To extract the dust at a crushing plant on its northern French site, Borax Français contacted Lybover AIR. Project Coordinator Laurent Tourneur was already familiar with the possibilities of Lybover AIR from his previous job at STAUB. It soon became clear that the crushing plant in the big bag unloading station did not only need a solution in terms of dust extraction. Therefore, the other business units of Lybover were also called in.
In the original set-up, the big bags were delivered in bulk and then passed through a vibrating screen and hopper into the crusher. However, the presence of foreign elements such as metals too often caused blockages, the cause of which was difficult to detect given the large volume of borates being discharged in one go. So there was a need for a solution to dose the borates before they go to the crusher.
New dosage system
Within the group, Lybover BULK was therefore contacted. Several options were examined, such as a normal conveyor belt or a screw. Finally the right solution was found at sister company Lybover RECYCLING. A vibrating screen from SPALECK was included in the design, which was also tested in the test centre with the intended material and throughput. This allowed Borax to confirm with certainty that the borates could be correctly dosed and discharged to the crusher at the correct flow rate. In order to increase efficiency and yield, the entire plant was eventually converted and largely renewed. Given its extensive experience in this field, Lybover BULK took the lead and coordinated the entire project from concept to assembly.
Maximum dust recovery
In terms of dust extraction, two major dust points were identified. On the one hand, the waste when opening the big bag and on the other hand, the waste in the crusher itself. The failure of the big bag proved to be the biggest challenge. It was important to find a solution that could guarantee both the efficiency of the dedusting and the accessibility for the operators of the unloading station. In consultation with the client, and based on well thought-out engineering, a solution could be devised in which the windblown dust is sucked away at a height that does not limit the accessibility for the operators.
A proper seal between the dynamic vibrating screen and the static covering is provided by means of a Trellex system, so that no dust is released when the material is dispensed. Finally, a second dedusting point was provided at the end. The dust that is removed ends up in a big bag and can be reused in production. A HEPA filter (High Efficiency Particulate Air) further filters and removes 99% of all particles. The quality of the outgoing air is so good that no discharge to the outside is necessary. The extract air is blown back into the hall. An extra sustainable advantage as there is no heat loss. Despite the different needs, Borax Français found a complete solution within the Lybover group. Apart from the dust extraction (AIR), the vibrating screen/dosing system (RECYCLING) and the complete rebuilding and renewal of the structure and all connections (BULK), Lybover METAL could also produce the stairs and landings within the group.
U.S. Borax, part of Rio Tinto, is a global leader in borates. These are naturally occurring minerals. About 30% of the world’s need for refined borates comes from the Borax mine in Boron, California. Refined borates are shipped in bulk from California to the Coudekerque site in northern France, where they undergo a secondary refining process to increase purity and produce high-quality specialty borates for the agricultural, nuclear, industrial and pharmaceutical industries.