氧肟酸基团含量高的改性絮凝剂制备及应用

以高分子量聚丙烯酰胺(PAM)为原料,合成了聚丙烯酰胺改性氧肟酸型絮凝剂产品(HPAM)。通过傅里叶变换红外光谱分析(FT-IR)证实了该产品中氧肟酸基团的存在。用电导滴定法与凯氏定氮法相结合,测得该产品中氧肟酸基团含量高达46%,羧基含量23%。用针铁矿含量高的合成拜耳法赤泥浆料研究了该絮凝剂产品添加量对针铁矿含量高的赤泥沉降分离效果影响。结果表明,该絮凝剂产品对于该针铁矿含量高的赤泥具有良好的沉降分离效果,与美国氰特公司产品Hx-600的赤泥沉降效果基本相当。     

吉布斯吸附等温式的应用—电解质溶液活度测定新方法

采用最大气泡压力法测定298.15 K,常压及不同离子强度(0.57~12.81 mol/kg)条件下氯化钴水溶液体系的表面张力,建立表面张力与浓度关系的经验公式。应用Gibbs吸附等温式推导出表面张力与活度的关系式,提出一种计算溶液活度因子的新模型,并利用实验数据回归得出了新模型参数。与文献中的数据相比,新模型计算数据的标准偏差为0.0632,与Kim归纳出的Pitzer模型参数计算数据的标准偏差相近。结果表明:采用电解质溶液活度测定新方法和计算模型可得到的氯化钴水溶液活度因子的精度较高,这使得通过测定电解质溶液表面张力计算其活度因子(或活度)成为可能。     

生物膜电极法降解实际工业废水的可行性研究

本文论述了生物膜电极法对以水性漆废水和香兰素废水为代表的实际工业废水降解的可行性。结果表明,生物膜电极法对成份复杂、浓度高、毒性大的实际工业废水的处理有一定的局限性,结合简单的预处理方法以提高废水的可生化降解性,可有效增强生物膜电极法和降解效果。     

Electrochemical properties of high-power lithium ion batteries made from modified spinel LiMn2O4

A prismatic 204056-type high power lithium-ion battery was developed. Modified LiMn₂O₄ and carbonaceous mesophase sphere (CMS) were adopted as the cathode and anode, respectively. The effects of proportion of conductive carbon black in cathode and the rest time after discharge on the electrochemical properties of batteries were investigated. The electrochemical tests show that the proportion of conductive carbon black in cathodes affects the high rate capability and discharge voltage plateau distinctly. The battery with 3.0% of conductive carbon black in cathode shows excellent electrochemical performances when being charged/discharged within 2.5?4.2 V at room temperature. The discharge capacity at 20C rate is 94.4% of that at 1C rate, and the capacity retention ratio charged at 1C and discharged at 5C is 86.6% after 390 cycles at room temperature. The test result of impulse discharge at 50C for 5 s shows that the battery has outstanding high rate discharge performance when the battery is in the depth of charge of 90%, 75%, 60%, 45%, 30% and 15%. The battery also shows good charge performance. When the battery is charged at 0.5C, 1C, 2C and 4C, the ratios of capacity for constant current charge are 98.4%, 96.4%, 91.0% and 72.9% of the whole charge capacity, respectively. In addition, the rest time after discharge affects the cycle performance distinctly when the battery is discharged at high rate.     

机械化学的研究发展现状与展望

介绍了机械化学的发展简史和基本特征,简述了机械化学过程中粉体(晶体)结构变化、粉体物理化学性质变化和粉体机械化学反应的研究现状,展望了机械化学、特别是其中的机械活化的研究发展前景.     

基于拓扑规则Pb-S-O体系优势区图的绘制与应用

应用相律对Pb-S-O体系内组分进行分析,确定了该体系可能存在的4个三凝聚相点。结合拓扑规则和相关平衡反应的热力学计算,绘制该体系三凝聚相点之间的两种关联图:α型平面拓扑图和β型平面拓扑图。分析结果表明:β型平面拓扑图与传统Pb-S-O体系优势区图一致,说明可以基于拓扑规则绘制Pb-S-O体系优势区图;α型平面拓扑图可以解释Kivcet炼铅工艺在高氧位、高硫位条件下直接生成大量粗金属Pb的现象。     

纯三水铝石溶出过程动力学研究

研究了纯三水铝石在氢氧化钠溶液中的溶出过程动力学。通过温度和浓度对溶出速率的影响,推导出溶出过程的动力学漠型。整个溶出过程系一级不可逆化学反虚控制。用微分法和积分法计算出动力学参数,其表观反应活化能为76.85kJ/molAl(OH)_3。     

氢氧化铝晶粒的应力与强度分析

根据国内氧化铝工业生产现状，结合氢氧化铝晶粒的显微结构，利用有限元方法，对氢氧化铝晶粒进行了结构静力分析，得到了氢氧化铝晶粒中填充小晶体的填充位置、数目及晶粒破损的缺口尺寸与晶粒强度的关系，并对实际产品的显微结构与强度的关系进行了考察. 结果表明，晶粒中存在小晶体填充且填充位置处于整个缺口尺度的75%时，强度改善最为明显，并且强度随填充小晶体数目的增多而提高；晶粒的缺口尺寸在1~2 mm范围内变化时，缺口越小，强度越好；通过氢氧化铝产品中晶粒的显微结构，应用有限元分析，可以从理论上判断氢氧化铝产品的强度.     

Effects of temperature and initial molar ratio of Na2O to Al2O3 on agglomeration of fine Al（OH）3 seed in synthetic Bayer solution

Fine Al(OH)3 crystals were aggregated from supersaturated aluminate solution in the batch reaction tanks. By means of laser particle size analyzer and scanning electron microscopy, the influences of temperature and initial molar ratio of Na2O to Al2O3 (αK) on agglomeration of fine seed in Bayer process were investigated. The results show that agglomeration is almost finished in 8 h, and seeds with size less than 2 μm are easily aggregated together, and almost disappear in 8 h under the optimal process condi...     

金属在真空状态下的蒸发速率

在阐明一些基本概念的基础上,系统地讨论金属在真空状态下蒸发的速率问题,在一定的真空度下,金属的蒸速率随着温度的升高而增大。在一定的温度下,金属的蒸发速率随着真空芳的变化出现对应“一般蒸发”、“沸腾蒸发”和“分子蒸馏”3种蒸发形式的3个阶段。当真空度高到一定程度以后,金属的蒸发速率与真空度变化无关而达到最大。同一个金属的“最大蒸发速率”与温度呈正相关。