Preparation of fly ash-based flocculant and flocculation performance

Abstract

Using fly ash from a thermal power plant in Yingkou City as raw material, The inorganic polymer flocculant polyaluminum ferric chloride (PAFC) was prepared by sodium carbonate impregnation, high temperature roasting activation, and acid leaching. The influence of activation temperature and activation time on the leaching of aluminum and iron was investigated through single factor test and orthogonal test. The PAFC preparation conditions were optimized, and the prepared PAFC flocculant product was applied to kaolin turbidity water. The test results showed that the content of aluminum in fly ash was 7.08%, and the content of iron was 4.95%. The mass ratio of the activator sodium carbonate and fly ash was 10:7, the activation temperature was 800°C, and the activation time was 2h. The leaching rates of aluminum and iron were the highest, 88.31% and 53.66% respectively. The optimal conditions for the preparation of the flocculant were as follows: the molar ratio of aluminum to iron was 5.7:1, and the reaction time was 1.5h. The liquid product obtained under these conditions was yellowish brown, and the solid product obtained after being dried was yellow powder.