Silver removal from molten lead through zinc powder injection
(1. ESIQIE, Instituto Politécnico Nacional, UPALM 07738, México D.F., México;
2. CIIM-UAEH, Carretera Pachuca-Tulancingo Km 4.5, 42084, Pachuca, Hgo. México)
2. CIIM-UAEH, Carretera Pachuca-Tulancingo Km 4.5, 42084, Pachuca, Hgo. México)
Abstract: A silver removal process was carried out on a Pb-Ag alloy through zinc powder injection of three different sizes (3.55, 44.4 and 734.8 μm) with a top submerged lance using nitrogen as carrying gas. The higher silver removal was obtained for the zinc powder size of 44.4 μm, while the lowest silver removal efficiency was attained for the smaller particle size. The AgZn phase was detected in the slag for the 44.4 and 734.8 μm particle sizes by XRD, which was in agreement with SEM-EDS analysis. Experimental behavior was explained according to the melting and residence time of the injected particles.
Key words: lead; silver; particle size; powder injection; residence time; desilvering ratio