| 摘要 |
<p>The present invention relates to a method for removing halides, in particular chlorides and fluorides, from starting secondary zinc oxides, for example Waelz or Primus oxides, comprising the steps (1) for washing the secondary zinc oxides with sodium carbonate and separating the solid residue from the basic liquid, (2) leaching at least one portion of the solid residue of step 1 by means of H2SO4, preferably up to a pH between 2.5 and 4, and separating the solid residue from the acid liquid, and (3) treating the liquid from step 2 by adding Al3+ and PO43−ions and a neutralizing agent in order to remove the residual fluoride, preferably at a pH<4, and separating the liquid from the solid residue containing fluorides.</p> |
