Method of preparing inorganic macromolecular flocculant by polymerizing silicate and zirconium chloride

A method for preparing an inorganic macromolecular polysilicic acid and poly-zirconium chloride flocculant, wherein starting materials used for the preparation comprises sodium silicate, zirconium tetrachloride, sodium hydroxide, and sulfuric acid, comprising the steps of:

• (1) weighing the starting materials and preparing solutions of each of the starting materials;
• (2) adding the sodium silicate solution to 0.2˜0.3 mol/L sulfuric acid solution dropwise, continuously stirring at 500˜600 rpm at 20˜25° C., maintaining pH under 2 for the mixture of the sodium silicate solution and sulfuric acid solution, curing by resting for 3˜4 hours to yield a polysilicic acid solution;
• (3) adding the sodium hydroxide solution to the zirconium tetrachloride solution dropwise, continuously stirring at 500˜600 rpm at 20-25° C. until the mixture of the sodium hydroxide solution and the zirconium tetrachloride solution becomes colorless and transparent, curing by resting for 3˜4 hours to yield a poly-zirconium chloride solution with alkalization degree (B) of 0.5˜2.0;
• (4) measuring out appropriate amount of the polysilicic acid solution at a level that keeps molar ratio of zirconium/silicon in a range of 5˜20, adding the polysilicic acid solution dropwise to the poly-zirconium chloride solution under continuous stirring at 500˜600 rpm at 20˜25° C., continuing to stir at 500˜600 rpm at 20˜25° C. for 5˜6 hours, curing by resting for 20˜24 hours to yield the inorganic macromolecular polysilicic acid and poly-zirconium chloride flocculant.