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废糖蜜还原浸出低品位软锰矿的工艺及动力学研究

Technology and Kinetics Study on Reductive Acid Leaching of Low-Grade Pyrolusite with Cane Molasess

【作者】 孙英云

【导师】 粟海锋;

【作者基本信息】 广西大学 , 化学工艺, 2008, 硕士

【摘要】 锰是冶炼合金钢的重要合金元素之一,锰盐在农业、轻工、化工等方面有着十分广泛的用途。因此,软锰矿浸出技术一直是国内外锰矿加工的一个重要研究内容。本文利用甘蔗废糖蜜这种可再生资源取代传统的无机物作还原剂,对在酸性溶液中还原浸出软锰矿的过程进行工艺和动力学的研究。在软锰矿浸出的工艺实验中,分别采用正交实验和单因素实验,探讨了反应温度、反应时间、硫酸浓度、废糖蜜浓度等因素对软锰矿浸出率的影响。通过单因素实验得出了浸出软锰矿的较佳工艺条件为:硫酸浓度2.35mol·L-1,废糖蜜浓度75g·L-1,液固比为4,搅拌速率为200 r·min-1,反应温度为90℃,反应时间为120min,Mn浸出率可达到95%及Fe 43.4%和Al 32.7%。通过对软锰矿中锰、铁和铝浸出的析因实验及单因素实验可知,温度和硫酸浓度是影响锰、铁和铝浸出的主要影响因素,铁的浸出率随废糖蜜浓度的增大而减小的。本文对锰浸出过程的动力学进行了研究,该动力学模型可用收缩未反应芯模型描述,实验结果表明反应属化学反应控制。表观反应活化能为45.62kJ·mol-1,硫酸浓度的表观反应级数为0.519,废糖蜜浓度的表观反应级数为0.280。符合反应动力学特征的锰浸出速率方程为:1-(1-x)1/3=2033.7/r0Ca0.518Cm0.280exp(-45.62/RT)t

【Abstract】 Manganese is one of the most important alloy elements in smelting alloy steel, but also manganese salt has intensive use in agriculture, light industry and chemicals. Therefore, the leaching technology of pyrolusite is always the important research content at home and abroad. The technology and kinetics of pyrolusite was studied in acid solution by using the cane molasses as reducing agent, which was the regeneration resource.The single factor experiment and orthogonal design were planned to study the effect of the process factors: temperature, time, sulphric acid concentration and cane molasses concentration and so on were taken in consideration in the experimental test. The optimum leaching condition were obtained using 2.35mol·L-1 H2SO4 and 75 g·L-1 cane molasses to pyrolusite for 120 min at 90℃and 200 r·min-1. These conditions resulted in leaching yields of 95% for Mn, with relatively low recoveries of 43.4% for Fe and 32.7% for Al.Temperature and sulphric concentration had the most important influence on the extraction of Mn, Fe and Al. Through the fractional experiment and single experiment, it was found the depression in Fe extractions in the presence of cane molasses.In addition, we had the study on the kinetics of the pyrolusite leaching. Leaching processing follows unteacted shrinking core model and the apparent activation energy was determined to be 45.62kJ·mol-1, the grades of sulphric acid and cane molasses were 0.518 and 0.280 respectively. It was concluded that the leaching process was controlled by chemical reaction control. The equation accorded with the kinetics characters was:1-(1-x)1/3= 2033.7/r0Ca0.518Cm0.280 exp((-45.62)/RT)t

【关键词】 软锰矿废糖蜜浸出动力学
【Key words】 pyrolusitecane molassesleachingkinetics
  • 【网络出版投稿人】 广西大学
  • 【网络出版年期】2009年 01期
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