OIL ADSORBENT COMPRISING CONCRETE SLUDGE AND METHOD FOR MANUFACTURING THE OIL ADSORBENT

PROBLEM TO BE SOLVED: To provide a low-cost oil adsorbent having a high oil adsorption capacity and a low environmental load.SOLUTION: Cement slurry obtained by recovering washing water generated in a process of manufacturing a concrete product and then removing ballast and sand from the washing water is supplied to a reaction tank 4 equipped with agitating means 5, and while agitating the cement slurry in the reaction tank 4, carbon dioxide is supplied by carbon dioxide supplying means 2 to perform carbonization. The pH value of the cement slurry before the carbonization is about 12.5, and the pH value is lowered to a slightly alkaline pH of 11 or less by the carbonization. Subsequently, the cement slurry is separated into concrete sludge and sludge water through recovery means 3. The concrete sludge is dried and then crushed to obtain an oil adsorbent.