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Size Reduction Spotlight - January 2010

January 21, 2010
High-Capacity, High-Speed Impact Grinding

Prater-SterlingThe M-Series fine grinder was developed for grinding dry, free-flowing material as fine as 200 mesh (75 µm) with tight distribution of particle size. It is best suited for heat-sensitive materials such as resins, sugar, and powder coatings. Utilizing a high-speed impact principle, the feed material is metered into the center of the mill where it is impacted by the rotor. The feed material is then thrown outward where it impacts with other particles, aiding in the reduction process. After initial impact, particles are projected across the screen and are sheared between the blades of the rotor and the sizing screen or jaws. This action continues until the particles are properly sized and are discharged through the bottom of the mill. Prater-Sterling, Bolingbrook, IL 630-759-9595 www.prater-sterling.com

Lab Attritor for Limestone Grinding

Union ProcessThis lab machine has been added to the company’s limestone and mineral grinding line. The CL-5 is the smallest member of the CL series stirred vertical ball mills. It is appropriate for research, scale-up studies, and small-scale production. Primary applications are for wet grinding limestone for flue gas desulphurization in power plants and for mineral grinding. Whereas CL series production attritors provide large, continuous production with throughputs in the tn/hr, the CL-5 lab attritor will process in the range of 200-500 lb/hr. The mill is equipped with a variable frequency drive (VFD) and a 15-hp inverter-duty motor. The CL-5 uses 2.5 gal of grinding media. Union Process Inc., Akron, OH 330-929-3333 www.unionprocess.com

Roller Mill

SwecoThe VRM roller mill provides efficient fine grinding of soft to medium-hard materials. Designed for continuous operation, the VRM’s basic concept is based on the combination of a high-quality mill body and highly efficient TC and Alpha classifiers. The mill body is designed with two or three rollers and provides a sharp and very fine top cutdown to d98 < 6 µm. The unit is ideal for fine grinding and classification of a wide variety of materials including calcium carbonate, dolomite, talc, bentonite, barites, petroleum, coke, calcium oxide, and gypsum. Sweco, Florence, KY 800-807-9326 www.sweco.com

Air Classifying Mill

HosokawaWith tightening standards for coal-fired and biomass power plants to reduce greenhouse and acid-rain gas emissions, Hosokawa is designing and manufacturing milling systems to produce grades of fine-ground sodium bicarbonate (SBC) and trona (sodium sesquicarbonate), to remove sulfur oxides (SOx)—a by-product of combustion of sulfur containing fossil fuels. When particles are reduced in size, the total surface area of the finer particles increases, thereby allowing for greater reactivity. After years of collaboration with customers, Hosokawa has standardized on system sizes and packages, from as little as 100–50,000 lb/hr of ground SBC or trona to average particle sizes as small as 5 µm, thereby improving SOx removal efficiencies. Hosokawa’s ACM system for dry sorbent injection takes the feedstock from storage silos and grinds and classifies it to the desired particle size before conveying the powder via a material handling fan to the flue gas stack. Here it reacts with SO2, reacting with and removing the gas as a harmless solid that is then trapped in a filter-house or electrostatic dust precipitator.  Hosokawa Micron Powder Systems, Summit, NJ 800-526-4491 www.hmicronpowder.com

Hammer Mill

The Rigimill hammer mill is a rigid blade design mill that suits applications from lab use to full production. The unit can be used for grinding or finishing products from grains to cake mix. Mills are available in agricultural, chemical, or sanitary construction, and in 16- and 24-in. models, ranging in size from 6–48 in. wide. A variety of blade shapes and screen sizes are available. The mill housing is a welded construction with a removable front cover for easy access to the grinding chamber. Machine and Process Design Inc., Anoka, MN 877-224-0653 www.mpd-inc.com

High-Pressure Grinding Rolls

Koppern Equipment engineers HPGR systems where the density and thickness of the press discharge flake is determined by the design, size, and operating parameters of the roller press. This allows size reduction to application-specific requirements. The system exerts high pressure on the feed material that is crushed and screened, or otherwise classified to specified particle sizes. Depending upon the grind ability, a certain recirculation rate may be used to achieve the required product size. The recirculating material is the coarse fraction from classification. The picture shows discharge flakes after processing. Koppern Equipment Inc., Charlotte, NC 704-357-3322 www.koppernusa.com

Lump Breaker

NBEThis lump breaker has dual 1-in. diam. counter-rotating shafts with eccentric rotor blades running between companion stators. The rotating shafts are designed for ease of cleaning as no tools are required for assembly and disassembly. The maximum discharge particle size for this application was 3/8 in. The quick clean material lump breaker easily integrates into an NBE bulk bag discharger. NBE Inc., Holland, MI 616-399-2220 www.nbe-inc.com

Screen Classifying Cutter

Munson Machinery CompanyThe SCC-15 screen classifying cutter cuts hard, soft, and fibrous materials into controlled particle sizes from granules down to 20–30 mesh with minimal fines, at rates to 500 cu ft/hr. The patented helical rotor design with dozens of cutter heads attached to a helical array of staggered holders called interconnected parallelograms continuously shear oversize materials against twin, stationary bed knives. Carbide tipped cutter heads along the entire shaft, with no frontal gaps between the tips, cut the product into uniform pieces with minimum fines and imperfections in the granulate, with little to no heat generation. The cutter has a 15-in. throat width and can be fitted with 30 parallelograms with 60 cutter inserts. Munson Machinery Company, Inc., Utica, NY 800-944-6644 www.munsonmachinery.com

Compact Sugar Grinding System

UCOM systems are ideal for grinding standard commercial icing sugar fineness (aka 6X). Available in three sizes for throughput up to 4000 lb/hr, they are explosion pressure shock resistant up to 10 bar (145 psi) overpressure. The milling system with air recirculation has a long history and is a proven design, built to the latest standards. The UCOM utilizes a cooling unit to extract the heat energy from the circulating air during grinding, eliminating the need to use ambient air, which prevents moisture and humidity from entering the system. Subsequently, there is no need for a dust filter, fan, or any explosion protection equipment. The mill is fed by a rotary airlock, which is flame penetration-proof and explosion pressure shock resistant. Bauermeister Inc., Memphis, TN 901-363-0921 www.bauermeisterusa.com/sugar.html

Lump Breaker

The LumpMaster eliminates lumps and agglomerations from material. Heavy-duty, yet compact in design, the unit fits right into most process applications. Two gear driven counter-rotating finger shafts and replaceable side combs are used to eliminate the lumps. The unit comes with the company’s exclusive Performantee performance guarantee. Hapman, Kalamazoo, MI 800-427-6260