The invention relates to a method for producing liquid pig iron (43) or liquid steel precursors from a hardening material formed by iron ore (5) and additives and having at least partially fines. To achieve a uniform reduction of the iron ore with optimum utilization of the reducing gas, the iron ore (5) is fractionated into at least two fractions, each of them having different grain size distribution, during a first reduction stage (1) with the help of the reducing gas. Each fraction is then reduced with the reducing gas in its own fluidized bed, whereby the reducing gas maintains a first fluidized bed (6) containing the coarse grain fraction and separates the fine grain fraction from it. An additional reducing gas is later introduced directly into the other fluidized bed (15). The reduced iron ore (5) is withdrawn both from the first and from the other fluidized bed (6, 15). The fine and coarse grain fractions reduced during the first reduction stage (1) are further reduced in ore or more additional reduction stages (2) operating in the same way as the first reduction stage (1). The fine grain fraction obtained during the last reduction stage (2) is fed into the smelting-gasification zone (39) under agglomeration by adding oxygen. The coarse grain fraction is gravity fed directly into the smelting-gasification zone (39).