Endothermic reaction nature in presmelting stage requires thermal input in pre-reduction. If oxygen introduction for combustion heat generation is allowed, reduced iron ores will oxidized again. So selective oxidation is needed.
in order to cut fuel consumption and minimize off-gas evolution, is oxygen induction in smelting reduction chamber is better, or pre-reduction chamber is better?
Dear Sumit Bhowmick
You only need a low partial oxygen pressure to re-oxidize iron. This means you cannot combust to get energy and do the reduction if there is good contact between the combusted gas and the alloy phase(s). There must be some barrier between these two phases that will prevent oxygen from being transferred to the alloy, while transporting energy from the gas to the alloy.
One option is to have a slag phase as a separation layer. Slag is a poor thermal conductor, which will be a problem. Another option is to transfer energy via radiation while limiting mass transfer of oxygen to the alloy or pre-reduced phases. This is what is done in the ESS process invented by Mr Louis Fourie.
Kind regards
Johan
Probably possible. At temperatures lower than 570 degrees Celsius, carbon monoxide imbalances are already starting to form soot carbon and carbon dioxide: 2CO = C + CO2. And at the same time, the forming carbon dioxide reacts with hydrogen gas: CO2 + H2 = CO + H2O. Because, the tendency of oxygen to hydrogen is greater than the tendency of oxygen to carbon. This means that at the end of the iron recovery period (for example, in the furnace ducts), only CO and H2O are present.
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