The study aims to contribute the approaches for optimizing the parameters of the cohesive zone in blast furnace, as well as for enhancing the efficiency of novel alternative ironmaking processes. Wetting conditions between primary slag and iron sponge determine carbonization of the latter, thus affecting the position in the blast furnace of the region where slag and metal separate into independent liquid phases. Wetting of solid iron by molten FeO-containing slags representing the primary blast furnace slag was studied experimentally using a sessile drop method. Effects of the FeO content and slag basicity on the contact angle of slag on the iron substrate have been revealed. The opportunities of controlling the wetting conditions between primary slag and solid iron by optimizing the basicity of iron ore materials are discussed.