IM 2020 November/December 20 | Seite 32

FLOTATION TECHNOLOGY
these products to the market in 2021 and 2022 showing our commitment to hard-to-treat mineral flotation .”
The new Hybrid is a combination of the best of Maelgwyn ’ s existing V-Cell and G-Cell . The V-Cell is optimised for concentrate yield by using co-current pneumatic flotation and a froth crowder to stabilise the froth . The V-cell has found application in both coarse potash flotation ( 1-3 mm sylvite ) and ultrafine copper tailings reprocessing ( -20 μm chalcopyrite ). The G-Cell is optimised to achieve concentrate grade when there are fine entrained gangue particles . The centrifugal motion of the froth increases froth draining of fine gangue whilst maintaining mineral recovery . The G-Cell is often fitted to plants when column flotation is achieving grade but not the recovery desired . To ease retrofit options , this cell can be supplied in a modular format .
“ Maelgwyn realised that what plant operators loved about our cells was the plant stability which they gave . The H-Cell ( Hybrid cell ) combines the V- and G-Cell into a single unit which can adjust the mix of vertical and tangential slurry flotation to optimise for either coarser feeds ( more vertical component ) or finer feeds with entrained fines ( more tangential component ). The H-Cell gives the same stability of our V- and G-Cells but this can now be achieved even through the most variable grade and ore hardness conditions .”
As if that was not enough , Maelgwyn is also addressing the already discussed area of coarse

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New innovation in laboratory flotation
MINPRO International has developed a new generation semi-automatic laboratory flotation machine . Rafal Helis , the CEO of MINPRO International in Poland , told IM : “ We have made a revolutionary laboratory flotation machine with the latest technology . It is designed for more efficient testing and to reduce the human error to a minimum . The flotation machine is automated and has the possibility to preset the tests stages that should be carried out which results in a detailed flotation report .” You can operate the machine with a built-in touchscreen or control it by wireless connection from a PC , tablet or smartphone . MINPRO says these machines are suitable for all types of laboratory test facilities including universities and science centres , in-plant laboratories for internal flotation R & D and environmental R & D test facilities .
The machine is robust and is made out of acid proof stainless steel . The flotation mechanism is selfaerating and there is no need for an additional air compressor . The electric motor is quiet so it does not cause a disturbance to run the machine in a laboratory . There are three sizes of the cell boxes : 2.5 l , 5 l and 10 l , each with dedicated mechanism ’ s size .
The machine can be run in manual start-stop mode , or in automated sequential mode . When the test procedure is completed , the operator may review and edit the detailed flotation report . In sequential mode the operator fills in sample weight , percentage of solids to be used and the main parameters for the test . " The software in the machine will calculate the amount of water that needs to be added into the cell box to obtain the correct percentage of solids . If there is a need to change the airflow rate , impeller speed or reagents used , the operator may adjust this on the go . The automatic froth scraper system makes is easier to collect the demanded froth to the concentrate ’ s tray . The froth scraper ’ s adjustable height and speed helps to reach the best froth collecting performance . It is also easy to attach and detach the froth scraper system from the cell box .”
All settings , process and operations data are saved by the machine ’ s software . After the test has been completed all data is imported by the operator into the report file giving the customer detailed information about the performed flotation test . The report also includes tables and diagrams like slurry pH , flotation airflow rate , concentrate grade and recovery chart . The software collects and registers all parameters continuously during the test period . The flotation report view and content can be customised on demand and the software can be updated remotely .
����������� partice flotation with its CP ( Coarse Particle ) -Cell range . “ Maelgwyn have gone back to the drawing board during COVID-19 and have optimised the CP-Cell for coarse flotation which launches in 2021 . The CP-Cell builds upon the Imhoflot pneumatic flotation technology success in coarse potash flotation but introduces a collection vessel and launder design optimised to stabilise the froth and recovery the coarse particles using a long launder lip-length . The CP- Cell retains the same low maintenance design philosophy as our previous cells with the drive pump being the only moving part . The high hydraulic shear used in Imhoflot technology generates improved froth handling characteristics meaning less launder water is used thus simplifying downstream concentrate dewatering .”
The CP-Cell can be applied in the flash flotation role when combined with a trash screen . The small unit footprint due to the short residence time ( accelerated flotation kinetics ) makes this a useful retrofit option .
Lastly , a note on the EU H2020 Project ' FineFuture ' which is an EU-funded research project aimed at unlocking the potential of fine-grained mineral deposits and Critical Raw Materials for the EU . Sambrook told IM : “ The potential for ultrafine flotation with the Imhoflot has been recognised for several decades . Our clients regularly achieve good recoveries down to 10 μm in the base metal flotation and 5 μm in coal flotation . FineFuture builds on the EU grant which Maelgwyn received for the development of our energy efficient Ultrafine Grinding Mill - Ro-Star . Maelgwyn R & D team member Duong Hoang is leading on the application of Imhoflot technology to the flotation of semi-soluble minerals such as dolomite , calcite and magnesite . The challenge with these minerals is that the surface is sparingly soluble so is constantly changing . Equally , high carbonate anions in solution can lead to surface precipitation .”
Maelgwyn says it has had some early success cleaning ultrafine magnesite which was previously being discarded as tailings . The project runs for another two years .
30 International Mining | NOVEMBER / DECEMBER 2020