碳中和背景下的钢化联产发展趋势

本工作针对钢铁行业副产的煤气、余热、钢渣及钢化联产现状进行了分析,论述了碳中和背景下钢化联产绿色低碳技术的发展趋势,展望了未来无碳炼钢的新型钢厂从“以化固碳”转变为“以氢代碳”的新模式,并提出了加快钢化联产新技术应用建议和举措,以期建立以钢铁行业为龙头,耦合化工行业的新型工业可持续发展生态链,支撑我国“双碳”目标的实现。要点：(1)钢铁副产煤气、余热、钢渣利用现状。(2)钢化联产技术现状与发展趋势。(3)未来新型钢厂钢化联产技术。(4)钢化联产发展构想与建议。     

玄武岩纤维和钢纤维含量对树脂基摩擦材料性能的影响研究

以酚醛树脂、丁腈橡胶、重晶石、玄武岩纤维和钢纤维等为原料进行摩擦材料的制备,研究了玄武岩纤维和钢纤维含量对摩擦材料力学性能和摩擦磨损性能的影响.结果表明,当玄武岩纤维含量为10％～25％(质量分数,下同)时,随着纤维含量的减少,摩擦材料的冲击强度增大、压缩强度减小;当纤维总量占30％且玄武岩纤维与钢纤维质量比为1:1时...     

初始缝高比对钢纤维混凝土断裂性能的影响

为研究初始缝高比对钢纤维混凝土断裂性能的影响,对三种不同初始缝高比(0.1、0.2、0.3)的钢纤维混凝土开展断裂韧性试验,计算相关的断裂参数,并借助声发射(AE)和数字图像法(DIC)分析了裂缝发展过程中AE能量和全场应变的变化规律。结果表明,钢纤维混凝土的断裂韧性随初始缝高比的增大呈减小趋势,当初始缝高比为0.3时钢纤维混凝土的断裂性能大幅下降。钢纤维混凝土的断裂过程可根据AE能量划分为弹塑性阶段、裂纹稳定扩展阶段和断裂阶段,随初始缝高比增加,弹塑性阶段持续时间减少。DIC分析结果表明,在整个加载过程中,预制裂缝尖端会产生较大的应力集中,裂缝的横向应变较大。研究结果揭示了钢纤维混凝土裂缝发展机理,可为其工程应用提供理论支持。     

钢渣配料生产水泥熟料的生产实验

选用两种钢渣配料生产水泥熟料,在生产试验中优选出两种钢渣的最佳配料方案,分析了钢渣对熟料煅烧过程、物理性能和能耗的影响。结果表明,钢渣中铁含量20%时,钢渣可作为铁质校正原料,三率值最佳取值,KH为0.91~0.93,SM为2.5~2.7,IM为1.5~1.6;钢渣配料,熟料煅烧生产状况良好,能明显提高熟料的产量,提高熟料的强度,降低熟料烧成煤耗,且碱度大的钢渣,熟料C_3S含量较高,煤耗降低也较多。     

中间包涂料对钢液洁净度的影响

实验研究了镁质、氧化铝质和镁钙质三种中间包内衬涂料与钢水反应,考察了其对钢中T.O, T.N及Al, Ti, Si, Mn含量、夹杂物组成、数量和尺寸分布的影响,并分析了钢水在钢/涂层界面对涂层的渗透和侵蚀程度. 结果表明,在1550℃下,相比于镁质涂料和氧化铝涂料,镁钙质涂料能对钢液T.O和成分有更好的控制,终点氧含量在8.5′10-5,对钢液的二次氧化很少,并有利于细小夹杂物的形成,其中<1 mm夹杂物占98.13%;钢中首先是Al, Ti被氧化,之后是Si, Mn被氧化;氧化铝涂料被损坏的机理主要是冲刷脱落,镁质和镁钙质涂料的损坏则以渗透侵蚀为主. 镁钙质涂料对钢液的二次污染小,有利于洁净钢的生产.     

Impact of TiO2 nanoparticles and nanowires on corrosion protection performance of chemically bonded phosphate ceramic coatings

The impact of the addition of TiO₂ nanoparticles and nanowires on the morphology, phase characteristics, contact angle, and electrochemical performance of chemically bonded phosphate ceramic coatings (CBPCs) was investigated. The chemical composition and surface morphology of the TiO₂ nanoparticle and nanowire modified with and without (heptadecafluoro-1,1,2,2-tetradecyl) trimethoxysilane were characterized. Results indicated that the hydrophobic –CF₂– and –CF₃ groups were successfully introduced into the TiO₂ nanoparticles and nanowires after modification. Corrosion resistance of CBPCs with TiO₂ was evidently improved compared with that without TiO₂. Such improvement was mainly due to the combined effects of low surface energy materials and micro/nano structures. In addition, CBPCs with TiO₂ nanowires exhibited higher hydrophobicity and corrosion resistance than those with TiO₂ nanoparticles because of the special columnar structure of the nanowires.     

