METHOD FOR RECOVERING BLAST-FURNACE GAS AND USE THEREOF FOR MAKING CAST IRON

摘要

The invention concerns a method for recovering blast-furnace gas, whereby the gases derived from the blast furnace are recovered, the carbon dioxide present in the gas is at least partly eliminated during a first CO2 purification step, so as to generate blast furnace gas depleted in carbon dioxide, said gas being either re-injected into the blast furnace, or recovered and sent to another site for use, after purification. Said method is characterized in that after the first carbon dioxide purification step, it provides for a second purification step of a substantial amount of nitrogen contained in said gas, so as to recover a rich gas, prior to re-injection or recovery to another site of use, whereof the nitrogen concentration is less than 10 vol. %, preferably less than 5 vol. %.