ABSTRACT
I. Introduction................................................................. 665 II. Electric Double Layer: Basic Terms .......................... 667
III. Potential-Determining Ions ....................................... 672 A. Correlation Between IP and EAP....................... 672 B. Stability of Mineral Dispersions......................... 677
IV. Mechanisms of Surfactant Adsorption ...................... 679 A. Basic Adsorption Isotherms and Terms ............. 680 B. Effect of Surfactant Concentration .................... 684
1. Hemimicelle Model According to Fuerstenau .................................................... 689
2. Admicelle Model of Harwell ......................... 692 3. Model of Gu ................................................... 693
C. Exchange Enthalpies of Surfactant Adsorption ........................................................... 699 1. PDI Hþ and OH: Oxides ............................. 699 2. PDI Lattice Ions: Salt-Type Minerals .......... 702 3. PDI Hþ, OH and Lattice Ions:
Silicates ......................................................... 705 D. Binding Energies of Hydrophobic Chains.......... 707
1. From Adsorption Isotherms ......................... 707 2. From Calorimetric Measurements ............... 708
E. Stability of Mineral Dispersion as Dependent on Surfactant Concentration ........... 711
F. Effect of pH Value................................................ 715 1. PDIH and OH ........................................... 715 2. PDI Lattice Ions............................................ 719
G. Stability of Mineral Dispersions as Dependent on pH ................................................ 720
H. Effect of Counterions .......................................... 723 I. Effect of Complexing Agents .............................. 731
1. Hydrophilization of the Mineral Surface by the Adsorption of Complexing Agents............................................................ 733
2. Modification of Collector Adsorption by Complexing Agents .................................. 735
3. Cationic Surfactant-Complexing Agent Interaction.......................................... 740
4. Complexing Agents Acting as Collectors....................................................... 742
5. Effect of Complexing Agents on the Aggregation State of Minerals ..................... 744
V. Surfactant-Lattice Ion Interactions .......................... 746 A. Minerals with PDI Hþ and OH ........................ 747 B. Minerals with PDI Lattice Ions.......................... 749
1. Anionic Surfactant Precipitation ................. 750 2. Adsorption of Anionic Surfactant................. 754 3. Flotation Experiments .................................. 759
References............................................................................ 760
I. INTRODUCTION
Mineral flotation is a heterocoagulation process for selective separation of individual components out of polymineral suspensions of ground materials (ores) by using dispersed gas bubbles. This method is based on different attachments of hydrophobized and hydrophilic mineral particles to gas bubbles, mostly in an aqueous medium. Hydrophobized mineral particles attach to the gas bubbles and are carried out as aggregates of lower specific density to the surface of the suspension where they form a froth layer. This froth layer, called concentrate, can be removed mechanically [1].
