Lead refining

Fig. 12. Flow diagram of a fumace-ketde and/or aH-ketde lead refining process.

The lead-bearing components ate released from the case and other nordead-containing parts, followed by the smelting of the battery plates, and refinement to pure lead or specification alloys. The trend toward battery grid alloys having Httle or no antimony, increases the abiHty of a recovery process to produce soft lead (refined). As requited in the production of primary lead, each step in the secondary operations must meet the environmental standards for lead concentration in ait (see Air pollution Lead compounds, industrial toxicology). 

Low bismuth, low silver, pure lead Refined pure lead Pure lead Chemical copper—lead... 

The lead—copper phase diagram (1) is shown in Figure 9. Copper is an alloying element as well as an impurity in lead. The lead—copper system has a eutectic point at 0.06% copper and 326°C. In lead refining, the copper content can thus be reduced to about 0.08% merely by cooling. Further refining requites chemical treatment. The solubiUty of copper in lead decreases to about 0.005% at 0°C. 

An estimate of world calcium consumption in 1986 indicated that lead refining uses 30% alloys, eg, with Pb, Al, and Si, 25% steel treatment, 20% calciothermic reduction, 10% calcium hydride, 10% and miscellaneous usage is 5%. More recent evidence, however, has suggested that increasing consumption of calcium in battery manufacture has made this the most significant use. 

Weichblei, n. soft lead, refined lead, weichbleibend, p.a. remaining soft, non-hardening. 

Dezincing, lead refining by, 14 754-755 DGEBA-aromatic polyamine adduct system, 10 416, 417. See also Diglycidyl ether of bisphenol A (DGEBA)... 

Liquation, lead refining by, 14 752 Liquefaction process, 10 287-288 Liquefied gas propehants, 1 775 alternatives, 1 780... 

Wet-pit volute pumps, 21 65, 66 Wet-process kilns, 5 489-490 Wet process lead refining, 14 751 Wet-process phosphoric acids, 18 819-820, 824-826... 

Lead refinement where sufficient information has been accumulated to use (Q)SAR-based design of compounds to achieve higher (optimal) efficacy and/or better property profiles. 

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