Flotation thickening

FIG. 14-97 The Flotator dissolved-air flotation thickener. (Process Kngineets, Inc., a division ofEtmco Corp., now Envitotech Corporation.)... 

Cleaning flotation Thickening and regrinding Counter-current flotation Copper leaching Thickening and filtering... 

Some mills may perform biosolids grinding, gravity, or flotation thickening or chemical preconditioning to achieve up to 10% biosolids concentration.53... 

This is a process for concentration of sludge by removing water. Either gravity thickening or dissolved air flotation thickening can be used. The thickening efficiency depends on the nature of sludge to be processed [15]. 

Two methods are used to thicken slndges gravity thickening and flotation thickening. In gravitational thickening, solids are thickened as a result of solids piling... 

Example 5.14 It is desired to thicken an activated sludge liquor from 3,000 mg/L to 4% using a flotation thickener. A laboratory study indicated an A/5 ratio of 0.010 is optimal for this design. The subnatant flow rate was determined to be 8 L/m -min. The barometric pressure is assumed to be the standard of 101.33 kN/m and the design temperature is to be 20°C. Assume/= 0.5 j3 = 0.95. The sludge flow rate is 400 m /d. Design the thickener with and without recycle. 

Sludge thickening and fiber separation by dissolved air flotation cells (2,3) are typical examples of nonfoaming flotation thickening in which the target sludges or fibers are originally in insoluble forms and ready to be floated. 

Once the phosphate matrix is pumped or transported, it is processed in a special phosphate rock treatment plant. Nordin (1982), of the Phospnate Development Corporation Ltd., described how each year a South African plant produces approximately three million tons of phosphate rock from foskorite and pyroxenite ores. The ore was then classified through flotation, thickening, and filters before being stockpiled. The result was fine gray-white crystalline powder of mineral apatite, with a 36.5% P2O5 content, a solid specific gravity of 3.17, and 106 p,m. The hardness of the apatite was measured at 5.0 on the Mohr scale. 

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