Indium recovery from zinc oxide flue dust by oxidative pressure leaching

Indium was recovered from zinc oxide flue dust(ZOFD)with sulfuric acid by oxidative pressure leaching in an autoclave, and the effects of different technological conditions on indium leaching were studied.Potassium permanganate and hydrogen peroxide were used as oxidants.The atmospheric pressure leaching experiments were also carried out.The experimental results show that the leaching rate of indium can be effectively improved by oxidative pressure leaching.The optimum conditions of pressure leaching are determined as sulfuric 5.10 mol/L acid,leaching time 150 min,temperature 90℃,and the H2O2 dosage of 0.5 mL/g or 2.5%KMnO4.The leaching rate of indium is more than 90%,which is increased by 13%compared with that of atmospheric pressure leaching process without oxidant under the optimum conditions.

The flue dust emission of the coal fired power plants in Zhejiang Province attains target

According to statistics, the average dust collection efficiency of flue gas emission in the large and medium- sized power plants in Zhejiang Province at present has attained higher than 97% which surpasses the 95% standard as stipulated by the Ministry of Electric Power. The dust collection efficiency of the Beilungang Power Plant has already attained 99.92%. In recent years, Zhejiang Electric Power Corporation has stipulated that all the newly constructed generating units shall be equipped with high efficiency electrostatic precipitator (ESP) while the existing power plants shall speed up their renovation work for their dust collectors. In combination with the fourth stage project of the Taizhou Power Plant, the improvement work of the dust

Recovery of gallium from phosphorus industry flue

The flue dust generated during electric furnace production of elemental phosphorus was investigated for the recovery of gallium. Then the flue dust was slurried with water and blended with concentrated sulfuric acid, followed by ageing. The gallium in the dust was thereby converted to soluble sulfate. The factors affecting the dust curing were investigated to understand the process chemistry of the pretreatment. The optimal curing conditions are determined as follows: the mass ratio of dust to water and acid is 1∶1∶1, ageing temperature and time are 200 ℃ and 2 h, respectively. Almost all the gallium available to acid dissolution in the dust, about 90% gallium, can be extracted by leaching the cured dust at 80 ℃ for 1 h.

Study on the System for Separating Sulfurfrom Flue Gas and Dust

This paper describes the structure of the system for separating sulfur from flue gas and dust. In the paper, the velocities of turbulent flow and laminar flow inside the tower, the total of liquid membrance, and the additional flow of rotation fogged fluid are calculated, and the separation of rotation air-solid affected by tower is analyzed. The velocity distribution in quasi free vortex area is obtained from experiment. The minimum separated particle diameter is computed. The paper also studies the chemical reactions of flue gas containing sulfide with the dynamic fogged sulfur separating agent and discusses the main factors related to the effect of separating sulfur and dust. At last, the applications of separating sulfur in industrial stove and collecting dust in environmental engineering are introduced.

基于YOLOv3的袋式除尘器滤袋破损自动检测方法

干式除尘装置中袋式除尘器的滤袋在长时间使用后会出现破损,造成能源消耗增加、除尘效率降低、污染环境等严重问题。为此,本文采用在除尘舱室处搭建粉尘烟雾检测摄像头,并基于YOLOv3算法检测袋口烟雾的泄漏情况。试验检测步骤:①根据真实除尘舱室尺寸设计袋式除尘器袋口烟雾泄漏实验室平台,采集不同洞口烟雾泄漏的图像数据;②使用软件标注这些图像数据;③搭建Darknet深度学习框架,采用YOLOv3算法对图像数据进行训练,并依据模型计算结果识别破袋情况。结果表明:模型对于批量图像的识别准确率能达到91%以上,对于连续视频的识别准确率可达95.65%。本文系统可以减少除尘器运行中的人工检测,降低工厂人力资源成本和工人劳动强度,可以避免生产中的安全隐患和损失,可以为工厂的生产安全及定期维护提供技术指导,也为全厂智能化生产提供了有效的方案。

