| 摘要 |
<p>The invention is to provide a method for removal of a lead ion in that a lead ion is effectively removed from an aqueous solution, such as a nickel chloride solution, containing a lead ion to a low concentration, and an organic solvent can be regenerated in an economical and effective manner, and it relates to a method for removal of a lead ion comprising a step of contacting, at least once, an aqueous solution containing a lead ion with an organic solvent having a thiophosphinic acid structure, to extract and remove the lead ion, and a method for removal of a lead ion from a nickel chloride solution comprising (a) a first step of contacting, at least once, a nickel chloride solution containing a lead ion with an organic solvent having a thiophosphinic acid structure, to extract and remove the lead ion; (b) a second step of contacting the organic solvent subjected to extraction of the lead ion with an acidic solution having a pH value lower than that on the extraction and removal of the lead ion and in a range of from 0.5 to 3.0, to put back a valuable metal having been extracted along with the lead ion to the nickel chloride solution; and (c) a third step of subjecting the lead ion contained in the extractant to stripping as lead sulfate by using a sulfuric acid solution, and separating the lead sulfate to regenerate the extractant.</p> |
