Study On The Preparation Of Manganese Sulfate From Manganese Spar And Titanium White Waste Acid

As an important chemical material, titanium dioxide is the most widely used inorganic white pigments and its output accounts for 80% of the world's white pigments. Titanium dioxide is widely applied in pigment, paint, ceramic, aviation and other fields. At present, the main production methods of titanium dioxide including sulfuric acid process, chlorination process, hydrochloric acid process. Sulfuric acid process is mainly adopted in China. During the sulfuric acid process, sulfuric acid isn't into the final product but only as intermediate medium in the reaction. So a large number waste acid was produced during the sulfuric acid process. At present, pollution treatment is emphasized in china, but comprehensive utilization of the useful components in the titanium white waste acid is usually neglected. There are great gap compared with foreign countries and also inconformity with our country's sustainable development strategy. On the other hand the electrolytic manganese factory in china widely use rhodochrosite and sulfate acid as raw materials to prepare manganese sulfate and during this process a large number of sulfuric acid was consumed.In view of the problems above, this paper adopted acid leaching method to prepare manganese sulfate using white waste acid and poor rhodochrosite as raw materials. However, because of the high iron content in the raw materials, the iron content in the manganese sulfate leaching solution is very high. If using the traditional iron removal method to remove iron, then as a result of too much ferric hydroxide was generated, a large number of manganese ions would be lost. Aiming at this fact, this paper tried to use the electrodialysis technology to remove iron in order to increase the recovery of manganese ion.At first, this paper confined that the main components and their contents in the titanium white waste acid by experiments. The experimental results indicated that the iron concentration was 42.11g/L, the titanium dioxide concentration was 40.31g/L, sulfuric acid concentration was 3.143mol/L.Then the optimum conditions for acid leaching process which obtained by the leaching experiment were reaction temperature 25℃, ratio of ore to titanium white waste acid 1:2.5, ratio of liquid to solid 3.5:1and reaction time 4h. In this condition, the extraction rate for manganese was 82.9%.Electrodialysis technology was applied in removing iron from leaching solution in this paper too. The results showed that the separation effects of mixed liquid of manganese ion and ferrous iron,manganese ion and iron ion was not obviously, but it had a preferable separation effect(2.5:1) using EDTA as a complexion complex selectively with iron ion.To prepare manganese sulfate by using of poor rhodochrosite and titanium white waste acid as raw materials, can not only solves the problem of high cost of manganese sulfate, but also achieves to maximize the utilization of resources and the outlet problem for low grade or abandoned Mn-core resource. Therefore, this process has enormous economic efficiency, social efficiency and also conforms to our country's sustainable development strategy.