Abstract: Electrolytic manganese residue is the major solid waste generated in the electrolytic manganese industry,and its organic matter content is a critical parameter for environmental risk assessment and resource utilization potential evaluation.Aiming at the challenges encountered when potassium dichromate oxidation-titration is directly adopted for organic matter determination in electrolytic manganese residue,an improved analytical method suitable for electrolytic manganese residue samples was established through methodological modification and conditional optimization in this study.The interference behavior of Mn(Ⅱ) was emphatically investigated,and its allowable threshold was clarified.The experimental results indicated that Mn(Ⅱ) had no significant interference on the determination results when its mass fraction was lower than 5%.A self-assembled condensation reflux device was applied to effectively inhibit reagent volatilization in digestion process,thereby greatly improving the titration precision.After systematic optimization,the optimal reaction conditions were obtained as follows:reaction for 3.5 min from boiling in an oil bath at 170-190 ℃.The contents of organic matter in 5 electrolytic manganese residue samples were determined according to the experimental method.The relative standard deviations(RSD,n=11) of determination results were between 0.31% and 4.3%,and the recoveries ranged from 98.0% to 100.6%.The proposed method filled the gap in dedicated testing standards for organic matter in electrolytic manganese residue,and it provided reliable technical support for environmental compliance evaluation and safe resource utilization of electrolytic manganese residue.