Collectors_in_Mineral_Processing_Presentation-2.pptx

Collectors_in_Mineral_Processing_Presentation-2.pptx

1. Collectors in Mineral Processing Understanding the Role, Mechanisms, and Applications of Collectors For Metallurgical Engineering Students Professor in Metallurgy

2. Introduction to Collectors In mineral processing, collectors are crucial reagents that are used to impart hydrophobicity to mineral surfaces, facilitating their separation from unwanted gangue by flotation. Collectors are surfactants, and their primary role is to modify the surface properties of minerals to make them more amenable to separation. This presentation delves into the various types of collectors, their mechanisms, and their applications in mineral processing.

3. Role of Collectors in Flotation Collectors play a pivotal role in the flotation process by making the surface of the targeted mineral hydrophobic, thereby enabling its attachment to air bubbles. This process is essential for the effective separation of valuable minerals from the gangue material. The interaction between collectors and mineral surfaces reduces the stability of the water layer, allowing air bubbles to attach to the mineral particles and carry them to the surface as froth.

4. Types of Collectors Collectors are broadly classified into two categories: nonionizing collectors and ionizing collectors. Nonionizing collectors, such as kerosene, are typically used for naturally hydrophobic minerals like coal and molybdenite. Ionizing collectors are further classified into anionic and cationic collectors, each used for specific mineral types based on their surface chemistry.

5. Nonionizing Collectors Nonionizing collectors are hydrophobic compounds that do not ionize in water. These collectors are typically used for minerals that are naturally hydrophobic. A classic example is kerosene, which is used to enhance the flotation of naturally hydrophobic minerals like coal and molybdenite. The mechanism involves the adsorption of the collector onto the mineral surface, increasing its hydrophobicity and making it more amenable to flotation.

6. Ionizing Collectors: Anionic Collectors Anionic collectors are characterized by their negatively charged polar group. This group typically reacts with the metal ions on the mineral surface, forming a hydrophobic layer that facilitates flotation. Sulfhydryl collectors, such as xanthates, and oxyhydryl collectors, such as fatty acids, are common examples. These collectors are widely used in the flotation of sulfide minerals and other non-sulfide ores.

7. Ionizing Collectors: Cationic Collectors Cationic collectors, such as amines, have a positively charged polar group. These collectors are particularly effective in the flotation of non-sulfide minerals like quartz. The cationic collector's positive charge allows it to adsorb onto negatively charged mineral surfaces, rendering the surface hydrophobic and suitable for flotation.

8. Mechanisms of Collector Adsorption Collector adsorption onto mineral surfaces occurs through two primary mechanisms: chemisorption and physisorption. Chemisorption involves the formation of chemical bonds between the collector molecules and the mineral surface, often through electron donation. Physisorption, on the other hand, is driven by electrostatic interactions between the charged collector and the mineral surface.

9. Chemical Adsorption (Chemisorption) In chemisorption, the collector molecules form strong chemical bonds with the mineral surface, typically through a donor-acceptor mechanism. This type of adsorption is selective and results in a stable hydrophobic layer on the mineral surface. An example of chemisorption is the reaction between oleic acid and calcium-bearing minerals, where calcium oleate is formed on the mineral surface.

10. Physical Adsorption (Physisorption) Physisorption occurs when collector molecules are adsorbed onto mineral surfaces through electrostatic interactions. This process does not involve chemical bonding, making it generally weaker than chemisorption. However, physisorption can be effective for certain minerals, particularly in systems where surface charge plays a significant role.

11. Factors Affecting Collector Adsorption Several factors influence the adsorption of collectors onto mineral surfaces, including pH, pulp potential, and the presence of competing ions. The pH of the system can alter the charge on the mineral surface, thereby affecting the adsorption mechanism. Pulp potential influences the electrochemical reactions that occur during flotation, impacting the efficiency of collector adsorption.

12. Collector Adsorption in Non-Sulfide Minerals

13. Conclusion: Key Takeaways Collectors play an essential role in the flotation process, influencing both the recovery and selectivity of minerals. Understanding the mechanisms of collector adsorption, the factors affecting their performance, and the environmental impact of their use is crucial for optimizing mineral processing operations. The ongoing research into 'green' collectors and advanced technologies promises to enhance the sustainability and efficiency of mineral processing in the future.

14. Further Reading and References For more in-depth information on collectors in mineral processing, refer to the following sources: - Bulatovic, S. M. (2007). Handbook of Flotation Reagents: Chemistry, Theory and Practice. - Nagaraj, D. R., & Farinato, R. S. (2014). Reagents in Mineral Technology. - Fuerstenau, M. C., & Somasundaran, P. (2003). Principles of Mineral Processing. - Pradip, & Fuerstenau, D. W. (2013). Advances in the Chemistry of Collectors.

15. Questions and Discussion Thank you for your attention! Please feel free to ask any questions or raise any points for discussion. Let's explore the concepts of collectors in mineral processing in more depth and clarify any uncertainties.