Jenike & Johanson is a leading company in powder and bulk solids handling, processing, and storage technology. Over the past 55 years, it has tested over 11,000 unique powders and bulk solids and worked on more than 7,500 projects, giving its team broad real-world and in- depth experience in the industry to address a wide variety of bulk material handling and engineering needs.
Its mission is to create value by assisting clients improve the efficiency, reliability, and safety of their operations by preventing, eliminating, or reducing problems related to bulk material flow, storage, conveying, or processing.
One of Jenike & Johanson’s recent projects in the bauxite/alumina field was carried out at Kaiser Aluminum & Chemical Corporation in Baton Rouge, Louisiana.
Kaiser Aluminum & Chemical Corp. produces alumina trihydrate which is calcined to make alumina, or it is dried and sold as hydrate. In addition to these two end products, Kaiser wanted to sell its wet alumina trihydrate. Kaiser needed a new, dedicated handling and storage system. According to Chess Millburn, a project engineer at Kaiser,“The handling characteristics of the wet alumina trihydrate were unknown to us. Just looking at the material, you could tell it was very different than the dry product. There was a general feeling among the plant personnel that we would have major difficulties handling it.”
- needs addressed: address process non-uniformity, solve or prevent poor flow
- bulk material handled: alumina trihydrate, alumina, bauxite
- equipment: storage, feeder.
After Jenike & Johanson’s site visit, it was decided that the next step was to test a sample of the alumina trihydrate in its laboratory, duplicating the process conditions.
J&J found that the wet cake was cohesive enough to arch and form stable ratholes in funnel flow silos and that a third flow pattern, expanded flow, would be most suitable. Expanded flow combines mass flow and funnel flow and consists of a mass flow
section at the bottom of the silo, extending up to a large enough diameter to prevent the formation of a rathole. Above this mass flow section, the silo is designed for a funnel flow pattern.
Kaiser installed the recommended silo and loadout bin and they have been reliably handling the wet alumina trihydrate since startup.