History and Techniques of Froth Flotation: From William Haynes to Modern Processes, Quizzes of Engineering

Download History and Techniques of Froth Flotation: From William Haynes to Modern Processes and more Quizzes Engineering in PDF only on Docsity! TERM 1 Froth Flotation DEFINITION 1 Best available separation process for fine particles. 0.5 mm x 0 for coal: 0.15 mm x 0 for minerals. TERM 2 William Haynes DEFINITION 2 Bulk Oil Flotation (1860) Sulfide mineral and oil from aggregates. Siliceous gangue stays in water. TERM 3 Carrie Everson DEFINITION 3 Bulk Oil Flotation (1885) Acidification of ore pulp. TERM 4 Skin Flotation DEFINITION 4 1890-1915 Oil-free Problems Requires dry ore feed. Inefficient with fine particles. TERM 5 Bessel and Bessel DEFINITION 5 Gas Bubbles (1877) 1-1.5% oil Boiling water to float graphite Gas Bubbles (1886) CO2 bubbles by adding carbonate mineral and acid TERM 6 Porter DEFINITION 6 Gas Bubbles (1901) Zinc ore dry fed to hot sulfuric acid solution. First commercial application of flotation process. TERM 7 Sulman and Pacard DEFINITION 7 Air Bubbles (1905) Air forced into flotation cell. Oil siphoned in along with air. TERM 8 Sulman, Picard, and Ballot DEFINITION 8 Air Bubbles (1906) Feed was agitated along with oleic acid. Air bubbles formed by vortex. Bubble-particle aggregates separated by spitzkasten. Tails recycled. TERM 9 F. E. Elmore DEFINITION 9 Air Bubbles (1906) Small bubbles TERM 10 Keller DEFINITION 10 1923 Xanthate as collector for sulfide minerals to eliminate use of oil as a hydrophobizing agent. TERM 21 Flotation of Sulfide Minerals: Metallic DEFINITION 21 Base Metal Sulfide Copper Lead Zinc Precious Metals Gold Silver PGM TERM 22 Electrochemical Theory DEFINITION 22 Sulfide minerals are semi-conductors. Collectors adsorb on sulfide minerals via electrochemical reactions. TERM 23 Effect of Potential DEFINITION 23 High Potentials: Electron deficient Oxidation reactions can occur. Low Potentials: Electron affluent Reduction reactions occur. Xanthate adsorption is an oxidation reaction. TERM 24 How to Control Potential DEFINITION 24 Adding oxidizing agents to increase potential. Adding reducing agents to decrease potential. Potentials can be measured using a potentiostat. TERM 25 Magnetic Susceptibility (K) DEFINITION 25 Ferromagnetic: Large positive KParamagnetic: Small positive KDiamagnetic: Small negative K TERM 26 Magnetic Separators DEFINITION 26 Low Intensity Drum Separators Used for recovery of ferromagnetic materials. Cross-belt Separator High Gradient Magnetic Separators (HGMS) Used for the recovery of paramagnetic materials. TERM 27 HGMS DEFINITION 27 Jones High gradients of magnetic field High magnetic forces Vertically unhindered flow High throughput rates 10 micrometers - 1 millimeter Batch TypeCarousel-Type Continuous Magnetic Separator TERM 28 High Tension Separation DEFINITION 28 Utilizes the difference in electrical conductivity.Electrodynamic. TERM 29 Electrostatic Separation DEFINITION 29 Conducting Non-conducting TERM 30 Separation Options for Beach Sand Operation DEFINITION 30 Magnetic Electrostatic Density TERM 31 Major Problems with High Tension Separation Techniques DEFINITION 31 Feed size should have a narrow size distribution. Fine particles are difficult to separate. The process should be operated in a dry atmosphere. Multiple stages of processing required due to poor efficiency. TERM 32 Circuit Analysis: Ideal Circuit DEFINITION 32 If middlings recycle employed, then separation approaches ideal as number of stages approaches infinity. TERM 33 How to Improve Separation Efficiency? DEFINITION 33 Use multiple stages Take middlings back to the start of separation TERM 34 Coal Fines to Impoundments in US DEFINITION 34 McHale (1994) = 2.5-3.0 billion tons Current Estimate = 4 billion tons Fresh fines = 70-90 millions tons/year TERM 35 Classification of Particles DEFINITION 35 Colloid D < 1 micrometer Ultra-fines 1 < D < 10 micrometers Fines 10 < D < 100 micrometers Coarse 100 micrometers < D TERM 46 High Pressure Filters: Plate and Frame DEFINITION 46 Rely on high delta P in Darcy's Law TERM 47 Centrifuge: Solidbowl Scroll Centrifuge DEFINITION 47 Bowl Diameter: 15 - 150 cm Feed Concentration: 0.5 - 70% solids Particle Size: 12 mm - 2 microns, or less with flocculation TERM 48 Screenbowl Centrifuge DEFINITION 48 Achieves lower moisture than the solid bowl centrifuge by removing ultrafine particles. TERM 49 Rotary Dryers DEFINITION 49 Hot drying gases Material passes by gravity TERM 50 Fluidized Bed Dryers DEFINITION 50 Homogeneous product Can be used to divide materials into coarse, medium, fine size TERM 51 Spray Dryers DEFINITION 51 Slurry introduced to dryer in fine droplets Instantaneously drying TERM 52 Hearth Dryers DEFINITION 52 Stacked circular floors or hearths Fine particles TERM 53 Rotary Tray Dryers DEFINITION 53 Central axis contains fans to circulate hot air across the surface of the trays. Fine particles TERM 54 Hydrometallurgy DEFINITION 54 Extraction of metal values in aqueous media. Application: Flotation concentrates to reduce SO2 emission and save energy Low grade feed ores that cannot be processed by flotation TERM 55 Pyrometallurgy DEFINITION 55 Extraction of metal values at high temperature Reduction using carbon as reducing agent Smelting Application: Flotation concentrates TERM 56 Perspective DEFINITION 56 Processing of copper sulfide ores High grade ores > 0.5% Cu Low grade ores < 0.5% Cu TERM 57 Leaching DEFINITION 57 Dissolution of metal TERM 58 Oxidation DEFINITION 58 Electron is produced Metal serves as anode TERM 59 Deposition DEFINITION 59 Coating with metal TERM 60 Reduction DEFINITION 60 Electron is consumed Metal acts as cathode