Batteries, lead-acid trade

Fleet operators and large scale industrial users of batteries are in a better position than the general consumer communities to collect discarded batteries. Because of the organizational structure of the former group, the establishment of collection systems within their existing organizations is relatively easy. The more difficult problem lies in the domain of domestic users, particularly the problem of the retrieval of batteries other than lead-acid batteries. The retrieval of spent automotive lead-acid batteries from domestic users, by far the most significant fraction of lead acid batteries, is relatively efficient because these batteries are sold on a trade-in basis in most cases. However, most consumer batteries are not sold in this manner. 

Metallic scrap is one significant source and can be pnrchased by the smelter or refinery at prices reflecting a nominal discount to the prevailing LME price for refined lead. However, the bulk of secondary lead is derived from the processing of recycled scrap lead-acid batteries. The trade is very localised with no general standard terms and the cost to the secondary smelter often simply reflects the cost of collection of scrap batteries. 

There is a well-developed and sophisticated network of trade in lead-acid batteries. This reflects both international imbalances in battery production and requirements (for original equipment and replacement units) and a high degree of intra-industry trade, based on a product differentiated by brand name, technology and performance. Trade is principally in SLI batteries, but both traction and stationary batteries are also involved, to a lesser extent. 

While concentrates and refined metal constitute the major material flows in lead, and are the ones for which regular statistics are most readily available, other industry raw and intermediate materials and products are also traded between East and West. Although accurate data is limited, China has been both a small importer and exporter of lead scrap in recent years, as have the Eastern European countries. In addition, there has been a small two-way trade in lead bullion in recent years. North Korea has regularly exported some 10-20000 tons of bullion annually, mainly to Japan, while the former USSR and Bulgaria have been minor, but sporadic, importers. The former USSR has also required the import of automotive lead-acid batteries, which it has satisfied with purchases from Italy and the former Yugoslavia, and from other Eastern Bloc countries. 

Even with knowledge of these dangerous properties, the world has not ceased to mine and trade lead the U.S. is a major international supplier. Indeed, the element has probably been mined for 8,500 years. About 123,000 metric tons of lead is extracted annually in the U.S., much of it in southeast Missouri, and another 1.2 metric tons is re-acquired from secondary production (recycling). As a whole, the world produces about 3-8 million metric tons a year - much of it now in lead-acid batteries, despite lead s known toxic properties - and that amount increases annually. ... 

Figure 18.22 shows that reducing the separator thickness improves cell voltage under high-rate discharge conditions. Although decreasing the separator thickness has a beneficial effect on cold cranking performance of the battery, it does have a deleterious effect on reserve capacity. This is because, with thinner separators, the volume of sulphuric acid adjacent to the plates is diminished, thereby decreasing the utilization of the lead and lead dioxide active material in the plates. This is illustrated in Figure 18.23. Thus there has to be a trade-off in selection of separator thickness to achieve a desired compromise between acceptable cold cranking performance on the one hand and acceptable reserve capacity on the other.

---