FeCl3-HCl-C2Cl4体系浸出硫化锌矿的动力学研究

针对FeCl3-HCl-C2Cl4体系浸出硫化锌精矿过程，建立了以固体产物层扩散控制和混合扩散控制浸出的核收缩动力学模型。动力学研究和浸出过程矿粒表面的SEM分析结果表明，在相同的搅拌强度下，FeCl3-HCl体系符合固体产物层扩散控制的核收缩过程，四氯乙烯能有效地溶解矿粒表面形成的固体硫层，提高固体产物层扩散控制的速度，并且随四氯乙烯加入量的增大；对于FeCl3-HCl-C2Cl4体系则由固体产物层扩散控制变为混合扩散控制的的核收缩过程，显著地提高了浸出速率。     

国内外四氯乙烯生产消费现状及市场前景

介绍了四氯乙烯的生产方法，分析了国内外四氯乙烯的生产消费现状及市场前景，提出了发展我国四氯乙烯生产的一些建议。     

四氯乙烯的生产和应用

介绍了四氯乙烯的生产及用途，分析了各种生产工艺的优缺点，提出了发展我国四氯乙烯生产的建议。     

The Principles and Applications of Chemical Vapour Deposition

Chemical vapour deposition (CVD) is a technique that relies on the formation of a gaseous species containing the coating element within a coating retort or chamber. Alternatively, the gaseous species may be generated external to the coating retort and introduced via a delivery system. These gaseous species (eg, chromous chloride) are then allowed to come into contact with the surfaces that require coating. The retort is held at a high temperature, normally in excess of 800°C. The application of this thermal energy and the presence of a reducing atmosphere results in the decomposition of the molecules containing the coating element which are subsequently deposited onto the surface of the substrate.

Using the CVD method a wide variety of coatings may be formed, ranging from soft, ductile coatings to those with hard, ceramic like properties. Coating thicknesses can vary from a few micron to over 200 mm, with hardnesses in the range 150–3000 HV (0.1Kg). Coatings formed by the CVD method are currently being used to combat the severe attrition of components used in a variety of industrial situations where corrosion, oxidation or wear is experienced.

The methods commonly used to apply CVD coatings will be discussed and their advantages and limitations examined. Several case studies will be highlighted, where CVD coatings have been used to solve specific industrial problems.     

Liquid-Liquid Chromatographic Separation of Neodymium,Samarium, and Gadolinium

Abstract

Neodymium, samarium, and gadolinium were separated by a liquid-liquid chromatographic technique. Sulfuric acid was more effective than hydrochloric or nitric acid as an eluent with di(2-ethylhexyl) phosphoric acid (EHPA) as the stationary phase. Recovery of 45% of the neodymium as >90% Nd₂O₃, 84% of the samarium as>99% Sm₂O₃, and 50% of the gadolinium as>99% Gd₂O₃ was achieved. The degree of separation and the time required for the separation can be varied by changing the concentration of the eluent and the number of stages in the system. A system comprising a primary amine organic extractant and an aqueous eluent containing diethylenetriaminepentaacetic acid (DTPA) was less effective for separating the rare earths.     

非溶剂对浇铸SPEEK膜性能的影响

首次采用磺化聚醚醚酮/N,N-二甲基甲酰胺(SPEEK/DMF)和非溶剂(四氯乙烯或对二甲苯)组成的铸膜液制备了SPEEK膜.采用交流阻抗法和隔膜扩散法分别考察了膜的质子传导性和透水性能.结果表明,由于在SPEEK/DMF中添加非溶剂,膜的透水率增加了约30％,质子导电率提高了50％左右.非溶剂的加入影响了铸膜液中聚合物的形态、尺寸和团聚情况,从而影响了成膜后膜的性能.本研究提出的控制膜微相结构的新方法将有助于提高SPEEK膜燃料电池性能.     

四氯乙烯混水法在镍阳极泥综合利用上的应用

在镍阳极泥的综合利用上，采有四氯乙烯混水法回收元素硫，有其独有的工艺特点和优势。通过试验确定了各工序的技术参数，指明了工序的技术要点。为保证产出的硫磺质量，提出并实施分液过滤法。该工艺具有贵金属富集倍数大、浸出速度快、能源省、产品质量好、溶剂经回收循环使用的特点，并且对以元素硫形态存在的高硫物料具有普遍适用性，是从其中回收元素硫的新技术。     

Adsorption of tri- and tetra-chloroethylene from aqueous solutions on activated carbon fibers

Recently the contamination of groundwater by trichloroethylene and related compounds have become a new environmental problem. As the first step to clarify the feasibility of applying newly developed adsorbent, activated carbon fiber (ACF), to adsorption treatments of water taken from such a contaminated groundwater source, the adsorption equilibrium and the adsorption rate of trichloroethylene and tetrachloroethylene from aqueous solutions on four ACFs with different pore-size distribution were investigated. The adsorption capacities of ACFs having larger volume of micropores are larger than those of granular activated carbons (GACs) usually used at present. Also, the adsorption rate on ACFs is far more rapid in comparison with GAC adsorption because of smaller diffusion path.     

聚氨酯橡胶表面DLC薄膜的制备及耐磨性能优化

目的 增强聚氨酯橡胶的耐磨性能。方法 选用四氯乙烯作为溶塑剂对聚氨酯橡胶进行预处理,再采用阴极放电等离子技术进行类金刚石（DLC）薄膜的镀制。通过扫描电子显微镜、拉曼光谱仪对制备的试样表面形貌和组成进行观察、表征。采用摩擦试验机对试样在干摩擦条件下的摩擦磨损行为进行分析,并观察试样的磨痕形貌。结果 随着四氯乙烯超声处理温度和时间的增加,基体表面原有条纹的深度呈现先增大后减小的趋势,镀制薄膜后,试样表面平整,且粗糙度逐渐降低;薄膜组成从非晶态碳结构,逐渐转变为金刚石相与石墨相混杂的典型类金刚石结构。在干摩擦过程中,镀膜试样的摩擦系数比未镀膜试样降低了40%以上,随着超声处理温度和时间的增加,镀膜试样的摩擦系数和磨损量均呈现先减小后增大的趋势,其中在50 ℃四氯乙烯超声处理15 min后,镀膜试样4的摩擦系数和磨损量最小。结论 四氯乙烯超声处理有助于改善聚氨酯表面DLC薄膜的摩擦性能,合适的四氯乙烯超声处理温度为50 ℃,合适的超声处理时间为15 min。     

Adsorption of chlorinated organic compounds on activated carbon from water

The adsorption capacities and rates of seven principal chlorinated organic compounds for six commercial GACs were investigated. All the adsorption isotherms were expressed by the Freundlich equation, and the isotherms for the chloroethylenes such as trans - 1,2-dichloroethylene, trichloroethylene and tetrachloroethylene could be shown by the modified Freundlich equation Q′ = k′ (C/C_s)^l/n for each GAC. The magnitude of adsorption of the chlorinated organic compounds was in the order of: tetrachloroethylene > trichloroethylene > trans - 1,2-dichloroethylene > 1,1-dichloroethane > carbontetrachloride > 1.1,1-trichloroethane > chloroform. The value of k for a certain GAC could be predicted from the quantity of pores smaller than 2 nm in diameter. The adsorbed amounts were decreased by 10–20% when humic substances coexisted. The working periods of a fixed bed adsorber before regeneration were predicted by calculating breakthrough curves for various influent concentrations of trichloroethylene and tetrachloroethylene at the space velocities of 5 or 10 h⁻¹, and it was certified that the adsorption method by GAC was feasible for removing these compounds from water.