Flotation methods

The principal experimental method used to measure the density of a solid is determination of the mass of liquid displaced by a known mass of solid. It is essential that the solid have no appreciable solubility in the liquid, that all occluded air be removed from the solid and that the density of the displacement fluid be less than that of the solid lest the solid float. Densities of crystalline solids also can be determined from the dimensions of the unit cell. Davis and Koch discuss other methods for measuring the density of liquids and solids such as hydrostatic weighing of a buoy and flotation methods. 

This is a unit operation process where air bubbles, as gas, are used to remove solid or liquid particles from the liquid wastewater. The air bubbles are often trapped in the morphology of the suspended particles and as a result of buoyant forces, the particles move up and float on the surface where they are skimmed out. The common flotation methods include dissolved air, air flotation, vacuum flotation, and chemical additives.3... 

The flotation of gold-bearing ores is classified according to ore type (i.e. gold ore, gold copper ore, gold antimony ores, etc.), because the flotation methods used for the recovery of gold from different ores is vastly different. 

Metallurgical results obtained using a sequential flotation method... 

Arsenical gold ores that do not contain significant base metals are treated using a bulk flotation method, where all the sulphides are first recovered into a bulk concentrate. In case the gold is contained either in pyrite or arsenopyrite, separation of pyrite and arsenopyrite is practiced. There are two commercial methods available. The first method utilizes arsenopyrite depression and pyrite flotation, and consists of the following steps ... 

Floatability of malachite is one of the most important oxide copper minerals for production of copper from oxide ores using flotation. Extensive research has been carried out by a number of researchers [4-7] in which various flotation methods were examined. 

In a number of oxide ores, cuprite (Cu20, Cu = 88.8%, SG = 5.9) is present as secondary minerals together with sulphides, malachite and tenorite. Cuprite can be floated using either sulphidization or anionic flotation methods. The flotation properties of cuprite are somewhat different from that of malachite. For example, using a sulphidization method for flotation of cuprite requires higher dosages of sulphidizer. 

In recent years, a new class of collectors, consisting of xanthated fatty acids (TY collector), and monoester-modified xanthate (PM230) have found industrial applications with improved metallurgical results. From plant practice, treating oxide copper and copper cobalt ores, two basic flotation methods are practiced (a) sulphidization flotation method, and (b) anionic flotation method. 

The presence of clay in the ore has a detrimental effect on copper oxide flotation. Results from experimental development test conducted on various clay containing ore types using AQ depressants showed that in the presence of these depressants, the results improved markedly using the sulphidization flotation method. 

These ore types are abundant in Northern Canada and Mexico. Extensive research work was carried out on these ores with the objective of developing a treatment process for commercial application. One of the major tasks in the development testwork was to use a non-cyanide flotation method in the sulphide flotation. Typical reagent schemes used in beneficiation of the mixed lead zinc oxide sulphide ores are shown in Table 20.5. 

This ore is treated using a bulk lead zinc sulphide flotation method followed by oxide lead flotation. The reagent scheme used in this circuit is shown in Table 20.7. 

Fatty acid flotation method. In this method, the smithsonite was floated using a short carbon chain fatty acid from calcific and dolomitic gangue minerals. The calcite and... 

The reverse flotation method. It was examined by several Russian scientists. This method involves depression of smithsonite using sodium phosphate and dextrin. Calcite and dolomite are floated using oleic acid in stage additions. The tailings become the zinc concentrate. 

Using a flotation method, about 30% Ta205 was recovered at a concentrate grade of about 6%. This concentrate was returned to the gravity circuit. 

Due to the nature of Ta/Nb-Zr, separation using a flotation method is not possible. Research using magnetic separation was carried out under different operating conditions. The efficiency of the Ta/Nb-Zr separation was a function of a number of factors, including... 

A large portion of titanium minerals (ilmenite, rutile) are produced from heavy mineral sands using physical preconcentration methods including gravity, magnetic and electrostatic separation. Over the past 30 years, advances have been made using flotation, where ilmenite, mtile and perovskite can be effectively recovered from both heavy mineral sands and hard rock ores using flotation methods. 

Over a period of years, the Titania A/S flowsheet has changed as the ore in the plant changed. The flowsheet that is currently being used is shown in Figure 25.6. This flowsheet utilizes a two-stage flotation method, where in stage 1, pyrite and apatite are recovered, followed by ilmenite flotation in stage 2. 

In the past, most of the rutile was produced from heavy mineral sands using physical concentration, involving gravity, magnetic separation and electrostatic concentration. The physical preconcentration method cannot be applied to a fine heavy mineral sand or hard ore. In some cases, heavy mineral sand contains zircon, tantalum, niobium and other heavy minerals, where in most cases a flotation method is used. 

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