国产络合铁法液相氧化还原硫磺回收脱硫溶剂研究及工业应用

通过实验室模拟性质和组成相似的炼油厂酸性气,在类似于LO-CAT硫磺回收装置工艺操作条件下,对国产络合铁法液相氧化还原催化剂进行了适应性研究。在陕西延长石油(集团)有限责任公司炼化公司延安炼油厂LO-CAT硫磺回收装置进行了工业试用,结果表明,国产络合铁法液相氧化还原催化剂完全可以替代国外专用脱硫溶剂,净化后尾气硫化氢平均含量3.2×10-6,硫回收率大于99.95%,每吨硫磺加工成本降低10%,各项技术经济指标均优于进口脱硫溶剂。     

Pt/CrCeAlO催化剂对二氯甲烷的催化氧化性能

催化氧化是消除挥发性有机废气的有效手段,而二氯甲烷是含氯有机废气的代表性化合物。采用沉淀法制备了不同CrO_x含量的CrCeAlO催化剂,并用浸渍法制备了Pt/CrCeAlO催化剂,将其用于二氯甲烷催化氧化。结果表明,催化剂均表现出较好的活性,Cr_0.03Ce_0.05Al_0.95O₂催化剂在390 ℃时即可完全氧化二氯甲烷。而负载Pt后的催化剂活性明显提高,2.0Pt/Cr_0.03Ce_0.05Al₀.₉₅O₂催化剂表现出最好的活性,在340 ℃条件下,转化率即达100%。采用XRD、SEM、TEM、H₂-TPR和NH3-TPD对催化剂进行表征,表明催化剂的活性主要受其表面酸性和氧化还原性的影响,表面酸性位提供二氯甲烷化学吸附位,而催化剂表面氧化还原性则有利于反应中氧物种的活化。催化剂中添加Pt后,由于Pt、CeO₂ 和 CrO_x物种间的相互作用而增强了催化剂的氧化还原性,从而进一步促进了反应活性的提高。     

工业氯化钡质量的快速测定

介绍利用硫酸银标准溶液滴定氯化钡溶液的快速测定工业氯化钡含量的新方法。     

水基型胶粘剂水分测试技术简介

水基型胶粘剂是一种用途广泛的胶粘剂品种,文章详细介绍了水基型胶粘剂中水分含量的几种测试方法,其中,卡氏加热炉-卡尔·费休滴定法是目前一种较为快速简便的水分测试方法。     

电位滴定分析ASP驱采出液中表面活性剂浓度

以十二烷基磺酸钠为例,考察了利用电位滴定方法分析ASP三元复合驱采出液中表面活性剂浓度时,pH值、盐度、聚合物含量、石油酸皂浓度等因素对分析结果的影响,研究出因石油酸皂和聚合物的存在导致结果偏高的消除方法,并对方法的检出限进行研究。该方法为ASP三元驱中十二烷基磺酸钠类阴离子表面活性剂浓度的分析提供了参考。     

酸碱滴定法测定葡萄糖氯化钠注射液中氯化钠不确定度评价

对葡萄糖氯化钠注射液中氯化钠的含量进行不确定度评价。建立评价酸碱滴定法测定葡萄糖氯化钠注射液含量不确定度的数学模型,对测定中的各影响因素进行考察。结果表明,氯化钠的扩展不确定度为0.004%,含量测定结果为(0.890±0.004)%。建立的计算方法实用、可靠,可以用于酸碱滴定法测定药物含量的不确定度评定。     

Solubilisation of calcium and magnesium from the marine red algae Lithothamnion calcareum

Marine minerals are a potential source of calcium and magnesium for nutritional supplementation. This study analysed the solubilisation of calcium and magnesium from the skeletal remains of Lithothamnion calcareum. Scanning electron microscopy analysis demonstrated a nonporous microstructure. Spectrophotometric determination showed that the calcium and magnesium contents were 30.01 and 6.22% (w/w), respectively. Solubilisation of calcium and magnesium was highly pH dependent. The temperature‐dependent solubilisation of calcium fitted the shrinking core model. The apparent activation energy for calcium solubilisation was 28.6 kJ mol^?1. Inclusion of caseinophosphopeptides (CPPs), casein‐derived mineral binding peptides, during the solubilisation of calcium and magnesium appeared to decrease the extent of calcium solubilisation at pH 6.0 and 8.0. The results herein have implications for the choice of optimal pH conditions for the sustained release of calcium and magnesium from marine mineral sources.     

The influence of pyrite content on the flotation of chalcopyrite/pyrite mixtures

In the flotation of copper ores, several processing plants report that copper recovery is affected by the proportion and reactivity of pyrite in the ore, with the effect becoming more intense when the feed particles are finer as a result of regrinding. In this work, a mixed model mineral system consisting of chalcopyrite (CuFeS₂) and pyrite (FeS₂) with varying pyrite content (20–80 wt.%) was used to investigate the effect of pyrite on the pulp chemistry and chalcopyrite recovery. Flotation tests showed that chalcopyrite flotation rate, recovery and grade, as well as the pulp oxidation potential, decreased with increasing pyrite content whilst pyrite recovery increased. Surface analysis (XPS, ToF-SIMS and EDTA) indicated that copper activation of pyrite increased with increasing pyrite content, facilitating pyrite recovery. The decrease in chalcopyrite recovery can be attributed to increased surface oxidation.     

Investigation of Nafion series membranes on the performance of iron‐chromium redox flow battery

To boost the performance of the iron‐chromium redox flow battery (ICRFB), opting an appropriate proton exchange membrane (PEM) as the core component of ICRFB is of great importance. For the purpose, in this paper, various widely adopted commercial Nafion membranes with a different thickness of 50 μm (Nafion 212, N212), 126 μm (N115), and 178 μm (N117) are chosen for the sake of evaluating the influence of membrane thickness on the ICRFB single‐cell performance. Physicochemical properties, electrolyte utilization, cell efficiency, long‐term cycling stability, and the self‐discharge process of ICRFBs based on a series of Nafion membranes are contrasted comprehensively. The cycling test of ICRFBs is carried out under the current density range of 40 to 120 mA/cm² for the charge‐discharge process. As a result of the good equilibrium of membrane resistance and electro‐active species permeability, Nafion 212 membrane exhibits the highest electrolyte utilization and energy efficiency during the operation, accompanied by the lowest overpotential. In the final part, the selection of Nafion membrane thickness was optimized on the basis of single‐cell performance and the overall cost of the system.     

排液滴定法快速测定球团矿体积

介绍一种通过排液滴定快速测定球团矿体积的新方法。该方法基于体积排液原理，滴定控制精度，经过大量试验验证准确可行，设备、试剂、程序简单，数据直观，便于复查核对，精度高，耗时短，单次测定仅需30 min即可完成。应用后可将球团矿相对自由膨胀指数的测定时间缩短3 h以上，弥补了GB/T 13240—1991《铁矿球团相对自由膨胀指数的测定方法》中推荐的球团矿体积测定方法的不足。