| 摘要 |
<p>PURPOSE:To efficiently recover unreacted sodium carbonate from slag contg. sodium carbonate by subjecting the slag to extraction while keeping the Z value (molar ratio of CO2/Na) at a prescribed value and by carrying out concn. and separation. CONSTITUTION:Slag produced in a stage for desulfurizing and dephosphorizing molten iron with sodium carbonate is fed to an extractor 1, where it is subjected to extraction with hot water while keeping the Z value at 0.5-1 by blowing CO2, and the extraction residue is separated and removed by means of a filter 2. The resulting liq. extract is fed to an evaporator 3, and while regulating the Z value to 0.4-0.51 by adding sodium hydroxide, the extract is concentrated by heating to deposit sodium carbonate monohydrate, which is then separated by means of a solid-liq. separator 4 and recovered.</p> |
