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KASON CORPORATION 67-71 East Willow St.Millburn, NJ 07041-1416 USATel: 973-467-8140 Fax: 973-258-9533E-mail: [email protected]
KASON CORPORATION, EUROPEUnits 12 & 13 Park Hall Business VillagePark Hall Road Longton, Stoke-on-TrentStaffordshireST3 5XATel: 01782-597540 Fax: 01782-597549E-mail: [email protected]
SEPARATOR ENGINEERING LTD.4119 Cousens St.Saint LaurentQuebec CANADAH4S 1V6 Toll Free (Canada only):877-694-4441Tel: 514-667-6777 Fax: 514-745-2074E-mail: [email protected]
Technical Article Series
www.kason.com
Screening Tests Produce ShiningResults
Screening Tests Produce Shining ResultsKason' s test center shows a brass recycler how a vibrating circularscreener can help recover valuable brass from crushed slag
This 24 in. vibrating circular screener wasused to separate slag dust from brass-ladenslag chucks in tests for a brass recycler.
The Kason test center is also equipped withthis blow-through vibrating sifter forsifting and scalping tests in dilute-phasepneumatic conveying systems.
Kason Corp., Millburn, N.J., manufactures a variety of separators for screeningand classifying bulk materials, including chemicals, foods, minerals, andgrains. Since 1970, the company has operated a test center to help itscustomers choose the right separator and options for their application.
In late October 1988, Dale Knepp, vice president and plant manager forAmerican Brass, Headland, Ala., saw an ad in a trade magazine for Kason'sVIBROSCREEN® vibrating circular screener. American Brass recycles scrapbrass into ingots, which are sold to manufacturers of plumbing fixtures andother hardware.
To make the ingots, the scrap brass is loaded into rotary furnaces and melteddown. Borax is added to the molten brass, causing impurities to rise to thesurface and form a slag that's skimmed off and cooled. The processgenerates about 40,000 pounds of slag per day.
Slag traps valuable brass
When slag hardens, it traps small beads of pure brass, valued atapproximately $.50 per pound. American Brass wanted to recover this brassby crushing the slag and separating the dust from the larger, brass-ladenchunks. The company already had the necessary size reduction equipment,but needed a screener. Limited space and housekeeping concerns dictatedthat the new screener be compact and dust-tight.
Knepp thought the VIBROSCREEN might meet the plant's needs, so he calledKason and arranged a screening test. Henry Alamzad, a Kason test centerengineer, asked Knepp to send two 55-gallon drums (about 300 pounds) ofslag to the test center, along with a Material Safety Data Sheet (MSDS).Knepp then arranged to visit the test center to witness the screening tests.
When the test center received the slag, Alamzad analyzed its angle of repose,bulk density, particle size distribution, and particle shape to prepare for thetest session.
Tests produce a clean separation
The tests were performed just 2 weeks after the initial contact. "It would've.been sooner," says Knepp, .'but Kason had to wait for me to find time to getthere." For the tests, a screw feeder discharged slag into a 24 in. diametervibrating circular screener fitted with a 20-mesh screen.
Based on his experience with similar materials, Alamzad installed ploughblades to catch material that collected along the edge of the screen and directit out the discharge spout. This prevented oversize material from accumulatingon the screen deck. He also installed reverse tie-downs to pull the center ofthe screen up. This created a sloped screening surface and prevented heavymaterial from collecting in the middle of the screen.
After the first separation test, Alamzad analyzed the particle size distribution of
the overs and the fines and found that too much dust was being dischargedwith the overs. To remedy this, he replaced the 20 mesh screen with an18-mesh screen. Further tests showed that this produced a cleanerseparation.
Tests also showed that the screener operated more efficiently when a10-mesh screen was placed above the 18-mesh screen. This reduced theload on the 18mesh screen and increased the available screening area.
After making these changes, Alamzad ran several more back-to-back tests tosimulate production conditions and generate additional data. A total of eighttest runs were made with good results.
The largest two fractions -- everything bigger than 18 mesh -- constituted 30percent of the slag and contained about 30 percent brass. The finesconstituted 70 percent of the slag and contained almost no brass.
The entire test procedure took 3 hours. "I was very impressed with theefficiency of the test center and with the way the vibrating circular screenerworked," says Knepp. "After seeing the test results, I saw no reason to lookany further -- the screener did exactly what we needed it to do." InDecember, American Brass purchased and installed a double-deck, 72 in.vibrating circular screener with 10-mesh and 18mesh stainless steel screens.
Screener helps reclaim brass beads from slag
The new screener handles as much as 12,000 pounds of slag per hour, withan average throughput of 40,000 pounds per day. Reducing and screening theslag allows American Brass to recover from 35,000 to 45,000 pounds of brassper month.
Facts about Kason's test center
Kason's test center is located at the company's plant in Millburn, NJ., about 15minutes from Newark International Airport. The test center occupies 1,250square feet and has two staff members. Besides helping customers choosethe most effective separation equipment, Kason engineers use the center totest new equipment.
The center staff can use a variety of equipment to determine your material'shandling and screening properties, including a device for measuring yourmaterial's angle of repose and a flow splitter for ensuring that your material isproportionately fed and completely mixed before a test begins. The centerstaff can also determine the particle size distribution of samples with sieves,analyze particle shapes under a microscope, and measure your material'sbulk density.
The center staff conducts separating tests with several types of equipment,including three lab-size VIBROSCREEN® vibrating circular screeners withdifferent frames. Each can make up to five separations with mesh sizesranging from 45 microns to 2 inches. The screeners also handle wet materials,including wastewater. For screening difficult-to-handle materials, a variety ofanti-blinding devices can also be tested, including top-side wipers, rings, andball trays.
The test center also has two CENTRI-SIFTER™ centrifugal sifters for siftingdry powders and granular materials, especially those that are likely to blind
conventional screens. One sifter has a self-purging trash trap thatcontinuously expels trash and oversize material without interruptions forcleaning. Occasionally, the center staff tests a material in both a vibratingcircular screener and a centrifugal sifter to see which will give the best results.
The test center also has a Blo-Thru Vibro-Sifter for sifting and scalping testsin dilute-phase pneumatic conveying systems. This unit accepts screens withopenings ranging from 50 mesh to 2 inches and can be equipped with severalanti-blinding devices.
Additional equipment includes a drum sifter for low-cost, simple,single-fraction separations and a 24 in. wide Cross-Flo® sieve forhigh-speed dewatering applications.
Most tests require a 55-gallon drum of material. Material Safety Data Sheets(MSDSs) are also required, and the staff won't work with hazardous orexplosive materials. Testing is free, except for material shipping charges. Testresults and recommendations can often be furnished in 48 hours or less.
For each test, the center staff produces a comprehensive report that includesyour material's bulk density, angle of repose, particle size distribution, blindingtendency, and fluidizing tendency. The weight of the feed material and theweight of each size fraction is also recorded, along with the particle sizedistribution of each fraction.
For vibrating circular screener tests, the report includes the type of frame,screen mesh sizes, motor speed, additional weight plates and lead angle,length of test run, feed rate, and type of anti-blinding devices used. Motoramperage and voltage as well as horizontal and vertical stroke values are alsorecorded.
For centrifugal sifter tests, the report includes the type and mesh size of thescreen, the rotor speed, and whether an end-baffle plate or screen brusheswere used.
The center staff also maintains a materials library. If you send in a samplethat's the same as one on hand, test results and recommendations can bequickly sent to you. Library materials include polyethylene, phenolic resin,rubber, sugar, flour, glass bead, lead oxide, cat litter, and wood chips.
