Abstract: White carbon black could be prepared from yellow phosphorus slag by nitric acid as leaching agent.The quality of white carbon black product was affected by the separation effect of CaO and Fe during the leaching process.The study showed that the leaching rates of CaO and Fe could reach 99.94% and 92.71%，respectively, and the content of Fe in solid white carbon black was 450 mg/kg；the content of silica（SiO₂） of prepared white carbon black could reach 99.20% （mass fraction）， specific surface area was 252 cm2/g，and white content was 88.51% under such optimum conditions as follow：reaction temperature was 100 ℃，fluid-solid ratio was 14∶1，mass fraction of nitric acid was 20%，reaction time was 6 h，and stirring speed was 350 r/min.

Key words: yellow phosphorus slag, nitric acid, iron, calcium