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Heavy Metals a Topic Of Concern in South African Foundry Waste Sand

Heavy Metals a Topic Of Concern in South African Foundry Waste Sand. Farai Banganayi University of Johannesburg Farouk Varachia University of Johannesburg Metal Casting Technology Station (MCTS). Presentation Lay Out. Introduction Background Preliminary Results Discussion

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Heavy Metals a Topic Of Concern in South African Foundry Waste Sand

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  1. Heavy Metals a Topic Of Concern in South African Foundry Waste Sand Farai Banganayi University of Johannesburg Farouk Varachia University of Johannesburg Metal Casting Technology Station (MCTS)

  2. Presentation Lay Out • Introduction • Background • Preliminary Results • Discussion • Conclusion

  3. Introduction MAP OF AFRICA L0cation • The University of Johannesburg is in South Africa • The Economic hub of Southern Africa • MCTS is located in a 20km radius to the Eastrand Area were most foundries are located • Positioned to service the foundries

  4. What we do • Effect technology and skills transfer to local foundries • Present short course training in foundry technology • Provide sand and metallurgical testing services • Provide assistance with trouble shooting in foundries • Place students in foundries • Host exhibitions ,seminars and workshops • Research and development in the foundry industry

  5. Background • Heavy metals definition is inconsistent and therefore necessary to deal with metals specified in regulations • Environmental issues concerning use of hazardous materials important in design and casting life cycle management • Environmental issues become of more concern at sand waste disposal (bulk) • There are about 180 foundries in South Africa • Major raw material is scrap ferrous and non ferrous

  6. continued • Metal scrap is the source of heavy metals • Prevalence due to scrap being acquired from old obsolete infrastructure • Old obsolete infrastructure and components had little emphasis on environmentally friendly designs

  7. Scrap components as a major source of heavy metals

  8. Sand metal interactions in the foundry • Pouring- sand burn on /that need to be fettled • Melting –Metallic oxide emissions deposit anywhere within the vicinity of the foundry

  9. Heavy metals’ potential entrance into the ecosystem Foundry Waste Sand water Plants Humans and Animals

  10. Effects on Microbes and plants • Heavy metals cause decreased microbial activity • Decreased plant growth when they cannot be accumulated in plant biomass

  11. Effects on Humans

  12. Heavy Metal threshold limits and Risk classification in South Africa • Limits set on toxicity and bioavailability • South Africa adapted the Environment European Commission (EEC) procedure and uses the Toxicity Characteristic Leaching Procedure (TCLP) to support or affirm the EEC.

  13. Preliminary Heavy Metal Assessment in some South African foundries. Green sand wastes TCLP extracts in mg/l

  14. South African foundry Green sand wastesTCLP extracts in mg/l

  15. South African foundry Green sand wastesTCLP extracts in mg/l

  16. Discussion • Environmental protection Agency (EPA) regulatory limits in mg/l was as follows As 5.0 mg/l, Ba 100 mg/l, Cd 1.0 mg/l , Pb 5.0mg/l ,Hg 0.2mg/l, Se 1.0mg /l, Ag 5.0mg /l (1998) • Lead most likely of concern in South Africa below EPA limits • Siddique et al. (2010) High Lead India • (Dungan and Dees, 2009) High Lead USA

  17. Disposal cost • South African foundries problem area is the disposal cost •  In the United Kingdom foundry waste sand, qualifies under the lower rate tax, which is £2.50 =$4.10 usd per tonne (FTJ, 2011). In South Africa general waste disposal is about R250=$34.00 usd per tonne • Of which at the moment some foundry sands will be considered as potentially hazardous depending on risk • This affects long term profitability of the foundry business

  18. South Africa Foundry Industry’s possible mitigation and remediation strategies • Development of new environmentally friendly alloys • Design of new effective extraction systems • Careful selection of scrap • Development and proper use of well documented Environmental Management Plans • Produce castings that require less fettling

  19. Possible Remediation • Development of a foundry waste sand bank • Phytoextraction

  20. Potential alternative uses • Agriculture soils • Asphalt mixes • Embankments • Bricks Reconstruction Development Programme houses (RDP) • Landfills • Advantage south Africa has a vibrant,agriculture,construction and mining industry for reuse • Research in India Siddique et al. (2011) Used Foundry sand for concrete and construction materials. There are similar initiatives in Brazil -Voge

  21. Conclusion • Need for collaboration between foundries,agriculture,environmental,construction industries and government departments. • Need to come up with scientific data and facts to convince environmental authorities that foundry waste sand is very low risk like in some states in the USA • Reuse reduces costs to the foundry and potential user so it saves energy • Reuse will ensure sustainability. • Reuse can create opportunities for SME creation.which is much needed in developing countries

  22. Obrigado / Thank you .

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