INDUSTRY BRIEF Unlocking value from waste foundry sand

This industry brief by GreenCape explores the economic and environmental opportunities of diverting waste foundry sand (WFS) from landfills in South Africa, specifically focusing on the Western Cape and the City of Cape Town. It details how WFS can be repurposed as a secondary raw material for industries such as brickmaking and road construction, provided that strict legal classifications and hazard management protocols are followed.

• Foundries in the Western Cape, consisting of one using green moulding sand (GMS) and five using chemically bonded sand (CBS), collectively produce an estimated 75,000 to 80,000 tonnes of waste foundry sand (WFS) annually.
• WFS is classified as a hazardous waste stream with hazard ratings of type 2, 3, or 4, containing contaminants such as barium, nickel, manganese, mercury, chrome (III, VI), and benzene that may exceed Globally Harmonised System (GHS) thresholds.
• The use of WFS as a secondary material can provide significant cost savings for off-takers; for example, companies in Cape Town typically pay over R140 per tonne for silica sand, which could be reduced by substituting it with WFS.
• WFS has proven application as an aggregate in clay brickmaking, where it can be incorporated at concentrations of 15% to 30% to counteract shrinkage during firing, though calcite inclusions must be managed to avoid "lime popping".
• Research from the University of Johannesburg indicates that concrete bricks supplemented with 30% WFS show improved durability and strength, although GMS requires the removal of clay (bentonite) to avoid negatively affecting strength.
• Other potential but less developed applications for WFS include use in thermal storage, as a supplementary aggregate in asphalt mixes for lightly trafficked roads, and as backfill in originating sand mines.
• Legal barriers to WFS diversion include the requirement for Waste Management Licences (WML) for off-takers and the need for strict classification under GNR 634, 635, and 636. Efforts by the South African Institute of Foundrymen (SAIF) and others to exclude all WFS from the definition of waste were declined due to high variability between foundries.

APA

GreenCape (n.d.). INDUSTRY BRIEF Unlocking value from waste foundry sand. https://greencape.co.za/wp-content/uploads/2023/06/Foundry-Sand-Industry-Brief-Final.pdf

Chicago

GreenCape. INDUSTRY BRIEF Unlocking value from waste foundry sand. n.d. https://greencape.co.za/wp-content/uploads/2023/06/Foundry-Sand-Industry-Brief-Final.pdf.

Wikipedia

{{cite report |author=GreenCape |title=INDUSTRY BRIEF Unlocking value from waste foundry sand |url=https://greencape.co.za/wp-content/uploads/2023/06/Foundry-Sand-Industry-Brief-Final.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{greencapendindustry, author = {{GreenCape}}, title = {{INDUSTRY BRIEF Unlocking value from waste foundry sand}}, institution = {GreenCape}, url = {https://greencape.co.za/wp-content/uploads/2023/06/Foundry-Sand-Industry-Brief-Final.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }