Manganese and its compounds are widely used in various fields of the national economy such as ferrous and nonferrous metal industries, chemical and electrical industries, glass and ceramic industries and agriculture due to their unique physicochemical properties. This leads to the gradual depletion of high-grade manganese ores and, hence, growing concern is focused on the treatment of low grade manganese raw materials. Pyrometallurgy processing of low-grade manganese raw materials consumes a great amount of energy and produces huge waste volume and low yield. Therefore, it is suitable to process such raw materials by hydrometallurgy method.
Sulfuric acid is mainly used as a leaching solvent in the hydrometallurgy process of manganese raw materials. This leaching solution of sulfate contains different impurities such as Fe, Co, Ni, P and As. These impurities reduce the quality of manganese products and affect the technical and economic index of the production process. Hence, it is necessary to remove all the impurities in the liquid in order to obtain the desired product. The impurity which is found in largest quantities is iron. How to remove the iron in high concentration has a considerable effect on process yield, cost of production, working conditions and environments.
Jon Yong Nam, a researcher at the Faculty of Metal Engineering, has proposed a jarosite precipitation and an absorption method by manganese concentrate for removing iron from manganese sulfate leach, and comprehensively analyzed the basic experimental results for their applications.
In the synthesizing process of (NH4)2Fe6(SO4)4(OH)12 using MnSO4 solution, several factors including reaction temperature, reaction time, pH of reaction, seed addition, etc. have significant effects on the removal rate of Fe3+, among which the reaction temperature is the most prominent. The appropriate reaction conditions are 95℃ of reaction temperature, two hours of reaction time, 2.5 of pH of reaction and 15g/L of the addition amount of seed. After Fe in the solution is basically removed by the jarosite method, the remaining iron in the solution can be removed by Mn concentrate absorption. The absorption reaction condition is 65℃, 6.5~7 of pH, 6~8g/L of addition amount of Mn concentrate, and at this time, the Fe content in the solution can be ensured below 0.03g/L.
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