A process and apparatus are presented for the direct production of molten iron from iron oxide ores in a metallurgical vessel. The process and apparatus involve decarbonization by oxygen blowing of an existing iron melt which has a carbon content above 1% and is covered with a slag layer. Heat is produced and the slag is oxidized and increased by foam formation. The thickness of the slag layer is continuously monitored, and overfoaming is prevented by directing into the melt an inert gas stream via charging units in the bottom of the vessel to counteract the formation of foam. Pulverized ore and carbon in an inert carrier gas are introduced into the slag foam through charging units in the vessel walls above the metal level. Blowing of oxygen and the injection of inert gas are regulated so that the slag level is essentially maintained at a fixed maximum height.