1736484703_Importance_of_Mineral_Processing

Importance of Mineral Processing

• Presented by: Dr. Subhendu Mishra in the context of Fuel Minerals and Metallurgical Engineering.

Interdisciplinary Nature of Mineral Processing

• Mineral processing integrates various fields including:

  • Mineral Engineering

  • Chemical Engineering

  • Chemistry

  • Electrical Engineering

  • Applied Geology

Definition and Concepts in Mineral Processing

• Mineral Processing: Techniques used to separate valuable minerals from ores.

• Related terms include:

  • Mineral Beneficiation

  • Coal Washing

  • Coal Processing

  • Coal Preparation

  • Ore Dressing

Characteristics of Minerals

• Minerals: Natural inorganic substances with definite chemical compositions and atomic structures.

  • Isomorphism: Substitution of atoms within a crystal structure without altering atomic structure (e.g., Olivine).

  • Polymorphism: Different minerals with the same chemical composition but different properties (e.g., Graphite vs Diamond).

Extended Definition of Minerals

• Economic materials extracted from the earth, e.g., coal, chalk, granite are considered rocks, not minerals

• Example of Granite: Composed of feldspar, quartz, and mica with varying compositions.

• Elements accounting for >99% of the earth's crust: Silicon (Si) and Oxygen (O) prevail; other important metals occur in low concentrations.

Mineral Occurrence and Economic Viability

• Minerals essential for metals are not uniformly distributed, influenced by geological conditions.

• Concentration: Natural agencies lead to sufficient concentrations of minerals to allow profitable extraction.

  • Native Ores: Metal in elemental form.

  • Sulphide Ores: Metal in sulfide compounds.

  • Oxidized Ores: Metal in oxide or related forms.

  • Complex Ores: Multiple valuable minerals present in one extract.

Ore Classification and Extraction

• Ore Definition: Accumulation of valuable minerals amenable to economic extraction.

• Viability varies per metal: e.g. Gold (5 ppm) vs Iron (≥15%).

• Economic classification relies on:

  • Contained value / ton > (total processing costs + losses + other expenses) / ton.

• Extraction Methods:

  • Pyrometallurgy (heat-driven methods)

  • Hydrometallurgy (solvent-based methods)

  • Electrometallurgy (electricity-driven methods)

Energy Consumption in Mineral Processing

• Example of Copper Ore: 1500-2000 kWh needed for treatment, highlighting cost concerns in remote smelting locations.

• Transporting mined ores can be more expensive than the ore value itself.

• Mineral processing aims to reduce bulk at mine sites using low-energy physical methods to enhance valuable minerals.

• Energy consumed in mineral processing significantly lowers overall smelting costs.

Challenges in Mineral Processing

• The efficiency of processing can dictate the economic viability of an ore deposit.

• Minimizing losses during milling and optimizing extraction technology are critical.

• Froth flotation advancements rolled out to exploit lower-grade copper deposits.

Separating Valuable Minerals

• Complex ores often require separation of individual valuable minerals.

• Balance improvements between metallurgical efficiency and processing costs are crucial.

• Economic considerations extend to ancillary service costs including utilities, roads, taxes, and safety measures.

Mineral Beneficiation Process

• Involves:

  1. Liberation: Size reduction of valuable minerals.

  2. Separation: Distinguishing coarse from fine particles.

  3. Concentration: Enhancing metal grade by separating gangue minerals.

  • Failure to correctly liberate minerals impairs separation efficiency.

Grade-Recovery Relationships

• Recovery: Percentage of total metal extracted from the ore.

• Grade: Marketable content in the end product.

• Enrichment Ratio: Grade of concentrate compared to feed weight, affecting concentration process efficiency.

Trade-offs in Concentration Processes

• Inversely correlated recovery and grade dynamics challenge mineral processors.

• Total success demands elevating both grade and recovery metrics.

• Concentrate grade and recovery are pivotal in metallurgical performance assessment.

Terminology in Mineral Processing Operations

• Most operations involve wet processes where:

  • Pulp: Mixture of water and solids.

  • Suspension: Solid particles uniformly dispersed in fluid.

  • Slurry: Mixture of fine solids and water.

  • Sludge: Thick pulp, indicative of low water content.

Slurry Density and Measurements

• Density measured as weight of the slurry per volume (g/cm³ or kg/m³).

• Use of a Marcy Scale for density readings.

Calculating Dilution Ratios

• Dilution Ratio: Weight of water to solids in slurry.

  • Formula: Dilution ratio = 1 - Cw where Cw is the solid concentration.

Metallurgical Balances Calculations

• Fundamental equations and tables established for analyzing product outputs:

  • F (feed) = C (concentrate) + T (tailings).

  • Define recovery, concentration ratios, and separation efficiencies based on feed and product assays.

Problem Solving in Balancing Operations

• Worked numerical examples on ore processing assessment, recovery calculations, and separation efficiency metrics.

• Case studies emphasize practical applications for consolidating metallurgical processes.

Conclusion: Performance Assessment

• Assessing economic factors alongside recovery and grade is essential in optimizing overall metallurgical efficiency.