海藻または活性炭を吸着材とするコバルト・リッチ・クラスト塩酸浸出液からの白金の回収

抄録

In order to recover trace of platinum (Pt) from hydrochloric acid (HCl) leaching solution of Cobalt-Rich Crust (CRC), the absorption properties of four kinds of seaweeds (Undaria pinnatifida, Laminaria angustata, Enteromorpha linza and Gloiopeltis tenax) and activated carbon were studied. At first, their adsorption abilities for Pt ion as well as selective adsorption properties for other coexisting metal ions contained in CRC (including iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni) and copper (Cu)) were investigated by using artificial solutions. Finally, the application to CRC HCl leaching solution was also carried out.
The results showed that all seaweeds achieved their best Pt adsorption capacity only at pH 2, whereas activated carbon possessed a high Pt adsorption ability over a wide pH range from pH 0 to 6 as well as in HCl solution up to 3 mol/L. Regarding the CRC leaching solution obtained by 0.5 mol/L HCl and 1 vol.% hydrogen peroxide (H₂O₂), 46.9% and 100% Pt was recovered by Enteromorpha linza and activated carbon, respectively. It was found that seaweed and activated carbon are both effective adsorbents for recovering Pt from HCl leaching solution of CRC.