Studies were carried out to determine the effect of iron-containing and alkaline slags on carbon, graphite and refractory brick material used for blast furnace linings. It was established that alkalies are an essential factor making possible the sticking of accretions to blast furnace linings. The presence of zinc also reinforces slag accretions. In addition, 'bridges' of metallic iron arising from the reduction of FeO contained in the accretions have a binding effect on the accretions.