Improving the early reactivity of activated basic oxygen furnace slag – The influence of particle fineness and grinding aids

Basic oxygen furnace slag (BOF slag), also known as Linz-Donauwitz slag, is an industrially by-product of the steel industry and produced during the converter process. In this research we have investigated the effect of grinding aids and particle fineness on the hydration of potassium citrate activated BOF slag. It was investigated the effects of five different grinding aids on the grindability and hydration of activated BOF slag in laboratory batch milling experiments. The grinding aids generally improve the grindability of BOF slag and therefore increase the particle fineness of BOF slag. This had the consequence that the hydration of activated BOF slag was improved. Only one grinding aid, triethanolamine (TEA) also improved the hydration of BOF slag besides providing higher particle fineness. The combination of the higher particle fineness and additional effect of TEA on the hydration improved the compressive strength to 60 and 78 MPa of activated BOF slag. An additional important of this research is that the hydration of BOF slag is significantly more sensitive on particle fineness compared to ordinary Portland cement.