激光诱导击穿光谱在冶金在线分析中的应用研究进展

化学成分在线直接测量是冶金分析长久以来的追求,也被誉为冶金分析面临的三大难题之一。激光诱导击穿光谱技术因其在无需复杂样品制备、直接快速、非接触等方面展现的独有技术优势,备受研究上的关注。文章综述了激光诱导击穿光谱在选矿、熔融金属在线检测方面的研究进展,总结了当前存在的主要问题,并对未来发展进行了展望。     

Electrochemical conversion of switchgrass and poplar in molten carbonate direct carbon fuel cell

One way of sustaining fuel cell technology is using renewable and sustainable energy means provided by biomass. This article explores switchgrass and poplar in a molten carbonate electrolyte direct carbon fuel cell. It investigates their electrochemical conversions and provides results of power density, current density, open circuit voltage (OCV) and other parameters. The biomasses were pyrolysed at 800°C to produce carbon fuels. Biomass carbon fuels were mixed with molten carbonate and subjected to different operating conditions (600–800°C) in the fuel cell. The electrochemical performances of the poplar fuel were better than those experienced with switchgrass fuel. At 800°C the OCV of poplar fuel (1.08?V) has higher output than switchgrass (0.87?V). The peak power density recorded for poplar fuel was 23.91?mW/cm² while switchgrass fuel was lower at 21.60?mW/cm². Poplar fuel (81.53?mA/cm²) gave a maximum current density with switchgrass fuel lower at 74.00?mA/cm².     

高温熔盐的制备及实验研究

为满足太阳能高温传热、蓄热的要求,分析了工业应用的高温热载体,制备了NaCl、KCl和无水MgCl2形成的新型高温熔盐,采用差示扫描量热法对混合熔盐热力学性质进行了测量,实验结果表明,高温熔盐具有较好的热稳定性,是一种理想的高温热载体．     

低钛铁水生产实践

高炉生产过程中铁水[Ti]含量与[Si]含量存在良好的线性关系,生产对[Ti]含量有特殊要求的钢种时必须将铁水[Si]含量控制在0.3%以下.由于长期冶炼低硅生铁需要有良好的原燃料条件和较高的操作水平作为保障,一般高炉很难达到.实验证明,使用10～30kg/t轧钢铁鳞作为脱硅剂,采用投撒法在铁沟内进行脱硅的同时,脱[Ti]效率可以达到20%～50%.该方法在铁水[Si]原始含量大于0.4%时也能生产出特种钢要求的低[Ti]铁水.     

电脱氧法的发展及应用研究

简述了电脱氧工艺发展经历的3个阶段:阴极精炼技术、改进的钙-卤化物熔盐脱氧法和FFC剑桥工艺;详细阐述了3种工艺的发展及反应机理;重点介绍了具有工艺流程简单、成本低、绿色环保等优点的FFC剑桥工艺,综述了FFC剑桥工艺在制备金属、合金及其他物质方面的广泛应用,并展望了该工艺的发展前景.     

熔融盐循环热载体无烟燃烧技术的(火用)分析

介绍了一种全新的燃烧系统——熔融盐循环热载体无烟燃烧技术．对以甲烷为燃料，Fe2O3为氧栽体，质量比为1：1的Na2CO3和K2CO3的混合物为熔融盐的循环热载体无烟燃烧技术透平做功系统与以甲烷为燃料的常规燃烧技术透平做功系统进行了比较．结果表明，利用熔融盐循环热载体无烟燃烧技术不但可以容易地对CO2进行回收利用，减少温室气体CO2的排放量，还可使燃料的火用利用效率有所提高．     

LiNO3-NaNO3-KNO3三元熔盐材料的设计及热稳定性研究

采用共形离子溶液模型(conformalionic solution model, CIS) 在二元熔盐体系相图的基础上，对三元熔盐体系LiNO₃-NaNO₃-KNO₃进行了相图计算，得到该三元体系最低共熔点为117.7℃，相应的摩尔分数组成分别为x(LiNO₃) = 0.375，x(NaNO₃) = 0.075，x(KNO₃) = 0.550。按照热力学最低共熔点计算结果，采用熔融法制备了三元硝酸熔盐，通过DSC和TG实验测定其最低共熔点为118.3℃，这与计算得到的结果(117.7℃)基本一致。TG测试结果表明当温度低于587.2℃时，该三元熔盐体系较为稳定，其工作温度范围为118.3~587.2℃，该三元硝酸熔盐适合在太阳能热发电中作为高温传热蓄热材料使用。     

Electrochemical behaviour of indium ions in molten equimolar CaCl2–NaCl mixture at 550 ∘C

The stability of indium chloride and oxide as well as the electrochemical behaviour of indium ions have been studied in the equimolar CaCl2–NaCl melt at 550 C by X-ray diffraction (XRD) and different electrochemical techniques, using molybdenum and tungsten wires as working electrodes. Voltammetric and chronopotentiometric studies showed signals attributed to the presence of three oxidation states of indium, i.e. 0, i and iii. The standard potential of the redox couples, as well as the solubility products of indium oxides have been determined, showing that In(iii) ions are completely reduced to monovalent indium by the indium metal according to the reaction: In () + 2 In 3 In () and that In₂O is a strong oxide donor according to the reaction: In₂O(s) 2 In() + O^2- These results have allowed the construction of E-pO2– equilibrium diagrams summarising the properties of In–O compounds. The electrodeposition of indium was uncomplicated at Mo and W electrodes. Very good adherence of liquid indium to the electrode materials was observed, with the formation of Na–In alloys at highly reducing potentials, and there was no evidence of indium dissolution into the melt. Moreover, the voltammograms corresponding to the electrochemical In(iii)/In(i) exchange were well defined. The two electrochemical steps were found to be quasi-reversible, and the values of the kinetic parameters, ko and , for both reactions, as well as the diffusion coefficients, DIn(III) and DIn(I) were calculated.     

Structural study of hexane-soluble products from hydroliquefaction of three Yallourn brown coal lithotypes over molten salt catalysts

The hexane-soluble fractions of hydroliquefied products from three Yallourn brown coal lithotypes have been separated into five fractions by combined silica-alumina packed column chromatography. Analyses of various fractions by g.c.-m.s. permitted the identification of ≈50 components in the saturate fraction and 40 components in the diaromatic fraction, together with 30 components in the monoaromatics. The components identified were quite similar among hexane-soluble portions of all three lithotypes. A marked predominance of even carbon number alkane (C₂₃-C₂₉) was observed in the hydrocarbon fractions from pale lithotype over $\text{ZnCl}{}_2\text{KCl}$, and medium light lithotype over both pure ZnCl₂ and $\text{ZnCl}{}_2\text{KCl}$. However, medium dark lithotype over both melt catalysts produced a saturate fraction with an odd carbon number(C₂₂-C₂₈) preference. Based on spectral methods, Soxhlet extracts obtained from untreated lithotypes (hexane and benzene solubles) were characterized as complex mixtures of higher molecular weight(300–1000) aliphatic hydrocarbons, which were supposed to be a precursor of the saturates produced from the corresponding lithotype in the catalytic hydroliquefaction.     

铝及铝合金熔体净化剂研究进展

介绍了铝及铝合金熔体净化过程中气体净化剂、排杂熔剂、精炼剂、覆盖剂等净化剂的研究现状,并初步分析了其在铝及铝合金熔体净化过程中的基本原理,同时提出铝熔体提高净化效果的主要途径及铝熔体净化剂的发展方向。