Additional samples from Cleveland Cliffs will be obtained and examined. SEM analysis indicates the phosphorus is most likely present as calcium phosphate in the gangue. Determine the behavior of phosphorus during the melting of DRI and HBI to determine if it remains with the gangue or is transferred into the metal. This will be accomplished by fast melting and analysis and possibly by use of a laser confocal microscope to examine the actual melting process. Fast melting experiments have been conducted and are currently being analyzed.
Initial results indicate that the phosphorus is transferred rapidly to the metal during melting.
The fast rate is due to the fact that the gangue particles containing phosphorus are very small and, consequently, the surface area with the metal enormous. Before the particles can separate they react very rapidly. This was confirmed in experiments using the laser confocal microscope in examining melting. The rate and rate controlling mechanism for transfer of phosphorus from slag to metal or metal to slag will be determined in laboratory experiments. These will be done on a laboratory scale of about 100-200 grams in an induction furnace.