absorbs the collectors during conditioning period making them hydrophobic . Froth is formed when they come in contact with flowing air bubbles and float to the surface . Sodium Isopropyl Xanthate and Potassium Amyl Xanthate are the commonly used collectors .
Frothers are surface-active chemicals that concentrate at the air-water interface . It prevents air bubbles from coalescing or bursting by lowering the surface tension of the slurry . Frothing properties can be persistent or nonpersistent depending on the desired stability of the froth . Pine oil and alcohols such as MIBC are most commonly used frothers .
Regulators or “ modifiers ” are used to modify the action of the collector by intensifying or reducing water-repellent effect of mineral surface conditions . This is done to assist in the selective flotation of minerals . Regulators can be classed as activators , depressants , or pH modifiers . Regulators may activate poorly floating minerals such as sphalerite by adding readily soluble copper sulfate . Similarly , regulators can depress certain minerals rendering it hydrophilic and preventing their flotation . Minerals like pyrite and arsenopyrite can be depressed by adding sodium cyanide or lime , so that a differential flotation can be performed on a complex ore . Nigrosene reagent is used for maximum depression or elimination of graphitic carbon from zinclead sulfides in graphitic host rock .
Separation of graphitic carbon aids in producing high-quality clean zinc and lead concentrates . Chemicals that change the pH of the slurry are also used as modifiers . An alkaline condition of medium is preferable in the flotation process where most of the collectors are stable . Alkaline environment minimizes the damage done by corrosion of cells and pipelines . pH modifiers include lime , soda ash and sulfuric acid . It can act as activators and / or depressants by controlling the alkalinity and acidity of the slurry . Modifiers can also counteract interfering effects from the detrimental slimes , colloids , and soluble salts that can absorb and thereby reduce the effectiveness of flotation reagents .
The design of mineral processing circuit requires integration and assembly of various unit operations . It starts from crushinggrinding-flotation with generation of valuable concentrates and rejection of tailing in continuous process . It is desirable to conduct laboratory , bench and pilot plant scale test works at the appropriate stages of exploration and mine development activities . It is done before adopting a commercial plant flow diagram of complex mineral assemblages .
The representative sample is obtained by compositing duplicate mineralized core covering the characteristics of entire deposit and bulk sample collected from initial mine development . The grind size , concentrate grades and other quality , recovery of valuable minerals , type of reagents and cost parameters are optimized .
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