Multidisciplinary treatment of molten aluminum combined burn:An unusual case report

Molten aluminum is among the most common causes of burns in the metal industry.However,only few reports are available on molten aluminum injuries.Herein,we report an unusual case of molten aluminum burn.The patient had burns not only on the body surface but also in the respiratory tract and esophagus,adding to the difficulty of treatment.Multidisciplinary consultation and cooperation led to the development of a treatment plan for the patient,which included tracheotomy,respiratory management,endoscopic therapy,infection control,and psychological support.To our knowledge,this is the first report of molten aluminum-induced burns involving the face,neck,respiratory tract,esophagus,and eyes.We also describe our experience with multidisciplinary treatment for the management of molten aluminum burns.

Review on corrosion-wear resistance performance of materials in molten aluminum and its alloys

The failure caused by the corrosion-wear of molten aluminum and its alloys is one of the main problems in aluminum industry. In this work, the resistance behavior of various materials, including Fe-based alloys, ceramics and corresponding high apparatus of corrosion-wear in molten aluminum and its alloys, were reviewed. The synergistic effect of corrosion and wear was discussed based on corrosion and wear mechanics. The effects of dynamic agitation due to rotating of friction pairs, physical property of liquid metal and size of grain etc., on the corrosion-wear resistance performance were investigated. In addition, the characteristics of corrosion-wear resistance performance of materials in molten aluminum and its alloy were summarized. According to our recent progress referred to kinds of materials, especially a TiA13/Ti3A1C2/A1203 composite, the ceramics/metal composites with a co-continuous structure will be of great advantage in the field of corrosion-wear environment of molten aluminum and its alloys.

Corrosion resistance of 91W-6Ni-3Fe refractory metal,TiAl compound and iron based alloys in molten aluminum

The corrosion behaviors of 91W-6Ni-3Fe （91W） refractory alloy, TiAl intermetallic compound and two types of iron based alloys （QT700 and H13 tool steel） in a liquid aluminum were investigated. Corrosion experiments or static immersion-tests were carried out in pure molten aluminum at 750 ℃. The surface micro-topographies, corrosion interfaces and phase compositions of the immersed samples were investigated by 3D optical microscopy, SEM, EDS and XRD. The results show that 91W exhibits the best corrosion resistance, followed by QT700, H13 and TiAl alloy, consequently. The corrosion mass loss of the four metallic materials adheres to parabolic criterion, and the corrosion rate trends to be stable after initial acceleration. The diffusion-reaction mechanism is proposed for the dissolution of materials in molten aluminum, and the diffusion process is the rate-determining step during the dissolution of 91W in molten aluminum, while the low activation energy for the reaction between TiAl-（TiAl3）-Al couple results in poor corrosion resistance of TiAl alloy in molten aluminum.

Properties of a reaction-bonded β-SiAlON ceramic doped with an FeMo alloy for application to molten aluminum environments

An FeMo-alloy-doped β-SiA1ON （FeMo/β-SiA1ON） composite was fabricated via a reaction-bonding method using raw materials of Si, Al2O3, A1N, FeMo, and Sm2O3. The effects of FeMo on the microstructure and mechanical properties of the composite were investi- gated. Some properties of the composite, including its bending strength at 700℃ and after oxidization at 700℃ for 24 h in air, thermal shock resistance and corrosion resistance to molten aluminum, were also evaluated. The results show that the density, toughness, bending strength, and thermal shock resistance of the composite are obviously improved with the addition of an FeMo alloy. In addition, other properties of the composite such as its high-temperature strength and oxidized strength are also improved by the addition of FeMo alloy, and its corrosion re- sistance to molten aluminum is maintained. These findings indicate that the developed FeMo/β-SiA1ON composite exhibits strong potential for application to molten aluminum environments.

