Waste Foundry Sand Gains Focus for Road Construction

The Institute of Indian Foundrymen (IIF) and CSIR–Central Road Research Institute (CSIR-CRRI) have recently entered into an agreement to promote the utilisation of waste foundry sand in road construction. The initiative aims to address environmental challenges associated with industrial waste while supporting sustainable infrastructure development in India.

What is waste foundry sand?

Waste foundry sand is a byproduct generated during the casting of ferrous and non-ferrous metals. It primarily consists of high-quality silica sand, which is repeatedly used in moulding and casting processes before being discarded. Its physical and chemical properties vary depending on the type of casting method and industrial application.

Types based on binder systems

Foundry sand is classified based on the type of binder systems used in metal casting. Two major categories exist. Clay-bonded or green sand is composed of natural materials, including silica sand (around 85–95 per cent) and bentonite clay (4–10 per cent), which acts as a binding agent. Chemically bonded sand, on the other hand, is used in core and mould making where higher strength is required to withstand molten metal temperatures.

Environmental concerns and challenges

Large-scale generation of waste foundry sand poses significant disposal and environmental issues. Improper handling can lead to land degradation and potential contamination. Managing this industrial byproduct has become a priority, especially with increasing industrialisation and limited landfill capacity.

Important Facts for Exams

• Waste foundry sand is a byproduct of metal casting industries.
• It mainly contains high-quality silica sand with varying properties.
• Two types: clay-bonded (green sand) and chemically bonded sand.
• Its reuse supports waste management and sustainable development goals.

Significance in sustainable infrastructure

The use of waste foundry sand in road construction aligns with national priorities such as resource efficiency, circular economy and waste minimisation. Its reuse can reduce dependence on natural sand, lower construction costs and minimise environmental impact. The collaboration between IIF and CSIR-CRRI is expected to pave the way for innovative and scalable applications of industrial waste in infrastructure projects.