Wasting the Nation.indd - Groundwork
Wasting the Nation.indd - Groundwork
Wasting the Nation.indd - Groundwork
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Chapter 4: The toxic cradle of productioncommercial construction has contracted sharply and <strong>the</strong> market is being sustainedby <strong>the</strong> state’s infrastructure programme, starting with <strong>the</strong> 2010 stadiums and withmassive demand from Eskom and Transnet’s expansion programmes to follow.The raw materials of cement production are limestone and silica and alumina from clay.They are ground to a fine powder and <strong>the</strong>n fed through <strong>the</strong> kiln, where temperaturesreach 1,400° to 1,500°C, to produce ‘clinker’. Kilns are traditionally fired by coal and<strong>the</strong> bottom ash is incorporated in <strong>the</strong> clinker. The clinker is <strong>the</strong>n cooled and groundwith various additives to <strong>the</strong> fine powder that is cement. The process is very energyintensive and <strong>the</strong> use of coal puts cement in <strong>the</strong> same bracket as <strong>the</strong> energy sector interms of its contribution to climate change.Internationally, <strong>the</strong> Cement Sustainability Initiative is putting a green spin onproduction but, as Jane Harley comments in a report for groundWork, it “has putout a great many documents, all of which avoid <strong>the</strong> central truth – that cement cannever be sustainably produced”. Ra<strong>the</strong>r, <strong>the</strong> industry has focussed on “<strong>the</strong> use of …‘alternative fuels’, which translates to <strong>the</strong> use of waste as a fuel” [2006: 2]. While<strong>the</strong> environmental benefits of <strong>the</strong>se fuels are dubious, <strong>the</strong> economic benefits to <strong>the</strong>cement industry are evident. Since 2003, coal prices have risen from around US$20to over US$160 a tonne. PPC comments that international demand is limiting “<strong>the</strong>availability of <strong>the</strong> appropriate coal quality for cement manufacture” while “spiralling”international prices are pushing up costs [PPC 2007: 24].The industry describes burning waste as ‘co-processing’ or ‘energy recycling’. PPCgoes so far as to suggest that co-processing replaces “fossil fuel with renewable sources”[50]. Apart from twisting <strong>the</strong> notion of ‘renewable’ beyond recognition, <strong>the</strong> statementimplies that waste will indeed be eternally renewed. The industry favours waste witha high calorific content, many of which are hazardous petrochemical wastes derivedfrom fossil fuels. Wastes used internationally include solvents, old tyres and oil, paintand dried sewerage sludge. The use of spent pot linings from aluminium smelters hasan added advantage as <strong>the</strong> alumina substitutes for alumina in <strong>the</strong> raw material fed into<strong>the</strong> kiln.Pot linings and dried sewage sludge are already used in some plants in South Africawith <strong>the</strong> approval of <strong>the</strong> DEAT. It is possible that o<strong>the</strong>r wastes have been used withoutapproval. Used tyres, however, would require modification of <strong>the</strong> kilns and <strong>the</strong> industryis, somewhat impatiently, “waiting for <strong>the</strong> relevant legislation to be enacted”, as PPC<strong>Wasting</strong> <strong>the</strong> <strong>Nation</strong> - groundWork - 123 -