| 摘要 |
<p>PURPOSE:Sludge resulting from desulfurization and dephosphorization of molten iron with sodium carbonate is subjected to extraction treatment with CO2- containing hot water to separate and recover the unreacting sodium carbonate remaining in the sludge. CONSTITUTION:The sludge resulting from desulfurization and dephosphorization of molten iron with sodium carbonate is sent to the extraction process 1 and subjected to extraction treatment with a hot water with a Z-value (the molar ratio of CO2/Na) of more than 0.5, which is obtained by blowing a CO2 gas into hot water, to leach out and extract only sodium carbonate without extraction of SiO2 in the sludge. In the following filtration process 2, the extract is separated from the undissolving residue, then subjected to spray-drying 3 into a powder of fine crystals. The powder is washed with water in the washing process 4 to remove contaminants such as S, P, V and so on, then sent to the separation process 5 and the drying process 6 to recover sodium carbonate which is free from P, S and other contaminants and reusable in desulfurization and desphosphorization.</p> |