铜冶炼烟尘金属分离及资源回收研究进展

以铜冶炼烟尘为研究对象,分析其理化及矿物学性质,对比铜冶炼烟尘金属分离与回收方法,包括碳热还原法、硫酸浸出法、碱性浸出法和湿法-火法联合工艺,总结各方法的原理、典型工艺、现状和存在问题,阐述非常规冶金方法在铜冶炼烟尘金属分离中的应用,展望铜冶炼烟尘资源回收的发展方向。研究结果表明:铜冶炼烟尘中砷、铜、锌含量受冶炼工艺、原矿品质的影响,不同元素赋存形态存在差异。碳热还原法可以通过金属砷酸盐和氧化物分解的方式释放砷,从而实现砷与其他有价金属的分离;硫酸浸出法可以高效浸提铜冶炼烟尘中的金属,实现多元素的回收;碱性浸出法可选择性浸提砷;湿法-火法联合工艺结合了火法工艺选择性分离砷和湿法工艺高效提取金属的优点,对于复杂高砷铜冶炼烟尘处理具有优势。铜冶炼烟尘兼具资源属性和环境风险,实现清洁生产及多金属资源化利用仍是关键,砷的无害化处置与锌、铜、铅等有价金属的高效协同回收工艺及分离机制、全过程物质流与环境效应是铜冶炼烟尘资源回收的发展方向。

HAMON电除尘器故障分析及应对措施

HAMON电除尘器可用于处理催化裂化烟气中的催化剂粉尘。由于催化裂化装置四年一修,电除尘器不能随时停运检修,因此针对HAMON电除尘器的运行情况进行研究,对于保障电除尘器及催化裂化装置的长周期稳定运行具有重要意义。在运行过程中,电除尘器出现电流和电压降低的问题。对故障原因进行分析,并在电除尘器停运后进行检查,发现:腐蚀泄漏导致电除尘器内部烟气湿度大。制定了检查、检修项目,更换了配件,同时结合冷态试验结果,调整了电除尘器的电流、电压、振打周期和振打力度。检修开工后,电除尘器入口粉尘质量浓度53.3 mg/m^(3),出口粉尘质量浓度4.8 mg/m^(3),远低于设计值(30 mg/m^(3))。检修开工至今超过2 a,电除尘器运行平稳,未出现任何故障,实现了长周期稳定运行。

pH对铜冶炼烟尘中重金属浸出行为的影响及其矿物学控制机理

以某废弃铜冶炼厂收集的铜冶炼烟尘作为样本,采用TCLP毒性浸出和宽溶液pH(3~13)范围浸出实验,研究了铜冶炼烟尘中重金属的释放行为及其矿物学控制机制。结果表明,TCLP浸出液中As、Cd、Cu、Pb和Zn浓度分别是我国《危险废物鉴别标准浸出毒性鉴别》(GB 5085.3—2007)中相应元素限值的704倍、82.7倍、2.08倍、3.1倍和3.26倍。在整个溶液pH处理范围内,As的释放率高达26.0%~28.1%。在酸性条件下Cd、Cu和Zn的浸出率明显较高,而Pb在pH 13.0时释放率较高。地球化学分析表明,在pH 5.5~11.5的溶液处理下,As的溶解度部分受新形成的Ca、Cu、Pb和Zn砷酸盐控制,而Cd、Cu、Pb和Zn的溶解度主要受碱性条件下氢氧化物沉淀形成控制。BCR顺序提取和XRD分析表明,浸出液中Cd和Zn浓度较高与其在灰尘中赋存活性态比例高一致。研究结果为烟尘处理或处置防止重金属污染提供科学指导。

高频燃烧红外吸收法检测铜冶炼烟灰中的硫

建立了高频燃烧红外吸收法检测铜冶炼烟灰中的硫分析方法。该试验过程中选择称量0.05~0.06 g样品,加入0.05 g纯铁助熔剂、0.15 g钨粒。将混合试样放入高频燃烧炉中,在富氧条件下高频感应加热燃烧,硫被转化为二氧化硫,气体通过高和低含量的二氧化硫红外检测室检测含量。标准加入法得到硫系数在0.95~1.05之间,该方法的检出限为0.003 3%,相对误差小于1.37%,相对标准偏差小于1.65%(n=11)。此方法操作简单、检测时间短、适合批量检测,结果准确,可满足快速检测的分析要求。

玻纤覆膜滤料研究进展及应用

袋式除尘器被广泛应用于工业除尘领域,其滤料的性能是影响除尘效果的关键因素。玻璃纤维覆膜滤料结合了玻璃纤维及PTFE薄膜材料的优点,为PTFE薄膜提供支撑力,PTFE薄膜孔径小能够实现对粉尘的表面过滤,因此被广泛用作工业除尘滤料。本文综述玻纤覆膜滤料的结构及组分特征、玻纤覆膜滤料在工业除尘领域的应用,分析各工业领域烟气产生特性并阐述玻纤覆膜滤料在各个行业的研究现状,并对玻纤覆膜滤料提出展望。

