Farai Banganayi University of Johannesburg Farouk Varachia University of Johannesburg

Metal Casting Technology Station (MCTS)

Presentation Lay OutIntroductionBackgroundPreliminary Results Discussion Conclusion

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

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

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 AfricaMajor raw material is scrap ferrous and non

ferrous

continuedMetal scrap is the source of heavy metalsPrevalence due to scrap being acquired from

old obsolete infrastructure Old obsolete infrastructure and components

had little emphasis on environmentally friendly designs

Scrap components as a major source of heavy metalsSource Heavy metals contained

Electrical components Cadmium,copper,zinc,lead and tin

Bearings Copper, lead and tin

Galvanised metal Mostly zinc or aluminium

Plated components Nickel ,cadmium, chromium or tin

Painted or coated cadmium,cobalt,copper,nickel lead and tin

Vehicle fuel systems and rims Mostly lead

Sand metal interactions in the foundryPouring- sand burn on /that need to be fettledMelting –Metallic oxide emissions deposit

anywhere within the vicinity of the foundry

Heavy metals’ potential entrance into the ecosystem

Foundry Waste Sand

water Plants

Humans and Animals

Effects on Microbes and plantsHeavy metals cause decreased microbial

activity Decreased plant growth when they cannot be

accumulated in plant biomass

Effects on Humans Heavy Metal Effects

Arsenic blood, kidneys, and central nervous, digestive, and skin systems. Chronic exposure leads to the development of skin and liver cancer

Cadmium liver, placenta, kidneys, lungs, brain, and bones

Chromium VI Carcinogenic

Mercury Target organs are the brain and kidneys

Lead Target organs are the bones, brain, blood, kidneys, and thyroid gland

Antimony irritation of the eyes and skin, lung disease and heart problems

Selenium include hair and fingernail , kidney and liver tissue, damage to circulatory tissue, and nervous system.

Heavy Metal threshold limits and Risk classification in South Africa

Limits set on toxicity and bioavailabilitySouth Africa adapted the Environment

European Commission (EEC) procedure and uses the Toxicity Characteristic Leaching Procedure (TCLP) to support or affirm the EEC.

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

South African foundry Green sand wastesTCLP extracts in mg/l

South African foundry Green sand wastesTCLP extracts in mg/l

DiscussionEnvironmental 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

Disposal costSouth 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

South Africa Foundry Industry’s possible mitigation and remediation strategies

Development of new environmentally friendly alloys

Design of new effective extraction systemsCareful selection of scrapDevelopment and proper use of well

documented Environmental Management Plans

Produce castings that require less fettling

Possible Remediation

Development of a foundry waste sand bankPhytoextraction

Potential alternative uses

Agriculture soilsAsphalt mixesEmbankments 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

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

.