Caisson thickeners

In even larger caisson thickeners, the central column is sufficiently large to accommodate a discharge pump at the bottom. The discharge passes through the column and along the access walkway above the basin. Caisson thickeners can be built having diameters of up to 200 m. These often have an earth bottom. 

Fig. 3. The beneficiation of taconite ore on Ihe iron range requires large volumes of water in concenlrating by magnetic separation. To eliminate massive waste-disposal problems, huge thickeners, such as the 300-foot (91,5-meter) diameter caisson unit shown here, are used. This system will handle over 70 million gallons (265 million liters) per day or 50,000 gallons (189,250 liters) per minute of liquid and 250 tons per day of suspended solids. Clarifying the waste tailing stream permits reclamation of water on a large scale for plant reuse...

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