Sulfate removal from chemical industries' wastewater using ettringite precipitation process with recovery of Al(OH)3

Abstract The objective of this study was to investigate a simple and less expensive process for the removal sulfate from Iranian Chemical Industries Investment Company' wastewater using ettringite (a calcium aluminum (Ca 6 Al 2 (SO 4 ) 3 (OH) 12 .26H O)) precipitation process. optimum experimental conditions Al(OH) recovery were determined batch experiments. Using Ca(OH) allowed achieve pH (pH = 12–12.5) precipitation. final residual concentration is dependent upon aging time reagent dosage. Sulfate ions entirely removed in step fresh (after heating hydroxide 10 h at 350 °C) recovered with 61 46 h, respectively. initial sample also reduced than 20.04 mg/l after carbonation 95% efficiency. This method through decomposition precipitated under low highly feasible cost-effective sulfate-containing industries' wastewater.