A new dynamic method for measuring hydrogen partial pressure in molten aluminum alloy

Hydrogen partial pressure is an important parameter to calculate hydrogen concentration levels in molten aluminum alloy. A new dynamic method for measuring hydrogen partial pressure in molten aluminum alloy is studied. Dynamic and rapid measurement is realized through changing the volume of the vacuum chamber and calculating the pressure difference ΔP between the theoretical and measured pressures in the vacuum chamber. Positive ΔP indicates hydrogen transmits from melt to vacuum chamber and negative ΔP means the reverse. When ΔP is equal to zero, hydrogen transmitted from both sides reached a state of dynamical equilibrium and the pressure in the vacuum chamber is equal to the hydrogen partial pressure in the molten aluminum alloy. Compared with other existing measuring methods, the new method can significantly shorten the testing time and reduce measuring cost.

Microstructure and Corrosion Resistance of CrN and CrN/TiN Coated Heat-Resistant Steels in Molten Aluminum Alloy

The components of the equipment for processing the Al melts into the molded parts can be markedly corroded by the molten Al. In this study, a 4 μm CrN coating or CrN/TiN multilayer coating for providing the physical and chemical barriers between the molten reactive Al and the steel substrate were deposited by Cathodic Arc Evaporation onto 10 mm-thick heat-resistant steel plates. The dipping tests were conducted in a 700℃ A356 melt for 1 to 21 h at intervals of 3 h. The damage of the coated steel was eva...

Mechanism of removing inclusions from molten aluminum by stirring active molten flux

Removal of inclusions from industrial pure molten aluminum(A01) by stirring active molten flux was studied. Wettability of nonmetallic inclusions in the molten aluminum was worse than that in active molten flux. According to the surface renewal model, the inclusions were easily transferred into molten active flux from fine aluminum droplets and then reacted chemically when molten aluminum was dispersed into fine aluminum droplets in stirring active molten flux. Tensile tests show that tensile strength of purified tensile sample(as-cast) increases by 8.59%. SEM photographs show that the fracture cracks of purified tensile sample are homogeneous, and the dimples are small and homogeneous. From metallographs and statistic results of Leco analysis software, it is found that the quantities and sizes of the inclusions in purified sample are obviously fewer and smaller than in unpurified tensile sample(as-cast).

Nitrogen Injection in Molten Aluminum in a Tank Degasser

The injection of nitrogen in molten aluminum through a static impeller in a tank degassing unit is studied. Using basic principles of fluid mechanics, it is analyzed the influence of the nozzle diameter on the bubble diameter and the mean residence time of the bubbles in the molten aluminum. By means of transient isothermal 2D Computational Fluid Dynamics (CFD) simulations, the influence of the nitrogen volumetric flow rate on the phase distributions and the tank degasser dynamics is studied. Finally, an adiabatic CFD simulation is carried out in order to elucidate the changes in the molten aluminum temperature due to the injection of nitrogen at ambient temperature. This simulation shows that molten aluminum does not suffer drastic temperature reductions given that, in spite?that?the nitrogen is fed at ambient temperature, the mass of nitrogen is relatively small compared with the mass of aluminum.

A New Ceramic Substrate Glaze with High Resistance to Molten Aluminum

Corrosion resistance of ceramic substrate glazes to molten aluminum was studied in this paper. The glazes can spread slightly in aluminum alloy according to SEM examination of solidified interface between the glazes and aluminum alloy. The components of B2O3-P2O5 glazes were not detected with electron probe at the side of aluminum alloy near the interface, but the components of boron-free glaze were detected. It is shown that borophosphate glazes can resist the corrosion of molten aluminum.

INTERACTION OF OXIDE FILM WITH MOLTEN FLUX DURING ALUMINUM BRAZING

The interaction of oxide film with molten flux during aluminum brazing has been studied by means of X-ray powder diffraction. The following conclusions have been deduced: The swell- ing of aluminum oxide film is caused by Li^+ inserting into the vacancies of octahedral or tetrahedral structure of 0 atom skeleton in у-Al_2O_3 . The strength of oxide film decreases as the crytallinity increases by the treating of flux containing LiF.

Removal of inclusions from molten aluminum with actively coated ceramic filters

Molten aluminum (A001) was filtered by using ceramic foam filters coated with active enamel. Tensile test shows that the elongation of filtered sample is increased by 15.5%, but the tensile strength of the sample is almost the same as that of unfiltered one. The fracture cracks and dimples of filtered sample are fine and homogeneous according to SEM examination. In addition, metallographic observation shows that the filtered sample has very few inclusions of approximately 8 μm in diameter, but the unfiltered sample has some inclusions of approximately 60 μm in length and 20 μm in width. However, it is suggested that the active enamel coat can effectively capture the inclusions and dissolve them during filtering molten aluminum.

