Chemical Form of Precipitate by Coprecipitation with Palladium for Separation of Trace Elements in High-Purity Metals

Abstract

The reductive coprecipitation with palladium has been reported for separation and pre-concentration of trace elements in high-purity metals. In order to evaluate the chemical forms of precipitate by this method, precipitates from acidic solution containing Se, Te, Au, Ag and Pd (only or mixture) were produced under the condition of quantitative precipitation and measured by X-ray diffraction and electron diffraction. The precipitates from solutions including single element were confirmed by X-ray diffraction or electron diffraction. In measurement of Te and Pd precipitate, X-ray diffraction peaks of each element were increase as leaving time lengthens. In measurement of Se precipitate, no X-ray diffraction patterns were found independent of leaving time in the acidic solution. But when leaving time was 24 h, electron diffraction spots of Se were found. The precipitates from solutions including mutual elements (mi xture of Pd and the other elements (Se, Te, Au and Ag)) were confirmed by X-ray diffraction or electron diffraction. In measurement of Pd-Au or Pd-Ag precipitate, these elements were respectively precipitated as elementary substance. However, in measurement of Pd-Se or Pd-Te precipitate, it was found that palladium selenide (Pd x Se y ) or palladium telluride (Pd x Te y ) was product.