共查询到17条相似文献,搜索用时 62 毫秒
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水合碳铝酸钙深度脱硅的工业实践 总被引:7,自引:2,他引:5
详细地论述了水合碳铝酸钙合成的机理,利用水合碳铝酸钙深度脱硅的机理以及在工业生产中的应用,使烧结法精制铝酸钠溶液的硅量指数由400-480提高到600以上,同时产品氧化铝的质量有了明显的提高。 相似文献
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在烧结法氧化铝生产工艺中,为了保证产品质量,必须对粗液进行脱硅,而基于形成水合铝硅酸钠的脱硅路线,由于渣中硅含量高、铝损失少,是进行粗液第一步脱硅的必要步骤。烧结法氧化铝生产,采用粗液常压预脱硅—中压压煮脱硅—加石灰常压深度脱硅的三段脱硅工艺,对粗液一段常压预脱 相似文献
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六方水合铁酸钙的合成及其脱硅 总被引:1,自引:0,他引:1
通过正交实验对六方水合铁酸钙的合成温度、合成时间和合成体系中CaO与Fe2O3的摩尔比及合成体系的搅拌强度等因素对其脱硅效果的影响进行研究,并给出六方水合铁酸钙的最佳合成条件。结合X射线衍射分析讨论水合铁酸钙的脱硅机理,提出水合铁酸钙是一种高度分散的含钙化合物,其晶面间距较大,脱硅活性较高,并可大幅度降低铝损。在最佳条件下添加水合铁酸钙进行深度脱硅时,脱硅后铝酸钠溶液中的SiO2含量可降低到7 mg/L,硅量指数可达14 000,且脱硅产物中SiO2的饱和系数可达0.46。 相似文献
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烧结法生产一级品Al2O3 总被引:1,自引:2,他引:1
烧结法生产Al2O3在我国已有40余年的历史,在技术进步上有多方面的重大成就,生产冶金级Al2O3以三级品为主,兼有部分二级品,与拜耳法种分产品相比,产品级别和Na2O的含量仍有差别,并反映到价格上的差别,开发和应用新的脱硅与分解技术,生产与种分质量相当的碳分产品,有利于低钠化学制品的生产,提高冶金级产品在市场的竞争力,提高企业的经济效益。 相似文献
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针对一水硬铝石型铝土矿采用联合法生产氧化铝、添加石灰脱硅和石灰法回收镓的国情,提出用烧结法系统产出的铝酸钙替代石灰去拜耳法溶出方案,试验表明,不仅回收了铝酸钙中Al2O3,对拜耳法溶出率也无不利影响。故可作为降低联合法生产氧化铝成本的途径。 相似文献
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Gui-hua LIU Wen-bo DONG Tian-gui QI Qiu-sheng ZHOU Zhi-hong PENG Xiao-bin LI 《中国有色金属学会会刊》2017,27(8):1878-1887
The stability of calcium oxalate is critical for the removal of sodium oxalate from sodium aluminate solutions. This study investigated the behavior of calcium oxalate in sodium aluminate solution containing sodium carbonate. Results show that calcium oxalate can be converted to tricalcium aluminate hydrate (TCA) and calcium carbonate in sodium aluminate solution and sodium carbonate solution, respectively. Elevating temperature, extending residence time, or increasing caustic soda concentration enhances the conversion ratio of calcium oxalate in sodium aluminate solution; as a consequence, anti-causticisation occurs. Stability of calcium-containing compounds in sodium aluminate solution containing sodium carbonate differs from that in sodium aluminate solution or sodium carbonate solution. Na2CO3 in aluminate solution accelerates the transformation of calcium oxalate; thus, alumina is lost because of 4CaO·Al2O3·CO2·11H2O and TCA formation. Calcium carbonate, 4CaO·Al2O3·CO2·11H2O and calcium oxalate can change into TCA in sodium aluminate solution at elevated temperature. Calcium oxalate remains relatively stable in dilute aluminate solution within a short residence time at low temperature. Thus, a novel process for removal of sodium oxalate by lime causticisation was presented and employed in an alumina refinery in China. 相似文献
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The liquor concentration, mineral proportion, crystal parameters and micro morphology of various desilication products (DSPs) precipitated in silica-supersaturated sodium aluminate solution at 95 °C under different reaction conditions were systematically researched. The DSPs formed under atmospheric pressure comprise amorphous phase, zeolite A, zeolite and sodalite, and the DSPs concentration and crystallinity increase with the increase of initial silica concentration, initial molar ratio of caustic Na2O to Al2O3 (αK) and desilication duration. Decreasing the initial silica concentration, initial αK and increasing the desilication duration can reduce the proportion of zeolite A. The zeolite and sodalite are the stable DSPs, while the precipitation of zeolite A occurs at a high silica-supersaturated state in sodium aluminate solution. The DSPs are precipitated in the form of agglomerates, but the morphologies of various DSPs are quite different. Both the molar ratios of Na2O to Al2O3 and SiO2 to Al2O3 in DSPs increase with the increasing desilication duration, resulting in the increase of the cell volumes of various DSPs. The precipitation sequence of DSPs under atmospheric pressure is: amorphous phase→zeolite A→zeolite→sodalite. 相似文献
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氧化钙或氢氧化钙与浓碱铝酸钠溶液的反应特性 总被引:15,自引:4,他引:11
研究了氧化钙、氢氧化钙与浓碱铝酸钠溶液的反应特性,在相同条件下,氧化钙的反应活性高于氢氧化钙,这归结于氧化钙在水化放出大量热量的同时,固相颗凿细化,比表面积增大。较多量的氧化钙加入反应体系后,体系主要因固相颗粒团聚容易发生膨胀。玎的扫描电镜分析表明:加入表面活性剂后,表面活必有因吸附“挤占”了新生因相表面吸附的小分子,破坏或削弱了体系的团聚,从而消除和体系的膨胀;同时,表面活性剂的会降低了固液界面 相似文献
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本文介绍了碳分、种分工艺对精液硅量指数A/S的不同要求,认为种分精液单独生产是很有必要的.本文从理论上分析了目前所应用的脱硅工艺,提出了一种常压生产种分精液的方法-常压混合脱硅工艺,并对某厂采用此工艺进行种分精液生产的情况进行了简单的介绍. 相似文献
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α-alanine was adopted as a new additive to elucidate the seeded precipitation mechanism of sodium aluminate solution. α-alanine has the inhibitory effect at the initial period of reaction, but the favorable effect in subsequent reaction. The combined effect of amino and carboxyl group in α-alanine was confirmed by investigating the effect of propionic acid, ethamine and the mixture of propionic acid and ethamine (mole ratio 1:1) on the precipitation of sodium aluminate solution, respectively. The inhibitory effect derives from the adsorption of amino or carboxyl group in α-alanine on the active surface sites of gibbsite, which was confirmed by the alleviating inhibitory effects of propionic acid, ethamine and α-alanine due to the double crystal seed mass. The semi-quantitative IR spectrum analysis of the relative concentrations of Al2O(OH)62- with the band at about 550 cm-1 and polynuclear aluminate ion with the bands at about 880 cm-1 and 635 cm-1, indicates that the dynamic balance among some aluminate species present in sodium aluminate solution is broken due to the addition of α-alanine, thus resulting in the change of the seeded precipitation ratio of sodium aluminate solution. 相似文献