Determination of average valence of manganese in spinel lithium manganate by potassium hypermanganate back titration coupled with ammonium ferrous sulfate titration
TIAN Jian-kun1, ZHANG Li-min2, ZHANG Hai-lang*2, ZOU Ai-lan3
1. Department of Chemical Engineering, Xinyang Vocational and Technical College, Xinyang 464000, China; 2. School of Chemical& Material Engineering, Jiangnan University, Wuxi 214122, China; 3. School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 , China
Abstract：After a single weighting, the amount of substance of reducing electron for high-valence manganese in spinel lithium manganate was determined by potassium permanganate-sodium oxalate back titration method firstly, and then, the content of total manganese in solution was determined by perchloric acid-ammonium ferrous sulfate titration method in phosphoric acid medium. By subtracting the manganese in potassium permanganate, the content of manganese in sample could be obtained. Combining with the amount of substance of reducing electron, the average valence of manganese in spinel lithium manganate was calculated. The determination conditions were investigated in detail, including the water bath temperature, dosage of sodium oxalate, phosphoric acid and perchloric acid. The optimized experimental conditions were obtained. The proposed method has been applied to the determination of average valence of manganese in mixed spinel lithium manganate. The results were between 3.57-3.69, which was consistent with the fact that the valence of manganese in mixed lithium manganate was higher than 3.5. The relative standard deviations (RSD, n=5) were 0.26%-0.30%.
田建坤，张利敏，张海朗*，邹爱兰. 高锰酸钾返滴定法和硫酸亚铁铵滴定法联合测定尖晶石型锰酸锂中锰平均价态[J]. 冶金分析, 2011, 31(9): 63-66.
TIAN Jian-kun, ZHANG Li-min, ZHANG Hai-lang*, ZOU Ai-lan. Determination of average valence of manganese in spinel lithium manganate by potassium hypermanganate back titration coupled with ammonium ferrous sulfate titration. , 2011, 31(9): 63-66.