熔盐电解质体系及在制备铝合金中的研究进展

铝合金具有抗腐蚀、易于加工、强度高、密度小等优点,在各行各业中都有着大量的应用。采用熔盐电解法制备铝合金具有生产工艺简单、效率高、生产成本低、生产周期短等特点,近些年来得到广泛关注,其中熔盐体系的选择成为主要的研究热点。本文以温度划分熔盐体系为高温熔盐和离子液体,综述了这2种熔盐体系的优点、分类以及一些反应机理,并从这2类熔盐体系出发,分别介绍了一些铝合金的制备工艺以及相关的技术创新。最后,分别阐述了高温熔盐和离子液体所存在的优缺点,并对其未来发展趋势进行了展望。

Nb对铁素体不锈钢耐铝液腐蚀性能的影响

研究了Nb含量对铁素体不锈钢的耐铝液腐蚀性能的影响及相关机理。不同含量的Nb元素对试样基体中的第二相分布有影响,这些第二相具有阻碍铝液腐蚀的作用。铁素体不锈钢在铝液中浸蚀后,会在界面处生成金属间化合物层,基体中Nb元素的含量会影响碳化物生成和聚集位置,从而导致耐铝液腐蚀性能的差异。试验结果表明:添加0.2wt.%的Nb元素,可以获得细小弥散第二相,最终获得优异的耐铝液腐蚀性能。

铝电解惰性阳极在熔融电解质中腐蚀过程的研究进展

惰性阳极是原铝生产保持低碳化的重要研究方向,近些年,惰性阳极材料的研究取得长足进展。通过对惰性阳极材料进行分类,综述了不同种类(合金阳极、氧化物陶瓷阳极和金属陶瓷阳极)的惰性阳极在熔盐电解质中可能发生的腐蚀反应,主要探究发生的化学腐蚀和电化学腐蚀,以及腐蚀后可能对阳极的影响。明晰增加阳极耐腐蚀性的方法,或者通过抑制腐蚀反应的进行,来降低惰性阳极在冰晶石熔盐中的腐蚀速率,从而促进惰性阳极在铝电解行业中的可行性发展。

冶金工艺开发中的借鉴与创新

资源转型、能源消耗和环境保护等方面对冶金工业的约束日益趋紧,亟待对现有落后的冶金工艺进行升级改造和技术创新,实现清洁绿色、节能减排和高效高值的生产目的。借鉴是创新的重要途径。一方面,借鉴已有冶金工艺来开发新冶金技术无疑是最直接的手段,特别是已工业化的冶炼工艺在“科学—技术—工程”方面提供了多维度的参考。另一方面,不同学科的交叉与融合更有可能产生颠覆性技术,例如地球化学、矿物加工学、电化学(电池)等学科对冶金的借鉴。

锌离子路易斯酸熔盐体系从粗四氯化锆中除铝机制研究

为了降低传统沸腾氯化法制备的粗ZrCl_(4)中Al杂质含量,达到高品质锆前驱体的精度要求,开发了适合粗ZrCl_(4)高效除Al的锌离子路易斯酸熔盐体系,使其中的杂质Al含量由0.16%降低至0.001%。同时,根据路易斯酸熔盐体系与粗ZrCl_(4)中Al^(3+)的反应,通过基于密度泛函理论的CASTEP模块对Al^(3+)在复盐中的结合量和结合能进行分析,进而确立粗ZrCl_(4)除Al机制。Al^(3+)结合量的降低和结合能的升高有助于Al^(3+)从复盐中脱离,从而降低粗ZrCl_(4)中Al含量。通过实验与理论计算验证了锌离子路易斯酸熔盐体系能够从粗ZrCl_(4)中有效除Al。本研究可为制备高品质核级锆提供新思路和理论基础。

