Production, refined lead trends

Until the 1950s, the trend in world refined lead production was similar to that of mine output, as one might expect. After passing 1 million tons per annum in the early years of this century, refined lead production took almost another 50 years to exceed 2 million tons. However, between 1950 and 1970 refined production grew at an average annual rate of about 4 per cent, though rather erratically. By the end of this period refined output approached 4.7 million tons. 

The key longer-term determinant of refined lead output is clearly the trend in metal consumption, though there may be long and variable lags involved. However, in the short term production decisions may be more directly based around movements in prices, industry stockholding behaviour, or simply perceived changes in market sentiment. Thus refined output has tended to show quite severe year-to-year fluctuations around the long-term trends that we have identified, reflected in variations in smelter capacity utilisation rates. 

Many forecasts, or projections, of future lead prices are based around some form of supply/demand analysis. Conventionally, the starting point is the construction of a metal balance, linking forecasts of raw material availability, refined production, refined consumption, and including trade flows in concentrates and metal between Western countries and the Eastern Bloc (see Chapter 2 for historical lead industry balances). This ensures a measure of consistency between tbe various elements. The intended end result is a forecast of potential metal surpluses or deficits, and thus expected future changes in industry metal stocks. This, in turn can be used as a basis for forecasting future price trends through an iterative process which attempts to maintain the consistency of price, production and consumption projections. 

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). 

Trending of process variables is used to refine range limits [3]. Manufacturing data can lead to superseded NORs and/or MORs, which are justified by the associated operational trends and product quality achieved [20]. Extreme parameter values subsequently can become acceptable in process validation if the acceptability of final product has been confirmed by multiple observations [12]. 

A useful summary of levels and trends in mine and smelter production, and of developments in refined metal consumption is provided by the industry metal balance. The balance can be drawn up for particular areas or regional markets, but most commonly covers the Western World, see Table 2.2. It pulls together the various elements of Western World lead supply and demand (including, separately, net trade with the Eastern Bloc in concentrates and refined metal), and focuses attention on the overall balance between them, with metal surpluses or deficits expressed in terms of an apparent change in stocks over a given period (usually a quarter or a year). In this way, the prevailing market position can be (fairly) accurately assessed and compared with developments in price and other market indicators (like reported stocks, turnover, etc). The construction of a metal balance also often forms the basis of forecasts of future trends in supply, demand and price (see Chapter 16). 

WBMS publishes a monthly bulletin providing summary production, consumption and trade data for a range of non-ferrous metals, including lead. The organisation provides an annual supplement detailing world trade flows in concentrates and refined metal. Reflecting its background and location, the WBMS collects and publishes particularly comprehensive statistics on trends in UK supply and demand for the various metals. 

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