Wasting the Nation.indd - Groundwork

Chapter 4: The toxic cradle of productionimpurities. Iron fumes, carbon dioxide and large amounts of carbon monoxide arereleased when the furnaces are charged and tapped. Water is used to scrub gases ofdust and fumes.In 2004, Vanderbijlpark’s BOFs produced solid waste consisting of 12,000 tonnes ofiron dust, 45,000 tonnes of desulphurisation slag and 504,000 tonnes of furnace slag,all of which was dumped. Other solid wastes – 36,000 tonnes of mud, 8,000 tonnesof grit and 36,000 tonnes of furnace slag – were re-used internally.In the EAF, an electric arc sprung between two giant electrodes provides most of theenergy to melt the scrap and iron feed. Oxygen lances are also used in this process. EAFsproduce low-carbon steels and ferroalloys used in the production of ferromanganese,ferrovanadium and ferrochrome. As in the BOFs, fluxing materials carry off impurities.EAFs “cause a rather high discharge of dust to the atmosphere” and wash water picksup very high levels of suspended solids [Kemmer 1971: 10].In 2004, the EAFs produced 16,000 tonnes of dust which was dumped, and 100,000tonnes of furnace slag which was reportedly re-used internally. The clouds of red dustthat are regularly seen rising through roofs at the plant are from this unit.The steel tapped from these furnaces is rolled or cast into intermediate and final formsat the hot or cold roll mills. In the rolling mills, water picks up oils and lubricants. Thesteel forms are then ‘pickled’ – treated in acid baths with sulphuric or hydrochloricacid – to remove rust from the surface. The waste – ‘spent pickle liquor’ – is stronglyacidic and contaminated with suspended scales. The steel forms are then coated orgalvanised with zinc or other substances at high temperatures, releasing fumes andheavy metals.Slag heaps are the most visible solid waste from iron and steel plants. As slag resultsfrom removing contaminants from the production process, these contaminants areagain leached or blown from the heap. The scale of slag production allows other wastesto be covered up. In 2005, activists observed Mittal staff burying what appeared tobe bag-house waste in the slagheap. The bags filter particulates from the air exhaust.Altogether, a toxic brew of more than 100 chemicals is known to be emitted by steelmills. Recent research in Canada has shown that this cocktail not only affects all lifeforms around the mills, but goes down to the genetic level with hereditary DNAWasting the Nation - groundWork - 101 -