对甲基苯磺酸络合-异戊醇萃取铬(Ⅵ)在有机铬催化剂中铬(Ⅲ)测定中的应用

乙烯齐聚合成1-己烯的主催化剂为有机铬系催化剂,铬系催化剂中铬(Ⅲ)能很好地与助催化剂烷基铝形成络合物,而铬(Ⅵ)会与烷基铝发生反应,降低催化剂的催化能力,因此需要准确测定铬催化剂中铬(Ⅲ)含量。实验提出在酸性条件下用对甲基苯磺酸络合、异戊醇萃取有机铬催化剂中铬(Ⅵ),使铬(Ⅲ)和铬(Ⅵ)分离,最后采用电感耦合等离子体原子发射光谱法(ICP-AES)测定无机相中铬(Ⅲ)。实验考察了硝酸的浓度和用量,以及络合剂和萃取剂的用量。研究表明:加入10 mL 10%(体积分数,下同)硝酸,用2.0 mL对甲基苯磺酸络合、20 mL异戊醇萃取就可以完全将样品中的铬(Ⅲ)和铬(Ⅵ)分离。铬(Ⅲ)校准曲线的线性相关系数大于0.999;方法检出限为1.45 μg/g。按照实验方法测定有机铬催化剂实际样品中铬(Ⅲ),结果的相对标准偏差(RSD,n=6)小于4%,回收率为94%～103%。     

EFFECT OF FINE GRINDING ACTIVATION ON LEACHING BEHAVIOUR OF SCHEELITE CONCENTRATE

The influence of mechanical activation on the leaching behaviour of scheelite was studied bymeans of fine grinding in an attritor and subsequently HCl leaching in presence of PO_4~(3-).Results showed that after fine grinding in the attritor,the reaction rate of scheelitewith HCl-Na_3PO_4 solution was remarkably increased,the extraction of W increased fromabout 8 to 99%.The IR spectra and X-ray diffraction analysis indicated that in addition toan enlargement of surface area the fine grinding action had made also changes of fine struc-ture and reactivity of solid surface,hence the leaching process of scheelite can be carried outunder mild leaching conditions.     

Behavior of calcium silicate in leaching process

1　ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｇｅｎｅｒａｌ ,ａｌｕｍｉｎａｃａｎ ｔｂｅｐｒｏｄｕｃｅｄｅｃｏｎｏｍｉｃａｌｌｙｂｙＢａｙｅｒｐｒｏｃｅｓｓｉｎＣｈｉｎａｂｅｃａｕｓｅｔｈｅｂａｕｘｉｔｅｃｈａｒａｃｔｅｒ ｉｚｅｓｉｎｄｉａｓｐｏｒｅａｎｄａｂｏｕｔ 80 %ｂａｕｘｉｔｅｅｘｉｓｔｉｎｌｏｗｄｅ ｇｒｅｅｏｆｔｈｅｍａｓｓｒａｔｉｏｏｆａｌｕｍｉｎａｔｏｓｉｌｉｃａ(Ａ/Ｓ)ｗｈｉｃｈｖａｒｉｅｓｆｒｏｍ 4ｔｏ 9[1] .Ａｎｄａｂｏｕｔ 4 0 %ｏｆａｌｕｍｉｎａｉｓｐｒｏ ｄｕｃｅｄｂｙｓｉｎｔｅｒｉｎｇ…     

Evaluation of high Ni-Cr-Mo alloys for the construction of sulfur dioxide scrubber plants

Corrosion in wet lime/limestone systems used for flue gas desulfurization in thermal power plants is of great concern. The frequent variations in acidity and in chloride and fluoride ion concentrations experienced by such systems pose a serious threat to the materials of construction. Currently used materials mostly type 316L stainless steel often fail to meet their life expectancy. The present study evaluates the performance of advanced Ni- Cr- Mo alloys 59 and C- 276 in a simulated sulfur dioxide scrubber environment. Accelerated tests showed that high Ni- Cr- Mo alloys have little tendency to leach metal ions such as chromium, nickel, and molybdenum at different impressed potentials. Scanning electron microscopy was used to examine the morphology of pitting attack.     

