湿化学法制粉中粉末颗粒的形成机制.Ⅰ——形核

在湿化学法制备粉体材料过程中,从过饱和溶液产生开始到最终粉末颗粒的形成,其间历经多个步骤。颗粒形成机制的研究就是通过理论分析和试验,揭示颗粒形成过程及其对颗粒结构、形貌和尺度的影响与控制规律。按形核、生长、团聚3方面介绍了湿化学制粉过程中的颗粒形成机制。     

固相诱导沉淀法制备单分散NiO微粒

将草酸以固体粉末形式添加到镍氨配合溶液中,沉淀出均一分散的草酸镍铵复合盐(类)球形颗粒,经热分解后可得到单分散NiO微粒。草酸以粉末形式加入,其固液界面对草酸镍铵沉淀微粒的形貌具有显著的诱导效应。实验研究表明,当配合溶液的氨镍摩尔浓度比等于5︰1(其中镍离子浓度设定为0.5mol·dm-3),反应温度为40℃,加入草酸后混合溶液pH值为8.8,反应时间为10min时,得到平均粒度为1.1μm的沉淀颗粒,450℃下热分解后粒子体积发生收缩,形成平均粒度为0.8μm的NiO微粒。该方法易于得到均一的单分散微粒,并可显著减小沉淀母液的体积量。     

Prediction of powder characteristics of uniform NiO precursor prepared by homogeneous precipitation

Uniform NiO precursor particles were prepared by homogeneous precipitation in the presence of urea. Optimal discrimination plan, one of the chemical pattern recognition techniques, was applied to analyze the experimental data and the quantitative relationships among the process parameters and powder characteristics of the obtained particles were determined. It proves that the model fits well with the experimental results and it is quite effective to guide the process design. Based on the above results, an improved La Mer model and the reasonable formation mechanism of the particles are proposed.     

多元醇还原制取球形钴粉

以自制 Co(OH) 2 为原料 ,乙二醇为溶剂和还原剂 ,制得了分散性很好的球形超细钴粉。研究了单位体积乙二醇中 Co(OH) 2 加入量对钴粉的粒径和形貌的影响。用SEM、XRD、BET和激光粒度分析仪测试粉体的粒子形貌、晶体结构、比表面积和粒度分布。测试结果表明多元醇还原的钴粉为球形 ,以面心立方晶体为主 ,还有微量的简单六方 ;钴粉粒度分布较窄 ,平均粒径为 0 .88μm,比表面积为 3 .46m2 /g,钴含量 >99.5 %。     

ITO废靶浸出过程研究

研究了铟锡复合氧化物(ITO)废靶回收工艺中的浸出过程,确定了最佳浸出工艺条件:温度363K;浸出后液酸度100g/LH2SO4;浸出时间120min;液固比8~12;ITO废靶粉粒度≤75μm。在此条件下,铟的浸出率大于99.5%,锡的浸出率为8.0%。     

湿化学法制粉中粉末颗粒的形成机制(Ⅱ):生长

有关晶体生长仍有一些值得研究的问题。在形核基础上,粉末颗粒进一步长大的方式有3种:生长,团聚,生长和团聚同时存在。介绍了晶体生长过程中的经典理论,总结了有关晶体生长研究的最新进展,指出了今后的研究方向。     

Life cycle inventory analysis of CO_2 and SO_2 emission of imperial smelting process for Pb-Zn smelter

1　INTRODUCTIONImperialSmeltingProcess (ISP) ,isaprocessavailableforproductionofzincandlead .Atpresent,about 13operatingISPsmeltersproduceabout 13%ofglobalzincandlead[1] .ButISPisasignificantcontributortoindustrialgreenhouseandacidityemis sionsduetoitshighenergyconsumption .Althoughcellemissionshavebeenreducedconsiderablyinre centyears ,thegrowingglobalconcernonenviron mentalissuesisimposingpressureontherelatedcom paniestoreducetheiremissions .Becauseofthelargenumberoffeedstreams ,by…     

Life cycle inventory analysis of CO2 and SO2 emission of imperial smelting process for Pb-Zn smelter

Based on the principle of life cycle assessment, CO₂ and SO₂ emission of Imperial Smelting Process in a certain zinc-lead smelter was analyzed by life cycle inventory method. According to the system expansion and substitution method, the environmental impacts of co-products were allocated among the main products of zinc, lead and sulfuric acid. The related impacts were assessed by use of Global Warming Potential (GWP) and Acidification Potential (ACP). The results show that the GWP index from 1998 to 2000 is 11.53, 11.65, 10.93 tCO₂-eq/tZn respectively, the ACP index decreases from 14.88 kgSO₂-eq/tZn in 1998 to 10.99 kgSO₂-eq/tZn in 2000. Power and electricity generation, followed by smelting and zinc distillation, are mainly responsible for GWP. Sintering individually affects ACP. Reduction in greenhouse gas emissions of the ISP may come from energy conservation measures rather than from technological developments. And recycling more secondary Pb and Zn materials effectively treated by ISP, and reducing the amount of primary metal are the main ways to put SO₂ emission under control. Biography of the first author: LI Qi-hou, postdoctor, born in Aug. 1972, majoring in ecodesign and the structure and morphology control of powders.     

高密度高活性球形Ni(OH)_2的制备研究

采用“受控中和水解法”进行了金属氢化物－镍电池用的高密度高比容量球形Ｎｉ（ＯＨ）２的制备研究，讨论了ｐＨ值、添加剂、加氨量等操作条件对Ｎｉ（ＯＨ）２堆积密度及电活性等性能的影响。实验结果表明：用本文论述的方法可以制得高密度高比容量球形Ｎｉ（ＯＨ）２颗粒，振实密度在２．０ｇ／ｃｍ３以上，比表面积在１５～２０ｍ２／ｇ。添加氨水后可以改变Ｎｉ（ＯＨ）２的结晶程度，采用复合添加剂比单一添加剂更能有效地提高Ｎｉ（ＯＨ）２的活性和改善镍电极的性能。使用该Ｎｉ（ＯＨ）２作为活性物质的电极，其容量可达到２６０ｍＡｈ／ｇ。这种Ｎｉ（ＯＨ）２特别适合于用作金属氢化物－镍电池的正极活性材料。     

粉末结构形貌控制新方法--生物矿化机理的模拟

介绍了生物矿化作用机理及其主要的生物控制因素,指出了模拟生物矿化机理控制粉末结构形貌的三个途径,展望了其发展趋势.