Corrosion resistance of Al–Cr-slag containing chromium–corundum refractories to slags with different basicity

Al–Cr slag is the solid waste generated by the smelting of Cr metal. It presents a range of environmental hazards. This study addressed the corrosion resistance of Al–Cr slag containing chromium–corundum refractories to slags with different basicity. Herein, we provide suggestions for the use of Cr–corundum of different basicity in kilns. Al–Cr slag, brown fused Al₂O₃, and chrome green were used as the raw materials, with pure calcium aluminate cement being used as a binder. The brick samples, prepared using different blends of chrome green and corundum, were fired at 1600?°C, and subsequently subjected to a slag corrosion test. After corrosion by slag of different basicity, the phase composition and microstructure of the sample were analyzed by X-ray diffraction, energy dispersive spectrometer and scanning electron microscopy. There were two major findings. First, Cr–corundum brick made from Al–Cr slag has a better slag corrosion resistance than that made from Cr₂O₃ and brown fused Al₂O₃. Second, Cr–corundum brick made from Al–Cr slag has superior corrosion resistance to slag with a CaO:SiO₂ ratio of 2:1.     

关于无机及分析化学课程教学的一些思考

《无机及分析化学》课程是本校生物技术专业的一门基础主干课程。既是该专业后续课程的基础,又是专业人才知识结构的重要组成,对它的教学就显得尤为重要。文章以《无机及分析化学》课程的实际教学为基础,得出该课程的一些教学方法和教学体会,包括上好绪论课、研究教材、结合板书、精心组织实验以及课后辅导等,以提高教学效果。     

基于世界大学城的《有机化学》空间课程教学模式探究

随着教育信息化教学的不断推进,基于世界大学城的课程空间资源建设越来越受到关注,本文就《有机化学》空间课程教学模式进行了探究,主要阐述了空间课程的定义、有机化学空间课程教学模式构建过程（培训阶段、课程资源准备阶段和网络化阶段及教学实施）、意义和不足。     

物理化学课程的创新教学模式研究及其效果分析

物理化学课程创新教学模式是以学生学习为中心,吐故纳新,优化精选,以新颖或变化的教学方式进行教学。调查表明创新教学模式受到绝大多数学生的肯定和认可,有效地调动学生的积极性,提高了学生对物理化学的学习和探究兴趣,学生提问问题的广度和难度发生显著变化。该教学模式能够逐步提升学生的创新意识和创新能力。     

Effects of aggregate microstructure on slag resistance of lightweight Al2O3-MgO castable

Corundum-spinel castables using lightweight aggregate have drawn much attention due to their energy-saving potential, in particular when they are applied in high-temperature areas, such as the work lining of refining ladle. One of the main issues which hinder their application is their relatively poor slag corrosion performance. In this study, one type of dense tabular corundum and three types of lightweight corundum were chosen as aggregates to prepare four different model corundum-spinel castables. Their slag resistance was evaluated by an induction furnace corrosion test method. As well as SEM, EDS, and XRD characterizations, thermodynamic and kinetic analyses were carried out to assist understanding the corrosion mechanism. Results indicated that size and shape of crystalline grain in aggregate were important for the slag corrosion (dissolution) resistance of lightweight corundum-spinel castables under dynamic condition (enforced convection), whereas the effects of pore characteristics were not significant. Use of aggregates having large average crystal size and flake-shaped crystals led to a thicker diffusion boundary layer and lowered dissolution rate, i.e., good corrosion resistance, whereas use of aggregates with small and spherical crystals and larger pores led to poor slag resistance.     

Synthesis of CaO·2MgO·8Al2O3 (CM2A8) and its slag resistance mechanism

CM₂A₈ is a solid solution of MA and CA₆. As a component in the ternary phase diagram of CaO-Al₂O₃-MgO, it was not reported in detail. So in this work, analytically pure CaO, MgO and Al₂O₃ were adopted as starting materials and batched stoimotrically according to CM₂A₈. The raw materials were ground, mixed, shaped and reaction-sintered at different temperatures (1550 °C, 1650 °C, 1700 °C, and 1750 °C) to synthesize CM₂A₈. The synthesized specimens were analyzed by XRD, SEM, and TEM and the corrosion mechanism against LF slag was also researched. The results show that high-purity CM₂A₈ can be synthesized by reaction sintering at 1750 °C. During synthesis, granular MA and flake CA₆ form and grow together; at 1650 °C, they solid-solve together to form C₂M₂A₁₄. As the temperature rises, solid solution reaction goes on, which results in the disappearance of CA₆, C₂M₂A₁₄, and MA in succession and forms high-purity CM₂A₈ growing towards hexagonal column crystals. In the high temperature reaction between CM₂A₈ and steel slag, Ca²⁺ in the slag reacts with CM₂A₈ to form CA₂, damaging the structure of CM₂A₈ and releasing excessive Mg²⁺ and Al³⁺ which move towards the molten slag. As the reaction between Ca²⁺ and CM₂A₈ proceeds, a dense CA₂ coating forms on the surface of CM₂A₈. The slag viscosity increases as well because of the entrance of Mg²⁺ and Al³⁺. Thus, the formation of the CA₂ coating and the enhancement of the slag viscosity restrain the penetration and corrosion of slag towards CM₂A₈.     

高校绿色化学实验室建设的探讨

加强绿色化学实验室建设是绿色化学研究的重要内容,通过绿色化学实验课程体系建设、实验室软、硬件建设、环境建设等途径实现绿色化学实验室的目标,是减少实验室污染和保护师生健康的保障,还能减少实验药品、试剂消耗,是培养具有绿色化学理念和环保意识的化学人才的需要。     

启发式教学法在有机化学“羧酸及其衍生物”教学中的应用

本文介绍了启发式教学法在有机化学＂羧酸及其衍生物＂课堂教学中的应用。在总结前期学习内容的基础上,针对羧酸分子中羰基活泼性,α-氢的活泼性及酸性等问题,我引导学生从比较甲酸与甲醛和甲醇分子结构入手,紧紧围绕甲酸分子结构中介于碳-氧双键与碳-氧单键之间的碳-氧键长,分析甲酸分子结构的特点,定性地解答甲酸与甲醛和甲醇化学性质的差异性,加深了学生对羧酸结构与化学性质的认识,提高了学生的学习积极性,取得了良好的教学效果。     

课程论文在公安基础化学教学中的实践

公安基础化学课程是公安高等院校化学教育的专业基础课。为了激发学生的学习热情,提高学生的学习能力,培养学生的创新意识,我们在公安基础化学课程中开展了课程论文的教学活动,对课程论文的选题、内容、格式、考核等方面进行了具体的实践。实践的结果表明:通过开展课程论文的活动,激发了学生的学习积极性,提高了学生分析问题、解决问题的能力,达到了培养创新型公安人才的目的。     

独立学院化工专业无机化学实验教学改革初探

指出了当前独立学院化工专业无机化学实验教学中的一些不足之处,对无机化学实验教学改革进行了有益的探索和实践,通过改革无机化学实验教学模式,优化教学内容,调动了学生实验积极性,增强了学生实验动手能力,取得了良好的教学效果,并积极倡导在无机实验教学中贯彻绿色化学的教育思想。