Study On Preparation And The Species Distribution Of The Polysilicate Aluminum Ferric Flocculants

A new method– ion exchange technique is used to produce polysilicic acid, which is then used as raw material to make polyaluminum silicate flocculants. Through processing papermaking wastewater, influences of Si/Fe molar ratio (Si/Al molar ratio), the pH and the dose on the flocculating effect are discussed, and the best preparing condition of the flocculant and the best conditions for wastewater treatment are obtained. On this basis, a series of polysilicate aluminum ferric has been prepared by changing the Fe/Al molar ratio, and influences of Fe/Al molar ratio, the pH and the dose on the flocculating effect are discussed, then the best preparing condition of the flocculant and the best conditions for wastewater treatment are obtained. The flocculating mechanism is discussed through measuring the species distributions and electrical characteristic of all series of Al flocculants. The morphological features of flocculant are observed by scanning electron microscope, and the influence of the flocculant morphology structure by adding to iron and aluminum is analysed. The flocculating mechanism is further discussed through it.The experimental results show that,compared with the traditional method, polyferric silicate(PFSC), polyaluminum silicate(PASS) and polysilicate aluminum ferric(PSAF)'s stability is enhanced by a new method.The primary factor which affects the flocculant performance is Si/Fe molar ratio (Si/Al molar ratio and Fe/Al molar ratio), and the best prepared condition of PFSC and PASS is determined that Si/Fe=1:30 and Si/Al=1:30; the best prepared condition of PSAF is determined that Si/(Fe+Al)=1:30, Fe/Al=1:1, and the species distributions show that, highly effective flocculant mechanism is that flocculant has the massive high polymerization material Fe_b(Al_b). The higher the Fe_b(Al_b) content, the better the flocculant effect, thus the wastewater disposal experimental result is explained theoretically, and the determination result of Zeta electric potential confirms this mechanism.