赤泥的特殊工程性能及其利用之研究

原赤泥强度低，工程上已很少应用。现研究表明，它含有１８种胶结力极强的化合物，针对该特点，提出用析水、脱水和加ＣａＯ的改造对策，增强了赤泥的强度，工程性能得到显著的改善。用赤泥筑坝，坝高可增加２～３倍，还可用于地基补强、做强防渗层以及铺筑路面等。     

Hydrogen synthesis from biomass pyrolysis with in situ carbon dioxide capture using calcium oxide

Hydrogen (H₂) and other gases (CO₂, CO, CH₄, H₂O) produced during the pyrolysis of cellulose, xylan, lignin and pine (Pinus radiata), with and without added calcium oxide (CaO), were studied using thermogravimetry-mass spectrometry (TG-MS) and thermodynamic modeling. CaO improved the H₂ yield from all feedstocks, and had the most significant effect on xylan. The weight loss of and gas evolution from the feedstocks were measured over the temperature range 150-950 °C in order to investigate the principle mechanism(s) of H₂ formation. Without added CaO, little H₂ was produced during primary pyrolysis; rather, most H₂ was generated from tar-cracking, reforming, and char-decomposition reactions at higher temperatures. When CaO was added, significant H₂ was produced during primary pyrolysis, as the water-gas shift reaction was driven toward H₂ formation. CaO also increased the formation of H₂ from reforming and char gasification reactions. Finally, CaO increased the extent of tar cracking and char decomposition, and lowered their onset temperatures. The production of H₂ from pine over the course of pyrolysis could be modeled by summing the H₂ evolutions from the separate biomass components in relevant proportions.     

水泥熟料-粉煤灰体系中粉煤灰活性的复合激发研究

通过水泥砂浆强度试验方法研究了水泥熟料-粉煤灰体系中添加CaO、Na2SO4、明矾等化学物质对其中的粉煤灰活性的激发效果,同时借助于XRD和SEM分析了水泥硬化浆体的组成和微观结构.研究结果表明:CaO-Na2SO4-明矾复合添加能够很好地激发粉煤灰活性,使粉煤灰水泥早期强度降低程度减小.采用42.5等级硅酸盐水泥熟料,粉煤灰掺量高达50％时水泥强度仍然能够达到42.5等级指标.XRD分析表明,CaO-NaSO4-明矾复合激发剂的加入引起了水泥硬化体样品中石英和Ca(OH)2衍射峰的降低,说明它们在一定程度上促进了水泥水化放出的Ca(OH)2与粉煤灰中酸性氧化物的反应,从而加剧粉煤灰潜在活性的快速释放.水泥硬化体样品的SEM照片显示,CaO-Na2 SO4-明矾的加入,使粉煤灰球体表面腐蚀明显,硬化体结构更加致密化.     

CaO顺序脱除SO2/CO2过程中的硫酸化特性

在固定床反应器和热重分析仪上,研究经历不同循环碳酸化/煅烧反应次数的CaO与SO2的硫酸化反应特性,考察循环次数、颗粒粒径、反应温度和微观结构对CaO硫酸化特性的影响。结果表明：在20次循环之前,CaO硫酸化转化率随循环次数的增加而迅速下降,继续增加循环次数,转化率则保持稳定,而130次循环后,硫酸化转化率则开始增长;初始CaO、经历40次和150次循环后的CaO硫酸化转化率分别为0.480,0.207和0.243;当循环次数不同时,颗粒粒径对CaO硫酸化转化率的影响一致,转化率均随粒径的增大而减小;在800～950 ℃,初始CaO的硫酸化转化率随温度的变化不大,但随循环次数增加,反应温度对CaO硫酸化影响变大,且反应温度越高,转化率越高。     

CaO-Al2O3基钢液净化剂组成的优化

运用CaO-Al2O3-SiO2三元系的熔点和等αAl2O3相图,分析了CaO-Al2O3渣系净化剂降低钢液中氧化物夹杂的能力与其组成的关系。从热力学角度看,CaO/Al2O3比值高（1.6～2.0）,则αAl2O3低（≤0.02）,有利于钢液中氧化物夹杂的降低;从动力学角度看,CaO/Al2O3低（1.1～1.26）,则熔点低（〈1400℃）,有利于钢液中氧化夹杂的排出。净化剂组成的优化结果表明,适宜的CaO/Al2O3比值为1.41～1.74,净化剂αAl2O3较低（0.02～0.04）,熔点较低（〈1450℃）。工业性试验表明,优化后的净化剂净化钢液效果显著。     

X射线荧光光谱法测定煤灰成分

介绍用作煤灰中的SiO2、AlO3、K2O、CaO、S快速分析的X射线荧光光谱法,探讨了样品制备条件,基体干扰及其校正,以及分析准确度和精密度。     

铝锆碳水口在浇注钙处理钢堵塞的原因分析

对生产中被堵塞的铝锆碳质浸入式水口分析表明,堵塞物质为六铝酸钙。该物质为水口内壁处的原位反应产物,其中水口内壁的刚玉骨料和细粉提供了六铝酸钙的氧化铝组分,钢液携带的钙提供了氧化钙组分。LF处理后添加的钙合金数量不当,导致夹杂物类型失控,是引起水口材料被侵蚀并造成堵塞的主要原因。     

Kinetics of Na2O evaporation from CaO–Al2O3–SiO2–MgO–TiO2–Na2O slags

The present work is carried out to study the evaporation of Na₂O from CaO–Al₂O₃–SiO₂–TiO₂–MgO–Na₂O slags with high basicity and high alumina in the temperature range of 1500–1560°C. The ratio of evaporation was determined by monitoring the Na₂O content change of the slag melt under isothermal reduction conditions. The results show that the evaporation ratio increases with increasing the temperature. Higher basicity and increasing concentrations of Na₂O, Al₂O₃ are also found to increase the evaporation ratio of Na₂O, while MgO addition only slightly enhances the evaporation ratio. With TiO₂ content increasing, the evaporation ratio first increases and then decreases. The evaporation rate of Na₂O appears to be controlled by chemical reaction at the slag/gas interface in the beginning, followed by a mixed reaction-mass transfer regime, and finally a liquid-phase mass transport step. The apparent activation energy is 134.74?kJ?mol^?1 for the chemical reaction regime and 268.53?kJ?mol^?1 for the liquid-phase mass diffusion step.     

Effects of super-gravity field on precipitation and growth kinetics of perovskite crystals in CaO–TiO2–SiO2–Al2O3–MgO melt

The precipitation and growth behaviours of perovskite crystals from CaO–TiO₂–SiO₂–Al₂O₃–MgO melt in a super-gravity field with different gravity coefficients at different cooling rates were investigated in this study. In a super-gravity field, the first precipitated perovskite crystals migrated quickly along the super-gravity direction, and gradually concentrated and grown into larger crystals in the bottom area, while the new perovskite crystals keep precipitating and concentrating towards the bottom area simultaneously. Furthermore, by simplifying the layered samples obtained by super-gravity into three areas along super-gravity direction: slag-rich area, interface area and perovskite-rich area, the variations in volume fractions and equivalent diameters of perovskite crystals against gravity coefficients and cooling rates were obtained by weighting the values of the three areas. And the results indicated that increasing gravity coefficient was not only beneficial for the precipitation but also for the growth of perovskite crystals in the slag melt. Afterwards, the effects of super-gravity field on the precipitation and growth kinetics of perovskite crystals were further discussed.