Waste/Recycled Material Utilisation - WRAP
The Waste and Resources Action Programme (WRAP) has established that the UK produces over 1.2 million tonnes of surplus recycled mixed colour and green container glass cullet every year. WRAP has set a primary goal of reducing the quantity of cullet sent to landfill.
WRAP wanted to investigate the potential use of powdered recycled glass as a substitute fluxing additive (Nepheline Syenite) in the manufacture of sanitaryware to:
- Lower energy usage
- Reduce firing temperature
- Increase recycled material content
- Maintain/improve product performance.
Ceram was commissioned by WRAP to examine the recycled cullet as a fluxing body agent to address several interconnected sustainability issues. These were:
- Diversion of waste from landfill and therefore waste utilisation
- Potential energy reduction
- Recycled material content and reduction in virgin material usage
- Further process optimization
- Carbon dioxide emission reduction.
What We Delivered
The ceramic materials experts at Ceram initially found that the substitution of Nepheline Syenite with powdered glass proved problematic; the rheological properties of the slip were compromised by the glass. Ceram identified the cause as being related to the ‘leaching-out’ of the sodium from the glass into the slip; a result of the ultrafine glass particle size. The complication was alleviated by our experts through a flash or spray drying technique which dried the surface of the glass powder following the wet grinding process. The drying heat effectively sealed the sodium into the glass structure and minimised release into the slip.
Value to the Client
Ceram trialled the technique in one of the world's largest sanitaryware manufacturers and proved that traditional flux could be replaced on a 50:50 basis.
WRAP were provided with an analysis of the key benefits of utilising recycled glass as a fluxing body additive in sanitaryware. These were:
- Energy reduction of 7% in the firing process
- 50oc reduction in the firing temperature
- Potential to divert 120,000 tonnes per annum of mixed colour glass cullet from landfill
- Increased utilisation of recycled materials as alternatives to the primary raw material flux (Nepheline Syenite)
- 10% reduction in raw material costs.