Study On The Preparation Of Manganic Manganous Oxide From Low Grade Rhodochrosite And The Control Of Its Forming Process

Ferrite is one kind of magnetic material which is widely used in communiction,the audio and video equipment,power switch and magnetic head industry,etc.And manganic manganous oxide is the main material to produce ferrite.It can be divided into four methods to prepare manganic manganous oxide from the raw stuff: electrolytic product of manganese,manganous salt,manganese oxide compound and manganese carbonate.Now in China the primary method to produce manganic manganousoxide is using the electrolytic product of manganese as raw stuff,the product produced though this method is high-quality and can meet the electronic grade manganic manganous oxide standard.However,with the exploitation of manganese resources,the method mentioned aboved faces the problems such as lacking raw stuff and cost raising.At the same time,most Mn-core resource in China is low grade rhodochrosite.Due to the quality of Mn-core resource and processing craft,this part of rhodochrosite can not be make full use,and will cause the waste of Mn-core resourse. In view of the problems above,this paper put forward a new craft route,which was preparing manganous sulfate from rhodochrosite by acid-leaching as raw material to get manganic manganous oxide. Through studying the course of the acid-leaching,the flow path and the important factors influencing acid-leaching was ascertained,and the optimum conditions were obtained. In the process of preparing manganic manganous oxide,though the contrast experiment of hydrolyzing-oxidizing of manganese sulphate and carbonized roasting of manganese sulphate,it was found that the production rate of hydrolyzing-oxidizing of manganese sulphate was low and the hydrolyzing-oxidizing of manganese sulphate was high production rate and high purity.Therefore,the important factors influencing production rate and impurity rate were found though the orthogonal experiments and single factor experiments.According to the above research work, the comprehensive conditions of the preparation craft were confirmed. It could be find that:① The optimum technological conditions of acid-leaching:leaching temperature was 80℃ ,ratio of liquid to solid was 5 to 1,leaching PH was 2,and leaching time was 4 hours.According to the technological condition of leaching manganese,leaching rate for manganese was 98.3%. ② The optimum technological conditions of carbonized roasting:molar ratio between urea and manganese sulfate was 2.1 to 1, molar density of manganese sulfate was 1.5, molar density of urea was 1.7,reation PH was 6.8, reation temperature was 65℃ and reation time was 2 hours. According to the technological condition of carbonized roasting,the production rate was 44.31%, the returns-ratio was 98.11%, the calcium ion concentration was 177.58ppm, total manganers was 70.86%, the sulfur content was 0.04%, the chlorine content was 0.10%, the moisture content was 0.30%, the average grain diameter was 3.2 microns and the relative surface area was 12m2/g, the product conformed to profession standard HG/T2835-1997 top-quality product request. The craft of preparation manganic manganous oxide from low grade rhodochrosite,can not only solves the problem of high cost of manganic manganous oxide,but also achieves the resources maximizing and solves low grade or abandoned Mn-core resource outlet question.Therefore,this craft has enormous economic efficiency and social efficiency.