Ore dressing .pptx

ore dressing is the process that occurs before the beneficiation process.

1. ORE DRESSING By Saguna Sharadbhai Oza Paper GEL 501 Roll no. 09 M.Sc. Sem III

2. Table of contents Definitions What is ore dressing ? Methods of ore dressing Conclusion References

3. Definitions Mineral A mineral is a naturally occurring, inorganic solid substance with a specific chemical composition and a highly ordered atomic structure. Ore Ore is a naturally occurring mineral or rock that contains valuable substances, typically metals or minerals, that can be extracted and processed for economic gain. Gangue Gangue refers to the non-valuable, or waste, material that is closely associated with an ore or mineral deposit.

4. What is ore dressing ? Ore dressing, also known as mineral processing or mineral beneficiation, is the process of separating valuable minerals from their ores. The goal of ore dressing is to extract and concentrate these valuable minerals, making them suitable for further refining or use. The process of ore dressing involves several stages, which may vary depending on the nature of the ore and the desired end product.

5. Methods of ore dressing Generally, mineral processing begins when an ore is delivered from a mine, to a processing facility. At this point, the ore is called run-of-mine material because there has been no treatment performed on it. The choice of ore dressing methods depends on the type of ore, its mineral composition, and the desired product specifications. The main steps typically include: Comminution Classifiers

6. Comminution Comminution involves the breaking down of larger chunks of raw ore into smaller particles to prepare them for further processing and extraction of valuable minerals. The process typically consists of two main stages, Primary comminution Secondary comminution

7. Primary comminution Primary comminution is the initial stage of particle size reduction, typically involving the coarse crushing or breaking down of larger chunks of raw material into smaller pieces. The primary goal of this stage is to prepare the material for further processing and make it suitable for subsequent processes. Primary comminution is often carried out using such crushers, Jaw crusher Gyratory crusher Impact crusher

8. Jaw crusher A jaw crusher has a fixed jaw and a movable jaw. The crushing chamber is formed by the two jaws, and it's where the rock or ore is placed and crushed. The movable jaw is attached to an eccentric shaft that's driven by a motor. When the motor is powered, the eccentric shaft rotates, and the movable jaw moves back and forth. As the movable jaw moves closer to the fixed jaw, the material between them is crushed and reduced in size.

9. Gyratory crusher The crushing action is created by the closing the gap between the hard crushing surface attached to the spindle and the concave liners (fixed) mounted on the main frame of the crusher. The gap is opened and closed by an eccentric drive on the bottom of the spindle that causes the central vertical spindle to gyrate.

10. Impact crusher Material to be crushed is fed into the crusher from the top via a feed chute or conveyor. Inside the impact crusher, there is a rapidly rotating rotor with hammers or bars attached to it. As the material enters the crushing chamber, it collides with the hammers or bars, shattering and breaking it into smaller pieces.

11. Secondary comminution After primary comminution, the ore is still not at the desired particle size for effective separation processes. Secondary comminution further reduces the particle size to enhance liberation. This is typically done using grinding mills, such as Ball mills Rod mills SAG (semi autogenous grinding) mills

12. Ball mills The ore or material to be ground is fed into the cylinder, which is partially filled with grinding media, such as steel balls. Once the mill is loaded and the ore and grinding media are in place, the mill is rotated on its longitudinal axis. As the mill rotates, the grinding media cascade within the mill, lifting and falling, which causes impact between the media and the ore particles. The impact and friction between the grinding media and the particles break the ore into smaller fragments.

13. Rod mills Rod mills are similar to ball mills but use long rods as the grinding media instead of steel balls. The rods grind the ore by tumbling within the mill, similar to the grinding action of ball mills. Rod mills are particularly useful for breaking up larger particles, especially when a finer product size is desired.

14. SAG mills In a SAG mill, a portion of the ore itself serves as grinding media. As the mill rotates, the ore particles and grinding media collide and impact each other, breaking down the ore particles through impact and abrasion. The autogenous grinding action is particularly effective for breaking down larger particles.

15. Classifiers In ore dressing and, a classifier is a machine that separates particles based on various specific gravities and sizes, often used in conjunction with other equipment like crushers, and grinding mills. Classifiers are commonly used to separate and classify particles into different size fractions and to remove undesired materials (gangue) from valuable minerals. Classifiers such as, Air classifier Rake and spiral classifier hydrocyclone

16. Air classifier Air classifiers use airflow to separate particles based on their size and density. Particles are introduced into an air stream, and centrifugal forces and airflow cause larger particles to be thrown outward and finer particles to be carried upward and collected as overflow. Air classifiers are often used in dry processing operations.

17. Rake and spiral classifier These classifiers operate similarly to spiral classifiers but use mechanical devices like rakes to remove the settled particles from the bottom of the tank. Rake and spiral classifiers are used for large particles or materials that settle quickly.

18. Hydrocyclone A hydrocyclone , or cyclone, is a classifier that utilizes centrifugal force to separate particles based on their size and density. The slurry containing particles enters the hydrocyclone tangentially, causing the particles to spin within the cyclone. The centrifugal force causes larger and denser particles to move to the outer wall and be collected as underflow, while lighter particles are carried toward the center and exit as overflow.

19. Summury In essence, ore dressing is a fundamental and multidisciplinary field that encompasses a range of processes and techniques. It plays a pivotal role in extracting valuable minerals and metals from their natural ores, supporting various industries and contributing to economic development while addressing environmental considerations.

20. References https://chat.openai.com/c/997dcee8-c596-41ca-b6a1-f975200d7727 https://www.kau.edu.sa/Files/0052737/Subjects/(8)%20Ore%20processing%20(beneficiation).pdf Notes of dressing and beneficiation provided by Dr. P. M. Solanki

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