Pneumatically conveying of wet, abrasive mica
Flexicon has supplied a custom-designed pneumatic conveying system to a LKAB Minerals in Derby, UK, for the transfer of hot, wet and abrasive mica to a drying system on the floor above. Samantha Bucknall, UK Group Performance Manager for LKAB highlights the systems advantages. L KAB Minerals has been processing mica, also known as muscovite, at its Derby facility since the 1950s, for use as a mineral filler for a wide range ings industries. One of the mica processing applications involves moving large volumes of wet, abrasive mica powder from a wet process to a drying system on the floor above. wear, the company has replaced mechanical conveyors with a pneumatic conveying system from Flexicon.
Wet mica processing Mica, received at the Derby Works as a fine powder in bulk bags, undergoes one of six size reduction processes, depending on its end use. One of these is a wet process, in which water is added to create a hot, sand-like mate- rial with high moisture content ideal for use in paints and coatings. The material was originally transported to a drying system on the floor above using a forklift and bucket elevator, and subsequently by a mechanical conveyor and bucket elevator so as to distance workers from the material. However, components of both systems suf- fered from abrasive wear. Most of the alternative equipment options evaluated could not be routed as needed to move the moist material efficiently and/or resist abrasive wear. “We looked at a number of conveying systems, but most suppliers considered the material and the restricted routing as too much of a challenge. Ultimately, only Flexicon was willing to take on the project and offer a viable solution,” says Samantha Bucknall, UK Group Performance Manager at LKAB. “It was a new material for them,” continues Bucknall. “We supplied a batch to Flexicon’s test lab and worked with them to find the best solution.” The resulting automated system com- prises a 560 cap acity floor hopper, which receives the mica from the wet process via a mechanical conveyor. Pneumatic rather than mechanical conveying permitted the most direct material transfer path. A 30 m, a 75 mm diameter PNEUMATI-CON ® vacuum line from Flexicon propels the muscovite vertically 11 m to the floor above and around two 90° bends to a 1 220 mm diameter filter receiver. The filter receiver separates the muscovite from the conveying air and is sized to hold 800 l of material. The dilute phase vacuum system is pow- ered by a 15 kW positive displacement vacuum pump delivering a pressure differ- ential of 500 mbar. The filter receiver is sized to hold an entire wet mill batch, and includes
of applications in the agricultural, building, construction, polymers and paint and coat-
To improve worker safety in the vicinity of the heated material and overcome abrasive
A 30 m conveying line transfers wet, abrasive mica powder from the wet process on the floor below into the filter receiver, which separates the material from the conveying air.
22 ¦ MechChem Africa • May-June 2024
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