FLOTATION
separation of ultrafine particles based on Maelgwyn ’ s Imhoflot™ pneumatic flotation , where the particle-bubble collision takes place instantaneously within the aerator in a high shear highly turbulent zone with little residence time as compared to the conventional rotorstator machines . The energy input is more efficiently directed into the bubble-particle collection , rather than energy being used to maintain the pulp in suspension as in mechanical cells . The intense mixing via the Richtmyer- Meshkov instability together with the generation of reactive microbubbles is assumed to be the main driver for enhanced collision frequencies and the probability of fine particles at microbubbles which is governed by the hydrodynamics . Thus , the kinetic energy with most of the current flotation apparatuses is not
Maelgwyn Imhoflot™ G- Cells at Kazzinc ' s Altyntau Kokshetau
yet sufficient for the capture of fine and ultrafine particles . The advanced aerator is not only a fine bubbles generator but also helps to clean the mineral surfaces , thus increasing reagent selectivity and reducing the dosing required ."
Hoang said that three case studies using pneumatic flotation with the new aerator type on ultrafine particles showed very promising results : n Fine gold recovery : Imhoflot™ G-Cells have been trailed at Kazzinc ' s Altyntau Kokshetau operation in Kazakhstan where the existing conventional cells were not achieving the desired grade-recovery profile with the main gold losses reported to be in the fine (< 38 µ m ) and ultra-fine (< 20 µ m ) size fractions . The application of two G-14 cells in an open circuit demonstrated the ability to recover the fine and ultra-fine gold loss to the tailings , with the G-cell achieving an average concentrate grade of 19.94 g / t , compared to the existing circuit final concentrate grade of 25-30 g / t achieved with two cleaning stages . Size by size analyses showed it was possible to achieve an additional recovery of 65 % and
68 % in the size fractions of < 20 µ m and 20- 38 µ m , respectively . n Slime magnesite from Magnesitas Navarras ( MAGNA ) - Spain ( cyclone overflow , d 80 = 17 μm which is currently discarding to the tailings ) - Using reserve-direct flotation , more than 90 % quartz has been removed with the reverse stage and a concentrate containing 80 % to 90 % magnesite with only MMS rougher flotation which is more selective than lab mechanical cells . n Ultrafine copper ( Cleaner Scavenger Tails - CST ), d 80 is about 20 μm - Mineral Liberation Analysis MLA showed that there are still liberated ultrafine copper and zinc-bearing sulfides that are currently lost to the tailings due to the inefficiency of recovering the fine particles using the existing mechanical cells . The CST contains about 1.0 % Cu and 0.7 % Zn with a large tonnage of production annually , ie 450 , 000 t / y , which is about 4,500 t of copper and 3,150 t of Zn lost yearly . With one MMS rougher flotation using the mini-pilot pneumatic flotation cell , about 50 % of the Cu and Zn have been recovered at a grade of 4-6 % and 5-8 % for Cu and Zn respectively . A pilot plant is currently commissioned and ready for testwork at the biggest copper concentrator in Europe , KGHM , Polkowice , Poland . Maelgwyn and FineFuture teams are looking forward to the pilot trials onsite in October 2022 and also concluding the successful FineFuture project .
IM
BGRIMM & intelligent flotation
As the largest supplier of flotation equipment in China , BGRIMM told IM it has made significant progress in the past year . The concept and development pathway of more intelligent flotation equipment were proposed . “ It covers modern sense technology , automatic control , artificial intelligence , Internet of Things , robots and other high-tech . The intelligent flotation equipment should have the capability of self-perceiving , selfdiagnosing , autonomously operating and self-maintaining . It is a kind of flotation cell system that adjusts operating parameters and process variables for optimum technical and economic indicator .”
It says that quite a few intelligent devices have already been developed by BGRIMM engineers , such as an on-line bubble size measuring device , in-situ bubble loading measuring system , solid suspension detector and froth lip cleaning robot . HIF cells equipped with multi-dimensional intelligent sensing system represent the first step made by BGRIMM towards its ambition . The HIF-680 intelligent flotation cell has been running in China ' s largest copper mine , Dexing Copper Mine , for one year . The comprehensive recovery rate of the flotation circuit has been increased by 1.05 % with the installation . The HIF-130 has been successfully applied in Wushan Copper Mine of Jiangxi Copper Group . The recovery rate of copper has increased by 1.10 %, and those of gold and silver have increased by 0.88 % and 0.89 %, respectively .
In the past year , BGRIMM says it has also been making efforts to develop special flotation equipment for energy minerals such as crystalline graphite ore and low-grade lepidolite lithium ore ( Li2O content less than 0.3 %). Some 16 sets of 100 m 3 forced-air flotation cells have been applied in the Luobei graphite mine in Heilongjiang , China , with a processing capacity of 7,500 t / d . The particle size of feeding is -0.074 mm , accounting for 40 %. The design graphite recovery rate is 85 %, design grade is 95 %, and more than 11 % of + 0.15 mm particles in the concentrate . “ Considering the strong hydrophobicity and drainage ability of graphite froth , the forced froth scraping technology arranged in parallel has been adopted on tank flotation cells .”
Then 30 sets of 320 m 3 BGRIMM forced-air flotation cells have been installed as roughers , scavengers and cleaners at CATL ’ s lithium mine in Yichun to separate lepidolite . The particle size of feeding material is -0.3 mm ( -74 microns approximately 35 %), and the processing capacity is 45 Mt / y . The grade of lepidolite is low , and the Li 2O content is about 0.3 %. Then six sets of 160 m 3 KYF flotation cells have been applied as roughers and scavengers for granitic pegmatite lithium ore at the Arcadia mine in Zimbabwe .
For copper , 17 sets of KYF-200 m 3 flotation cells have been utilised for the selective separation of copper and cobalt ore at the TFM Project of CMOC in DRC . Also in DRC for the Longshi project , 28 KYF-70 m 3 flotation cells have been adopted for separation of copper and cobalt ore , which are currently under installation . For Codelco ’ s Rajo Inca project , KYF-8 / 4 flotation cells for copper-molybdenum selective separation have been delivered . Finally , 16 sets of CLF-40 flotation cells are going to be dispatched for a Mexican copper slag project .
56 International Mining | OCTOBER 2022