连二硫酸锰碳化干渣热解回收硫酸钠的研究

利用软锰矿进行湿法冶金或烟气脱硫技术研究时,因其即可控制大气污染亦可回收锰资源而备受关注。然而,反应过程会生成影响脱硫尾液中硫酸锰的品质的副产物—连二硫酸锰（杂质）,如何回收或去除该杂质是技术研发和推广的难题。本文提出了连二硫酸锰先经碳酸氢钠碳化得到连二硫酸钠和碳酸锰,两产物分离后,结合低温热解的方法将连二硫酸钠制备成无水硫酸钠;实验考察了热解制备过程的各产物和控制反应步骤的温度,进而推理出动力学参数和反应机理。热解实验结果表明：255 ℃（摄氏度）是连二硫酸钠热解制备无水硫酸钠的最佳热解反应温度,并且热解反应过程经历脱硫和脱水两大步骤;热解产物的X射线衍射（XRD）和离子色谱（IC）表征结果表明：产物为单一相的立方体结构硫酸钠晶体。利用热重示差扫描热分析（TG-DSC）对连二硫酸钠热解过程进行表征,结合Kissinger微分法和Coats-Redfern积分法对热解法中脱水和脱硫过程中的活化能进行推算,脱水和脱硫活化能分别在14.75-18.11 kJ/mol（千焦/摩尔）和132.61-137.18 kJ/mol范围内。热解尾气测定结果表明：连二硫酸钠热解制备无水硫酸钠时释放出的尾气主要为二氧化硫。因此,经低温热解工艺处理软锰矿脱硫尾液中连二硫酸根的方法是可行的,不仅可以避免液相处理工艺中酸性废水产生的问题,还可以利用热解制备过程中的尾气去除残留的碳化剂（碳酸钠）,以达到资源化回收目的。     

纳米级炭黑在不同热处理温度下的结构研究

在惰性气氛保护下,对炭黑样品进行不同温度下的热处理,得到具有不同石墨化度的炭黑样品。通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、热重分析仪(TG)、以及拉曼分析仪(Raman)等对其进行了结构表征,结果表明随着碳化温度的升高,炭黑样品的石墨化程度显著增大,尤其在经过2 800℃高温热处理的炭黑样品中出现了中空的石墨化结构,有望成为具有较大吸附性能的橡塑弹性体材料的较好补强剂。     

Attribution of white-light emitting centers with carbonized surface in nano-structured SiO2:C layers

Carbon incorporated silicon oxide layers were fabricated by carbonization of porous silicon layer in acetylene atmosphere followed by oxidation in wet argon. The resulting porous SiO₂:C material exhibited a strong white photoluminescence. Subsequent thermal treatment in oxygen at 600 °C significantly decreased the green-yellow part of photoluminescence band while blue shoulder remained unchanged. Annealing at the same temperature in pure argon did not change light-emission properties indicating that the green-yellow light-emission sites originate from the surface. This study focuses on the interface of silicon oxide matrix and carbon inclusions by high-resolution scanning transmission electron microscopy (STEM) combined with electron energy loss spectroscopy (EELS). It is confirmed by EELS and STEM that the green-yellow emission band is associated with the carbonized interface in the porous layer.     

非水体系快速挥发法直接合成有序介孔炭

采用非水溶剂快速挥发法,以表面活性剂和酚醛树脂为结构导向剂和碳前驱体制备介孔炭.通过透射电镜、氮吸附-脱附和扫描电镜对产品的结构进行了表征.结果表明:所制介孔炭具有高度有序的二维六方结构.表面活性剂与酚醛树脂的配比对介孔炭的有序性有较大的影响,当其质量比高于1:0.25时,可保持良好的有序度.随着比值的减小,有序度逐渐降低.与蔗糖液相浸渍法相比,非水体系快速挥发法所制介孔炭具有较少的外微及大孔.     

Evaluation of usher wood and karkadeh stem for charcoal in Sudan

Two unusual biomass materials Hibiscus sabdarifja var. sabdariffa (karkadeh) stem and Calotropis procera (usher) wood were investigated in the laboratory as potential raw materials for charcoal making in Sudan. The materials were characterized physically and chemically and despite the low density and high bark-to-wood ratio by volume, good yields and quality of charcoal were predicted. The carbonization trials with a laboratory retort at conditions close to those of field metal kiln gave very good charcoal yields (35% for karkadeh and 38% for usher) with high energy transformation (58% and 62%, respectively). The karkadeh charcoal, except for a somewhat high ash content, was good for domestic uses (79% fixed carbon and 30.3 MJ kg⁻¹ heat value). The usher charcoal was better with respect to fixed carbon (86.5%) and gross heat value (32.4 MJ kg⁻¹ ). Both charcoals were of low density (140–160 kg m⁻³) and further assessment of their economic suitability should be carried out under field conditions. The carbonization by-products were also collected and characterized by means of gas chromatography.     

焦炉炭化室传热模型的研究

传热模型用于研究焦炉炭化室内煤料通过炉墙的导热过程,模型用有限差分法由电子计算机进行数值解。提供了计算机的程序框图,给出了某些计算的结果。     

Effect of carbonization time on the structure and electromagnetic parameters of porous-hollow carbon fibres

A series of polyacrylonitrile-based porous-hollow carbon fibres (PAN-PHCFs) were prepared by carbonizing PAN porous-hollow cured fibres at 1073 K for different times in nitrogen. The effects of carbonization time on the structure, electrical volume conductivity and electromagnetic parameters were investigated. Results indicate that the degree of graphitization increases as carbonization time increases. The electrical volume conductivity increases as the degree of graphitization and carbonization time increase. The real and imaginary parts of the complex permittivity (′ and ″) increase with carbonization time increasing. The values of ′ and ″ of composites of PAN-PHCFs and paraffin are 13.76 and 10.09 when the carbonization time is 240 min, and the electrical volume conductivity of PAN-PHCFs is 190.47 Ω⁻¹ m⁻¹.     

Carbon particles modified macroporous Si/Ni composite as an advanced anode material for lithium ion batteries

Carbon particles modified macroporous Si/Ni composite (MP-Si/Ni/C) is easily obtained via a facile fabrication of porous Si/Ni precursor by dealloying SiNiAl alloy followed by a surface growth of carbon nanoparticles. MP-Si/Ni/C composite possesses the multiply conductivity modification that are built through mixing Ni dispersoid and growing one layer of carbon particles. Coupled with the structural advantages of interconnected network backbone, rich voids, and the coated carbon particles, MP-Si/Ni/C exhibits dramatically enhanced lithium storage performances with excellent reversible capacity, enhanced rate performance, as well as outstanding cycling stability compared with pure MP-Si and MP-Si/Ni. Especially, the reversible capacity remains up to 1113.1 and 708.8 mA h g⁻¹ at the current densities of 200 and 1000 mA g⁻¹ after 120 cycles, respectively. Besides, it shows excellent rate capability even when continuously cycled at high current density of 3000 mA g⁻¹. With the advantages of unique structure, excellent performances, and facile preparation, the as-made MP-Si/Ni/C composite shows promising application potential as an alternative anode for lithium ion batteries.