Reduction of NO_(x)emission based on optimized proportions of mill scale and coke breeze in sintering process

Reducing NO_(x) emission of iron ore sintering process in a cost effective manner is a challenge for the iron and steel industry at present.Effects of the proportion of mill scale and coke breeze on the NO_(x) emission,strength of sinter,and sinter indexes were studied by com-bustion and sinter pot tests.Results showed that the peak value of NO concentration,total of NO emission,and fuel-N conversion rate gradu-ally decreased as the proportions of the mill scale increased because NO was reduced to N_(2) by Fe_(3)O_(4),FeO,and Fe in the mill scale.The strength of sinter reached the highest value at 8.0wt%mill scale due to the formation of minerals with low melting point.The fuel-N conver-sion rate slightly fluctuated and total NO_(x) emission significantly decreased with the decreased proportions of coke breeze because CO forma-tion and content of N element in the sintered mixture decreased.However,the sinter strength also decreased due to the decrease in the amount of the melting minerals.Furthermore,results of the sinter pot tests indicated that NO_(x) emission decreased.The sinter indexes performed well when the proportions of mill scale and coke breeze were 8.0wt%and 3.70wt%respectively in the sintered mixture.

Production of Iron from Mill Scale Industrial Waste via Hydrogen

Mill scale is very attractive industrial waste due to its richness in iron (about = 72% Fe). In this paper, the characterizations of mill scale were studied by different methods of analyses. The produced mill scale briquettes were reduced with hydrogen at varying temperatures, and the reduction kinetics was determined. Two models were applied and the energy of activation was calculated.

Pilot Scale Mill Characterization and Evaluation of Rice Bran Oil Concentration of Jazzman Rice

The demand for aromatic rice has increased in the United States during the last two decades. Jazzman, the first US-bred jasmine-type rice variety, was released by the Louisiana State University (LSU) AgCenter Rice Research Station in 2008 to compete for a market share of jasmine-type rice. Jazzman, a long grain aromatic rice variety, was developed from a cross between Ahrent and an unreleased aromatic Chinese rice line 96a-8. In pre-release field tests and laboratory scale evaluation, Jazzman rice yield and milling quality compared favorably with two high-yielding and good-milling non-aromatic long grain varieties, Cypress and Cheniere. Pilot scale evaluation of Jazzman for milling quality supported laboratory scale evaluation while providing additional data for milling optimization. Pilot scale milling uses larger rice samples than laboratory scale testing and employs a continuous process instead of the batch process used at laboratory scale. As a result, pilot scale milling offers more comprehensive information regarding the milling yield and quality of rice varieties as they are considered for industrial scale release. Another consideration for new rice varieties involves their potential for value-added processing, in which waste streams during processing can be used to create valuable products. The oil from rice bran is one such product. The objective of this study was to use pilot scale milling to determine the potential of Jazzman for industrial scale release, including its potential for value-added processing. Results showed that bran was easily removed during milling;the head rice recovery ranged from 66% to 74% as a function of milling flow rate. Water polishing had little effect on head rice recovery, but improved the final degree of milling (DOM) to a commercially acceptable level of 87 - 90. Additionally, rice bran oil concentration decreased as pilot scale flow rate increased, indicating that oil was concentrated in the outer bran layer of Jazzman. Pilot scale milling shows that Jazzman is a high-yielding and good-milling aromatic long grain rice variety.

球磨对细鳞片石墨破坏程度的影响研究

以东北某细鳞片石墨矿为研究对象,考察球磨时间、球磨质量分数和介质填充率等因素对石墨鳞片破坏程度的影响,分析磨矿产物累计产率和颗粒中石墨鳞片平均粒径,探索石墨鳞片破坏机理。结果表明,磨矿过程中,粗粒石墨颗粒最先被破坏,球磨时间越长石墨鳞片破坏程度越高,当球磨时间为30 min时破坏程度最高,达到68.17%;球磨质量分数改变对连生体中石墨颗粒粒径变化影响较大,+300μm和-300+180μm区间粒级中连生体颗粒中石墨鳞片平均粒径下降幅度分别为6.69%和12.79%;介质填充率对石墨颗粒粒径影响较小。石墨矿物颗粒表面裂纹发育特征表明,颗粒越大,表面裂纹越多,越容易被破坏,石墨单体颗粒中的穿晶裂纹和连生体中的晶内裂纹是影响石墨鳞片破坏的主要因素。

