Regaining Glass
Rota-Mill, a hammer mill originally designed for small-scale aggregate production is also much in demand in the demolition, materials recovery and recycling industries.
As well as successfully producing road chippings and agricultural lime and reducing demolition rubble to useful hardcore, Rota-Mill has recovered clay, cement and valuable metal from blast furnace slag.
Now Rota-Mill is playing a key role in glass recycling.
The materials that go into glass making - sand, soda ash, limestone, - are relatively abundant and inexpensive. The major cost is the 1800 deg of energy required in the melting process.
The 10% energy saved in recycling glass is more than absorbed by the cost of collection, consolidation and transportation to the glass making plant. Since we no longer have a ‘returns’ culture, the simplest and by far the most economical disposal method is to chuck waste glass into the nearest big hole and bury it. However, a shortage of suitable sites combined with the requirements of environmental legislation has inspired some creative solutions.
At Eggborough, St. Gobain Glass Ltd, a major supplier of plate glass, offers its customers a welcome add-on service. By combining delivery of glass panes with the collection of double-glazing manufacturers’ off-cuts and breakages, St Gobain reduces customers’ overheads and optimises their transport useage.
Meanwhile, in Wales, Nationwide Recycling Ltd has turned a municipal headache into a economical and useful by-product.
In both instances a Rota-Mill is playing a key role in the recycling process.
In the St Gobain recycling process a wheeled loader first lifts the scrap glass into a hopper. From there, the glass is gravity-fed onto a vibrating feeder equipped with an overhead Eriez rotating drum magnet which removes metal contaminates before the feed reaches the Rotamill.900.
Capable of reducing 150 mm feed to powder, the aperture of the Rota-Mill is hydraulically set to output a consistent flow of 20mm glass fragments at rates of up to 40 tph. The processed cullet is then stockpiled for use as admixture in the making of new sheet glass.
Nationwide Recycling Ltd, a relatively new kid on the block, has a contract to collect and recycle container glass from the entire Welsh Principality. Collections from roadside containers, bottle banks and municipal yards are shipped in 40 tonne truck-loads to Nationwide’s dedicated Llandarcy facility.
On the advice of consultant, Tony Llewelyn, a quarry engineer with 40 years of plant experience, Nationwide opted for the flexibility of a 900-M
In this process, bottles and jars – clear, green and brown – are loaded unsorted straight into the hopper and fed from there to the Rota-Mill which is set for a well-cubed end product of -3mm. The crushed product then goes through a three-tier screening process to separate labels, bottle tops and other contaminants from the glass fines which are stockpiled under cover.
With properties similar to sand, the Rota-Milled glass fines have found a ready market and a wide range of uses across the
Engineers are, by nature, practical and cautious people so, in both instances, prior to purchase, the Rota-Mill was acquired on a ‘trial by rent’ basis before committing to purchase.
After 20 weeks on hire, St Gobain opted to replace their mobile Rota-Mill and ordered a fixed in-line Rota-Mill 900 while Nationwide is planning to up-grade to a tracked Rota-Mill M-1200 with a potential output of 200 tpd.
Rota-Mill, Carr House,
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