Study on Extraction of Mesophase from Steel Slag by Potassium Hydroxide-Sucrose (KOSH) Solution Method

The mesophase (iron aluminate, etc.) in steel slag was extracted by potassium hydroxide-sucrose (KOSH) solution method. The effects of partical size of steel slag, temperature and time of extraction on dissolution of mesophase phase were studied. The composition and morphology of the residue were analyzed by XRD and SEM. The results show the mesophase in steel slag powders (the weight was and the fineness was) could be fully dissolved when 4.00 g sample with a fineness about 600m2/kg is used and extraction temperature is kept at 90oC, however, other minerals in the steel slag could be hardly dissolved. The reason might be for that, in alkaline environment which provided by potassium hydroxide, the replacement of ions were took place between the mesophase in steel slag and the organic ligands formed by sugar and potassium hydroxide, and through the adsorption and polarization between ligand and steel slag surface, it will result in the decrease of activation energy of iron aluminate.

Influence of Slag Fineness on High-Performance Concrete Properties

This research focuses on investigating the high performance concrete containing slag with different fineness and dosage. For this purpose, the workability, compressive strength at different ages, and chloride ion penetration were investigated, with slag surface area 420m2/kg, 530m2/kg, 610m2/kg, and 720m2/kg, and replacement percentage 0%, 20%, 40%, and 60%, respectively. It was found that the workability and chloride ion penetration resistance were affected by the fineness and dosage of slag. The 7-day compressive strength decreased with slag replacement increasing when the fineness of slag is lower than 530m2/kg, and 28-day and 56-day compressive strength increased; For the fineness higher than 530m2/kg, the 7-day compressive strength is higher than that of control concrete, when the slag replacement was 40%, the concrete reached the highest value, and the 28-day and 56-day compressive strength increased with slag incorporation.