HEAP LEACHING & SX
pXRF powers productivity in SX-EW plants
Olympus is known in the minerals industry for the application of its portable X-ray fluorescence ( pXRF ) analysers to measure solid samples in the exploration and mining phases of the mining lifecycle – Vanta™ pXRF analysers are , for instance , used routinely around the world on soils , sediments , tills , drill cuttings and cores , as well as blastholes , run of mine , feeds , concentrates and tailings .
However , these same analysers are used globally to measure copper in liquids in solvent extraction and electrowinning ( SX-EW ) plants .
All samples within the SX-EW process , from barren samples to pregnant leach solutions , can be accurately tested in less than 30 seconds with a Vanta pXRF analyser , Olympus said . This quick test is typically performed in a benchtop Vanta Work Station within the mineral processing operations office or the plant laboratory . pXRF analysers reduce reliance on complicated , expensive laboratory instruments , such as atomic absorption spectrometers or inductively coupled plasma optical emission spectrometers , typically used to analyse copper in liquids . As a result , the skilled technicians that operated these complex instruments can focus on other critical tasks . Further , more data points from active monitoring with pXRF have shown to increase efficiency and yield .
“ By knowing process parameters , you can decide when to replenish the bath or when the extraction is complete ,” the company said .
The ability to collect a liquid sample , put it in a sample cup or bottle , present it to the Vanta pXRF analyser and get an accurate result in seconds has drastically increased the monitoring , management , and response capabilities of major mining companies around the world that process copper via SX-EW , according to Olympus .
Another useful tool for SX-EW plants is Olympus ’ Vanta iX in-line XRF analyser , a system designed for real-time process monitoring . Built to operate 24 / 7 , the analyser delivers instant chemistry of samples . The result is continuous quality control and reliable , actionable results to guide critical decisions .
“ Better efficiency and lower operating costs make SX-EW monitoring with in-line XRF a smart choice ,” Olympus said .
The Vanta iX analyser ’ s fully automated , 24 / 7 operation removes variables and human mistakes that can impact production . Like pXRF , the high-throughput testing with an in-line analyser can reduce operational overheads for a modest capital investment .
Vanta™ pXRF analysers are used globally to measure copper in liquids in SX-EW plants
The Vanta iX analyser is designed to seamlessly integrate with various production systems and scenarios with no external control box , so the system is easily controlled by an API or a PLC and discrete wire , the company said . Several connector options are available , such as Ethernet ( RJ-45 ) for Power over Ethernet , USB , discrete I / O ( 16 pins ) and auxiliary DC power , as well as mounting options for integration onto robotics and other systems .
Designed to endure the high levels of vibration , electromagnetic and acoustic noise , dust and moisture of mining production facilities , the Vanta iX analyser is IP54-rated and can operate from -10 ° C to 50 ° C with continuous testing . A built-in heat sink lowers the internal temperature , while fan attachment points are available if additional cooling is needed . The analyser offers tool-less window changes for fast maintenance .
Todd Houlahan , Director of International Mining at Olympus , stated : “ The Vanta iX in-line analyser is an exciting addition to our XRF product line . The industry demands increased automation capabilities of their XRF instruments , and we now have a dedicated product in the Vanta iX . It is robust and versatile , so it can easily integrate into a vast number of locations in any mining operation that can benefit from automated realtime , in-line analytical chemistry .”
the project should proceed to the next phase of test work ,” Sixth Wave said .
Sixth Wave will perform recovery tests from leach solution using its technology and the leaching columns already commissioned and used by Rio2 to evaluate adsorption kinetics and other parameters .
Testing was expected to start this quarter , the companies said back in August .
Oxidating the leach
IM has been reporting on developments with FLSmidth ’ s Rapid Oxidative Leach ( ROL ) process for some time now .
Unlike other refractory processing techniques , the ROL process uses the application of mechanical energy coupled with oxidation under atmospheric conditions . The process relies on stirred media reactors to accelerate the oxidation of sulphide minerals . This eliminates the need for ultrafine grinding , high temperatures and high pressure which makes it energy saving and very cost-effective , according to the OEM .
In August , Trevali Mining announced the commencement of a pilot plant testing program using Caribou run-of-mine and milled material at FLSmidth ’ s ROL process testing facility in Salt Lake City .
The program expands on previous laboratory test work and is aimed at demonstrating the potential to recover zinc , lead , copper , gold and silver as a precipitate or metal , and additional zinc and lead from Caribou ore and mill tailings .
The leach test program is targeting an improvement to zinc , lead , copper , gold and silver metal recoveries , the potential to produce a precipitate or metal on site to replace the current ore concentrate produced at Caribou – which , if implemented , would lead to savings on transport costs and off-site treatment costs – and the opportunity to process historic mill tailings , which include gold and copper metals , in
addition to run of mine ore .
Trevali said the use of FLSmidth ’ s ROL technology also provides the potential to reduce its carbon footprint at Caribou , extend the mine life and treat lower-grade deposits in the wider Bathurst camp of Canada , renowned for its zinc mines .
FLSmidth claims ROL leaches 97-99 % of copper directly on-site in six to eight hours , from concentrates as low as 5 % Cu . In gold , meanwhile , ROL has the potential to unlock the value of undeveloped refractory gold deposits with less than 3 g / t gold head grade .
Trevali said a successful pilot plant test program using ROL may allow Trevali to replace the existing flotation circuit at Caribou with atmospheric leach vessels and potentially an SX- EW train , introducing the possibility of producing base and precious metals on-site and thereby saving transport costs and off-site treatment costs .
24 International Mining | NOVEMBER / DECEMBER 2021