Over the past four decades, foundries have significantly intensified their recycling efforts. However, the disposal of materials such as filter dust, sand, slag, and refractory materials still largely takes place in landfills, often at relatively low cost. In recent years, environmental regulations and a reduction in landfill capacity have led to higher disposal costs and increased liability risks. Adding to the challenge, some foundry waste is now classified as hazardous, further increasing financial and regulatory pressure on the industry.
Foundry Waste
The UK government has set ambitious targets to reduce municipal landfill waste to less than ten percent by 2035 and nearly zero by 2045. These goals are intended to force local authorities to close landfills or face penalties for non-compliance. As a result, disposing of foundry waste through general landfills is becoming increasingly difficult and expensive.
Currently, foundry waste is subject to a reduced landfill tax of £4.05 (approx. €4.60) per tonne compared to the standard rate of £126.15 (approx. €143.26), provided its Loss on Ignition (LOI) is below 10 percent. However, the government is currently conducting consultations and may abolish this reduced rate. If implemented, disposal costs could increase thirtyfold, significantly raising financial pressure on the foundry industry.

Waste Acceptance Criteria (WAC) and Classification Issues
While the exemption from landfill tax for foundry sand offers some relief, it does not affect the WAC, which determine whether waste is classified as inert, non-hazardous, or hazardous. Foundry sand is increasingly being classified as hazardous due to high levels of dissolved organic carbon (DOC) exceeding 800 mg/kg or the presence of phenols. Disposal costs for such hazardous waste can range from £45.00 to £600.00 (approx. €51.12 to €681.60) per tonne depending on the severity of contamination.
Hazardous sand waste cannot be reused without additional treatment. Many chemically bonded sand foundries using simple dry abrasion recovery methods produce sand that exceeds these thresholds. Although these regulations have been in place for some time, enforcement has varied significantly by location. This inconsistency is now changing, and foundries are facing a sharp increase in disposal costs—a trend likely to continue unless proactive measures are taken. Foundries must review their processes to reduce the volume of waste generated.

Green Sand Recovery
Green sand systems are complex and require a precise balance between multiple inputs and outputs (see process map). As castings become increasingly complex and core-intensive, the amount of new sand and core sand has increased, leading to more waste and a higher demand for bentonite and carbon-based additives. This shift has driven up both material and disposal costs.
To counter this, recovery systems have been developed to reclaim waste sand, bentonite, and carbon-containing materials. In recent years, several technologies have emerged to clean waste sand and return it to the core shop, significantly reducing the consumption of new sand and the burden on landfills.
However, non-thermal recovery methods can generate substantial amounts of dust with a Loss on Ignition (LOI) above ten percent, making them unsuitable for landfill disposal under current regulations. Thanks to recent innovations in rehydrating the high content of bentonite and carbon-based materials in the dust, these can now be reintegrated into the green sand system, reducing both waste and raw material costs. Alternatively, the material must be diluted with waste green sand to keep the overall LOI below ten percent, though this leads to a reduction in total recovery volumes. The type of recovery system—whether cold or thermal—…

Cooperative Solutions and Cost-Effective Strategies for Waste Reduction
Due to the high capital costs associated with recovery technologies, small and medium-sized green sand foundries can benefit from partnerships or clusters with similar operations. By sharing costs and investing jointly, these groups can explore more economical methods for recycling waste materials—such as incorporating green sand into asphalt and other construction products. In fact, green sand waste is already being used as cover material at some landfills. For any successful reuse strategy, it is essential to ensure consistency and prevent cross-contamination in the waste stream. The era of indiscriminate waste disposal is rapidly coming to an end.
Moreover, there are several low-cost, practical measures to reduce overall waste generation:

Core Package Casting and the Shift Away from Green Sand
In recent years, some foundries—particularly those producing castings such as truck engine blocks and cylinder heads—have completely moved away from green sand processes. This development has led to facilities that generate minimal or no sand waste. Most of these foundries use large core shooting machines to blow phenolic-urethane cores, creating integrated core packages that are then placed into a support system for casting.
By using thermal reclamation technologies, these foundries achieve a high degree of sand reuse while drastically reducing waste. Furthermore, this level of efficiency opens the door to replacing traditional quartz sand with ceramic sands such as Cerabeads, thereby eliminating serious health and safety risks associated with respirable crystalline silica.
This transition also allows for better control of casting tolerances and greater flexibility in casting design—especially in light of recent advances in rapid 3D sand printing and cellular manufacturing. Overall, the core package approach represents a significant leap toward a more sustainable and adaptable foundry model.

