SEPARATION OF PLATINUM METALS FROM SPENT AUTOCATALYSTS

11th International Multidisciplinary Scientific GeoConference SGEM2011, www.sgem.org, SGEM2011 Conference Proceedings/ ISSN 1314-2704, June 20-25, 2011, Vol. 3, 883-888 pp

ABSTRACT

In the world, over 18 million vehicles are rejected annually from operation. The spent
catalysts are obtained from the vehicles at the end of their life cycle as well as the
vehicles which do not meet the prescribed standards in the ECO test respected to the
composition of exhaust gases. The basis of each catalyst is a ceramic monolith with
deposited valuable platinum metals. The spent catalysts are solid waste and also the rich
raw material for recovery of precious metals. The aim of this paper is a separation of
present precious metals from spent catalysts. Samples of spent catalysts were used for
laboratory experimental researches with the following average content of platinum
metals: 0.2% Pt, 0.03% Pd and 0.005% Rh. A series of laboratory experiments was
carried out with the aim to examine the main parameters of translation process the
precious metals into ionic form. The tests were focused on selecting the most suitable
solvent, process time, temperature and ratio of solid: liquid. The highest degree of
transformation the precious metals into ionic form was achieved during the following
conditions of the leaching process: reagent of hydrochloric acid in the presence of
oxidant, process temperature 95oC, time 1 h and the S:L ratio of 1:3. The obtained
results indicate a high degree of extraction the precious metals >95 % from spent
catalysts for the automotive industry.

Keywords: autocatalyst, platinum, palladium, rhodium, leaching