Preparation method of flocculating agent for dyeing wastewater treatment

The invention discloses a preparation method of a flocculating agent for dyeing wastewater treatment. The preparation method comprises the following steps: 1) respectively grinding 7-8 weight parts of dolomite, 4-6 weight parts of ringwoodite and 2-4 weight parts of magnesium carbonate, enabling the grinded dolomite, ringwoodite and magnesium carbonate to pass a 370-380 mesh sieve, and calcining for activization for 5-6 hours at the temperature of 840-850 DEG C; 2) respectively grinding 170-180 weight parts of red mud produced by the Bayer process and 120-130 weight parts of red mud produced by the mixed combination process, allowing the two grinded red mud to pass a 400-450 mesh sieve, and calcining for activization for 2.5-3.5 hours at the temperature of 850-860 DEG C; 3) putting the activated dolomite, dolomite, ringwoodite, magnesium carbonate, red mud produced by the Bayer process and the red mud produced by the mixed combination process into a reaction kettle, adding 360-370 weight parts of hydrochloric