Pilot Crushtec International’s Twister vertical shaft impact (VSI) crushers are being extensively used in the glass recycling industries in countries including Australia, New Zealand, and the United Kingdom. “Our Twister VSI crushers are proving to be an ideal solution in the recycling of glass bottles, glass factory waste, and cullet material,” explains Sandro Scherf, CEO of Pilot Crushtec International, South Africa’s leading supplier of crushing, screening and material handling equipment to the recycling, construction, civil engineering, quarrying and mining industries.

Twister VSI crushers conventionally use either ‘rock-on-rock’ or ‘rock-on-steel’ crushing technologies, or in the case of glass recycling, “glass-on-glass” or “glass on steel,” depending on the feed size of the glass to be crushed. Scherf elaborates: “The glass-on-glass method is used when the glass fed to the crusher is below 65 mm in size, while glass-on-steel is used when the glass fed to the crusher, often including bottles, is larger than 65 mm.”

Benefits of using VSI crushers

When glass-on-glass crushing is the preferred option, a six port rotor is used to accelerate the glass into the crushing chamber, which is fitted with a build-up chamber which becomes filled with a glass “shelf,” thereby providing a glass-on-glass crushing action.

When larger cullet or glass pieces, and even entire bottles, need to be crushed, then the Twister can be fitted with an open table rotor and an anvil ring. This open table rotor accelerates the large pieces of glass into steel anvils, crushing the glass into fine grains. “Tests have proved that the steel contamination in the fines is minimal and well within the strict tolerances set by bottle and glass manufacturers,” says Scherf, “so Twister VSI crushers are clearly very efficient in handling this very abrasive material, as well as other abrasives such as ceramics and porcelain products, including tiles and sanitaryware waste.”

The Twister VSI crusher range can handle throughput capacities from 10 tons per hour up to 320 tph, and can be easily incorporated into existing plants. The mobile TwisterTrac VSI crusher can handle a throughput of up to 220 tph.

“Glass is a 100% infinitely recyclable product, and the production of new glass from old glass requires substantially less energy than manufacturing it from scratch,” says Scherf. Further advantages of recycling glass include the preservation of finite resources, increasing the life of landfills, and reducing carbon emissions resulting from the glass manufacturing process itself as well as the production of glass’ constituent materials. According to the Glass Recycling Company, a non-profit organisation set up to promote glass recycling in South Africa, some 550,000 tons of glass waste finds its way into landfills annually. Currently, about 200,000 tons of all glass containers are retrieved for recycling.

Apart from recycling glass for re-use in the glass manufacturing process, crushed glass is being used extensively in New Zealand, Europe and the USA in landscaping for decorative and mulching purposes, for filter media in water purification processes, for primary aggregates in construction, for abrasive blasting, and even for beach sand replenishment.

“With the general pressure for all companies to become more ‘green,’ and with recycling legislation being introduced in South Africa, there are many opportunities for companies to grow their businesses,” feels Scherf. He concludes: “Pilot Crushtec has a large database of information, ideas, products and methods to help our customers grow, and at the same time make a contribution to a ‘greener’ world.”