MINERAL SEPARATION
Redefining particle liberation analysis with 3D analytics
Traditionally , mineral liberation analysis has been carried out using light microscopes ( LM ) and scanning electron microscopes ( SEM ). These valuable tools help deepen the understanding of samples in 2D , however , there is more to gain with 3D analysis .
ZEISS explained : “ The advent of sophisticated analytical workflows for micro-computed tomography ( uCT ) or X-ray microscopy ( XRM ) has ushered in a new era in mineral processing , offering a comprehensive solution to the challenges of traditional mineral liberation studies . XRM has a transformative impact on mineral processing , from ore characterisation through to leaching operations and beyond . It redefines the approach to analysing precious and base metals .”
3D XRM enables rapid , non-destructive 3D characterisation of ores . This technology minimises sample preparation requirements and leverages large volume statistics for high-resolution characterisation . Unique to XRM is the ability to distinguish between mineral polymorphs , which significantly enhances the precision of mineralogical distinction .
ZEISS Xradia Versa 3D X-ray microscopes exemplify the pinnacle of this technology , according to the company , using computed tomography principles to achieve unprecedented spatial resolution and contrast mechanisms . This allows for detailed discrimination of valuable mineral phases and the visualisation of internal fracture networks , thereby optimising comminution processes and enhancing plant design and optimisation efforts .
ZEISS Mineralogic 3D represents a leap forward in automated mineralogy , according to the company .
Applying deep learning algorithms alongside 3D XRM techniques simplifies sample preparation and eliminates the reliance on stereological assumptions , ZEISS explains . Mineralogic 3D offers a comprehensive view of each grain , delivering critical data on particle identification , mineral classification , liberation , and association measurements rapidly and accurately .
“ One of the key operational benefits of Mineralogic 3D is the dramatic simplification of the sample preparation process , significantly reducing the time from sample collection to actionable data ,” ZEISS says . “ The application of machine learning for particle segmentation and the use of deep learning algorithms for noise reduction and mineral classification streamline the analysis process , allowing for a detailed assessment of
Unlike traditional 2D measurement techniques ( left ), Mineralogic 3D uses a 3D-quantitative-CT scan to measure the surface and interior of every particle ( right ) to enable discovery of the real liberation of valuable minerals
morphological parameters and the mineralogical composition of samples .” Moreover , the ability to analyse the interior mineralogy of particles without the need for mechanical alteration preserves the integrity of the sample and provides a more accurate representation of its composition , the company claims . This approach not only enhances the quality of liberation and association measurements but also offers a more nuanced understanding of the geometallurgical behavior of ores .
The integration of 3D X-ray microscopy into mineral processing signifies a transformative shift towards more accurate , efficient and comprehensive ore characterization , ZEISS says . Being able to analyse samples in 3D offers a plethora of benefits , from improved analytical information and streamlined workflows to enhanced plant design and optimisation .
“ As the mining industry continues to advance , the adoption of XRM and Mineralogic 3D is poised to play a pivotal role in unlocking the full potential of mineral resources , marking a new era in mineral processing ,” the company concluded . n Self-closing nozzles .
Some of these features have been proven out by a Germany-based customer that contacted AKW to assist in evaluating a process solution to reduce the organics in its washed silica sand . AKW started the investigations by reviewing the composition of the input material , followed by comprehensive test work performed in its own technical laboratory . This test work was used to define a suitable concept for the reduction of organics in the < 500 μm washed silica sand . Based on the test results achieved in close cooperation with the customer , the relevant process was defined and the following equipment was selected and sized accordingly : n A rubber-lined AKA-SORTER upstream sorter ; n A high-performance AKA-VORTEX hydrocyclone ; and n A rubber-lined pump sump .
With this setup , the organic content level of the silica sand could be reduced by up to 95 %, the company claims .
“ In order to be able to cover a wide range of applications , AKW Equipment + Process Design has various sizes of AKA-SORTERs in the delivery program , ranging from 1.2 m up to 3.6 m diameter ,” it says .
The Cavex 2.0 evolution
It was an application in iron ore slimes that led to the development of one of Weir ’ s most recent mineral separation innovations .
In the company ’ s 2023 annual results , Weir hydrocyclones and – in particular – Cavex ® 2.0 technology received a shout out .
The company said it made progress with its technology-focused growth initiatives , launching and commencing field trials of a number of innovative new solutions , including Cavex 2.0 technology . This solution , it said , led
to an increase in its hydrocyclone market share .
The Cavex 2 hydrocyclone marks a new era in separation technology , according to Weir . Its LIG + ™ advanced laminar spiral inlet , together with the size of the feed chamber , reduces turbulence and allows the hydrocyclone to classify up to 30 % more feed slurry , while occupying the same footprint as the original Cavex and competitor cyclones . This enhanced performance is unmatched by any known hydrocyclone in operation today , according to the company .
Vale and Weir pioneered the use of the Cavex 2 CVD hydrocyclone in an iron ore desliming application and achieved a 9 percentage point gain in mass recovery , increasing recoveries to 56 %.
The two companies partnered to optimise the desliming stage at Vale ’ s Vargem Grande 2 Plant
66 International Mining | APRIL 2024