• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.2
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• pp.76-81
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• 2006

The leaching behavior of heavy metal ions with pH and colloid/interface property was analyzed by ICP and SEM. The heavy metals in EAF dust are 'amphoteric metal' and the heavy metal ions leached a little at pH 10. And the leaching concentrations of heavy metals at pH 12 were higher than the that at pH 8. The leaching concentrations of heavy metal ion were decreased with adding the clay to the EAF dust. Especially, the leaching concentrations of heavy metal ion were effectively decreased at pH 12. The observation of colloid/interface properties shows that the soluble silicon hydroxide from clay at pH 12 was precipitated at the surface of the heavy metal and clay particles. This silicon hydroxide precipitates were named the PSHP. The leaching concentrations of heavy metal ion were effectively decreased by the formation of PSHP when adding the clay to the EAF dust and controlling the pH of the slurry at 12.