Novel approach for recovery of palladium in spent catalyst from automobile by a capture technology of eutectic copper

In worldwide, more than half of palladium is used to produce exhaust catalysts in the automotive industry. However, the recycling of palladium is a great challenge due to its low content and chemical inertness. A novel approach for recovery of palladium in spent catalyst material from automobile by a capture process of eutectic copper was proposed. In the capture process, copper is used as capture agent. The palladium is concentrated and entered the alloy phase under a certain temperature. Because the different density of the smelting slag and alloy, they are layered to realize the separation of the metals. The results were summarized as follows: (i) palladium in the spent catalyst material was captured by copper with 97% of recovery rate of Pd under optimal condition; (ii) the palladium atoms replaced to copper in Cu crystal to form Cu–Pd alloy by analysis of EDS, XPS and first principles calculation; (iii) the carrier of cordierite from spent catalyst material achieved glass transition and prepared the glass ceramics after the capture; (iv) a thermodynamic mechanism of the capture process of copper was proposed. Firstly, under molten state of the copper phase and the slag phase, palladium can be transferred from the slag phase to the copper phase when ΔEsurface = 2πrΔS1 (σpalladium-copper-σpalladium-slag-σslag-copper cosα)