高温加热至硫酸烟冒尽,将铂坩埚移入800℃马弗炉中灼烧3h,使锂生成硫酸锂并恒重、称量,并用电感耦合等离子体原子发射光谱法(ICP-AES)测定固体中的氧化硼和硫酸镁的含量以修正测定结果。方法用于测定3种锂硼合金实际样品中锂,结果的相对标准偏差(RSD,n=11)为0.34%~0.56%;加标回收率为98%~103%。     

Kinetics study on leaching of rare earth and aluminum from polishing powder waste using hydrochloric acid

In this study,a novel hydrometallurgical process consisting of hydrochloric acid three-stage countercurrent leaching and solvent extraction was proposed to recover rare earth oxide(REO) from the rare earth polishing powder waste(REPPW).The effects of HCI concentration,liquid-solid ratio(L/S ratio),temperature and time on the leaching yields of rare earths(in REO) and aluminum(in Al_2O_3) were studied.The result shows that the leaching yields of REO and Al_2O_3 are 90.96% and 43.89% respectively under the optimum leaching parameters of HCl concentration=8.00 mol/L,L/S ratio=4 mL/g,leaching temperature=353 K and leaching time=180 min.Meanwhile,the leaching kinetics of REO and Al_2O_3 were investigated in this study.The leaching behaviors of REO and Al_2O_3 follow a shrinking sphere/core model and the general leaching process is controlled by the surface chemical reaction.The leaching activation energies of REO and Al_2O_3 are 9.86 and 13.68 kJ/mol,respectively.The leaching yield of each substance in three-stage countercurrent leaching is improved substantially compared with single-stage leaching,with a change from 90.96% to 95.38% for REO and from 43.89% to 46.22% for Al_2O_3,respectively.Especially,the total concentration of REO in three-stage countercurrent leaching solution is greatly increased to above 300 g/L,and the acidity of which is decreased to ca.pH=2,which is conducive to subsequent solvent extraction directly.High purity REO(99.92%) is obtained by solvent extraction separation,oxalate precipitation and calcination.The total recovery yield of REO is 85.13%.     

微囊藻毒素的检测和脱除方法综述

近年来,由于富营养化,全球有害蓝藻水华的发生率持续上升,形成水华的蓝藻会释放出多种毒素,微囊藻毒素是有害蓝藻产生的常见毒素,具有肝毒性、肾毒性、神经毒性、生殖毒性等多种毒性,严重威胁人类和生态系统健康。微囊藻毒素在水中非常稳定,难以通过传统水处理工艺去除。因此,寻求经济有效的微囊藻毒素检测和脱除方法至关重要。本文综述了定量检测和去除微囊藻毒素的方法,包括物理法、化学法和生物法,并分析总结了这三类方法用于检测和脱除微囊藻毒素的优势与局限性,总结了不同方法脱除微囊藻毒素的机理,重点介绍了绿色高效的光催化降解微囊藻毒素的脱除方法,最后,基于当前的研究结果,对未来微囊藻毒素脱除研究方向进行了展望,为解决环境中微囊藻毒素的污染问题提供思路。     

含锰反萃液制备高纯碳酸锰工艺研究

以含锰反萃液为原料,经针铁矿法除铁、硫化除重金属、碳化、洗涤制备了合格高纯碳酸锰。考察了终点pH、反应温度对除铁率的影响和(NH4)2S加入量、温度、反应时间对重金属去除率的影响,结果表明:在pH=4.0、反应温度95℃的条件下可将铁除至1.5 mg/L以下;除铁滤液加入2.2倍计量比的(NH4)2S,在反应温度35℃、反应时间60 min的条件下,Ni、Co、Zn可降低至1 mg/L以下;除重金属滤液加入碳酸氢铵调节pH在7.0~7.2,过滤、洗涤,获得满足HG/T 2836—2011(Ⅰ型)产品标准的合格高纯碳酸锰,锰回收率为93.9%。     

铅银渣氯化浸出液净化及有价金属回收试验

采用净液-置换工艺处理铅银渣氯化浸出液并提取银、铅,重点研究了铅粉置换银、铁粉置换铅的工艺影响条件。结果表明:利用Fe~(3+)易水解的特性,采用中和除铁,石灰调节溶液pH为4.0即可完全除铁,铅粉加入量为6 g/L,pH=1.5～2.5,温度60℃,置换时间40～60 min,在此条件下,银的置换率大于98%,溶液中残银浓度低于1 mg/L;两段逆流可以较完全置换出溶液中的铅,两段综合置换率为87.08%,最终置换产物含铅量90%,满足精炼要求。