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。     

Corrosion of metals and alloys in mixed gas environments at elevated temperatures

The attack of nickel, cobalt, iron, and alloys of these metals containing chromium and aluminum, by gases containing sulfur-oxygen, carbon-oxygen, and nitrogen-oxygen has been studied at temperatures of 600 and 900°C. The degradation of these metals and alloys was characterized by using standard analytical techniques with emphasis on optical metallography. Three types of accelerated degradation were identified for the attack of alloys by gases containing another oxidant in addition to oxygen. One type of degradation occurred because of the formation of reaction products composed of mixtures of phases involving both of the oxidants. Another type resulted from the reaction of second oxidant phases with oxygen. The third form of degradation involved the development of less protective phases due to thermodynamic instabilities. Thermodynamic stability diagrams are used to help account for the effects produced by different elements in the alloys.     

混粉电火花镜面加工技术及应用

利用自行研制的混粉电火花镜面加工装置，对混粉电火花镜面加工影响因素，加工表面性能等进行了深入研究，找出了粉末特性，工件材料，粉末浓度及放电参数等对混粉电火花镜面加工的影响规律，给出了合理的混粉电火花镜面加工工艺条件，以文中确定的加工工艺条件对铸造和压铸模具进行混粉电火花镜面加工，结果表明，该技术能提高模具制造质量，降低工人劳动强度，缩短模具制造周期。     

STUDY ON PERMEATION OF ACETONE/NITROGEN MIXED GAS THROUGH AL2O3 MICROPOROUS MEMBRANES: MOLECULAR DYNAMICS

In this work, by applying Materials Studio 2.2 software package, molecular dynamics (MD) was performed to investigate the dynamic processes of 1:4 acetone/nitrogen mixed gas permeating through different Al₂O₃ microporous membranes. Three systems were modeled by considering different box lengths, microporous sizes, and textures of Al₂O₃ membranes to compare different permeation behaviors. In each system, initial mixed gas contained 20 acetone molecules and 80 nitrogen molecules, and its density was set to 0.1 g/cm³. Analysis on the concentration profiles of nitrogen molecules (N2) and acetone molecules (Ace) in each system at different sampling times was implemented to discuss the permeation behaviors of smaller N2 and larger Ace. The results showed that adsorption and diffusion occurred synchronously but adsorption was dominant for acetone molecules and that the adsorption on the floor surface of the feed gas region more easily reached equilibrium (local equilibrium) than the diffusion and the adsorption on the ceiling of the initially vacuum region. Furthermore, for nitrogen, adsorption followed diffusion. Higher temperature is in favor of the enrichment of acetone on the floor surface of the feed gas region but against the adsorption of nitrogen. The adsorptive layer was found to be a double-layer with COMPASS force field and to be a monolayer with PCFF force field.     

甲醛法测定铵盐含氮量

对甲醛法测定铵盐含氮量进行了研究，提出采用百里酚酞和酚酞混和指示剂进行测定。该法简单、快速、准确，能满足生产实际和样品检验需要。     

Surface Areas of Nitrated Hydrotalcites

Hydrotalcites in the nitrate form were prepared using microwave irradiation in the hydrotreatment step. The surface area (BET) of nitrated hydrotalcites was evaluated. Solids were characterized by atomic absorption, X-ray diffraction and BET analysis. Thermal pretreatment temperature determined the surface area of the hydrotalcites.     

超薄聚合物表面上滴状冷凝的传热研究

本文采用等离子体聚合和离子束动态混合注入技术在不同的基材(黄铜、紫铜、不锈钢和碳钢)上制备了聚六氟丙烯和聚四氟乙烯的超薄膜,并进行了垂直管外的水蒸汽的滴状冷凝实验。实验发现,对于不同的基材,表面制备的工艺参数对冷凝传热性能及维持滴状冷凝的寿命具有显著的影响。表面性能的测试和估算为预测给定蒸汽在某表面是否成滴提供了依据。     

A kinetic study on medium temperature desulfurization using a natural manganese ore

Natural manganese ores were selected as raw materials for the desulfurization sorbent because of economical efficiency and high reactivity on hydrogen sulfide. Initial reaction rates between H₂S and desulfurization sorbent of natural manganese ores were determined in a temperature range of 400-800°C using a thermobalance reactor. All reactions were first order with respect to H₂S and were expressed by the Arrhenius relation. When the sulfidation reaction was controlled by diffusion, the temperature dependence of the effective diffusivity was given by the Arrhenius equation. Activation energies and frequency factors were obtained from the product layer diffusion coefficient of various sorbents by plotting as an Arrhenius equation form. Several additives were mixed to improve the sulfidation capacity, and NiO was the best additive.     

Oxidation of acrolein on a multicomponent oxide catalyst

Catalytic oxidation of acrolein to acrylic acid has been studied and the optimum composition of the multicomponent catalyst Mo _a V _b Cu _c Fe _d O _x has been found. The reaction kinetics has been measured.     

Comparison of the Effect of a Hydrocarbon Oil and a Terpene Tackifier on the Autohesion of Styrene-Butadiene Rubber

Blends of uncrosslinked styrene-butadiene rubber (SBR) with a terpene tackifier resin or a naphthenic oil have been characterized, and their autohesion and cohesion determined using a T-peel geometry. SBR/oil blends are homogeneous at all proportions, while SBR/resin blends, based on DSC and DMA analysis, undergo bulk phase separation at about 50% resin. However, migration of tackifier to the surface region is proposed at much lower resin contents. Compositions diluted with oil have autohesion similar to the neat SBR. This is attributed to compensating effects; although oil hastens self-bond formation by increasing chain mobility, this is nearly equally balanced by more facile chain separation during bond rupture. In short, oil-diluted compositions are soft and weak. On the other hand, SBR compositions containing small amounts of resin have high autohesion. Resin-diluted specimens deform easily at low strain, just as those containing oil, but intertwined chains of the former have greater resistance to separation, due at least in part to higher glass transition temperatures. It is proposed that autohesion is further enhanced by migration of tackifier to the surface. This causes SBR/resin compositions to be both soft and strong-a necessary condition for high autohesion.