The chemical composition of the sinter obtained without Bakal siderite concentrate in the batch is calculated. The influence of Bakal siderite in the batch on the sinter composition is assessed. The sinter content in the blast-furnace batch, the MgO content in the slag, the slag yield, and the slag basicity are plotted against the content of siderite concentrate in the sintering batch. © 2012 Allerton Press, Inc.