重金属强化含金矿石的氰化浸出

通过分析铊、铋、汞和铅等重金属强化金氰化溶解的电化学原理,对含金氧化物矿石和难浸硫化物金精矿进行了重金属强化浸金研究.结果表明:重金属对金氰化溶解的阳极过程有显著的强化作用,但在常规供氧条件下,金的溶解速率并未显著提高;只有同时采用阴极强化措施,才能使重金属起到显著提高金溶解速率的作用;对于含金氧化物矿石,单独采用重金属强化即可明显提高浸金速率,如果在过氧化氢助浸的基础上添加重金属,金的浸出速率会有更大幅度的提高;对硫化物金精矿而言,单独采用重金属无明显强化效果,只有在添加过氧化氢作为辅助氧化剂的基础上,重金属对金的浸出才能起到强化的作用,该体系中过氧化氢起到了强化阴极过程和氧化硫化物的双重作用.     

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。     

形态对钯-氢体系热力学性质的影响

基于实验测定海绵Pd颗粒在278K-323K范围内吸放H2，D2的P-C-T曲线．结合文献给出的其它形态的Pd吸放氢结果进行系统比较分析．探讨了形态对钯-氢体系热力学性质的宏观影响和微观本质。在室温附近，氢的饱和固溶度与坪压随Pd的粒度减小而增加；Pd的形态或粒度对氢的饱和固溶度和吸氧坪压的影响程度刚随温度升高而减小，而且坪压之间的差别在温度较高时不再明显甚至消失。吸氘坪压差别大，解吸坪压差别小。Pd—H体系中α→β的相变热焓、热熵（绝计值)随粒度减小而减小，单晶Pd相应热力学函数最小。海绵Pd颗粒中的压力迟滞效应最明显．材料本底缺陷密度决定不同形态Pd-H体系的压力迟滞效应的大小。     

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。     

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.     

Synthesis and property of nanosized palladium catalysts protected by chitosan/silica

A chitosan (CTN)/silica‐supported nanosized palladium catalyst was obtained from a silica‐supported chitosan palladium complex through a complex transition method. An adsorption model was employed to simplify the structure of the di‐supporter. It was indicated that when the polymer coil adsorbed on the silica surface with even a monolayer the catalytic activity would reach an optimum value, and different situations of the, nanosized palladium particles would cause a different catalysis. The molar ratio of the chitosan structure unit to the palladium would affect the metal's size, which therefore influenced its catalytic activity. The experimental results corresponded with the inferences. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 989–994, 2002     

Characterization of nanoporous materials prepared from montmorillonite clay and its application to the decolorization of mare's milk oil

Nanoporous materials have been prepared by leaching the purified montmorillonite clay with sulfuric acid (H₂SO₄) solution with varying concentrations (0.5–2 M) at 80°C for 0.5–4 h. Acid leaching causes partial amorphisation of the clay with depletion of MgO, Al₂O₃, CaO and Fe₂O₃ components mostly from interlayer and octahedral sites. This increases the specific surface area by more than 3 times, i.e. from 49.1 to 157 m²/g. The pore-size distribution curves calculated from the adsorption isotherms of the leached montmorillonite show that most of the pores are in the mesoporous region with their diameter ranging 3–4 nm. This material turns out to be appropriate for bleaching of the mare's milk oil. The chemical and structural changes of the acid-leached montmorillonite are discussed in terms of the decolorization capacity.