Making sand from glass
The production of sand by means of glass recycling is a developing market in Australia, and Alex Fraser has been supplying asphalt plants for five to six years with product from various crushing methods. After an impressive couple of months using a rented Pilot Crushtec TwisterTrac AC210; the Alex Fraser group purchased one of their own (Fig.). The company’s recycling project manager Brent Alford says that Alex Fraser has invested considerable time and money into the research and development of recycled glass sand as a viable product. “We are in the development stages of releasing a high quality sand replacement product into the Victorian market and the TwisterTrac was an integral part of the crushing, screening and cleaning process that we have put together,” Alford explained.
Working in conjunction with other crushing equipment, the TwisterTrac produces two products at the moment, recycled sand of -10 mm and recycled sand of -5 mm. According to Alford, the material used for making sand would normally have gone into landfill sites and Alex Fraser’s customers are slowly but surely accepting this product as the norm. “It is now the case that recycled concrete is seen as an equivalent product to the virgin rock product it is competing with. Recycled sand has already met with considerable success as we recently delivered recycled sand to a large pipe line project where our product was compared favourably to the best pipe bedding sand from local sand quarries,” he explains.
Recycled sand has the following advantages for the Melbourne recycling operation:
• Transport – the closest sand deposits are more than 50 km away whereas the glass recycling plants are situated not more than 5 km away
• Landfill – without recycling the glass waste into sand it would be buried as landfill which is a bad outcome for the environment
• Similarities – the recycled sand has all the physical characteristics of traditional quarried sand
Pilot Crushtec export sales manager Paul Chappel explained that Alex Fraser first became interested in acquiring the TwisterTrac after company representatives were shown the mobile vertical shaft impact (VSI) crusher at the bauma trade fair in 2010. Arrangements were made that Alex Fraser hire a unit from an Australian dealer for a trial period. “This proved successful as Alex Fraser was particularly impressed with the TwisterTrac’s ease of use and reliability,” Paul explained. “Due to a VSI’s impressive reduction ratio of up to 10:1, it is ideal for recycling glass into a sand product. Both our mobile TwisterTrac and our modular Twister AC210s have been used successfully in this application,” he explained. Pilot Crushtec’s mobile TwisterTrac has a variable rotor speed of between 1000 and 1600 rpm and has a maximum feed size of 65 mm for hard rock and 75 mm for soft rock. The 1200 mm wide discharge conveyor can offload to a height of 3,7 m. While working, the TwisterTrac is about 14.5 m in length, 3.2 m wide and weighs 29 t. Several rotor configurations provide throughput capacities between 100 and 225 t/h.
