Eucalyptus bark (EB) is a promising biomass to replace fossil fuels, but its ash content is high and the energy density is particularly low. In this paper, it was proposed to upgrade EB to prepare solid biofuel by mild hydrothermal treatment (HTT) and pelletization. It was found that HTT could effectively remove troubling elements like Na, K, Zn, Mn, S, Cl, and P in EB. The remaining ashes tend to form higher melting point compounds, whose softening temperature (ST) and flow temperature (FT) increased from 1326 °C to 1399 °C and from 1348 °C to 1425 °C, respectively. The higher heating value of EB increased from 16.32 to 17.68 MJ/Kg after HTT. The density, volume expansion, compressive strength, and durability of the bio-pellet fuel after HTT were all superior to raw EB. HTT and pelletization is a promising method to prepare solid biofuel from EB.

The inorganic matters in biomass contain quite a lot of alkali and alkaline-earth metals (AAEMs) which cause slagging/fouling while combustion, limiting the utilization of biomass. This study investigated the de-ash treatment and ash characteristics of eucalyptus bark (EB) after washing by water and acetic acid, respectively. In particular, the optimal washing condition was investigated by response surface methodology. For water washing, the optimal condition was 67.80 min, 58.87 degrees C, and 50.34:1 liquid-solid-ratio, while it was 87.72 min, 2.36 mol/L, and 49.55:1 liquid-solid-ratio for acetic acid washing. The ash in EB (Raw-ash) contains a large amount of AAEMs, while the ash of treated EB (WL-Ash, AL-Ash) mainly containing CaO. The de-ash treatment increased the melting temperature of the ash. Acetic acid is better than water for ash removal, with a shorter leaching time, smaller liquid-solid-ration, milder temperature, and lower tendency to slagging.

为了克服盐酸滴定法、温升速率法等测定生石灰活性度的方法试剂用量大、适用条件受限和操作复杂等缺点,提出一种试剂用量少、操作简便且适合不同活性度水平的生石灰活性度电导率测定方法.考察了搅拌时间、搅拌转速、溶液温度、生石灰与水的用量等因素对生石灰活性度与溶液电导率对应关系的影响,探究了生石灰活性度与电导率大小呈线性关系的最适宜条件.结果表明,生石灰活性度测定的最适宜条件为搅拌时间为12 min、溶液温度为25℃、搅拌转速为200 r/min、生石灰与去离子水的加入量分别为1 g、1000 mL;生石灰活性度与溶液电导率之间的线性关系表达式为A=(σ-0.5657)/0.01246,拟合的线性相关系数R2=0.9931,相较于现行标准YB/T 105-2014《冶金石灰物理检验方法》规定的盐酸滴定法,该方法具有节省时间、节约药品、降低能耗、操作简便等优点,与盐酸滴定法测定值的最大相对偏差为0.366%,精密度完全可靠,可用于工业推广.

The surface modification of ground calcium carbonate(GCC)was accomplished by mechanically activated of GCC,sodium polyacrylate and nano calcium carbonate together and the CaCO3 composite coated with nano calcium carbonate was applied to the adsorption of Cu2+ in solution.The adsorption properties were also investigated.The results showed that SEM and XRD analyses confirmed that the nano calcium carbonate was successfully coated on the surface of GCC.FTIR analysis found that the hydroxyl groups increased on the composite surface,and BET analysis indicated that the specific surface area of composite was 20.5m2/g with a mesoporous structure.The maximum adsorption capacity of composite calcium carbonate for Cu2+ was 65.5mg/g and the removal rate could reach 98% .The absorption process studies revealed that the adsorption kinetics followed the pseudo-second-order kinetic model and the adsorption isotherms followed the Langmuir-Freundich model,proving that the adsorption was dominated by ions exchange and was exothermal.

为了改善现有塑料地膜难降解、危害作物的现状,采用氧化淀粉、碱性木质素、丙三醇、戊二醛与疏水蜡乳液制备一种液体地膜(liquid mulch,LM).通过正交实验,使用综合分析法选出最佳液体地膜配方(最佳液体地膜命名为LM1),通过XRD、FT-IR、SEM及喷枪喷涂、培养皿保湿、土壤温度、人工紫外老化、降解性和植物发芽率实验,表征LM1的物化结构与实际性能.结果表明,当氧化淀粉用量10 g,碱性木质素用量0.25 g,戊二醛用量1.5 g,丙三醇用量6 g,蜡乳液用量2 g制备的液体地膜最佳,其中的氧化淀粉和碱性木质素在戊二醛作用下醚化交联生成了致密光滑的薄膜.LM1在施工时易喷涂,具有一定的保墒保温性,抗紫外性良好,且可降解、能促进作物发芽生长.

为了探究热处理对拜耳法赤泥胶凝特性的影响,采用对比强度法评价不同温度煅烧下赤泥的胶凝特性;并将赤泥与水泥熟料、石灰石粉、石膏按比例混合制备低碳胶凝材料,探究赤泥的热处理温度对低碳胶凝材料性能的影响,通过XRD分析赤泥的热处理温度对物相变化和胶凝材料的水化产物的影响.结果表明:随着热处理温度的升高,赤泥胶凝特性逐渐增强后减弱,在600℃时达到最佳;所制备的胶凝材料早期强度较高,但后期强度增长缓慢;胶凝特性好的赤泥在的水化反应中消耗更多的CH,同时会生成少量的单碳铝酸盐;利用热处理活化的赤泥制备的低碳胶凝材料每吨可减少约30%的CO2 排放和 20%的能耗.

本文采用van't Hoff等压方程,对CaCO3的热分解反应温度进行计算,通过热力学和动力学分析,对CaCO3热分解反应过程的传递强化、化学平衡和温度效应进行研究.结果表明,CaCO3热分解为CaO的理论温度为1109.5K(836.35℃),用热重分析测得的石灰石(CaCO3含量为98.8%)的实际热分解温度为1088K(815℃).假设CaCO3直接热分解为Ca(OH)2,则可节能109.182kJ·mol-1,但其热分解温度为4456.1K(4183℃),在实际生产中难以实现.采用提高石灰窑内的气体流速和减小石灰石(CaCO3)粒径的方法,可以消除石灰石热分解反应过程的内、外扩散阻力;提高CaCO3热分解反应的温度,则有利于CaCO3热分解反应的化学平衡并提高热分解反应速率,但会受到石灰窑体制造材料的限制,因此选择CaCO3的热分解反应温度为1000℃左右较适宜.

磷石膏的化学成分与天然石膏类似,磷石膏通常用作水泥的缓凝剂,通过一定比例与熟料混合制成水泥.向磷石膏中外掺一定量的可溶性氟,研究可溶性氟含量对硅酸盐水泥与外加剂相容性及强度的影响.研究结果表明:在减水剂掺量较少的情况下,随着氟离子掺量的增加,Marsh时间有着明显的增加;随着氟离子的增加,硅酸盐水泥3 d和28 d的抗压、抗折强度变化不明显,与对照组的差异不大.

研究了煅烧温度(200～800℃)对凹凸棒土外观、矿物组成和活性SiO2含量的影响,煅烧前后凹凸棒土对水泥浆体化学结合水量、反应程度和水泥胶砂抗折、抗压及劈裂强度等力学性能的影响.结果表明:煅烧温度改变了凹凸棒土的矿物组成,从而影响了水泥基材料的水化活性,经500℃煅烧的凹凸棒土对水泥基材料水化活性的提高效果最佳.