| 摘要 |
<p>PURPOSE:To improve the efficiency in recovering zinc in the method for thermally decomposing the filtrate of the ammonium carbonate eluate of zinc by repulping the substitution-cleaned pressure filter cake and then distilling the obtained dust slurry. CONSTITUTION:A zinc-contg. slurry 1 of blast-furnace dust, etc., is mixed with NH3, supplied to a thickener 2 and then introduced into a soln. tank 6. Carbon dioxide 7 and aq. ammonia 8 are supplied, the obtained zinc carbonate eluate is transferred to a soln. tank 14, H2O2 15 is added, and then the zinc carbonate slurry is filtered by a pressure-filtration cleaning machine 16. The zinc carbonate eluate obtained by sprinkling and depositing aq. basic ammonium carbonate on the filter cake is substitution-cleaned, the slurry repulped with hot water is supplied to an NH3 recovering distillation tower 22, and the slurry is recovered as an iron recovering dust slurry 24. Meanwhile, the basic zinc carbonate soln. is distilled by a distillation tower 28 to recover (NH4)2CO3, the slurry from the tower bottom is concentrated and filtered, and the cake is dried and cooled to recover zinc carbonate 33. The zinc eluate is surely separated from the dust in this way.</p> |
