含硫酸镁废水石灰乳法制备氢氧化镁工艺中的分析方法建立

【作者】 程功；

【导师】 张跃军；

【作者基本信息】 南京理工大学 ， 应用化学， 2010， 硕士

【摘要】 红土镍矿制镍过程中产生含硫酸镁约10%的废水,而废水处理对制镍工艺至关重要。本课题组以硫酸镁废水为原料,采用改进的石灰乳法制氢氧化镁产品。本文研究该氢氧化镁制备工艺中的分析方法及其应用。氢氧化镁制备工艺中待分析物料可分为原料、中间产物和产品。对原料中生石灰、氯化钙的分析沿用文献方法；对原液中镁和硫酸根、中间产物中四种钙镁混液的分析,通过对取样方式和分析操作改进,完善氢氧化镁制备工艺中的分析方法；对氢氧化镁标准中缺少的硫酸根分析方法,在文献基础上建立新的方法,形成了一套适应于改进的石灰乳法含硫酸镁废液制氢氧化镁工艺的系统分析方法。进而,对整套系统分析方法进行精密度和准确度研究,对分析方法进行评价。此外,将系统分析方法应用于含硫酸镁废液制备氢氧化镁实际工艺,分别对其原料、中间产物和氢氧化镁产品进行跟踪分析,并对氢氧化镁制备工艺提出了改进建议。结果表明,整套系统分析方法分析原料、中间产物和氢氧化镁产品的标准偏差最小为0.01%,最高为0.50%,均在1%以下,相对标准偏差基本都在0.1%-2%范围内；分析方法的低、中、高浓度加标回收率最低为95%,最高为104%，均在95%-105%范围内,能满足氢氧化镁制备工艺分析的要求(精密度标准偏差<1%,准确度加标回收率在90%-110%)。应用该系统方法对工艺进行跟踪分析,同一工艺两次跟踪分析结果平衡稳定,氢氧化镁产品分析结果如下：氢氧化镁98.7%-98.8%,氧化钙0.32%-0.36%,盐酸不溶物0.21%-0.23%,氯化物0.26-0.28%,硫酸根0.34%-0.35%,铁0.27%-0.30%,水分0.30%-0.33%。由此可见,整套系统分析方法能准确分析氢氧化镁制备工艺中各工艺段物料分配和走向,进而实现为含硫酸镁废水制氢氧化镁工艺中原料采购把关,为氢氧化镁制备工艺中的过程控制提供指导,为氢氧化镁产品的质量检测提供标准,为优化含硫酸镁废液制备氢氧化镁工艺提供参考建议的目的。更多还原

【Abstract】 In this dissertation, a systematic series of analytical methods and its application were studied, to meet the analytical requirements of improved process for preparing magnesium hydroxide from the～10% magnesium sulfate wastewater generated from the nickel producing of laterite.Based on the magnesium hydroxide preparation process, the materials were classified and summarized as raw materials, intermediate products and products. The standards of lime and calcium chloride were directly used to analyse the raw materials. The analytical methods for the magnesium and sulfate in the magnesium hydroxide original fluid and the calcium and magnesium in four kinds of intermediate mixture, were approved via improving the sampling operating methods, so as to adapt to the practical technology. The analytical method of the sulfate in product was built based on references, since it is absence in the standard. All of these formed a set of systematic method, which is applied to the preparation process of magnesium hydroxide. Then, both the exactitude and accuracy of the analytic methods were studied, including the evaluation of the analytic result. In addition, the analytical methods were applied to the practical preparing process, and the suggestions for further improvement were given as well.As a result, the standard deviations of the systematic methods were below 1%, and the recoveries were from 95% to 105%. Tracking analysis of preparing process and the analysis of magnesium hydroxide were tested twice, and the results were basically stable. Results of products analysis were followed:the content of Mg(OH)2 in magnesium hydroxide were 98.7%-98.8%, and the content of impurity including CaO, HCl insoluble ash, chlorides, sulfate, Fe and moisture were 0.32%-0.36%, 0.21%-0.23%,0.26-0.28%,0.34%-0.35%,0.27%-0.30% and 0.30%-0.33%, respectively.It was showed that the systematic analytical methods can provide the precise imformation of the distribution and the ratio of materials, and these methods can meet the analytical requirements of raw material purchase, preparing process control, quality testing of products, and they were useful for technology optimization.更多还原