Manganese carbonate only affects the indicators of the phosphating solution and does not directly affect the quality of the phosphating film. The amount of manganese ions in the phosphating solution, rather than manganese carbonate, affects the quality of the phosphating film. That is to say, the phosphating film is not generated by manganese carbonate, but by manganese dihydrogen phosphate. The content of manganese ions has a significant impact on the phosphating film, and the heavy metal indicators in manganese carbonate also have a particularly significant impact on the phosphating sediment, especially zinc, sulfate, etc. Fine adjustments need to be made for different materials of workpieces.