Browsing by Author "Engesser, John"
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Item Bentonite Quality - The Effect Of Water Chemistry And Antifreeze Agents On Bentonite Binding Characteristics(University of Minnesota Duluth, 2000-10-17) Engesser, JohnThe primary objective of the project was to determine what test or tests best predict pre-fired pellet binding characteristics of bentonite clay. A secondary objective was to determine which antifreeze chemicals have detrimental affects on pre-fired pellet quality and which antifreeze chemicals have no affect and/or positive affects on pre-fired pellet quality.Item Metallurgical Testing of Copper-Nickel Bearing Material from the Duluth Gabbro(University of Minnesota Duluth, 1998-12) Benner, Blair R; Engesser, John; Niles, Harlan BItem The Reduction of Fluoride Dissolution During Induration Off-Gas Scrubbing(University of Minnesota Duluth, 2001-05-10) Engesser, JohnA research project supported by the Minnesota Department of Natural Resources and the Iron Ore Cooperative Research Committee was undertaken to reduce the dissolution of fluoride into process water during taconite processing. Leach tests were conducted using rod mill feed samples and water containing varying concentrations of calcium and sodium. Laboratory liberation grinds were performed to evaluate fluoride rejection during grinding and magnetic separation. Tube furnace tests were conducted to evaluate fluoride volatilization during pellet induration. The results indicate that fluoride concentration of process water is a function of both calcium and sodium concentration in process water. It appears that less than 1 percent of the fluoride present in rod mill feed will dissolve in process water during grinding. More than 90 percent of the fluoride present in rod mill feed is rejected with tailings during siz.e reduction and magnetic separation. The furnace tests demonstrate that bentonite and fluxstone (calcite and dolomite) addition to taconite concentrate during pellet production increases the amount of fluoride that volatiliz.es during induration. Lime hydrate addition to pellets decreases the amount of fluoride that volatilizes during pellet induration. During acid pellet production approximately three times more fluoride enters the water during indurationoff- gas scrubbing than during grinding. When fluxed pellets are produced three to eight times more fluoride enters the water during off-gas scrubbing than during taconite grinding.Item Round Robin Analyses: (1) EP Toxicity Test: (2) ASTM Water Leach Test(University of Minnesota Duluth, 1988-01-15) Bleifuss, Rodney L; Niles, Harlan B; Engesser, JohnThe Natural Resources Research Institute supervised and evaluated a round robin analyses for the EP Toxicity and ASTM Water Leach tests on samples of incinerator fly ash. Samples were distributed to 14 laboratories for analyses. The leachates were analyzed for Pb, Cd, Hg, As and Se. Statistical analyses of the Pb and Cd data from the EP Toxicity tests give unreliable results for Pb with somewhat better reproducibility for the Cd. The Pb variability within, and between laboratories was very high and a single data point or single test result would be statistically meaningless. The corresponding analyses for Cd are somewhat better. The results for Hg, As and Se are too low for proper evaluation. The results from the ASTM Water Leach test were inconclusive because much of the data reported was below the limits of detection. We assume that the wide variations among the values reported for Pb are in large part related to the extraction step; i.e., the Cd data are better and the Cd compounds are more readily soluble. The data do not permit differentiation between errors related to extraction and those related to the analytical step. It appears logical that the control parameters applied to the extraction procedure are not sufficiently precise.Item Taconite Process Water and Tailing Water Quality Cationic-Exchange Effect on Balling and Flotation: Final Report(University of Minnesota Duluth, 1999-10) Engesser, JohnA research project supported by the Minnesota Department of Natural Resources and the Iron Ore Cooperative Research Committee was undertaken to 1) evaluate the problems related to cation exchange mechanisms that occur during wet grinding, flotation and balling and 2) investigate ionic formation and precipitation that occurs in the processwater during taconite processing. The cation exchange capacities of rod mill feed samples from two taconite plants were determined. Ball mill grinding, magnetic separation, bench scale flotation and balling tests were performed to establish the effect that cation exchange has on flotation and balling. Tests indicate that balling and flotation are affected by the cation exchange capacity of processed taconite ore. The rate of formation of sulfate, fluoride and bicarbonate anions during the grinding of taconite rod-mill-feed was determined. Sulfide oxidation to sulfuric acid followed by neutralization with carbonate minerals was studied. Fluoride liberation from the taconite ore was also investigated.