Corrosion mechanism of cement-bonded Al2O3–MgAl2O4 pre-cast castables in contact with molten steel and slag

In this work, a cement-bonded corundum-spinel (Al₂O₃–MgAl₂O₄) pre-cast refractory brick with two typical Al₂O₃ aggregates was designed as the refractory lining. Corroded microstructure of the used corundum-spinel bricks after industrial trials in a commercial RH refining ladle was analyzed. Degradation processes of two types of alumina aggregates in the same corroded interface also were discussed. Typical corroded microstructure revealed that needle-like calcium hexaaluminate (CA₆) was observed in the matrix of the original layer. The formation of CA₆ was attributed to the reactions with pure calcium aluminate cement and matrix components under a high-temperature gradient during refining. Furthermore, the corrosion process of the used Al₂O₃–MgAl₂O₄ bricks would be discussed based on a post-mortem microstructural characterization, and the corrosion mechanism of the two types of aggregates was also elucidated.     

Laser damage resistance of plasma-sprayed alumina and honeycomb skeleton/alumina composite ceramic coatings

Al₂O₃ and honeycomb skeleton-Al₂O₃ composite coatings on Titanium alloy (Ti–6Al–4V) were prepared by atmospheric plasma spraying. A laser ablation experiment on as-sprayed coatings was performed. In this paper, the laser damage resistance, microstructure, phase composition of Al₂O₃ coatings were examined. 3D Dimensional Confocal Microscopy, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Energy Dispersive Spectrometry (EDS) characterized the laser damage morphology, microstructure, phase composition, and element analysis, respectively. The influence of the honeycomb skeleton on the laser ablation damage on as-sprayed coatings was investigated by a comparative analysis of the laser damage morphology with different laser ablation times and gas flow. The results show that the honeycomb skeleton raises thermal conductivity and thermal diffusivity. Moreover, a “tower”-like dendrite was generated during the laser irradiation of the composite coating. The honeycomb skeleton refined the structure, suppressed crack propagation, and reduced the influence of gas flow on cracks. Under the same experimental laser ablation parameters, the laser damage area of the honeycomb skeleton-Al₂O₃ composite coating was smaller than that of the Al₂O₃ coating. It was demonstrated that the laser damage resistance of the honeycomb skeleton-Al₂O₃ composite coating was superior to that of the Al₂O₃ coating.     

Capped inhibitor-loaded halloysite nanoclay-based self-healing silica coatings for corrosion protection of mild steel

The effect of polymeric nanocapsule capping in benzotriazole encapsulated into halloysite nanoclay (HNTs) dispersed into hybrid silica coatings was investigated for corrosion protection of mild steel. Optimization of the amount of inhibitor-loaded halloysite nanotubes with and without capping in the coating sol was carried out. The prepared formulations were dip-coated on mild steel substrates using dip-coater and then cured at 130 °C for 1 h. Surface morphology and elemental analysis of the nanoclay were studied using scanning electron microscopy and energy dispersive X-ray spectroscopy. X-ray diffraction and Fourier Transform Infrared spectroscopy analyses were carried out to confirm the encapsulation and capping of the halloysite nanoclay. The anti-corrosion and autonomic-healing properties of bare and coated substrates in 3.5 wt% NaCl solution were studied using electrochemical impedance spectroscopy, potentiodynamic polarization measurements and scanning vibrating electrode technique for varying exposure times. The coatings generated from the capped inhibitor-loaded HNTs dispersed sol-gel matrix was seen to provide higher corrosion resistance when compared to uncapped HNT based silica coatings. Electrochemical studies carried out for capped inhibitor-loaded HNT based coatings have shown an increase in charge transfer resistance to 10⁸ Ω cm² from 10⁶ Ω cm² of uncapped inhibitor-loaded HNT based coatings.     

钢渣对水泥性能的不利影响分析与改进

我公司下属企业使用钢渣作混合材试验时,发现部分钢渣会导致水泥速凝、速干和强度下降等问题。分析导致其原因为该类钢渣含有较高含量的七铝酸十二钙（C12A7）,其水化速度快,当钢渣掺量较高时导致水泥水化过快和性能发生较大变化。通过提高石膏掺量可一定程度改善其造成水泥性能的负面影响,强度明显提高,但水泥稠度和流动性能改善有限。因此,该类钢渣质量需加以监控,不建议在对工作性能要求较高的水泥中使用,可考虑在对早强快凝需求的情况匹配适宜的石膏掺量使用。