铝-空气电池废电解液制备片状氧化铝的研究

以铝-空气电池废电解液为原材料,用硫酸铝调节pH值,用硫酸钾作为熔盐制备片状氧化铝(α-Al_(2)O_(3)),研究了合成温度、晶种添加量对α-Al_(2)O_(3)粉体体积分数、粒度大小及粒度分布的影响规律。通过X射线衍射仪、扫描电子显微镜和激光粒度仪等,对加入不同晶种量的α-Al_(2)O_(3)粉体的结构和形貌进行表征。结果表明,添加晶种后可以提高α-Al_(2)O_(3)粉体的体积分数,减小α-Al_(2)O_(3)粉体的粒度,使α-Al_(2)O_(3)粉体的粒度分布更集中,同时使α-Al_(2)O_(3)粉体更分散。此外,当晶种添加量为5%(质量分数)时,制备出的片状α-Al_(2)O_(3)的体积分数可达97.0%,平均粒度约为7.24μm。

低温熔融盐体系电沉积制备铝锡合金

以AlCl_(3)-NaCl-KCl低温熔融盐体系作为电解质,无水SnCl_(2)作为原料,对电沉积制备Al-Sn合金进行研究。通过扫描电子显微镜(SEM)、能谱(EDS)和X射线衍射仪(XRD)分析合金产物的形貌和成分组成;通过极化曲线法和摩擦磨损实验对合金产物的耐蚀性和耐磨减摩性进行检测分析;通过维氏硬度计和涂层附着力自动划痕仪对合金产物的硬度与膜基结合力进行表征。结果表明:当SnCl_(2)添加量为0.04~0.08 g时可制备出锡含量为10%~18%的中锡铝合金,最佳沉积温度为160~200℃、沉积时间为40~50 min、电流密度为40~50 mA/cm^(2);随镀层中锡含量的提高,其耐蚀性逐渐变差,而耐摩擦磨损性能先提高后降低,并在SnCl_(2)添加量为0.06 g,即镀层中锡的含量为14 wt%时有最佳摩擦磨损性能;沉积温度对合金镀层的硬度及结合力有很大影响,随沉积温度的升高,合金镀层的膜基结合力和硬度均呈现先提高后降低的趋势,当沉积温度为200℃时,其结合力和硬度最佳。

铝合金硝盐热处理超温爆炸机理分析及安全管控建议

为探究熔融硝盐热处理工艺超温爆炸的原因和机理,准确定位铝合金硝盐热处理工艺可能引起爆炸的关键因素,对照国家标准、物料安全技术说明书等资料,以50wt%硝酸钾和50wt%硝酸钠的混合硝盐为加热介质,进行铝合金热处理工艺,开展混合硝盐加热试验、混合硝盐与铝合金共同加热试验,并从控制温度、避免全密闭设备和加强现场排风3个方面提出安全管控措施。结果表明:混合硝盐在超温状态(600~900℃)下无爆炸危险特性;含有铝合金的硝盐混合液在达到780℃后,会发生剧烈的燃烧反应和炽热物质喷溅,未直接发生爆炸;含有铝合金的硝盐混合液在达到一定温度后会因为硝盐自身分解或者与铝合金发生剧烈燃烧反应而生成气体,气体积聚产生压力超过设备耐压极限时可能发生物理爆炸。

废铝回收再利用的研究现状

铝及铝合金的抗腐蚀性强,在使用过程中损耗程度极低,具有极高的再生利用价值,促进废铝回收可显著降低铝行业的能耗和碳排放。本论文主要对废铝的重熔降级回收、保级回收及越级回收工艺进行了总结,对各工艺的优缺点进行分析。采用传统的废铝重熔降级再生工艺无法完全去除铝中的合金元素与金属杂质,再生铝只能降级利用,但随着再生铝量的增加,传统的降级利用技术将无法消纳过量再生铝。保级回收可实现废铝资源价值最大化,但是只有极少量的优质废旧铝合金能实现其固有价值,大部分废铝资源难以实现。废铝越级回收技术能够将铝合金中铝与合金元素进行有效分离,使回收的铝达到原铝的质量水平,可实现废铝的彻底再生,是废铝再生的最佳途径之一。熔盐电解法是最具发展前景的废铝提铝再生技术。