Challenges for No-Bake Foundries
Most jobbing foundries in the United Kingdom rely on mechanical abrasion combined with organic binders, primarily alkaline phenol-furan or phenol-urethane systems. Recovery rates for these systems typically range between 60 and 90 percent, with a large portion of the waste sand classified as hazardous due to the presence of leachable organic compounds such as phenols.
The dust generated during the classification process is also hazardous, complicating disposal and posing challenges for environmental compliance. Additionally, the high concentration of organic compounds in the waste makes reuse or recycling through meaningful recovery pathways difficult—an increasing concern for foundries that depend on these organic binder systems. Recovery rates can be improved to over 90 percent by introducing secondary crushing, incorporating thermal reclamation into the process, or fully replacing mechanical crushing.

Considerations for Thermal Reclamation and Binder Processes
Thermal reclamation combined with the phenolic-urethane process offers the most effective method for eliminating hazardous sand waste, as it completely removes organic compounds from the sand. The result is a clean, reusable material that typically no longer requires classification as hazardous waste.
However, each binder system presents its own challenges:

Furan binders: While thermal reclamation is effective for furan systems, it produces sulfur emissions that raise environmental concerns and may require mitigation measures.
Alkaline phenolic binders: At reclamation rates above 90 percent, potassium and sodium oxides can accumulate in the sand. This buildup may reduce mold strength and lower the sand’s sintering temperature, potentially affecting casting quality. To ensure optimal performance, up to ten percent of new sand is typically required.
Despite these limitations, sand processed through thermal reclamation—regardless of the binder type—is no longer classified as hazardous, significantly simplifying disposal and improving opportunities for beneficial reuse.

No-Bake Foundries and Innovations in Inorganic Binders
Traditionally, many British jobbing foundries have relied on organic binder systems combined with simple mechanical abrasion for sand reclamation. This process generates hazardous waste sand, whose disposal is becoming increasingly complex and costly, with limited options for meaningful reuse.
As a result, inorganic binder systems are gaining importance as a more sustainable alternative. Although they often achieve lower reclamation rates when using standard dry abrasion methods, the resulting sand is non-hazardous and significantly easier to reuse or repurpose.
This gives foundries the opportunity to avoid these burdens without major capital investment. Furthermore, when using inorganic binders from John Winter & Co Ltd., reclamation rates of eighty to ninety percent can be achieved through a dual mechanical abrasion process combined with drying.

Other Foundry By-Products and Recovery Potential
Beyond sand waste, foundries generate by-products from melting, blasting, and cleaning processes. These waste streams may contain untapped value and require smarter management:

Fine dust from electric melting dust collectors can often be reused. For example, fumes from galvanized steel scrap contain zinc oxide, which can be extracted and sold for industrial use.
Silica-rich dusts may have significant reuse potential in the glass and ceramics industries.
To preserve reuse potential, it is essential to separate heavy metals from dust to prevent contamination of other waste streams.
Smaller foundries can benefit from pooling resources to develop viable reuse pathways for filter dust from melting operations.

Material Selection to Promote Reuse
To encourage the reuse of waste and reduce environmental hazards, foundries should consider the following approaches:

Use non-crystalline silica refractory materials to facilitate safe disposal and reuse.
Employ ceramic sands to reduce the content of crystalline silica in blasting and cleaning dust.
Apply good operating practices to minimize chemical waste and used oils—ideally in collaboration with suppliers through recycling or take-back programs.
Switch to non-hazardous materials throughout the process wherever possible.
Conduct regular audits of all waste streams to identify opportunities for reuse or safe treatment options.
Air Emissions and Sustainable Alternatives
Foundries in Europe are under increasing pressure to control volatile organic compounds (VOCs) and airborne pollutants such as formaldehyde. Some facilities have installed afterburner systems, but these come with a high CO₂ footprint.

More Sustainable Alternatives Are Emerging
Inorganic binders are now widely used in the aluminum sector and are being tested in iron casting applications to reduce emissions.
Products such as JW’s Winterbond and Geopol inorganic cold-box systems contain no VOCs and produce non-hazardous molding sands—ideal for reuse.
JW’s zero-VOC release agents for green sand include:

PF880 (hydrocarbon-based)
PF990 (plant-based), which significantly reduces the CO₂ footprint.
By implementing these materials, foundries can virtually eliminate air emissions and odors.

Conclusion: Handling Foundry Sand Waste

Increase the use of beneficial reuse opportunities.
Invest in advanced reclamation technologies.
Adopt non-hazardous processes to enable safe reuse.
Continuously review and optimize sand waste management.

Conclusion: Handling Metallurgical and Process Waste

Separate waste containing heavy metals to prevent cross-contamination.
Collaborate with customers to eliminate hazardous alloying elements.
Use refractory materials with low silica content to reduce air pollution.
Recover and reuse aluminum dross and slag.
Minimize melting losses through the use of appropriate fluxes.
Reduce chemical waste—work with suppliers on take-back systems.
Strategic Key Message
Above all, foundries should prioritize non-hazardous production, optimization of waste streams, and cooperative approaches—such as forming clusters—to make sustainable practices economically viable.