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Abstract

The invention relates to a method for the treatment of fluoboric electrolyte resulting from the processes of electro-extraction of metals such as copper and lead comprising a leaching stage with fluoboric acid, in order to recycle said fluoboric acid to be recirculated to said leaching stage devoid of impurities of metals such as Me=Fe, Zn, Ca, Mg, Cd, characterized in that it comprises the stages of: a) treating said fluoboric electrolyte comprising Cu(BF.sub.4).sub.2 or Pb(BF.sub.4).sub.2 with H.sub.2 S in order to precipitate CuS or PbS respectively in accordance with the reactions Cu(BF.sub.4).sub.2 +H.sub.2 S=>CuS+2HBF.sub.4 (1) Pb(BF.sub.4).sub.2 +H.sub.2 S=>PbS+2HBF.sub.4 (2) thus obtaining a solution of HBF.sub.4 containing the fluoborates of said metals Me, said solution being separated, b) treating said Me fluoborates with H.sub.2 SO.sub.4 in accordance with the reaction 2 Me(BF.sub.4).sub.n +n H.sub.2 SO.sub.4 =>Me(SO.sub.4).sub.n +2n HBF.sub.4 (3) (where Me=Fe, Zn, Ca, Mg, Cd) it being possible for said sulphates Me(SO.sub.4).sub.n to be removed so as to obtain a solution of HBF.sub.4 substantially free from impurities of said metals Me.

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First Claim