二十辊轧机辊系耦合振动特性及振动控制

精密极薄带因具备高精度、耐腐蚀、优异表面光洁度等性能,被广泛应用于微制造、微电子等高技术领域。二十辊轧机辊系的耦合振动对极薄带的生产有着重要的影响。考虑到轧制工艺和润滑状态等变化形成非线性轧制界面,建立了一种二十辊轧机辊系耦合动力学模型。应用多尺度法求解主共振和内共振的幅频特性方程,分析了不同参数对幅频特性曲线的影响。基于奇异性理论探究了不同参数与系统分岔的关系。同时,根据李雅普诺夫一次近似稳定性判据,结合系统动相平面相轨迹图,对系统稳定性进行判断分析。然后,基于Washout filter控制器原理设计了一种状态反馈控制器,通过对系统进行状态空间表达式变换,分析了控制增益对幅频特性的影响。利用时域图、相位图、频谱图以及Poincaré截面图进行仿真对比,验证了所设计控制器的可行性和有效性,为二十辊轧机振动及其控制的研究提供了一定的理论指导。

硫酸法钛白粉生产中产生的水解垢制备三价钛的工艺技术研究

硫酸法钛白粉生产过程之水解环节,水解锅内会产生水解固相物(废固渣)——水解垢,其产量占钛白粉总产量的0.3%~0.5%,结构坚硬、铁含量高、硅/钙杂质多,无法回收利用。通过对水解垢的性质进行分析,提出“湿球磨解聚—漂洗净化—酸溶还原制三价钛”的回收技术路线,实现了水解垢的高效率、高质量回收利用,达到与正常偏钛酸同等的漂洗效果以及等效的经济价值。该技术既解决了钛白粉生产过程的废固处理问题,又产生了经济效益,对硫酸法钛白粉清洁生产技术开发和提升有重要意义,具有一定的行业推广价值。

可转位轮槽铣刀在大型转子加工上的应用

为满足大型转子的加工效率及产品质量的要求,提出引进可转位轮槽成型铣刀进行铣削加工。介绍了该刀具的试切削过程及遇到的问题,包括粗铣刀崩刃、加深铣刀寿命过短、接刀出现台阶和节距超差等,并提出了相应的解决方案。通过重复试验并改进,最终完成了该轮槽可转位成型铣刀的应用方案的制定。对比了新铣刀加工方案与原整体式加工方案,相关切削参数、尺寸及粗糙度数据验证了该方案可靠性高,可以提升效率。所述方案可以大幅提高大型转子轮槽表面加工质量及加工效率。

Nano-scaled metal powder improving tribological properties of lubricant

Cu nanoparticles were fabricated by ball milling with the anhydrous alcohol as dispersant. The size and figure of Cu nanoparticles were characterized by X-ray diffractometry and transmission electron microscopy. The tribological properties of adding Cu and MoS2 nanoparticles to the pure grease were measured on MM-200 tester, compared with the single additive and pure grease. The results show the size of Cu nanoparticles is about 50 nm. The surface with lubricant added nanopowder as additive possesses a remarkable decrease in wear volume. The friction coefficient and wear volume of lubricant mixed with 5% copper and 30% disulfide molybdenum nanoparticles are 0.09 and 1.80mm3, respectively. This mixed additive can not only increase the ability of supporting heavy load but repair the microscopic channels and cracks on the wear surface. Under higher load and long period of time, this lubricant has the characteristics of self-repairing, occluding resistance and ability of enduring higher temperature.

