Farmland passivator for treating soil heavy metal pollution and preparation method thereof

The invention discloses a farmland passivator for treating soil heavy metal pollution and a preparation method thereof, and belongs to the field of soil remediation. The passivator is prepared from the following components in parts by weight: 50-150 parts of MgO; 50 to 350 parts of KMnO4 modified active carbon; 50 to 250 parts of clay minerals; 100 to 200 parts of humic acid; and 50 to 200 parts of phosphate. The preparation method of the passivator comprises the following steps: grinding and sieving MgO, KMnO4 modified activated carbon, clay minerals, humic acid and phosphate according to theformula mentioned above, then injecting the powder into a suspension device, and mixing and stirring to obtain the passivator. The passivator is low in preparation cost, the operation is simple and easy, and various heavy metals in soil can be fixed and inactivated by the passivator and are converted into insoluble metal salts or alkalis. The activity, mobility and bioavailability of the heavy metals in the soil are grea