Effects of slag composition and oxygen potential on distribution ratios of platinum group metals between Al2O3-CaO-SiO 2-Cu2O Slag System and Molten Copper at 1723 K

Waki Nishijima, Katsunori Yamaguchi

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The demand of platinum group metals (PGM) such as platinum, rhodium and palladium is recently increasing for a catalyst for decomposition of toxic gases in automobiles. The worldwide scarcity and high price of PGM accelerate the PGM recycling. The liquid copper has been used as a collector metal in one of the major methods for the recovery of PGMs from scraps of the automobile catalyst. With the aim of the minimization of the loss of PGM into slag phase, the distribution ratios of platinum, rhodium and palladium between the molten copper and the Al2O3-CaO-SiO2-Cu2O slag under MgO saturation with Q=0.36 and 0.52 (Q= (mass%CaO + mass%MgO)/(mass%CaO + mass%MgO + mass%SiO2)) were investigated at 1723 K in the range of the oxygen partial pressure 10-8 to 10-3 kPa. The copper solubility in the slag increases with increasing the oxygen potential, and liquid Cu2O separated from the Al2O3-CaO- SiO2-Cu2O slag with the oxygen partial pressure of 10 -3 kPa. When the distribution ratio of PGMs between the slag and liquid copper was defined as L3/CUPGM = (mass%PGM in slag)/[mass%PGM in Cu], L3/CUPGM for platinum, rhodium and palladium were almost constant with increasing the oxygen potential up to 10-6-10-5 kPa and increased in the range of higher oxygen partial pressure. Based on these distribution ratios, activity coefficients of Pt and Pd oxides in the slag were ther-modynamically calculated. The activity coefficients increase with increasing the oxygen potential.

Original languageEnglish
Pages (from-to)267-273
Number of pages7
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume78
Issue number7
DOIs
Publication statusPublished - 2014 Jul
Externally publishedYes

Keywords

  • Distribution ratio
  • Liquid copper
  • Molten slag
  • Platinum group metal
  • Recycling

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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