Water Chemistry in Oil and Gas Operations: Scales Properties and Composition

Oil and gas operations depend heavily on water in many different aspects. Water is present wherever there is hydrocarbon production. It is produced along with the hydrocarbons and helps in mobilizing them. It is also injected into the reservoirs to aid in mobilizing the hydrocarbons, maintain the pressure and increase the recovery of the development project. With water presence, some serious problems occur such as scaling. Scaling is a well-known problematic precipitation caused mainly due to mixing of two incompatible fluids, changes in temperature and pressure conditions and disturbance to thermodynamics and kinetics of reservoir fluids. They can be found at any point of the operations starting down at the formation up to the surface tanks. Scales are directly responsible for compromising the economics and safety of development projects. This review paper is going to include a recap of the importance of water in the oil and gas industry, then review the different types of scales as well as their properties including carbonate and sulfate scales. After that, famous scales from each type is going to be reviewed as well as their properties and precipitation conditions such as Calcium Carbonate CaCO3, Calcium Sulfate CaSO4, Barium Sulfate BaSO4 and Strontium Sulfate SrSO4. Moreover, common practices and precautions steps in the industry are going to be reviewed as well. Finally, the paper presents the common practices used by the operators for scale removal.

轧钢皮资源综合利用技术研究进展

轧钢皮是钢锭和钢坯在轧制过程中因表面氧化层脱落而产生的铁屑,其产生量约为钢材产量的2%~3%,主要成分是铁氧化物,其中的杂质和化学成分稳定,可作为二次资源进行综合利用。介绍了轧钢皮的资源特点,综述了轧钢皮在各个领域的综合利用研究现状:在钢铁冶金领域,其可用于铁矿造块、生产还原铁粉和硅铁合金等;在化工领域,其可用于生产三氯化铁、硫酸亚铁等化工原料;在材料领域,其可用于合成催化剂或磁性铁氧体等功能性材料以及用于生产建筑材料。提高产品附加值、避免产生二次污染是未来轧钢皮资源化利用研究的重点方向。

大型硫酸盐木浆厂石灰窑碳排放及其减排路径分析

首先分析了大型硫酸盐木浆厂中石灰窑的温室气体排放特征,阐述其为硫酸盐木浆厂化石燃料最大消耗单元的主要原因,然后重点探讨石灰窑温室气体排放核算的路径,最后进一步提出石灰窑实现碳中和的可能技术途径,包括生物质燃料在石灰窑中的应用、石灰窑和碳捕获与封存(CCS)的集成技术以及石灰窑技术改造等。

颗粒阻尼吸振器对轧机辊系减振特性的研究

轧机在高速轧制过程中经常会发生垂直振动现象,这种振动行为会影响轧制过程的稳定性以及复合板表面质量和结合强度,不利于轧制生产高效连续进行。为了抑制轧机辊系在轧制过程中产生的垂直振动,该研究设计了一种多自由度颗粒阻尼吸振器。建立了安装吸振器的轧机上工作辊垂直非线性参激振动模型。运用多尺度法求解了系统的幅频特性方程,仿真分析了振动系统的奇异特性、时域特性、频谱特性以及幅频特性。对静定轧机上工作辊进行了垂直振动控制试验,对比发现理论分析与试验结果基本吻合,证明所建立的四自由度振动模型的可靠性。结果表明,颗粒阻尼吸振器能够有效地抑制轧机辊系的垂直振动并满足设计要求。

某钨矿老选厂大型化球磨机改造应用

某钨矿选矿厂为了改变磨矿设备台数多、规格型号小、设备检修工作量大、岗位操作人员较多、生产成本高及管理不便等问题,结合该钨选矿厂原有厂房尺寸,进行了不同磨矿分级改造设计方案论证。通过采用一段磨矿和两段磨矿优化方案对比,确定采用1台MQG3660大型化球磨机对该钨选矿厂进行改造,不需扩建原有厂房,减少了基建投资,简化了磨矿系统工艺流程,具有投资最省、占地面积不大的优势,使老选厂处理能力由700 t/d提高至1300 t/d,实现了规模效益。

