The Prepared And Applied Study On Composite Flocculant Polyalumium Silicate Sulfate

A series of polyaluminum silicate-sulfates(PASS) with different basicities andAl/Si molar ratios were synthesized by the reactions of alum with sodium silicate andsodium aluminate. And their synthetic process, structure characteristics, aluminumspecies,product stability and coagulation performance were studied.It was found that the stability of aluminum-silicate mixture which was composedwith alum, sodium silicate and sodium aluminate played a key role in the synthesisprocess.In the subsequent polymerization reaction，the reaction temperature should keepin a low level. It would lead to the failure of the polymerization reaction if thetemperature was too high.The structure characteristics of PASS were analyzed by means of infrared,and thealuminum species in PASS aqueous solutions were identified with Al-Ferron complextimed colorimetric method. From the FTIR analysis，the Al－O－Si bonds existed in thesamples，indieating that Si was introduced into the poly-aluminum matrix and formedthe polymers. As expected that the content of Ala decreased, but the content of Alcincreased with the Al/Si molar ratio increasing, as a result, the degree of polymerizationincreased.The stability of the liquid product of PASS was studied in this paper. Theparameters of the process were discussed by the method of orthogonal design. Criticalfactor analysis revealed that the reaction temperature was the primary facter inimproving the stability of PASS product, and basicity, molar ratio of Al/Si and mixingspeed were followed by.The PASS was found to be more effective in the removal of turbidity bycomparison treating dyeing wastewater. The PASS had a wide applicable range of pH. Itcould achieve a good result in the removal turbidity.Basicity has an important effect onflocculation for PASS, in a contrast, molar ratio of Al/Si has a lesser impact.