Solving the Clogging Problem for an Iron Ore Storage Bin in the Direct Reduction of Iron Process: An Experimental Approach

The direct iron reduction process is a novel technique in the steel manufacturing industry. This is done by heating the iron ore palettes at high temperature and pressure. To stabilize the pressure a day bin storage is used before the reactor. This bin gets clogged due to the high residual iron dust. One of the solutions used is to introduce a cement–water mixture on the pallets before entering the day bin. This study investigated the use of several coating additives with various concentrations on iron ores to prevent clogging. An experimental setup mimicking the factory at a leading steel manufacturing company was constructed and similar conditions in terms of temperature and pressure were inducted to properly capture the effect of different solutions. The literature has addressed numerous solutions, but the analytical hierarchy process based on current conditions demonstrated that either adding sugar (Garci Juenger and Jennings in Cem Concr Res 32(3):393–399, https://doi.org/10.1016/S0008-8846(01)00,689–5 ) to delay the settling time of the cement or applying dry cement to wet iron ores. The analysis of variance (ANOVA) approach was then utilized to assess the statistical significance of the captured and analyze the settling setting time for both methods. Despite that the data illustrated that sugar reduced the risk of clogging by retarding the settling time by 55 min, pre-wetting, and dry cement on the iron ore before entering the day bin prevented clogging completely. Besides, the prewetting technique reduced the amount of cement to be sprayed on the iron ore compared to the currently used mixture by almost 30%. This study concluded that this solution significantly decreases the bin clogging problem as well as provides positive economic and environmental impact due to a reduction in cement use.