利用分子级助磨剂制备均匀小尺寸石墨烯及其润滑油添加剂应用

目前研究者已开发出了多种石墨制备石墨烯的产业化制备方法,其中最为常用的是化学氧化还原法和插层解剖法。然而,实现径向尺寸小于1μm的石墨烯的低成本规模化制备始终是一个挑战,诸如纺织纤维、车用润滑油、高分子材料等,需要小尺寸石墨烯的应用领域的技术发展也因此受到限制。为此,本文提出了一种原位合成纳米助磨剂辅助的球磨方法,可以实现均匀小尺寸薄层石墨烯的低成本可控制备。此方法制备的石墨烯径向尺寸小于1μm,且该方法对石墨烯片的晶体结构破坏较小,面内几乎没有含氧官能团,因而石墨烯的基本物理属性没有遭到破坏。此外,利用处理过的小尺寸石墨烯作为润滑油添加剂,不仅可以解决目前石墨烯在润滑油中存在的分散稳定性差的问题,还能够降低27%以上的摩擦系数,减少38.8%以上的磨损。本文提出的这种小尺寸石墨烯制备方法简单、成本低廉、润滑应用效果显著,具有很大的应用潜力。

X射线衍射法鉴定铁矿石中氧化皮

考察了不同粒度下氧化皮的X射线衍射图谱,结果表明,270～400目粒度下氧化皮衍射峰强度最强。利用分析评估程序处理了氧化皮的X射线衍射图谱,并和PDF-2数据库(国际衍射数据中心)中数据进行比对,以找出其特征物相。结果表明,氧化皮的特征物相为三氧化二铁、四氧化三铁、氧化亚铁共存,而其它杂质物相含量极低。经过与天然铁矿石的特征物相进行比对,发现其中氧化亚铁物相是氧化皮区别于铁矿石的主要特征,因此氧化亚铁物相的存在可以作为鉴定铁矿石中是否掺杂氧化皮的重要指标,由此建立了铁矿石中氧化皮的X射线衍射鉴定方法,方法能够对含量高于10%的氧化皮进行鉴定。

镍基高温合金Inconel718微铣削毛刺试验研究

基于微小型机床的微铣削(Micro-milling)技术是加工镍基高温合金微小结构/零件的可行技术手段。文章通过镍基高温合金微铣削加工实验,利用扫描电子显微镜和能谱分析仪对刀具的磨、破损形态及局部化学成分和槽的表面形貌进行了研究分析,发现镍基高温合金微铣削毛刺形貌及成因与镍基高温合金传统切削或其他材料微铣削具有很大不同:首先,毛刺长度过长;其次,刀具磨损对鳞刺的产生有很大影响;鳞刺只出现在槽的一侧边界。在实验研究基础上,分析了毛刺的成因,为后续镍基高温合金微铣削毛刺的有效抑制研究提供参考。

电感耦合等离子体原子发射光谱法测定氧化铁皮中11种杂质元素

用王水微波消解样品,样品溶解后用氢氟酸挥硅,高氯酸蒸发,盐酸溶解盐类,然后用电感耦合等离子体原子发射光谱法测定溶液中Al,Pb,Co,Cr,Cu,Mg,Mn,Ni,Zn,P,Ca 11个元素。硅对铝的测定有影响,但在试样溶解后已通过氢氟酸挥硅将其除去;基体元素铁产生背景干扰,绘制校准曲线时通过在标准系列溶液中加入与试液同量的铁而消除。本法已用于进口氧化铁皮样品11种元素的分析,相对标准偏差小于8%,回收率在95%~106%范围。

微径球头铣刀铣削力建模与仿真

以微径球头铣刀铣削力为研究对象,分析了刀具刃线模型。将刀具沿刀轴方向离散为若干切削单元,分别依照单齿切削及两齿切削求得各切削单元的实际瞬时切削厚度。基于实体造型的方法提取了参与切削的切削刃段,并通过实验识别了瞬时切削力系数及主轴径向跳动参数,建立了综合考虑主轴径向跳动、微细铣削所特有的尺度效应的影响及可能出现的单齿切削现象的微径球头铣刀铣削力模型。实验结果验证了所提模型的有效性和可行性。

乌努格吐山铜钼矿SABC碎磨流程的设计与应用

根据乌努格吐山铜钼矿的矿石性质及选矿厂建设规模,介绍乌山SABC碎磨工艺流程的设计和主要设备选型,对其生产实践进行阐述,分析讨论生产中出现的问题。乌山SABC碎磨工艺流程和大型半自磨机Φ8.8 m×4.8 m、大型溢流型球磨机Φ6.2 m×9.5 m的成功应用,不仅为国内其他类似矿山建设提供了宝贵的经验,对振兴民族工业也做出了贡献。