Determination of Manganese in Iron, Steel and Ferromanganese. II : Determination of Manganese in Ferromanganese

The suitable concentration of acids and other conditions in ferrous-permanganate method after oxidation with persulfate for the determination of manganese in ferromanganese were studied and the following results were obtaind. (1) On the relation between the amount of manganese and the requisite amount of phosphoric acid, using about 2g of ammonium persulfate in total volume of 200ml, the amount of phosphoric acid added must be increased with the increase of manganese content. But the amount of phosphoric acid necessary was smaller, when the total volume is made to 400ml and 4g of ammonium persulfate are used. (2) On the concentration of the acid, using 4g of ammonium persulfate in total volume of 400ml, 4～28mg of manganese was determined in the concentration range of 1.4～2.6N H_2SO_4 or 0.6～1.0N mixed acid of H_2SO_4 and HNO_3 (3:1). (3) Boiling the solution for 1～5 minutes gave quantitative results while a somewhat lower values were obtained when boiled more than 6 minutes. (4) From the above results, the suitable analytical procedures for the determination of manganese in ferromanganese were established and the analysis of several actual samples were carried out and good results were obtained