MechChem Africa November-December 2024

Moving non-free-flowing bulk materials using Flexicon solutions Brynn Thomas, MD of Flexicon Africa, describes the challenges, solutions and the results for three companies, each moving a different but commonly used non-free flowing material. To overcome the transporting issues with these materials, all three partnered with Flexicon, a global specialist in bulk material handling solutions. N on-free-flowing materials such as titanium dioxide, calcium carbon ate and carbon black tend to pack, cake, smear and agglomerate. They

particles, each cartridge is coated with PTFE. As a result, when an automatic reverse-pulse filter-cleaning system directs short blasts of compressed air inside the cartridge filters, the dust buildup on the outer filter surfaces falls easily into the hopper. This maintains the filters’ ability to capture dust, and lengthens their life-cycle. A combination of agitation devices and the design of the hopper overcomes TiO 2 ’s tendency to bridge, even over wide openings. The hopper has a ‘high flow’ configuration that causes titanium dioxide to topple and flow toward and down the unit’s steep back wall, preventing the powder from bridging between

the unit’s sidewalls. Additionally, it is equipped with a pneumatic vibrator and an agitator to promote flow to ward the conveyor’s inlet. The hopper charges an enclosed BEV CON™ flexible screw conveyor with optimised geometry to handle materials with TiO 2 ’s characteristics without binding or jamming. The design of the flexible screw conveyor also isolates bearings from the product contact zone, which can be prone to wear. The plant's product engineer says that, in addition to protecting workers and keeping the surrounding plant area clean, the system reduces material waste and eliminates the

are typically dusty, and frequently ‘rat hole,’ dome and/or bridge in process equipment, bulk bags and rigid storage vessels. Therefore, moving these products ef fectively requires specialised equipment, as described through the applications outlined below. Titanium dioxide (TiO 2 ) heightens white ness and is used in products as diverse as paints, plastics, floor coverings, roofing ma terials, pharmaceuticals, papers, inks, tooth paste and cosmetics. It has a bulk density of 595-920 kg/m 3 . Moderately abrasive, cohesive and adhesive, TiO 2 does not flow readily. It forms deposits in the conveying lines, clogs filters, can bind mechanical equipment and is likely to ‘rat hole’ or bridge in hoppers, preventing flow. Also, manufacturers handling TiO 2 may also find it difficult to contain dust, especially if plant personnel are slicing handheld sacks and dumping the material into process equipment. Small particles of TiO 2 will coat almost any surface they come into contact with. Ameron International manufactures PVC linings for which TiO 2 is weighed and blended with PVC resin prior to extrusion. The compa ny contains the dust using a Flexicon bag dump station specifically designed to handle TiO 2 and transports the powder to a blender using a custom-designed flexible screw conveyor. The bag-dump station’s dust collector is mounted directly on the 0.16 m 3 floor hopper, which is equipped with a waist-high bag tray support for operators to stage and open bags prior to dumping. The operator opens the hop per lid, activating a high velocity vacuum fan, and dumps TiO 2 through a screen that keeps foreign objects out of the system. The fan draws airborne dust onto two filter cartridges rated at 99.99% collection efficien cy for materials with a particle size of 1.0 µm or greater, which helps to prevent the cartridges from being blinded by the small particles of TiO 2 . To facilitate the clean release of these Ameron International handles titanium dioxide

Plastics Group of America (PGA) uses a flexible screw conveyor to transport the CaCO 3 additive from the hopper beneath the BULK-OUT ® BFC bulk bag discharger to a compounding line. Integral agitation plates raise and lower the bottom side of the bag to promote total discharge.

24 ¦ MechChem Africa • November-December 2024