Possibilities Of Metals Extracton From Spent Metallic Automotive Catalytic Converters By Using Biometallurgical Method

Abstract

The main task of automotive catalytic converters is reducing the amount of harmful components of exhaust gases. Metallic catalytic converters are an alternative to standard ceramic catalytic converters. Metallic carriers are usually made from FeCrAl steel, which is covered by a layer of Precious Group Metals (PGMs) acting as a catalyst. There are many methods used for recovery of platinum from ceramic carriers in the world, but the issue of platinum and other metals recovery from metallic carriers is poorly described. The article presents results of preliminary experiments of metals biooxidation (Fe, Cr and Al) from spent catalytic converters with metallic carrier, using bacteria of the Acidithiobacillus genus.

Status of Recovery of Strategic Metals from Spent Secondary Products

“…The methods involve energy-intensive processes and/or the generation of large amounts of effluents to be treated. However, the hydrometallurgical recovery process has been shown to be the most economical option, with low energy consumption and an average PGM recovery efficiency of about 90% [29]. Aberasturi et al also demonstrated the recovery of platinum group metals from car catalytic converters using hydrometallurgical processing routes [39].…”

“…The proportion of Pt, Pd, and Rh is dependent on the level of emission control, metals prices, and the type of car [28]. The amount of Pt, Pd, and Rh in a carrier differs: for a small car it can range from 1 to 5 g, for a truck from 12 to 15 g [29], and for a sports car from 6 to 30 g due to the large quantity of exhaust gases [30]. The Pt concentration is larger than Pd and Rh: the range for Pt is 300-1000 ppm, for Pd it is 200-800 ppm, and for Rh it is 50-100 ppm [30] and other authors suggest that the total content of PGMs is lower than 1000 ppm [31,32].…”

“…The metallic monolith also comes in different components, such as Fe-Cr-Al-(Y), Fe, Fe-Al, or Fe-Cr-Al-Co. The addition of rare earth elements to FeCrAl alloys assists in improving the oxidation resistance of alumina at high temperatures by reducing oxidation rates and enhancing the scale of adhesion [29].…”