高浓度熟料溶出的工艺研究

优化烧结法生产 ,提高产量、节约能耗是氧化铝生产急需解决的问题之一。实现高浓度溶出可以提高精液浓度 ,减少湿法系统物料流量 ,达到提高产能、增加产量、降低成品成本的目的。本文通过对国内外高浓度熟料溶出发展情况和烧结法影响高浓度溶出的因素进行分析研究 ,提出了提高熟料A/S的必要性 ;指出了适合我国条件的熟料A/S大小和生料配方 ;分析了温度和αk 对溶出和分离的影响机理和规律 ;提出了适合高浓度溶出的溶出条件和浓度大小。对生产有一定的指导意义。     

Quantification of response time in poly(vinyl alcohol)–metal complex thermochromic polymeric systems

Thermochromic poly(vinyl alcohol) (PVA)‐based material was synthesized and an extensive study of its thermochromic behavior with respect to response time was carried out. It was observed that it is possible to manipulate the response time by keeping control over chemical and physical parameters. The response time, which is the most important property of a smart material, has in this case been found to be very much influenced by rate of heat transfer into the material. Different compositions of the thermochromic material and their corresponding response time with respect to rate of heat transfer were studied and correlated. First, a theoretical equation was derived and later on it was experimentally verified to quantify the response time in PVA–metal complex‐based thermochromic systems. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4832–4834, 2006     

Solvent-free oxidation of benzyl alcohol with oxygen using zeolite-supported Au and Au–Pd catalysts

The oxidation of benzyl alcohol to benzaldehyde has been investigated in the absence of solvent using zeolite-supported Au and Au–Pd catalysts. Three zeolites were investigated, ZSM-5, zeolite β and zeolite Y, and these were contrasted with the titanoslicalite TS-1 and TiO₂ as supports. For the Au catalysts the best results are obtained with zeolite β as the support and the conversions were comparable or better than those observed with TiO₂ in terms of turn over frequencies. However, the selectivities observed with the acidic zeolites were lower than the non-acidic TS-1 and TiO₂. This is due to the subsequent reaction of benzaldehyde via acid catalysed reactions to give benzyl benzoate and its dibenzyl acetal, and, in some cases dibenzylether. Initial catalysts were evaluated with a gold loading of 2 wt% and increasing this to 4 wt% showed the expected increase in activity, indicating that there is scope to improve the performance of these catalysts. The most active catalysts were prepared by impregnation and catalysts prepared by deposition precipitation were considerably less active. Introduction of Pd into the catalyst improved the activity without significantly affecting the selectivity.     

铜浸出液的净化除铁研究

研究了氧化－中和沉淀法从铜浸出液中除铁的工艺条件，并介绍了工业实践。     

糖蜜酒精废液处理技术

介绍了甘蔗制糖生产中国内外糖蜜酒精废液的处理方法，对不同处理技术的特点进行了分析，认为焚烧法既能彻底处理糖密酒精废液，又能把废液处理和资源回收相结合，并概述了国内外废液焚烧技术。     

Guayule seedling response to nitrogen fertilizers

Slow growth and high seedling mortality limit direct seeding establishment of guayule (Parthenium argentatum G.). This study was conducted to assess seedling growth enhancement by the addition of different rates and forms of N fertilizers and Ca salts. Experiments were conducted in a greenhouse with cultivar 593 under both surface and subirrigated conditions using water low in salts (salinity of 0.8 dSm^–1, SAR of 5.0 and 10 mg Ca L^–1). Under surface-irrigated conditions, seedling height and fresh plant weight increased with N application to the irrigation water to 70 mg L^–1. The best seedling growth was observed when (NH₄)₂SO₄ was added in combination with CaCl₂ or CaSO₄. Progressively less growth was observed by addition of (NH₄)₂SO₄ alone, CO(NH₂)₂ plus CaSO₄, CO(NH₂)₂ alone and Ca(NO₃)₂. When seedlings were subirrigated, however, the best growth was observed with Ca(NO₃)₂. Intermediate growth was obtained with (NH₄)₂SO₄ plus CaSO₄ and lowest growth rates with (NH₄)₂SO₄ alone. These differential responses may be explained by the differences in leaching and volatile characteristics of the N forms. Growth enhancement from N and Ca additions increased with time with significant increases 45 days after seeding. Nitrogen application with Ca may be effective amendment in promoting subsequent growth of direct seeded guayule.