| Rich-manganous slags are enriched from poor-manganous mineral, and the content of manganese is about 35%45%. The output of rich-manganous slags, the main material of smelting manganese-iron alloy these years, is 200250 kt in our country. For its single use, rich-manganous slags are liable to the fluctuant market of iron alloy industry. To developing the use of rich-manganous slags, this article discussed the technology of preparing manganese chloride by using rich-manganous slags as feed stock, hydrochloric acid as leaching solvent, and through pickling, impurity removing, crystallization and drying.In the process of pickling, it was studied the effect of leaching time and temperature, concentration and dosage of hydrochloric acid on leaching rate. The result shows:①Based on the orthogonality experiments, the sequence of all factors that affect the leaching rate is: temperature> HCl concentration> HCl dosage> leaching time;②The highest leaching rate of manganese is 87.74%, when HCl concentration is 2mol/L, leaching time 1h, temperature 25℃and HCl dosage 1.8 times as much as theory.In the operation of impurity removing, feasibility of iron separation was studied, so as selecting of neutralizer and precipitant, the method of manganese or magnesium separation by solvent extraction. It concluded:①Pickling solution was oxidated enough by MnO2 at 80℃, Fe3+ could be completely extracted for 20 minutes at room temperature by 0.9mol/L P204 dissolved in kerosene. It also could be hydrolyzed and then precipitated with aluminum(pH=56);②Manganese carbonate was selected as neutralizer;③Ca2+ could be precipitated by manganese sulfate;④heavy metal could be precipitated at pickling solution pH≈1.8, temperature 50～60℃and sodium sulfide as vulcanization precipitant;⑤Acidic extractant P204 is suitable for extracting manganese and magnesium. Separating Mn and Mg could be operated for 20 minutes at 25℃with 0.9mol/L P204 dissolved in kerosene by multistage counter-current extraction method. The average separation coefficient was 47.23, and the loading organic phase could be reconstituted by stripping with 2mol/L HCl.The manganese chloride could be obtained by concentrating, crysaling and drying decontaminated solution, in which the content of manganese chloride is 95.10%. The product could achieve industrial level. |
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