World of Metallurgy ERZMETALL 68 2015 No 3 151 Paul B Queneau et al Recycling Lead and Zinc in the United States tained in spent lead acid batteries particularly as compo nents of newly manufactured batteries This advancement was driven by the battery manufacturers who looked for ways to control costs and reduce waste and also by suc cessful secondary smelters leadership as environmentally responsible operations Until the early 1970s batteries were dismantled by saw ing off the top of the battery then dumping the contents Figure 1 depicts a typical 1970s secondary lead processing flow diagram Non lead bearing components primarily hard rubber separators and sulfuric acid electrolyte were discarded Selective reduction of the lead bearing compo nents in a reverberatory furnace produced relatively pure soft lead for the refinery along with a PbO rich slag con taining the Sb Sn As alloying elements Sulfur was vented as SO2 after baghouse filtration to remove dust which was returned to the furnace The reverberatory slag was then further reduced in a blast furnace to produce hard lead bullion and discard slag Alternatively the decased batter ies i e the plates were smelted directly in the blast furnace to produce bullion matte and slag 5 During the 1980s the secondary lead industry installed efficient gravity systems to physically separate spent au tomobile batteries into manageable fractions as shown in Figure 2 Components in a typical spent auto battery are summarized in Table 2 analyses of the grid and paste fractions appear in Table 3 While not significantly different from past analysis changes have occurred to the alloys used in the manufacture of new batteries Calcium silver and selenium are now prevalent as alloying agents Antimonial alloys are currently used only for deep cycle applications Future changes to the lead acid battery will potentially introduce higher levels Fig 1 Typical 1970s secondary lead pro cessing flow diagram Table 2 Typical US automo bile battery compo nents Description Weight lbs Battery paste 14 Battery grids posts 9 Casing 2 Separators 1 Sulfuric acid 10 Total 36

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