Scavenging flotation

Effect of type of collector on PGM rougher-scavenger flotation from high-chromium ores... 

The flowsheet used in this plant (Figure 19.8) consists of a rod mill-ball mill grinding system and a copper rougher-scavenger flotation circuit, followed by two cleaning stages. Initially, the plant used a rake classifier, but now the rake classifiers have been replaced by cyclones. 

Under suitable pulp potential in the OPCF process, the flotation speed of galena is very fast and most galena has been floated just in rougher flotation stage. So the flotation cell of galena scavenger flotation operation can be diminished and the flotation circuit is further optimized. The comparison of operation parameters between traditional flowsheet and OPCF flotation is presented in Table 10.13. As can be seen, the flotation potential and time are lower in OPCF than in traditional flowsheet. 

Froth Flotation A separation process using flotation, in which particulate matter becomes attached to gas (foam) bubbles. The flotation process produces a product layer of concentrated particles in foam termed froth. Variations include dissolved-gas flotation, in which gas is dissolved in water that is added to a colloidal dispersion. As microbubbles come out of solution, they attach to and float the colloidal species. See also Scavenging Flotation. 

Scavenging Flotation A flotation separation process, in which particles or droplets become attached to gas bubbles that are injected (sparged) into the flotation medium. Also termed induced gas flotation. Example the froth flotation of bitumen. See also Froth Flotation. 

Chem. Descrip. Hydrogenated tallowamine CAS 6178845-2 61789-79-5 EINECS/ELINCS 262-976-6 263-089-7 Uses Emulsifier acid scavenger flotation collector dusting additive chem. intermediate filming amine corrosion inhibitor oil additive mold release agent food-pkg. adhesives defoamer in food-contact paper/paperboard in food-contact rubber articles food-contact animal glue... 

Miscellaneous. In ore flotation, sodium sulfite functions as a selective depressant. In textile processing, sodium sulfite is used as a bleach for wood (qv) and polyamide fibers and as an antichlor after the use of chlorine bleach. Synthetic appHcations of sodium sulfite include production of sodium thiosulfite by addition of sulfur and the introduction of sulfonate groups into dyestuffs and other organic products. Sodium sulfite is useful as a scavenger for formaldehyde in aminoplast—wood compositions, and as a buffer in chrome tanning of leather. 

When the ore contains a large amount of clay minerals, these form difficult to separate slimes, which hinder the recovery of the minerals (see Clays). The tailing from the scavenger cells can be cycloned to remove the slimes before the coarse material is floated in a tailings retreatment plant. The flotation product from the rougher cells of this plant can be reground and cleaned. This additional treatment of the tailings from the main copper flotation plant may improve the recovery of metal values by 1—3%. 

Lead Flotation Circuit Cells 1-2 Cleaners Cells 3-5 Roughers Cells 6-8 Scavengers... 

Flotation feed ------ Bulk rougher -------->- Bulk scavenger... 

The flowsheet used to treat dolomitic oxide copper ores is somewhat different from that used in the beneficiation of siliceous oxide copper ores. This is due to the fact that dolomitic ore usually contains elevated amounts of slimes, in which case a split circuit flowsheet has been adopted in a number of operations. The typical flowsheet used for treatment of dolomitic ores is shown in Figure 19.8. Usually, the scavenger tailings are deslimed and the sand fraction is retreated in a scalp copper flotation stage. When the ore is deslimed before flotation, a large amount of fine copper is lost in the slime fraction. 

The third step in the hot-water process is scavenging. Froth flotation with air is usually employed. The scavenger froth is combined with the separation-cell froth to be further treated and upgraded to synthetic crude oil. Tailings from the scavenger cell join the separation-cell tailings stream and go to waste. 

Scavenging Circuits. These are combinations of gravity separation and flotation to recover die loss via slimes occurring in the classical procedure. A simplified flow sheet of the Cantung Mine beneficiation plant (Canada Tungsten Mining Corporation) is given in Fig. 5.3. 

Condition the solids to alter the wettability of the mineral and the gangue. The fundamental surface wettability for sulfide ores is different from oxides, silicates, and salt-type minerals. pH is a critical variable. Typical conditioning chemical additions include collector about 0.01 to 0.1 kg/Mg solids frother about 0.01 to 0.5 kg/Mg solids activator about 1 to 4 kg/Mg solids depressant about 0.02 to 2 kg/Mg solids. Allow 6-min contact for conditioning. Bubble size about 1000 pm. Flotation rate constant is 0.2 to 1 min sink rate constant is 0.005 min-. Flotation cells mechanical cell for fast float, sequential separation, and relatively coarse particle diameter 1.6 to 2.4 kW/m cell volnme. Pneumatic cell for relatively dilute feed concentrations and smaller particle diameters. Air blower 0.5 kW/m cell volume. Typical solids throughput 0.4 to 0.8 kg/s m feed concentration 10 to 40% w/w. Air escape velocity 0.02 m/s. Float times 6 to 20 min. Feed concentration to rongher or scavenger 30% w/w to cleaner 10% w/w. 

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