Designed Collectors for Selective Flotation of Sulfide Minerals
Modern life without metals is unimaginable. The extraction of minerals and metals in modern times involves a complex process that has evolved over centuries.
Modern life without metals is unimaginable. The extraction of minerals and metals in modern times involves a complex process that has evolved over centuries. An important step in this process is called flotation, which separates various minerals from ores. To achieve this, a type of reagent called a collector is used. Collectors have a functional group that binds to metal atoms present on mineral surfaces. To improve the separation of different minerals, additional compounds called modifier reagents are often included in the flotation mixture. However, modifying reagents are often toxic and their use can have negative effects on the environment, although they improve the separation process.
Despite using both collectors and modification reagents to recover metals, a significant amount of process-rejected material remains after flotation. Further extraction of metals from this process-rejected material is challenging and not economically feasible, resulting in the material being classified as process-reject and deposited in a specific area near the mines. Leaching of heavy metals and toxic ions from these process-reject materials due to acid rain drainage can cause environmental damage.
Our project focuses on developing environmentally friendly collectors that are more efficient and selective compared to traditional ones. These innovative collectors aim to extract valuable minerals from mining process-reject, even if present in small quantities, without the need to use toxic modification reagents.
These advanced collectors enable a significant reduction in environmental damage by eliminating the need for harmful modification reagents and extracting minerals from conventional process-reject. This significantly reduces the risk of acid rain drainage. Therefore, our project encourages the responsible and sustainable use of natural resources by enabling the extraction of valuable minerals that would otherwise be thrown away as process-reject.
The chemical composition and crystal structure of minerals vary, leading to differences in the distance between the metal atoms on their surfaces. Mineralogical characterization enables a comprehensive identification of minerals and metals in process-rejected material. With this information, the distances between metal atoms on different mineral surfaces can be calculated by molecular modelling. Then, collectors can be designed with two functional groups specifically tailored to match the unique spacings on the mineral surfaces that we want to recover. Traditional collectors have only one functional group and therefore are not mineral specific. This geometric matching ensures that the designed collector binds selectively and efficiently to the desired mineral and not to other minerals that have different distances between its metal atoms on the surface.
To analysethe function of the collector, flotation tests will be carried out on a laboratory scale. The results, involving the flotation products, will be evaluated using elemental analysis as well as various spectroscopic methods to optimize mineral recovery.
Our collectors are made from environmentally friendly chemicals, such as fatty acids and amino acids, which are essential components of food that people consume every day. After use, if the collectors are released into the wild, they will self-dissolve into ingredient biomolecules, which in turn will undergo complete microorganism-mediated degradation. So, these collectors leave no footprint on the environment. The mines of sulfide minerals (e.g., copper ore chalcopyrite) contain large amounts of the iron sulfide mineral pyrite. Because iron is much cheaper than other transition metals, pyrite ends up as process-rejected material in sulfide mines. "Process-rejected pyrite" contains minerals of copper, nickel, cobalt in significant amounts but these valuable minerals are difficult to recover with conventional collectors with a functional group. The particular focus of our project is to separate these valuable minerals from process-reject using our efficient mineral specific collectors. These process-reject will also be treated in a furnace under different conditions such as varying temperature and atmosphere as oxidizing (air), inert (nitrogen) or reducing (hydrogen). The purpose of the heat treatment is to facilitate the physical separation of the coexisting minerals in the process-reject and thereby improve the recovery of Cu- and Co-containing minerals. Extracting these minerals from process-reject in an environmentally friendly and efficient way will be valuable both economically and ecologically.
The Swedish Governmental Agency for Innovation Systems VINNOVA-supported project will be administered and most of the laboratory experiments will be carried out by Chemistry of Interfaces research subject, Luleå University of Technology. In this project, together with industrial partner Clariant AB External link., collector synthesis will be scaled up. In the future project, the produced collectors will be tested for pilot scale flotation experiments at Boliden AB
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Contact
Anuttam Patra
- Senior Lecturer
- 0920-491934
- anuttam.patra@ltu.se
- Anuttam Patra
Hesham Ahmed
- Associate Professor, Associate Professor
- 0920-491309
- hesham.ahmed@ltu.se
- Hesham Ahmed
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