Chemical and biological method for synchronous resource treatment of three kinds of rare earth metallurgical wastewater

The invention discloses a chemical and biological method for synchronous resource treatment of three kinds of rare earth metallurgical wastewater, and belongs to the technical field of rare earth industrial environment protection. Specifically, ammonia nitrogen wastewater, magnesium sulfate wastewater and sodium phosphate wastewater are subjected to mixing proportion blending, the mixing sequence and the pH value of a system are controlled, and then chemical precipitation is performed, so that unified treatment of phosphorus removal, nitrogen removal and magnesium reduction is achieved, valuable elements in the three kinds of wastewater are fully utilized, MAP is generated and recycled, MHP is prepared through roasting, and the MHP serves as an ammonia nitrogen adsorbent to be reused. The effluent is deeply treated by a biological method, and a nitrobacterium agent is utilized to carry out a specific fermentation process so as to treat residual low-concentration ammonia nitrogen, phosphorus elements and magne