Preparation of New Type Poly-silicate Coagulant and Its Coagulation Property

摘要

A new poly-silicate coagulant named poly-aluminum-calcium-silicate sulfate coagulant (PACSS) was prepared to effectively eliminate suspended solids and organic matter in the wastewater. It was prepared by calcium carbide residue, sodium silicate, aluminum sulfate and sulfate as raw materials. The effects of silica acid activation pH, poly-condensation reaction time, mass fraction of Si02, molar ratio of Al/Si and molar ratio of Ca/Si on the coagulant preparation were studied. The optimal preparation conditions of this coagulant are as follow: the silica acid activation pH is 2; the poly-condensation reaction time is lh; the mass fraction of Si02 is 6%, the molar ratio of Al/Si is 0.8; the molar ratio of Ca/Si is 0.5 and the curing time is 6h. The results indicate that the removal rates of turbidity and CODCr of wastewater can reach up to 96.2%, 84.3% respectively. PACSS coagulant has a better coagulation effect compared with aluminum (AS) and polymeric aluminum sulfate (PAC).