フェロニッケルスラグの冷却条件と組織に関する研究

アルカリ骨材反応防止のための冷却条件

抄録

The effect of the cooling condition of ferro nickel slag melts on retained glass and crystalline phases (enstatite, forsterite, cristobalite) has been discussed.
Commercial ferro nickel slags were classified into two groups; one (slag A, B, C) was located the composition of the olivine (forsterite) primary phase field and the other (slag D)was the eutectic field between pyroxene (enstatite) and olivine in the FeO-MgO-SiO₂system.
The critical cooling rates for glass forming determined directly from the CCT diagrams were in the range of 120 to 20°C/sec and those were dependent on the content of SiO₂as a network former. Forsterite, enstatite, and ristobalite crystallized from all of the ferro nickel slags in that order with decreasing the continuous cooling rate. The first crystalline phase at isothermal heat treatment from the slag A, B, C was forsterite, while those of the slag D were forsterite and enstatite. Enstatite and cristobalite gradually crystallized with the holding time at this treatment.
In addition, the possibility of alkali-aggregate reaction were evaluated by the chemical test, ASTMC289 for the as-received and the heat-treated slags.