杂质锌对顶吹炉铜熔炼系统的影响

鉴于杂质锌对顶吹炉生产中产品质量和生产率的不利影响,系统研究了入炉精矿中锌含量对铜熔炼顶吹炉系统冰铜、炉渣、烟尘的影响。结果表明,随着入炉精矿中锌的平均品位由0.88%上升至3.59%:冰铜中锌含量由0.68%上升至2.16%,不利于后续降低吹炼渣及精炼渣中铜含量;电炉渣中的锌含量由2.02%上升至5.80%,将导致更多的含锌铁尖晶石固相在高温下析出,使炉渣熔化温度出现升高趋势;上升烟道烟尘中锌含量增至3.34%,含锌物相增加将引入高熔点、高黏度锌铁尖晶石,诱发半熔融状或致密坚硬的结瘤物产生,难以破碎清除;电收尘系统烟尘率由0.96%提升至6.88%,烟尘中锌含量由4.25%增至8.44%,增加电收尘系统负担,降低除尘效率。

粉尘浓度高对于电厂脱硫系统的影响分析与改造

为保障脱硫系统的高效稳定运行,阐述平海电厂吸收塔系统的工艺流程与反应原理,分析粉尘浓度高对脱硫系统的不利影响。提出优化的石膏一级脱水系统,用以解决排废水与产石膏之间的矛盾,通过新增一路直排到废水处理系统,提升吸收塔浆液品质,又保证石膏品质。实践表明,此技术改造方法可行。

烟气除尘技术在大气污染治理过程中的应用思考

在社会发展过程中,随着城市化进程的加快及工业的发展,废气排放总量不断增加,造成了严重的大气污染,因此大气污染治理十分必要,需要相关人员结合实际进行方案设计。而在实际治理环节,由于大气污染的类型较多、总量较大,治理存在一些难点,相关人员应通过烟气除尘技术对大气污染进行治理,实现对环境的保护。本文从大气污染治理入手,浅谈烟气除尘技术的必要性及优势。相关人员应结合大气治理的需要,合理安排烟气除尘技术,发挥其优势,实现对大气污染的治理。

负压大布袋除尘器在高纯硅冶炼烟气净化系统中的应用

本文就负压大布袋除尘器在高纯硅冶炼烟气净化系统应用情况展开了研究,介绍了负压大布袋除尘器技术的技术原理,通过负压大布袋除尘器与正压布袋除尘器对比,并结合实际应用情况表述了负压大布袋除尘器在应用中的优势,为高纯硅冶炼企业选择烟气净化设备提供参考.

Flow Characteristics Diagnosis and Optimization for Dust Collectors Inflow Duct in Thermal Power Plants

火电厂烟风道用于输送烟气、冷风等介质，其设计优化水平不但影响火电厂烟风系统阻力的大小，而且影响与烟风道直接相连的各个设备的运行状态。某600MW机组除尘器前烟道设计不合理，存在磨损严重、进入除尘器烟气分配不均等问题，文中采用标准缸￡模型，利用Fluent求解器对该部分烟道的流场进行数值计算，诊断分析其存在的主要问题，提出的3个改造方案均可使烟道阻力大幅度下降、烟道磨损减轻、进入除尘器烟气分配均匀。同时，研究了缓转半径及烟气流速对该段烟道阻力和烟气分配的影响情况，计算结果表明该段烟道缓转半径宜选在0．875以上，烟气流速对该段烟道的性能基本没有影响。

钙级颗粒移动床脱硫工艺在焦炉烟气处理中的应用实践

从钙级颗粒移动床焦炉烟气脱硫技术工艺的选择、塔体的设计、焦炉烟气处理的实际应用等方面的问题出发,首先对焦炉烟气在干法脱硫塔体的走向进行合理设计;然后创新的提出增加隔热挡墙,为干法脱硫塔仓室创造条件;最后从脱硫剂的选择、脱硫剂上下料的自动化、二氧化硫不合格的解决方法、粉尘颗粒物不合格的解决方法等方面解决实际运行中存在的问题。对焦炉烟气脱硫工艺的选择,现有钙级脱硫装置的稳定运行、经济运行方面具有一定的借鉴和指导意义。

