Attrittors

Attrittors

Attrittors are used for wet grinding limestone for flue gas desulphurization. The process uses limestone feed stock of approximately 6mm in size and wet grinds the limestone to 95% minus 325 mesh. The Attritor operates in continuous processing mode. The grinding circuit includes the separation tank, mill recirculating pump, mill product tank, hydrocyclone, hydrocyclone feed pump and all necessary controls. Due to the Attritor’s high efficiency, the power consumption for this mill is 50% less compared to conventional ball mills of a similar size. This results in substantially lower operating costs.

Process

The process begins with 1-1/2" limestone, which is fed from the silo to the crusher. The limestone is reduced to 6mm pieces in the crusher. The crushed limestone is then mixed with water in the Premix Chamber and fed into the CL Attritor Mill. The limestone slurry exits the CL Attritor Mill and enters the Separation Tank. Any oversized particles are pumped back into the Mill while finer slurry overflows into the Mill Product Tank.

Applications

• paints, toners, inks
• Ceramics
• agricultural flowables
• Food products
• Chocolate, confectionery
• paper coatings, calcium carbonate, clay
• Chemicals
• Ferrites
• metal oxides
• minerals, ores, coal
• sulphur dispersions

Common Types

Circulation Attritor

The circulation grinding attritor (“Q” machine) is a combination of an attritor and a large holding tank which is generally about ten times the size of the attritor. the attritor is filled with media and contains grids which restrain the media while the slurry is allowed to pass through. the unique principle of the “Q” attritor is the high circulating (pumping) rate. the entire contents of the holding tank are passed through the attritor at least once every 7-1/2 minutes, or about 8 times per hour.

Advantages:

• Faster grinding with narrower particle size distribution
• Uninterrupted, large-scale production
• excellent temperature control
• simple and safe to operate
• Low maintenance and power consumption

Continuous Attritor

The continuous Attritor is a compact vertical design suitable for continuous production of large quantities of materials. Premixed slurry is pumped through the bottom and discharged at the top of a tall, narrow jacketed tank with internally agitated grinding media. The fineness of the processed material depends on the time the material stays in the grinding chamber (“dwell” time).

Dwell time is controlled by the pumping rate. The slower the pumping rate, the longer the dwell time and the finer the grind. The grinding media used in continuous Attritors range in size from 2mm to 10mm in diameter. Carbon steel, stainless steel, chrome steel and ceramic balls are commonly used media.

Continuous Attritors can also be set up in series. This can be accomplished by using larger media in the first unit which is equipped with grids having larger openings for accepting a coarse feed size. Subsequent units then utilize smaller media, resulting in a finer grind.

Advantages:

• Continuous large production
• Fastest grinding and processing
• Excellent temperature control
• Simple and safe to operate
• Low maintenance and power consumption