FLOTATION dry stacking . The technology also incorporates a recycle stream to fluidise the bed , minimising the overall plant fresh water consumption .”
Laureate Professor Graeme Jameson says NovaCell™ is at the forefront of the coarse particle separation field . " The NovaCell™ recovers valuable particles from one micron to one millimetre for base and precious minerals , and greater than two millimetre particles for coal . This is achieved in a simple flowsheet , where the NovaCell™ treats the full process flow without a fines removal plant . The technology is also sustainable , reducing energy and water consumption ."
Jord is now collaborating with industry partners to apply the technology at full-scale . The company has 50 years of experience in modular design , manufacture and installation of process plants . It offers the NovaCell™ technology as equipment supply or as a full turn-key solution , with trial assembly depending on requirements .
Novel collectors for flotation of slimes to increase iron mining sustainability
The Clariant team of Livia Marques Faustino ; Nathalia Prado Costa ; Leandro Seixas Bicalho and Wagner Claudio da Silva reviewed for IM the role its FLOTINOR™ 5530 is playing in the industry – which was specifically developed for ultrafine iron ore reverse flotation .
“ The mining industry is an enabler of a more sustainable future , providing the metals and minerals that are needed to support a low carbon economy . Additionally , mining companies are focused on reducing their own footprint and improving the sustainability of their operations . In order to maximise the amount of minerals that are recovered and minimise the amount of waste generated , mining companies are turning their attention to slimes , the fine particles that are generated while grinding minerals , in order to achieve the optimal particle size for flotation .”
Froth flotation is a process that uses air bubbles and differences in wettability to selectively separate hydrophobic from hydrophilic minerals . The process is most
Iron metallurgical recovery (%)
95 85 75
50 g / t
70 g / t
30 g / t effective in a fairly narrow range of particle sizes . Sizing of the flotation feed through crushing , milling and classification requires multiple desliming stages . In the beneficiation of iron ore , for instance , the coarse fraction returns to the comminution process until the optimal particle size ( -300 to + 10 μm ) is reached , and fine particles , or ‘ slimes ’ (< 10 μm ) are removed from the concentration process in the desliming overflow . These slimes account for a loss of 10- 30 % of the mass and 40-50 % of the iron in the ore . As the mining industry explores safer destinations for tailings , Clariant says it is committed to developing sustainable solutions to recover iron from the slimes , and by incorporating high grade tailings in ore production , disposal costs are instead turned into value .
“ Selective separation of valuable mineral and gangue through flotation is initially a function of physical characteristics of the three phases involved in the flotation process ( particle , bubble and fluid ). The physicochemical properties as well as the main causes for poor recovery in slimes flotation differ from the challenges of conventional flotation feeds . While the challenges of coarser particles recovery are related to their high probability of detachment from bubbles , the poor recovery of the ultrafine particles in slimes is due to the low efficiency of particle-bubble collision .”
Ultrafine particles are more susceptible to inertial forces and to being dragged through the hydrodynamic preferential fluxes . Additionally , they do not have enough energy to rupture the intervening liquid film between the particles and the bubbles . “ There is a critical hydrophobicity level required for flotation that increases as the particle size decreases , which , in addition to ultrafine particles much higher surface areas , requires increasing collector dosages . From the rheological and hydrodynamic perspectives , the process requires a substantial level of agitation , particle dispersion and pulp dilution to increase particle-bubble collision and attachment efficiencies .”
These differences from conventional flotation
400 g / t
65 400 g / t
55 600 g / t
45 800 g / t
600 g / t
35 800 g / t
25 0 2 4 6 8 10 12
FLOTIGAM TM 7100 Conventional Flotation
FLOTIGAM TM 7100 Slimes Flotation
FLOTINOR TM 5530 Slimes Flotation
Silica grade (%) in the concentrate
Flotation of ultrafine iron ore versus conventional feed : the necessity of increasing collector dosage and the higher performance of FLOTINOR™ 5530 call for special solutions for slimes flotation . The hydrophobicity of the particles may be increased by adding higher reagent dosages , but overdosing may actually make the mineral surface more hydrophilic , thus making the particle lose floatability . Therefore , slimes flotation requires tailor-made chemicals that allow increasing dosage and particle hydrophobicity without affecting selectivity , froth stability and overall performance .
In response to this challenge , Clariant ’ s application and development teams are partnering with customers to develop and test special collectors to reduce ultrafine particle losses and to recover value from tailings . Clariant has developed FLOTINOR™ 5530 specifically for ultrafine iron ore reverse flotation , and flotation tests have shown that although higher dosages of collector are required in comparison to tests with conventional flotation feed ( with larger particles ), the tailings flotation with FLOTINOR™ 5530 yielded a 64 % iron grade concentrate with 30 % better metallurgical recovery and half of the dosage compared with tailings tests with FLOTIGAM™ 7100 . Additionally , it was possible to decrease the silica grade in the concentrate by increasing the FLOTINOR™5530 dosage without lowering metallurgical recovery below 40 %.
“ Clariant understands that flotation of tailings involves specific challenges that call for tailormade solutions . Carefully addressing the challenges of ultrafine particles flotation , FLOTINOR™ 5530 helps mining operators increase the amount of iron they recover , ultimately increasing the value of the ore mined and decreasing waste .”
TAKRAF DELKOR flotation cells commissioned in India
The first commercial application of the TAKRAF DELKOR BQR flotation cell equipped with the MAXGen mechanism has been commissioned on a project where the technology has been applied to maximise limestone recovery . The flotation cells were ordered by one of India ’ s leading cement producers , as part of a contract covering the supply of flotation , thickening and filtration equipment for one of its cement works in India .
TAKRAF states : “ DELKOR BQR flotation cells , equipped with the MAXGen mechanism , achieve superior process performance in maximising recovery . DELKOR BQR flotation cells achieve optimum operation through improved particlebubble interaction , faster flotation kinetics and precise froth level controls .”
The order comprises design , engineering , supply and supervision of erection and commissioning of two banks of DELKOR flotation cells , with each bank comprising three BQR flotation cells for single stage roughing flotation .
OCTOBER 2021 | International Mining 43