Application of hydrogen for producing soft iron and phosphorus-rich slag from high-phosphorus iron ore

The paper presents the results of experimental studies on the selective reduction of iron from high-phosphorus oolitic iron ore using hydrogen. It is shown that hydrogen, as an alternative to carbon monoxide, enables the production of metallic iron with low phosphorus content at relatively low temperatures. X-ray diffraction analysis was used to determine the phase composition of the samples after reduction roasting. During hydrogen reduction, α-iron is formed, while phosphorus remains in the form of iron, calcium, and aluminum phosphates. Micro X-ray spectral analysis revealed that at a reduction temperature of 900 ℃, phosphorus is virtually absent in the metallic phase. However, during the smelting of hydrogen-metallized samples at 1600 ℃, phosphorus transfers into the metallic phase due to its redistribution between slag and metallic iron under the influence of high temperature. To prevent this, lime was added to the crushed raw ore before smelting. The resulting mixture was roasted in a Nabertherm muffle furnace in an air atmosphere at 1200 ℃ for 1 hour. Roasting leads to the decomposition of iron phosphate and the formation of more stable calcium phosphates. As a result, hydrogen reduction of fluxed samples followed by smelting allows for the production of low-phosphorus soft iron and phosphorus-rich slag. Based on the analysis of the obtained results, a process flowsheet and a set of equipment were proposed for processing high-phosphorus iron ore to obtain soft iron and phosphorus-containing slag.