Method for preparing magnesium phosphate cement by using salt lake method low-grade phosphorus magnesium material

The invention relates to the technical field of magnesium phosphate cement material preparation, and particularly discloses a method for preparing magnesium phosphate cement by using a salt lake method low-grade phosphorus magnesium material, which comprises the following steps: (1) carrying out heat treatment on a mixed solution formed by polyacrylamide powder, acetone and polysiloxane powder, and grinding the obtained solid product to obtain a modified organic silicon defoaming agent. And (2) uniformly mixing the alkali liquor and the red mud powder, carrying out a heating reaction, adding water-soluble carbonate, standing, and taking the supernatant after the reaction is completed, so as to obtain the modified alkali-activated solution. (3) taking the following raw materials in parts by weight: the modified organic silicon defoaming agent, a modified alkali-activated solution, a sodium stearate solution, a low-grade phosphorus-magnesium material, a retarder, metakaolin, illite powder, sodium chloride, sodi