Methods Of Analysis In The Magnesium Sulfate-containing Wastewater Milk Of Lime Prepared By Hydrogen Magnesium Oxide Process To Establish

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.