New Tyrone International wash plant for Leicester’s urban quarry
AR Aggregates, operating from a successful urban quarry in the heart of Leicester, has embraced innovation in the recycling and processing of construction materials. With the recent installation of a state-of-the-art Tyrone International wash plant, capable of processing 100 tonnes per hour (tph) of recycled aggregates, the company is poised to meet increasing demands for high-quality recycled materials while actively promoting sustainability within the construction and civil sectors.
The Need for Increased Recycling
The urban quarry serves as a vital supplier of both virgin and recycled materials, facilitating a responsible approach to resource management. The site encompasses its own rail head, which simplifies the import of virgin aggregates from local quarries. However, AR Aggregates recognised a pressing need for increased recycling, particularly in the construction sector, where a significant volume of materials containing sand and gravel continues to be sent to landfills.
To address these challenges, AR Aggregates has positioned itself as a champion of sustainability and the circular economy. The company aims to lower its carbon footprint by reducing the road miles that aggregates must travel, thus minimizing both transportation costs and environmental impact. With existing operations focusing on crushing and screening dry recycled materials, they acknowledged limitations posed by weather conditions and the variability of available feed material. This drove the decision to invest in a wash plant, allowing them to produce consistent, high-quality materials year-round, irrespective of external conditions.
The Tyrone International Wash Plant
The Tyrone International wash plant is a modular design, allowing for quick erection on-site and providing unparalleled access to all components for ease of maintenance. This design not only enhances operational efficiency but also supports AR Aggregates' objective to add value to their products while expanding their offerings. The plant is particularly equipped to process difficult feed materials from various sources, thereby increasing the range of products available to customers.
The facility outputs five distinct washed products: fine sand, coarse sand, and aggregates sized at 10mm, 20mm, and 40mm. This diverse product line caters to various construction needs and enhances AR Aggregates' marketability. To ensure the purity and quality of the aggregates, the wash plant is fitted with a heavy-duty electromagnet that effectively removes ferrous metals from the feed material before washing, consequently enhancing the quality of the final products.
Notably, the wash plant features spray bars that raise easily on the pre-screen, simplifying access to the screen deck for maintenance and ensuring optimal performance of the spray nozzles. The main pump tank, which collects sand, silt, and fine trash, is fitted with a self-cleaning system designed to remove polystyrene and fine trash particles before the sand plant, ensuring cleaner fine and coarse sand products.
Advanced Water Treatment System
Integral to the wash plant's operation is its expertly designed water treatment system, engineered to handle high silt content in the feed material. This system begins with dirty water being processed through a high-frequency dewatering screen to eliminate small trash materials before it reaches the thickener.
Several innovations contribute to the efficiency of this water treatment system. The dynamic thickener is a standout feature of the system, capable of raising and lowering the rake to produce a high-density, consistent sludge that is optimal for filter press operations. It is equipped with an analyser to measure the settlement rate of silt particles, automatically adjusting the use of flocculent to maintain performance. Additionally, it continuously monitors the overflow water to ensure cleanliness, enhancing the overall efficiency of the water treatment process.
In addition, the thickener employs a surface scraper that efficiently removes any remaining fine trash material, thus maintaining the cleanliness of the water treatment plant. The clarified water then flows into a large steel holding tank fitted with an agitation system that prevents sedimentation buildup. This mechanism ensures that the clarified water can be reused effectively in the wash plant, further aligning with AR Aggregates' sustainability goals.
Automated Filter Press Operations
The thickened sludge is transferred to a large steel buffer tank fitted with two stirrers to ensure uniformity in consistency. From here, the sludge is pumped at high pressure to a cutting-edge filter press equipped with 100 2m x 2m filter plates. This system is designed for fully automated operation, featuring a robotic mechanism that can quickly open filter plates in batches of ten, shake them to release the filter cake whilst also washing each plate for optimal filtration and extended wear life of the filter cloths.
The automation of the filter press not only enhances throughput but also significantly reduces operational downtime, as there are fewer moving components prone to wear. This advanced setup allows AR Aggregates to maintain a high standard of performance in producing dry filter cakes, which can then be repurposed effectively.
Environmental Benefits of Recycled Aggregates
Using washed recycled aggregates offers a multitude of environmental benefits that directly align with AR Aggregates' objectives. First and foremost, the transition to recycled materials leads to reduced vehicle movements, which in turn diminishes CO2 emissions associated with transportation. Additionally, by reusing aggregates rather than excavating virgin materials, natural resources are preserved along with natural habitats and ecosystems.
Conclusion
AR Aggregates’ investment in the Tyrone International wash plant and the accompanying water treatment system exemplifies a commitment to innovation, efficiency, and sustainability within the recycled aggregates industry. By integrating advanced technologies throughout their processes, AR Aggregates not only enhances product quality but also pioneers environmentally responsible methods in construction material production. As the demand for recycled materials continues to grow, such advancements position AR Aggregates as a leader in the field, driving the future of sustainable construction.