Chapter 4 - Lead Industry Profile
LEAD PRODUCTION
About 60% of lead produced world-wide is derived from ore. Lead ore is mined in many countries around the world, though three quarters of world output comes from only six countries: China, Australia, USA, Peru, Canada and Mexico. Small amounts are mined in several countries in Europe, with the biggest producer being Sweden. Total production has been at a similar level since the 1970s; new mines open or are expanded to replace old mines (Note: all these mines contain at least two metals (also zinc, sometimes silver, gold and copper) so lead extraction is not the only reason for the mining.)
The production of refined metallic lead from minerals dug out of the ground involves a number of steps which are outlined below.
Mineral extraction – mining and separation of the lead-rich mineral (ore) from the other extracted materials to produce a lead concentrate.
Primary production – production of metallic lead from lead ore concentrates involves the following process steps:
Smelting – reacting the lead rich mineral with other ingredients, to yield impure metallic lead. This is traditionally done in two stages:
l roasting in air, turning the lead concentrate (usually lead sulphide) into lead oxide;
l heating the lead oxide in a blast furnace with coke to yield metallic lead.
Alternative single stage methods offer many potential advantages in terms of overall efficiency, energy consumption and lower emissions (e.g. QSL, Kivcet, Isasmelt, TBRC).
Refining – the removal of impurities and other metals from the crude lead (S, Cu, Ni, As, Sb, Bi, Ag, Au, etc.). The refining process is applied in several steps in kettles with addition of specific agents, or alternatively, smaller quantities are processed by electrolytic refining.
Total production of refined lead (from all sources) has a different pattern, with the highest production rates being in the more industrialised countries. North America and Western Europe produce over half the world’s refined lead, and the trend is for slowly rising production. Production in China and some countries are now major producers. The world-wide trend is for a slow increase in production, though there have been short-term falls in production in the 1970s and 1980s, as a result of oil crises and economic recession.
Alloying – of refined lead with other metals to give the desired composition.
Secondary production – the production of refined metal by processing lead scrap. It is often possible to simply re-melt scrap lead, with very little extra processing. However, compounds of lead (such as battery pastes) require smelting. Refining is often needed to remove any unwanted contamination and alloying additions in the feed material. The procedures are similar to those outlined for primary processing, but in general, fewer operations are required.
The proportion of lead produced from secondary sources (i.e. scrap metal), which represents about 60% of total world-wide production, is also higher in the more industrialised countries. North America produces 70% of its lead from secondary sources, and Western Europe 60%. In contrast, Chinese production is almost entirely from ore.
In Western Europe the lead producing industry consists of:
Primary production - eight smelters in five countries with a total capacity of 600,000 tonnes and a labour force of 2,000.
Secondary production - 30 smelters in 12 countries with a total capacity of 750,000 tonnes and a labour force of approximately 3,000. Secondary production requires much less energy (less than half) than producing lead from ore. (Primary production 7,000-20,000 MJ/t lead, secondary production 5,000-10,000 MJ/t lead).
TRADE IN LEAD
Lead is bought and sold by many countries on the world market, in the forms of ore, impure metal and refined metal, as well as final products. The USA, South East Asia, and Western Europe are the largest importers of lead in its various forms, though many of these countries also export refined metal. The main exporters of lead are the countries which mine large amounts of lead ore.
CONSUMPTION OF LEAD
Lead is used by all industrialised nations. The USA is by far the biggest consumer, with some countries in Asia (China, Japan, Korea) and Europe (UK, Germany, France and Italy) also using large amounts. Most of the lead is used for batteries, an application which has grown enormously in importance. The use of lead pipe has declined, as it is no longer used for potable water supplies, though lead sheet is used in roofing and other applications, particularly in the UK. The use of lead in chemicals remains at about 10% of European consumption; much of this is used in glass for TV screens and stabilisers in PVC. Lead cable sheathing, shot and alloys are minor uses of lead. The addition of lead compounds to petrol was at one time a significant market, but this has already been phased out in the USA and most of Europe, and is declining in many other countries. It now represents a minor market segment with less than 1 percent of total consumption worldwide.*
ECONOMIC VALUE OF LEAD
It is impossible to calculate this accurately. The battery market is chosen as an example as the major lead-based product sold world-wide. Data for 1999 suggest that the automotive battery market had a turnover of $6-10 billion, and batteries for back up power supplies $2.85 billion, with the latter expected to expand rapidly.
Employment in lead and related industries
Though there are no precise figures, estimates by the lead industry suggest that between 70,000 and 90,000 people are employed in lead mining, smelting and refining, and over 2,000 more in lead oxide manufacture. Battery manufacture is estimated to employ about 60-70,000 people. Many more work in industries which use small amounts of lead in their products.
* In countries which are members of the ILZSG, including: Australia, Austria, Belgium, Canada, Finland, France, Germany, India, Italy, Japan, Republic of Korea, Mexico, Netherlands, New Zealand, Scandinavia, South Africa, South East Asia, Spain, Switzerland, United Kingdom, United States.
