The purpose of this book is to provide a broad, comprehensive, up-to-date coverage of current beneficiation techniques and processes that are used for both metallic and nonmetallic minerals; and for other materials, such as household and industrial solid wastes, that are also processed by conventional beneficiation methods in their standard methods of recycling and reclamation. Conservation of natural resources is an adjunct of beneficiation in that we have used up once-available deposits of high-grade ores, leaving only the low-grade deposits that must be beneficiated to upgrade them to sufficiently high levels for processing and metal recovery by current extractive technology. Conservation is also important in the reclamation and recycling of indestructible, noncorrosive materials, so that they may be recovered and reused many times over. The mainly physical, relatively uncomplicated, beneficiation treatments also save large quantities of energy, as these comparatively simple operations are all relatively low energy consumers, when compared with the later separation operations of pyro and electrical nature, which are very high energy consumers. Environmentally, both air and water pollution from beneficiation treatments are either quite low or can easily be controlled, and are gas-free and operated at ambient temperature, to make them one of the cleaner and lower polluting processes used in material treatments.
Table of ContentsEconomic Justification.- Economic Benefits.- Conservation, Reclamation, and Recycling.- Energy Conservation: Air and Water Pollution.- Stages of Beneficiation.- History of Beneficiation.- Hand Picking.- Washing.- Crushing.- Gravity Concentration.- Jigging.- References.- 1 Crushing.- Energy Consumed in Comminution.- Rittinger’s Law.- Kick’s Law.- Primary Crushers.- Jaw Crushers.- Gyratory Crushers.- Comparison: Jaw and Gyratory Crushers.- Secondary Crushers.- Cone Crushers.- Rolls Crushers.- Hammer Mills.- Stamp Mills.- References.- 2 Screens and Sizing.- Purpose of Screening.- Vibrating Screens.- Revolving Screens and Trommels.- Crushing and Screening Flow Sheets.- Closed Circuit.- Open Circuit.- References.- 3 Fine Grinding.- Purpose of Fine Grinding.- Main Grinding Mill Shapes.- Ball Mills.- Liners.- Speed of Rotation.- Wet and Dry Grinding.- Types of Ball Mills.- Rod Mills.- Pebble Mills.- Autogenous Mills.- Processes of Grinding and Grinding Mill Characteristics.- References.- 4 Classification.- Factors Influencing Settling Rates.- Stokes’ Law.- Newton’s Law.- Free-Settling and Hindered-Settling.- Classifier Categories.- Sorting Classifiers.- Sizing Classifiers.- Air Classifiers.- Concentration by Classification.- Classifier Capacity.- Classifier Efficiency.- Classifier Costs.- Classifier: Grinding Mill Circuits.- References.- 5 Dewatering.- Thickeners.- Design and Operation.- Operating Efficiency.- Settling Rate of Flocs.- Thickener Area.- Thickener Height.- Thickener Circuits.- Filtering.- Pore Size and Spacing.- Additional Variables That Effect Filtering Rates.- Types of Filters.- Drum Vacuum Filters.- Disk Vacuum Filters.- Horizontal Filters.- Pressure Filters.- References.- 6 Magnetic Separation.- Relative Magnetic Attractions.- Design Features.- Types of Separators.- Dry Magnetic Separators.- Wet Magnetic Separators.- Purification and Reclaiming.- Demagnetizing.- References.- 7 Electrostatic Separation.- Electrostatic Separators.- Electrodynamic Separators.- References.- 8 Gravity Concentration.- Application of Gravity Concentration.- Shaking Table.- Operating Principles.- Table Capacities.- Jigs.- Pulse Speed.- Water Velocity and Stroke Length.- Plunger Area.- Bed Depth.- Ragging.- Screen Size.- Stroke and Cycle Relationship.- Heavy Media Separation (HMS).- Media.- Separation Devices.- Humphreys Spiral.- Operating Principles.- Reichert Cone.- Operating Principles.- References.- 9 Flotation.- Application of Flotation.- Wetability.- Bubble Column Concentration.- Cell Types.- Flotation Circuits.- Preliminary Feed Pulp Preparation.- Particle Size.- Pulp Density.- Conditioning.- Pulp Temperature.- Reagent Feeders.- Flotation Reagents: Functions and Properties.- Frothers.- Collectors.- Regulators.- Activators.- Depressants.- Dispersants.- References.- 10 Recycling.- Purpose of Recycling.- Recycling Plant Equipment.- Treatment Methods.- Treatment Processing.- Raw, Unburned Mixed Refuse.- Incinerated Refuse.- Unburned-Mixed Refuse.- Industrial Wastes.- References.