Studies On Preparation And Performance Of A Inorganic Polymer Flocculant-Poly Aluminum Ferric Silicate

Polysilicate aluminum ferrite chloride(PSiAFC)shows the excellent flocculent capability in water treatment, which made from kaolin by the step of Calcination, acid soluble and polymerization. By experiment of the PAFSC was used as coagulant in the treatment of simulated kaolin wastewater, the influence of various factorsr was researched in the process of preparation of polyaluminium ferric chloride(PAFC) and PAFSC and the flocculating effect was compared with Polymeric aluminium chloride(PAC), PAFC and PAFSC. IR, SEM and XRD analysis were used to characterized the PSiAFC.Through laboratory study, it is found that the best dissolving of aluminium was get by that the kaolinite calcined at 750 ℃for 2.5 hours and dissolved in a concentration of 20% hydrochloric according to the solid-liquid ratio of 6:1. The temperature of acid soluble is 90 ℃and the time is 2.5hours. We use PAFC as a coagulant to treatment the simulated wastewater by kaolin.The results shows that the max turbidity removal rate was 90%, When the reaction temperature was 70℃, reaction time was 2 hours, n(Al)/n(Fe) was 5:1 and the pH value was 4. On the infrared spectrogram of PAFC,we find that Al and Fe were polymerized well with –OH.According to the PSiAFC removal rate of wastewater, the best preparation conditions were determined. They are respectively temperature is 80 ℃, reaction time for 3 hours and the n(Si)/n(Al+Fe) for 1:3. The best conditions of flocculation also were determined that flocculant dosage is 0.4 g/L, wastewater pH value of 7-9 and the flocculation time for 20 minutes. The results also shows that the effect of the treatment of low turbidity wastewater are better than high turbidity wastewater.when we use PSiAFC to treat xiangjiang river water, the turbidity removal rate can reach 93%, COD removal rate for 84%, chroma removal rate for 75%. The treatment effect of PSiAFC on the xiangjiang river water is obvious higher than PAC and PAFC. Through the characterization and analysis of IR,XRD and SEM, we found that PSiAFC solid is a porous amorphous structure and it forms a iron-aluminum-silicon polymer.