The iron nugget process is an economical, environmentally friendly, cokeless, single-step pig iron making process. Residence-time dependent process requirements for the production of pig iron nuggets at a fixed furnace temperature (1,425°C) were investigated. Depending on the residence time in the furnace, three chemically and physically different products were produced. These products were direct reduced iron (DRI), transition direct reduced iron (TDRI) and pig iron nuggets (PIN). The increase in the carbon content of the structure as a function of residence time was detected by optical microscopy and microhardness measurements. Sufficient carbon dissolution for the production of pig iron nuggets was obtained after a residence time of 40 minutes. The pig iron nuggets produced had chemical and physical properties similar to blast furnace pig iron. They were liquid-state products, and the slag was completely separated from the metal.