MINERAL SEPARATION
The largest electro overband magnet ever built at the Bunting manufacturing plant in Redditch , England , has been installed at the Agnico Eagleowned Kittilä gold mine , in northern Finland
“ In operation , any tramp iron present in the conveyed ore and reaching the end of the conveyor is attracted to the magnetic head pulley and held onto the surface of the conveyor ,” Bunting explained . “ As the returning conveyor leaves the under surface of the pulley , the separated tramp iron falls away under gravity into a designated collection area .”
In charge
Full flowsheet provider Metso Outotec knows all about protecting equipment in the processing plant .
It recently introduced a magnetic separator portfolio that , it says , caters to a wide variety of applications and provides improved recovery of fine and ultra-fine particles .
Metso Outotec High Gradient Magnetic Separators are designed to recover weakly magnetic material from non-magnetic matter and can be used for many applications including the processing of iron ores , rare earths and other weakly magnetic minerals not normally treatable by ordinary magnetic separators .
The Low Intensity Magnetic Separators – designed to recover magnetic material from nonmagnetic matter – are part of Metso Outotec ’ s Planet Positive product offering . The separators use physical separation and require no chemicals in the process , hence the environmental credentials .
Featuring a modular design with several frames and process tank designs , these separators use a common magnetic drum for ease of selection of the best machine for each
individual application , the company said .
Metso Outotec ’ s offering also includes the SLon ® Vertically Pulsating High-Gradient Magnetic Separator , which attracts fine , weaklymagnetic minerals . These units are WHIMS that use a combination of magnetic force , pulsating fluid and gravity to process minerals .
Jan Jirestig , Product Manager , Magnetic Separators , Metso Outotec , said : “ We have a long history in magnetic separation , and we delivered the first separator back in the 1890s . Since then , we ’ ve developed and delivered thousands of magnetic separators worldwide . We are continuously developing our products , securing our position at the forefront of the magnetic separation industry .”
Cyclone considerations
For many years , hydrocyclones have been the pillar of primary classification in hard-rock mining while also playing supporting roles in dewatering and tailings densification .
Within this context , Cavex ® hydrocyclones provide value in many applications due to their ability to efficiently classify particles , according to Juan Manuel Maquera Coyla , Mineral Processing Product Manager at Weir Minerals .
While often straightforward to operate , hydrocyclones deal with a large number of variables within the circuits they
operate in . These variables include hydrocyclone feed slurry characteristics and the desired product .
The selection process can be just as much art as science , requiring the combination of mathematical models to quantify variables such as specific gravity , turbulence , particle size distribution ( PSD ), slurry density and pressure , with a practical understanding of how the hydrocyclone will be used over its lifetime on site , Maquera Coyla says .
The key when selecting a hydrocyclone is to avoid focusing too narrowly on the equipment itself . If one does not factor in the entire process , the margin of error will increase as hydrocyclones are linked with the performance of other equipment in the circuit .
Although datasheets provide a substantial amount of important application information in this respect , it is important to avoid solely relying on them and also work with the in-situ equipment when available and consult with operators , according to Maquera Coyla .
“ In addition to basic information including the slurry ’ s viscosity and PSD , consultation will
The Cavex CVX hydrocyclone is designed to provide exceptional performance in a wide range of applications , Weir Minerals says . The cast housing of the hydrocyclone can be lined with a variety of wear-resistant materials such as rubber , ceramic , and polyurethane , among others . The laminar spiral inlet geometry design provides a natural flow path into the hydrocyclone . Its unique shape , without sharp edges , shelves or square corners , allows the feed stream to blend smoothly with rotating slurry inside the chamber
12 International Mining | MAY 2022