Mineral Beneficiation

Transcription

1 Mineral Beneficiation A Concise Basic Course D.V. Subba Rao Head of the department of Mineral Beneficiation S.D.S. Autonomous College Andhra Pradesh, India CRC Press Taylor & Francis Group Boca Raton London New York Leiden CRC Press is an imprint of the Taylor & Francis Croup, an informs business A BALKEMA BOOK

2 Contents Preface Foreword Acknowledgements List of tables List of figures xv xvii xix xxi xxiii 1 Introduction I 1.1 Minerals Important Terminology Beneficiation Mineral Beneficiation Mineral Beneficiation Operations Unit Operations Technology 7 2 Ore formation, identification and analysis Ore Formation Identification of Minerals Mineral Analysis 10 3 Sampling 13 4 Size Sieve Analysis Testing Method Presentation of Particle Size Distribution Data Applications of Particle Size Distribution Data Sub-Sieve Sizing 25

3 x Contents 5 Screening Purpose of Screening Screen Surfaces Screen Action Types of Screens Factors Affecting the Rate of Screening Screen Efficiency 32 6 Liberation 35 7 Comminution Fracture Laws of Comminution Objectives of Comminution Types of Comminution Operations 42 8 Crushing Jaw Crushers Gyratory and Cone Crushers Roll Crushers Impact Crushers Bradford Breaker High Pressure Grinding Rolls (HPGR) Crushing Operation Open Circuit and Closed Circuit Operations 49 9 Grinding Ball Mill Rod Mill Tube or Pebble Mill Autogenous Mill Wet and Dry Grinding Grinding Circuits Separation operations Separation of Ore Particles According to their Size Separation of Ore Particles According to a Property Where Valuable Mineral Particles are Different from Gangue Mineral Particles in that Property Separation of Ore Particles from the Mixture of Solids and Fluids 58

4 Contents xi 11 Density Settling of solids in fluids Principles of Settling Free settling Hindered settling Equal settling particles Settling ratio Classification Classifiers Sizing classifiers Sorting classifiers Centrifugal classifiers Beneficiation operations Gravity concentration Float and Sink Heavy Medium Separation Chance cone process Centrifugal separators Jigging Flowing Film Concentration Froth flotation Contact Angle Flotation Reagents Types of Flotation Flotation Machines Flotation Operation Column Flotation Flotation Practice of Sulphide Ores Magnetic separation Magnetism Electro-Magnetism Types of Minerals Magnetic Separators Tramp iron magnetic separators Concentrators 115

5 xii Contents Dry magnetic separators Wet magnetic separators Electrical separation Charge and Charge Interactions Conductors and insulators Polarization Methods of Charging Electrostatic Separation Electrostatic Separator High Tension Separator Dewatering Thickening Filtration Types of filters Materials handling Properties of Bulk Solids Size of the particles Shape of the particles Surface area of the particles Particle density (Density of the bulk solids) Bulk density Compressibility Cohesion and adhesion Angle of repose Angle of fall Angle of difference Angle of spatula Angle of surcharge Angle of slide Tackiness Abrasion Corrosion Friability (Degradation) Dispersibility Moisture content and hygroscopicity Storage Conveying Feeders 20.5 Disposal of Products

6 Contents xiii 21 Beneficiation of minerals Agglomeration Mathematical Model Simulation Automatic Control Applications Assay Value and Grade Sieve Analysis Distribution of Metal Values Efficiency of the Screen Laws of Comminution Reduction Ratio Size of Roll in Roll Crusher Crushing Circuits Critical Speed Grinding Circuits Density and % Solids Settling Velocities Recovery, Grade, Loss of Metal etc 165 References 169 Further readings 171 Subject index 173