Iron ore pellets use bentonite clay as binder at dosages from 0.5to 1.0% (10 to 20 pounds per ton) of moist iron ore concentrate.Bentonite is typically shipped hundreds of miles from Wyoming to theLake Superior iron ore district. It is therefore best to know howeffective a bentonite will be before it is shipped and used to bindconcentrate into pellets. Current tests of bentonite effectivenessinclude: plate water absorption, methylene blue uptake, free swell,exchangeable cations, and glycolated layer expansion. However,these tests have many disadvantages: First, they only measure theability of a bentonite to expand, disperse, or absorb, not how well itwill bond. Second, most of the tests require up to 20 hours to perform.Bentonite only has a few minutes to interact within the concentratebefore it is indurated (sintered). These long-term tests may not reflectthe true behavior of bentonite. Third, the tests are tedious and oftenresults are inconsistent between different iron ore concentrates, labs,and technicians. Fourth, some of the testing equipment is difficult toprocure. Fifth, procedures are often difficult to standardize. In thispaper, the Binder Effectiveness Strength (BESt) test to evaluatebinders for iron ore pellets is presented that: measures the ability ofbentonite to bond, requires only about two hours to complete, issimple and reproducible, and utilizes readily available equipment thathas been standardized for decades.
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