Method for preparing flocculating agent for red mud precipitation

The invention relates to a method for preparing flocculating agent for red mud precipitation. The flocculating agent is prepared by the following raw materials by the weight portion: 100 to 200 of acrylic acid, 100 to 200 of 50 percent sodium hydroxide solution, 100 to 200 of deionized water, 4 to 10 of Tween-80, 0.4 to 1.5 of evocating agent, 150 to 170 of organic solvent, 0.01 to 0.10 of sodiumbisulfite and 10 to 20 of alkylphenol polyoxyethylene. The method for preparing flocculating agent for red mud precipitation is as follows: the acrylic acid and the deionized water are neutralized bythe 50 percent sodium hydroxide solution until the PH value reaches 5 to 9, thereby obtaining aqueous phase solution; the Tween is dissolved in part of the organic solvent to obtain the oil phase solution, and the aqueous phase solution, the oil phase solution, the evocating agent and the rest organic solvent are led into a reaction kettle and are protected by nitrogen to be reacted for 5 to 12 hours at the temperature of 20 to 40 DEG C; and the sodium bisulfite is added, the mixture is filtered, and the alkylphenol polyoxyethylene is added so that the flocculating agent can be prepared. Applied to the production of alumina, the flocculating agent has the function of bridging flocculation, forms compact structure chelate with ions and can accelerate the precipitation.