Extraction and recovery of Au, Sb and Sn from electrorefined solid waste

Acid leaching of gold, antimony, and tin from the electrorefined solid wast e was investigated. The parameters affecting the leaching process such as, acid concentration, shaking time, temperature, chlorine gas and pulp densit y were evaluated. Quantitative extraction of Au from the leaching liquor co ntaining Sb and Sn species in HCl (2 M) employing Aliquat-336 in kerosene ( 10% (v/v)) was achieved. Maximum recovery (99.2 +/-3.4%) of Au from the or ganic phase was obtained quantitatively using thiourea-hydrochloric acid (2 % (w/v), 0.2 M) stripping system. Quinol solution at 6% (w/v) concentration was found able to reduce Au(III) in the striped aqueous solution to Au. Ex traction of Sb species from the leachant liquor at HCl (6 M) was quantitati vely obtained using Aliquat-336 (10% (v/v)) in kerosene after oxidation wit h 8% (w/v) sodium periodate. The Sb(V)-Aliquat-336 ion associate in the org anic phase was then stripped as Sb(m) by reduction with oxalic acid(l M), p recipitated as Sb2S3 by sodium sulfide (2% (w/v)) and finally reduced to Sb with hydrogen. Sn(IV) species in the leachant liquor containing HCl (6 M) was reduced to Sn(II) with zinc granules (6.5% (w/v)) and extracted with Al iquat-336 (10% (v/v)) in kerosene as an ion associate. The produced complex ion associate was then stripped from the organic phase using sodium hydrox ide (1 M), precipitated as Sn(II) oxide and finally reduced to Sn with hydr ogen. (C) 2001 Elsevier Science B.V. All rights reserved.