Wasting the Nation.indd - Groundwork

Chapter 4: The toxic cradle of productionIron and steel making takes place on giant scale. It involves the movement of millionsof tonnes of raw materials, large volumes of water and large amounts of electricity,resulting not only in the finished product, but also huge quantities of waste andpollution to air and water. It is widely regarded as the most polluting industrial activityon earth. The raw materials – iron ore, scrap metal and coal – contain substantialimpurities which must be removed to preserve the quality of the product and arediscarded as gas through smokestacks, in liquid form or as solid wastes.Impurities in iron ore include sulphur, manganese, and traces of heavy metal includingcadmium, lead, zinc and mercury. Scrap is predominantly contaminated with tin,lead and copper and increasingly contaminated with plastics and paints. Some scrapmetal is radio-active as described in Box 15 above. Flux materials such as limestone areused to act like “a kind of chemical sponge” [Davis 2002: 10] to capture and removeimpurities and unwanted chemicals like sulphur from the furnaces. Slag is used fluxand the scale on which it is produced is evident in the mountainous slag heap thatlooms over Steel Valley.While impurities are removed, other metals are added to the iron-carbon mixture togive the steel special properties. Nickel and tungsten add strength, chromium increasesthe hardness, vanadium reduces the effects of metal fatigue, and lead makes steel morepliable. If large amounts of chromium and nickel are added, a hard oxide forms onthe metal surface to make stainless steel. Zinc is used to coat or galvanize steel so itdoesn’t rust. All these additives are toxic heavy metals that can and do escape from themanufacturing process into the environment.The coke ovens are particularly toxic. Coal is purposely starved of oxygen to create coke,used in blast furnaces, and so produces carcinogenic polycyclic aromatic hydrocarbons(PAHs). Water used to quench the coke catches much of this but the rest escapes asfumes and is particularly dangerous to workers. The gas created by heating the coal isled off to the coke by-products plant where ammonia and a range of volatile organicchemicals (VOCs), notably benzene, xylene, toluene, phenol and naphthalene, arerecovered. During recovery, the gas is sprayed with water to produce flushing liquor.“This represents a very difficult pollution control problem,” according to steel pollutionexpert Frank Kemmer, “since the liquor is very high in ammonium chloride … andcontains such other contaminants as phenol, cyanide and thiocyanates” [1971: 10-16]. In addition, dioxins are formed in coke oven exhaust. Liquid and solid waste fromthe ovens includes highly toxic tars containing phenols, cresols, naphthols, acridine,and pyridine.Wasting the Nation - groundWork - 99 -