Abstract: Boron-rich slag，obtained by treating boron-bearing iron concentrate based on carbon bearing pellet reduction and melting technology，was taken as the raw material.The composition of boron-rich slag was studied and then leaching experiments on it with H2SO4 were carried on.The influence of amount of sulfuric acid，reaction temperature，reaction time，and ratio of leaching liquid to solid on boron extraction rate was investigated respectively.Results showed that the mass fraction of diboron trioxide of the boron-rich slag reached 20%，and suanite and olivine were the main phases of the slag.In leaching experiments，it was found that boron extraction rates increased with the increasing of sulfuric acid amount，reaction temperature， and reaction time，while the extraction rates decreased with the increasing of ratio of liquid to solid.When the 80% of theoretical amount of sulfuric acid was added to the boron-rich slag，and the ratio of liquid to solid was 8 mL/g，reaction temperature was 40 ℃，and reaction time was 60 min，the boron extraction rate of the slag could reach 93.56%.

Key words: boron-rich slag, sulfuric acid leaching, boron extraction rate