“A collective approach towards green foundries in South Africa”

Moving towards green foundries in South Africa

MCTS Colloquium 201127 October 2011, Johannesburg

Adrie El MohamadiProject Leader

1. Setting the context

Foundry waste sand

NOT WASTE

NOT USED

RATHER

Spent foundry sand

Colloquium 2009: Major joint problem raised by companies was the irregular

manner in which foundry spent sand is regulated in SA -

Exorbitant costs to dispose of spent foundry sand

No facility to assist with process

Industry not willing to unite to deal with the problem

Regulatory context

Waste management in South Africa is regulated under the National Environmental

Management: Waste Act 2008.

The Waste Act is supported bythe National Waste Classification and Management

Regulations, the Standard for Assessmentof Waste for Landfill Disposal, and the National Standard

for the Disposal of Waste to Landfill,

These are all currently in draft form.

Current bottleneck

is that foundry sand is classified as hazardous waste according to the

Minimum Requirements for the Handling, Classification and

Disposal of Hazardous Waste

“Minimum Requirements”

Regulatory context - continued

South Africa is applying the leaching test: Toxicity Characteristic Leaching Procedure (TCLP), however the problem is that other than the international standards

SA included elements Al, Fe and Mn to the list

These macro elements would leach from inorganic materials under the

acidic conditions of the TCLP test. 

On this basis, many materials are classified incorrectly as hazardous

Even virgin garden soil was demonstrated to be hazardous in a test case

submitted by concerned academics

These elements are highly abundant in natural soils and are very important

since they produce oxides.

Only under extremely low pH conditions do they present a phytotoxicity

issue

In the US comparisons are made between foundry sand and soils.

 

In the United Kingdom foundry waste sand, qualifies under the lower rate tax, which is £2.50 =$4.10 per tonne (FTJ, 2011)

In South Africa general waste disposal is about R250=$34.00 per tonne

Problem is not only the cost but the inconsistency of applying this regulation

Cost to foundries

2. Taking action

February 2011; a Foundry Waste management working group was initiated

April 2011; an external consultant was appointed to do tests on 4 green sand foundries spent sand

Chemical Analysis Interpretation of the analysis Documents for submission at Department of

Environment Sept 2011; received results of the above, stating that

“Overall, spent foundrysand should be regarded as inert, rather than

low-risk waste”

3. Way forward

Give feedback to 4 foundries; on the results of their sand

Next few weeks; set up a meeting with Department of Environment

Influence regulation; engage America and Germany in this

Start working on alternative uses of spent foundry sand

German Recycling of spent sands, dust and slags in

Road construction

Cement production

Landfill liner

Backfilling

Recycling of spent sands, dust and slags

Recycling of used sands and slagsRoad construction,(limit values in Germany)

Foundry sand I

Foundry sand II

pH value >9 >6

Conductivity [microS/cm]

1,500 2,700

Fluoride[mg/l]

9 80

DOC [mg/l] 30 200

Metals, e.g. Chromium[microg/l]

115 120

Recycling of used sands and quartz dust Cement production,(limit values of the cement industry)

Limit value

Phenole [mg/kg]

40

PAH [mg/kg] 20

Metals, e.g. Chromium[mg/kg]

400

Nickel [mg/kg] 250

Recycling of spent sands, dust and slags

Landfill: road construction, landfill liner, (limit values in Germany)

Landfill Cat. 0

Landfill Cat. I

Landfill Cat. II

Landfill Cat. III

Loss of ignition [%] <3 <3 <5 <10

pH value 5.5-13 5.5-13 5.5-13 4-13

Fluoride[mg/l]

<1 <5 <15 <50

DOC [mg/l] <50 <50 <80 <100

Metals, e.g. Chromium [mg/l]

<0,05 <0,3 <1 <7

Only landfill liner:Permeability [m/s]

< 1* 10-10 < 1* 10-10 < 1* 10-10 < 1* 10-10

Recycling of spent sands, dust and slags

Recycling of dust and used sands Backfilling in mines,(Limit values (not regarding salt mines) in Germany)•

Limit value

TOC [mg/kg] < 6

PAH [mg/kg] 20

Metals, e.g. Chromium[mg/kg]

600

Nickel [mg/kg] 600

Naphtaline (PAK) [mg/l]

2

Metals, e.g. Chromium[mg/l]

50

Nickel [mg/l] 50

Recycling of spent sands,dust and slags

3. Summary

These has been progress since 2009

Bottleneck – legislation

Draw on international experience

Develop a reliable publicly owned testing facility

Start working on alternative uses for spent foundry sand

Government, Academia, Industry and Research to joint

hands

Adrie El MohamadiProject LeaderNFTN012 841 2127082 902 4083adrie.elmohamadi@nftn.co.zawww.nftn.co.za