Abstract: Calcium silicate is a kind of industrial waste,after the extraction of high aluminum powders from fly ash.In order to study the calcium silicate′s absorbing performance,its adsorption to COD from the effluent of biochemical treated coking wastewater was studied.The absorbing performance of calcium silicate was investigated by analyzing the influencing factors including the wastewater′s pH,calcium silicate dosing quantity,and oscillated time.Results showed that the removal rate of COD could reach 46.3% when adsorption was equilibrious,under pH was 4，calcium silicate dosage was 3.15 g per 100 mL waste water，and the oscillated time was 45 min.Adsorption isotherms fitting results showed that the correlation coefficients of Freundlich and Langmuir isotherms were 0.984 3 and 0.969 respectively,and the correlation coefficient of Freundlich was higher.So it proved that the calcium silicate′s adsorption to COD from the effluent of biochemical treated coking wastewater was more suitable to the Freundlich isotherm model. 

Key words: calcium silicate, coking wastewater, COD