Abstract: Slag ceramisites were made from steel slag，as well as a small percentage of clay and pore forming materials.Slag ceramisites were compared with raw steel slag in physicochemical property，phosphate removal efficiency，and isotherm adsorption.Results showed that slag ceramisites were light and porous，with higher phosphate removal rate.The isotherm adsorption data of both slag ceramisites and steel slag followed the Langmuir model at 20 ℃，however the maximum adsorption capacity of the former was 3.3 times of steel slag.X-ray fluorescence（XRF） and chemical extractions were performed on both slag ceramisites and raw steel slag，results showed that Ca2+ released from both materials to form phosphate precipitates was the most significant P removal mechanism achieved.Additionally，dicalcium phosphate was much higher in the exhausted slag ceramisites than steel slag.

Key words: steel slag, phosphate removal, isotherm adsorption, chemical extraction