“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 [email protected]