News of 17 November 2023
Prof Graeme Jameson, inventor of flotation cells, visits HZDR
The Helmholtz-Zentrum Dresden-Rossendorf (HZDR) is hosting an extraordinary scientist today: following the 11th International Flotation Conference in Cape Town, the 87-year-old Australian Professor (em.) Graeme Jameson pays a flying visit at HZDR to discuss the fundamental principles of the Concorde CellTM in the flotation of very fine ore particles. Participants in the discussion are scientists from the Institute of Fluid Dynamics (FWD) and the Helmholtz Institute Freiberg for Resource Technology (HIF). Traveling with Prof Jameson are two of Metso’s Finland-based Concorde Cell specialists.
Froth flotation is one of the great scientific yet highly practical discoveries of the 19th century. Flotation is the most important method in the mining industry for extracting valuable raw materials from ores. One of the best-known faces of this process worldwide is Professor Jameson, the inventor of the eponymous Jameson Cell, which is regarded as Australia's best-earning innovation of the past 25 years and is licensed by Glencore Technologies. Every year, several billion tons of ore are extracted worldwide using flotation, including copper, nickel, platinum, silver and zinc.
Further developments of the Jameson Cell by Jameson led to his invention of the Concorde Cell, which turned out to have great potential for separating particularly small – below 30 micrometer – mineral particles. Particles of this size are barely visible to the human eye. Due to the high demand for raw materials for the green transition, the mining industry must increasingly focus on deposits with lower quality and complex mineralogy. In order to extract valuable metals and minerals from these deposits using flotation, the rock must first be ground down to the fine sizes. The now exposed mineral surfaces are made water-repellent using chemical reagents and thus floatable with gas bubbles.
In Prof Kerstin Eckert's department for Transport Processes at Interfaces, Dr. Till Zürner, a young scientist in the HZDR High Potential Program, is responsible for the demonstrator of a Concorde-like cell. Zürner is using a simplified model geometry to investigate the so-called "plunging jet", the plunging water jet-loaded with particles, which flows into the flotation cell simultaneously with air. "A special feature of the Concorde Cell is the constricting nozzles at the beginning and end of the Concorde Blast Tube™. They compress the stream of particles and air bubbles and increase the turbulence," explains Zürner, who visited Metso’s Research Center in Finland last October. The scientist's aim is to reach the speed of sound in his Concorde-like cell with the 2- and 3-phase flow - hence the name of the flotation cell.
The assumption of the scientists is that sonic shockwaves are created by the plunging jet upon exiting the Concorde Blast TubeTM, supporting the generation of stronger turbulences of the particle-gas bubble flows in the cell, and increasing the probability of particularly small particles adhering to the bubbles. But this has yet to be observed. Scientific studies of the multiphase flow in the lower area of the flotation cell have so far been scarce, because it becomes increasingly difficult to visualize the interaction between small model particles and the equally tiny gas bubbles at high flow rates. Together with the Computational Fluid Dynamics department, Kerstin Eckert and her research group are looking for ways to make the invisible visible using optical and electrical tomography, pressure sensors and other sensors currently under development, as well as software programs.
The Finnish company Metso, one of the world's leading suppliers of flotation technology, is also very interested in this data. A research cooperation between the HZDR and Metso has recently been established, promoted via the HZDR alumni network. One of the alumni network members is Dr. Nathalie Kupka, who completed her PhD in the field of flotation at the HIF in Freiberg and headed the Processing Department’s modeling research group as a scientist. She now works at Metso and manages the R&D on the Concorde Cell. "The expertise I developed at the HIF under Dr. Martin Rudolph’s leadership has been critical in my work as a Technology Manager at Metso," says Kupka. Metso licensed Jameson's Concorde Cell in 2017, and has been further developing this technology, which became part of its product portfolio in 2021. "To further increase the efficiency of flotation, we need to understand how fine bubbles interact with fine particles in the cell so that we can optimize and scale-up the design in the future," explains Alejandro Yáñez, the Product Manager of the Concorde Cell within Metso. The visit with Jameson was a great opportunity to take a look at the test apparatus at HZDR. Thanks to a DAAD-funded alumni project at HZDR, the research collaboration with Metso was able to move forward last year.
Prof Sebastian M. Schmidt, Scientific Director of the HZDR, thanked Prof Jameson for his visit: "It is a great honor to welcome such a renowned scientist to the HZDR and to benefit from his wealth of first-hand experience." Kerstin Eckert added: "There are so many questions for us that can only be clarified in a direct exchange of knowledge with Professor Jameson and the colleagues of Metso. This visit is priceless for us."
Dr. Till Zürner | Department of Transport Processes at Interfaces
Institute of Fluid Dynamics
Phone: +49 351 260 2800 I Email: firstname.lastname@example.org
Dr. Martin Rudolph I Department of Processing
Helmholtz Institute Freiberg for Resource Technology
Phone: +49 351 260 2800 I Email: email@example.com
Dr. Nathalie Kupka I Metso