Abstract: In order to improve the utilization rate of slaked lime in neutralization treatment of acid mine wastewater，reduce reagent consumption and reduce operating costs，aiming at the problems of large dosage and large sludge production in the treatment process of a high manganese acid mine wastewater in Maanshan City，based on the traditional neutralization treatment method，the experimental study of grading neutraliza⁃ tion treatment was carried out，and the target pH control value of grading neutralization treatment was deter⁃ mined. The results show that when the pH value of the first stage neutralization control wastewater is 5~6， and the pH value of the second stage neutralization control wastewater is 9.8，the total amount of hydrated lime added in the grading neutralization treatment is 2.23 g/L. The amount of hydrated lime was reduced by more than 40% compared with the traditional neutralization method. The amount of sludge produced by the grading neutralization treatment is 3.37 g/L，which can be reduced by more than 65% compared with the tra⁃ ditional neutralization method. The manganese content of the sludge produced during the secondary neutral⁃ ization treatment was 38.66%. The use of graded neutralization treatment can effectively reduce the amount of lime dosage and reduce the amount of sludge.

Key words: acid mine drainage, neutralization, segmented neutralization, high concentration manga? nese