Study of fluxing in Al refining process by rotary and crucible furnaces

The process used to obtain recycled Al alloys depends on the scrap quality. Rotary furnaces are normally used in Europe as they allow a great productivity and they can process low quality scrap using a salt flux to protect the molten metal from oxidation. In this article, the effect of the quantity of salt on the metal recovery has been experimentally investigated by melting several types of scrap under a mixture of NaCl–KCl–Na₃AlF₆ salts. The quantity of salt has been related to the salt factor (SF), which is the ratio between the non-metallic content in the scrap and the quantity of salt required. The same levels of salt factor have been tested by melting the scrap in rotary and crucible furnaces. The metal recovery increases with the salt content for both furnaces. The results obtained with the different melting processes are comparable because the yield difference is similar considering different salt factors. Crucible furnace gives greater metal recovery but it cannot replace rotary furnace in Al refining industry due to lower melting capacity. However, the results highlight that the optimisation of the Al refining process can be supported by preliminary tests through crucible furnaces reducing the time and material consumptions.     

Evaluation and application of blast furnace slag as a mud cake modifier

The aim of this research was to reuse blast furnace slag (BFS) as a mud cake modifier (MCM) to improve the annular isolation quality in oil and gas wells. For the optimum formula of drilling fluid, the effects of MCM on the drilling fluid rheology were investigated. The relationship between the MCM addition and shear strength at cement–formation interface (SSCFI) was evaluated. The experimental results showed that the optimized formula of the drilling fluid has 1.0 wt% MCM and 0.5 wt% XY-27. The simulation results showed that SSCFI increased significantly with the addition of MCM. Based on the mechanism analysis of BFS as an MCM to improve SSCFI, it is found that the transformation of mud cake to agglomerated cake can be the main reason. The application results showed that the success rate of five wells reached 100%, and the rate of quality in cement was 100%. Especially, the average high quality rate of five wells reached 83.7%. Compared with conventional methods, the average high quality rate is increased by 32.6% points. This research provides a new way for sustainable utilization of BFS.     

炉排炉焚烧垃圾过程中主要污染物的控制

概述了二恶英、重金属、酸性气体、灰渣等垃圾焚烧的主要污染物,以二段式（往复）焚烧炉为例,介绍了炉排炉焚烧处理工艺和污染控制设备。提出通过控制垃圾焚烧条件、尾气处理以及吸附等方法,可以有效控制二恶英类污染物的排放;重金属的控制可以用除尘器或使用相应的吸附剂处理;采用较为成熟的烟气处理技术,可以控制处理酸性气体;灰渣可采用固化稳定化或酸提取法处置。     

抛煤机链条炉烟尘超标的改进措施

抛煤机链条炉属于半悬浮燃烧型锅炉 ,具有着火条件好、燃烧强烈、煤种适应性强和负荷调节灵敏等其他炉型所不具备的优点 ,但在实际运行中 ,该炉型又有排烟黑度高、含尘浓度大的缺点 ,大大超过环保要求的锅炉排烟标准 ,其生产及应用受到极大限制 ,因此 ,有效解决抛煤机链条炉消烟除尘问题具有十分现实的意义。本文对抛煤机链条炉普遍存在的排烟超标、出力不足、热效率低下等问题进行了详细分析 ,并结合实际提出了改进措施     

基体改进剂对石墨炉原子吸收法测定钡的影响

根据EPA方法7081、ISO方法208.2测定钡的原理,添加基体改进剂,确定<基体改进剂石墨炉原子吸收法测定钡>方法灵敏度及测试条件.方法用于测量水中微量钡,结果令人满意.     

处理含铁尘泥的DRI工艺优选及废气污染防治

将高炉炼铁及炼钢时产生的含铁尘泥作为配料回用于烧结生产是目前较常使用的方法,但是这些尘泥之中的重金属Zn和Pb可能会对烧结和后续的高炉炼铁产生不良影响,通过对直接还原铁的工艺和设备进行综合对比,确定以转底炉为主要设备的煤基直接还原工艺较为适合处理炼铁及炼钢的含铁尘泥,并对转底炉工艺的原理及污染防治措施进行了讨论,最后提出了该工艺和钢铁联合企业之间的循环经济产业链。     

轧钢企业加热炉生产过程的危险分析与控制

在轧钢企业生产过程中,加热炉使用热煤气作为燃料加热金属料坯,存在火灾、爆炸、中毒等危险因素,一直是从事安全工作人员关注的重点.对某企业轧钢加热炉使用过程、设备设施及人员操作进行了危险有害因素分析与辨识,运用道化学火灾爆炸指数法对加热炉爆炸事故进行分析评价,得出加热炉火灾爆炸危险程度为中等,事故暴露半径为25.46ft(7.76m).并从安全设施、安全管理等方面提出有效的安全对策,使加热炉火灾爆炸危险程度降为较轻,事故暴露半径降至20.51ft(6.25m),有效的降低了加热炉火灾爆炸危险程度及危险波及范围,为企业安全运行提供了参考依据.     

分解炉分级燃烧降氮脱硝技术的研究与应用

低NOx高温燃烧技术与大容积分解炉系统有机结合,具有热效率高、分解炉温度分布均匀、降氮脱硝、NOx排放浓度低等特点。文章介绍了高温分级燃烧技术在水泥窑中的应用,重点分析了分级燃烧、降氮脱硝在分解炉系统中的应用原理,以及推广的价值。     

相干结构涡中NOx的初生形态

首次应用六线涡量探针测量了大型电站锅炉四角燃烧器射流形成的涡量场 ,发现了射流向火侧相干结构性质的涡 ,采用兰金复合涡 (RankineVortex)旋涡模型描述了该剪切大涡的尺度及其旋转速度 ,该剪切大涡的涡核半径r0 为 2 5mm ,流体微团作刚体式旋转的角速度为 - 1.5 6× 10 5r min ,应用粒子在相干结构中运动的研究成果以及燃料型NOx 的生成和破坏机理 ,分析了NOx 在相干结构涡中的初生形态 ,射流向火侧剪切大涡的结构里 ,在剪切大涡的边缘会形成富燃料区 ,当过量空气系数α <1时 ,燃料N会尽可能多地转化成挥发分N ,并且在还原性气氛条件下 ,燃料N转变为分子N2 ,由挥发分N生成的NOx 会大大减少 ;在剪切大涡的涡核内 ,是α>1的贫燃料区 ,设法降低过量空气系数α ,可以抑制NOx 的生成     

20 MW水泥窑纯低温余热发电工程设计介绍

利用生产过程中产生的废气余热发电,是水泥生产企业发展循环经济的一种选择模式.介绍了江苏恒来建材股份有限公司水泥窑配套20 MW纯低温余热发电工程的设计方案、工艺流程和设备选型.该工程正常运行后的效益分析表明纯低温余热发电装置目前在我国水泥企业具有广阔的推广应用前景.