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Beneficiation for the Fly Ash Industry
Sturtevant® has been supplying Air Classifiers for over 70 years with numerous industry applications, including Fly Ash. Sturtevant® Air Classifiers produce a fine saleable Fly Ash product with low LOI, and also reduces the amount of Fly ash that would otherwise fill up landfills by 50%. These systems save disposal costs and contribute to saving our environment.
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Whirlwind Air Classifier
Models: 20' to 26' Diameter
Feed Capacities: 1 to 800 TPH
Fineness: 100 - 400 Mesh
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SuperFine® Air Classifier
Models: 3' to 6' Diameter
Feed Capacities: 0.5 to 15 TPH
Fineness: 44 - 5 Microns
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Side DraftTM Air Classifier
Models: 3' to 24' Diameter
Feed Capacities: 4 to 1,150 TPH
Fineness: 100 - 400 Mesh
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Sturtevant has been supplying Air Classifiers for over 70 years with numerous industry applications, including Flyash. Generally speaking, by air separating Flyash at 200-325 mesh (75-45 microns), product quality can be consistently achieved by controlling the fineness and by reducing the LOI carbon content by 50% or more to a level that is tolerable for use in cement, as a filler for land reclamation, soil improvement, lightweight aggregates, and agricultural uses. Everyday, Sturtevant Air Classifier installations not only produce a saleable Flyash product, but also reduce the amount of Flyash that would otherwise fill up landfills by 50%. In addition, these systems save disposal costs and contribute to saving our environment.
Three Sturtevant Models are available to meet a variety of needs. Some distinct advantages are -
| Whirlwind Air Classifiers (100-400 mesh product sizes): |
For power plants producing a consistent Flyash output, the Whirlwind may be the most economical selection. The Whirlwind Air Classifier incorporates a fixed speed self-contained fan and rejecter blade classification system. Its internal fan design uses low HP and does not require Cyclones, Airlocks or Baghouse to collect the fines. The feed is conveyed into the air separator by gravity. The fines and coarse also exit the air classifier by gravity. Major changes in product fineness are achieved by changing the quantity of internal selector blades. Minor changes are achieved by adjusting the position of external control valves.
| Side Draft Air Classifiers (100-400 mesh product sizes): |
For power plants where Flyash output or desired Flyash market specifications may vary, the SD Side Draft Air Classifier offers flexibility. The SD High Efficiency Air classifier incorporates a variable speed rotor design and produces better efficiencies with more versatility than the Whirlwind Air Classifier. By using an external fan to generate the system airflow, the speed of the independently driven rejecter cage can be adjusted according to various feed characteristics and thus, maintain consistent product fineness and quality. The feed is conveyed into the Air Classifier by gravity and the coarse exits from the bottom of the Classifier by gravity. The fines are pneumatically conveyed through the rejecter cage and collected in a cyclone or dust collector. The SD also comes with alumina ceramic liners for maximum wear protection.
| The Superfine Air Classifiers (5-30 microns product sizes): |
For power plants desiring to market to the highly specialized pozzolanic cement manufacturers with ultra-high strength and high Blaine specifications. The Superfine Air Classifier has a variable speed rotor with multiple, closely spaced rejecter blades and high speed operation for ultra-fine and ultra-efficient applications. The system uses an external fan to generate the airflow and the speed of the rejecter cage is adjusted according to the desired fineness or a change in feed characteristics, thus producing superior product fineness and quality. The feed is conveyed into the Air Classifier by gravity and the coarse exits from the bottom of the classifier by gravity. The fines are pneumatically conveyed through the rejector cage and collected in a product dust collector. Generally, the Superfine is suited for lower production rates of highly specialized ultra-fine products.
The Sturtevant test lab can demonstrate Flyash beneficiation in either air classifier. Below are some questions that will help us evaluate the process:
1. % moisture in the Flyash feed?
2. % LOI (loss on ignition, unburnt carbon) in the Flyash feed before air classifying?
3. % minus 325 mesh (45 microns) and % minus 200 mesh (75 microns) in the Flyash feed before air classifying?
4. % plus 325 and % plus 200 mesh allowed in the Flyash fine product after air classifying?
5. % LOI (loss on ignition, unburnt carbon) allowed in the Flyash fine product after air classifying?
6. Desired feed rate capacity in TPH and numbers of hours per day & days per year?
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