Production of iron powder from hematite iron ore by using non-coking coal through Hoganas process and comparison of its properties with Hoganas sponge powder grades

Nowadays, the need for iron powder in various industries, especially in powder metallurgy, is increasing due to the development of production of parts in powder metallurgy. In this study, iron powder was produced using the Hoganas process in a laboratory scale. The iron ore concentrate was pressed to form a hollow cylinder and afterward was buried in a mixture of non-coking coal and calcium carbonate and placed in a cylindrical steel mold.The reduction process by the mixture of non-coking coal and calcium carbonate was carried out at 1050 °C for different times. The degree of reduction was measured based on the weight loss and degree of metallization using wet chemistry method. The produced sponge iron was then turned into powder under crushing and subsequently annealed in a belt furnace under a broken ammonia atmosphere at 870 °C.Optical microscopy and scanning electron microscopy were used along with X-ray diffraction technique to detailed characterization of the produced powder particles. The results indicated that the degree of metallization of the produced iron powder reached to 95 ± 1 and 98 ± 1 percent before and after the annealing process in the ammonia atmosphere, respectively. A comparison between the properties of the produced spong iron powder with those of the Hoganas grades reveals that it is possible to produce iron powder with metallization degree of higher than 98 percent in laboratory scale by means of hematite iron ore and non-coking coal in Hoganas process.