玻璃窑炉烟气排放有色烟羽分析及对策研究

通过对玻璃窑炉使用不同燃料(天然气、重油、煤制气、石油焦)以及相同燃料配套不同烟气处理工艺下进行比较,从能源角度和环保处理工艺过程对烟囱有色烟羽的主要成分和产生原因进行分析。再结合现有玻璃窑炉的烟气处理技术与龙净环保近些年开发的“高温干法脱硫+复合滤筒尘硝一体化”协同脱除技术,在实际改造项目中对其效果进行了对比。最后根据当前行业情况提出具体治理烟囱有色烟羽现象的措施,为玻璃工业的烟气治理提供更为先进的解决方案。

Nanosize-effect on the distribution of heavy metals in copper smelting dust:Based on sophisticated dust sorting approach

Dust particles emitted from smelters can be hazardous to ecosystems and humans,as they are often enriched in metallic compounds.Here,we combined multi-method mineralogical analysis with a sophisticated size sorting approach for copper smelting dust to study the nanosize-effect on heavy metal distribution,which has hitherto been underestimated.Three types of dust were collected from a copper flash smelter and then size-sorted using a Dekati low-pressure impactor.Results showed that all three samples could easily sort out nanoscale dust particles(<1μm,grades 10–2)and even those smaller than 100 nm(grades 5–2).Especially for electrostatic precipitators dust,the mass fraction of nanoscale dust(<1μm)could reach 10.71%.The presence of heavy metals(Pb,Zn,Cu,and As)and their mineral species in dust was examined at various particle sizes.It was discovered that different heavy metals are enriched on nanoparticles in specific sizes.In micron-sized particles,heavy metals are generally found in discrete phases(e.g.,CuSO_(4),PbSO_(4),and As_(2)O_(3)).In nanoscale particles,the dominant phase is Fe_(3)O_(4),while heavy metals are mostly found in lattice substitution(e.g.,CuFe_(2)O_(4)and ZnFe_(2)O_(4)).Two distinct nano-dust morphologies were found:One with irregular mesh or chain structures consisting of particles of a few nanometers,and the other with polygonal crystals in larger sizes of hundreds of nanometers.The enrichment of heavy metals in the latter morphology is more pronounced,possibly because lattice substitution of heavy metals is more likely to occur when polycrystalline particles are formed.

410 t/h燃煤电站高温除尘技术试验研究

针对燃煤电站SCR脱硝技术中高浓度飞灰造成的催化剂使用寿命缩短、大量氨逃逸及空气预热器堵灰的问题,将高温除尘器布置在SCR反应器之前。在410 t/h燃煤锅炉上对高温除尘技术进行了工程示范研究,分析了高温除尘器的除尘特性对下游脱硝单元和空气预热器性能的影响。结果表明:在70%和90%锅炉负荷下,高温除尘器出口烟尘平均质量浓度均小于8 mg/m3;90%负荷下,烟气流经高温除尘器的压降仅为500 Pa左右,大幅低于传统布袋除尘器的烟气压降;与典型的超低排放烟气后处理技术相比,应用高温除尘器能实现在相同脱硝效率下显著降低SCR反应器的烟气压降,并能减少相应的气氨消耗量与氨逃逸量;与常规布置布袋除尘器的锅炉环保岛相比,高温除尘器+SCR脱硝单元+空气预热器的模块的烟气压降可降低约500 Pa。

硫酸熟化—常压浸出综合回收锡烟尘中铟锌试验研究

某锡烟尘含Sn 37.43%、Zn 8.82%、In 0.56%,具有较高的综合回收价值。采用硫酸熟化—常压浸出工艺回收烟尘中的有价金属铟、锌,而锡有效富集在渣中。通过条件试验确定适宜的工艺参数为熟化温度140℃,熟化保温时间40 min,硫酸与锡烟尘质量比0.7∶1,浸出时间1.5 h,浸出温度90℃,浸出液固比4∶1 m L/g。在此条件下,铟和锌的平均浸出率分别达到96.68%和97.70%,锡的平均浸出率降低到0.52%。与常压酸浸提取工艺相比,硫酸熟化常压浸出工艺可显著提高铟和锌的浸出率,并显著降低锡的浸出率,实现了铟、锌与锡的高效分离。