Browsing by Subject "Geochemical analysis"
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Item Bench Scale Tests to Separate Mercury from Wet‐Scrubber Solids from Taconite Plants(University of Minnesota Duluth, 2007) Benner, Blair RItem Characterization of Residue from the Pressure Oxidation Leaching of Bulk Copper-Nickel Sulfides from the Duluth Gabbro(University of Minnesota Duluth, 1999) Benner, Blair R; Niles, Harlan BThe copper-nickel bearing material in the Duluth Gabbro represent a potentially significant reserve of copper and nickel with lesser amounts of cobalt and platinum group elements (PGEs). To help promote the development of this resource, the Coleraine Minerals Research Laboratory (CMRL) has conducted a series of investigations into methods of processing the material. A bulk sulfide flotation process followed by oxidation pressure leaching resulted in high extractions (>98 %) of the copper and nickel in the flotation concentrate. During the leaching, the iron in the flotation concentrate leaches and precipitates as either hematite (crystalline or amorphous) or as a basic iron sulfate (jarosite). The leaching should also leave the PGEs in the residue. If the hematite was present as a crystalline material, then if may be possible to recover a high grade iron product from the residue. If any PGE minerals could be found, then it may be possible to develop a method to recover and concentrate the PGEs. The Minnesota DNA through the Minerals Coordinating Committee funded the current study. The purpose of the research was to characterize the leach residue as to the iron bearing material and to determine if any PGE minerals could be found either by X-ray diffraction (XRD) or by electron microprobe analysis.Item Chemistry, Mineralogy & Liberation Characteristics of Samples of EVTAC Concentrator Unit Operations(University of Minnesota Duluth, 2005) Niles, Harlan BMinnesota taconite operations frequently encounter quality problems due to chemical-mineralogical variations in crude ore blends. Mine personnel have expressed interest in determining ore blend behaviors in unit operations of concentrators. This knowledge could assist in providing ore blends that produce more uniform and desirable final concentrates. The behavior of ores in intermediate concentrator stages may also help concentrator operators to adjust units to produce optimum results. A project proposal submitted to the Permanent University Trust Fund (PUTF) to determine chemistry, mineralogy, and indicated magnetite liberation for samples of unit operations of two EVTAC ore blends was approved. Feed, concentrate, and tailing samples from concentrator unit operations that represented two crude ore blends were received by the Coleraine Minerals Research Laboratory (CMRL) in 2001 and 2002. They were designated Set 1 and Set 2, respectively. The samples were dried, mixed, and split into portions for "As Is" Davis tube magnetic separations and other splits to be pulverized for chemical analyses and for x-ray diffraction. Chemistry was run at the CMRL and x-ray diffraction patterns were run at the University of Minnesota Shepherd Laboratory in Minneapolis. Mineral percentages in each sample were calculated from the chemical analyses on a spreadsheet in a "Quattro Pro for Windows" computer program after examining x-ray patterns to determine the minerals that were present. The spreadsheet was adjusted to comprehend minerals present and their chemical compositions, and so that the sum of mineral percentages in a sample was within 0.50 percent of the chemistry total oxides (near 100 percent). The results of “As Is" Davis tube separations are given in Table I. It shows magnetic weight recoveries and concentrate iron and silica percentages and provides an indication of the progressively improved magnetite liberation through the concentrator operations. It also shows that liberation in sample Set 2 was somewhat better than in Set 1, and, when compared to the sample chemical analyses in Table 2, separation efficiencies in concentrator units are demonstrated. Calculated mineral percentages in cobber feed samples showed that total silicates were nearly equal in Sets 1 and 2, that the hematite percentage was considerably higher in Set 1, and that total carbonate was higher in Set 2. In the final concentrates, most hematite and silicates had been rejected from both sets, but the total carbonate from Set 2 was 3.6 percent, about double that for Set 1. A set of bar graphs was made for each unit operation, which shows percentages of each mineral in the feed, concentrate and tailing. They illustrate the recovery and rejection of each mineral in each concentrator operation. Company personnel may therefore distinguish the effectiveness of each unit in recovering and rejecting particular gangue minerals.Item Extraction Metallurgy of Copper from Chalcopyrite Concentrates without Sulfuric Acid Generation via Chlorination - III. Integration of Gaseous Chlorination and Selective Oxidation(University of Minnesota Duluth, 1999) Iwasaki, Iwao; Tamagawa, T.; Fu, N. X; Kobayashi, MA 3-stage fluidizing bed process of chlorination, selective oxidation and sulfur chloride conversion was tested for processing of a chalcopyrite concentrate. It was found that the use of excess oxygen was essential to a stable operation in the oxidation reactor. The oxygen-excess gas will inevitably cause the oxidation of the sulfide concentrate in the chlorination and sulfur chloride conversion reactors. A new flowsheet is proposed to separate the chlorination and the selective oxidation steps with separate flow paths of the fluidizing gases, thereby preventing the passage of oxygen-excess gas in the chlorination and sulfur chloride conversion reactors. The feasibility of the proposed flowsheet was demonstrated in a laboratory-scale fluidizing bed setup.Item Extraction of Copper from Chalcopyrite Concentrates without Sulfuric Acid Generation via Chlorination - I. Gaseous Chlorination of Sulfide Concentrates(University of Minnesota Duluth, 2000) Iwasaki, Iwao; Tamagawa, T.; Tabaian, S. H; Fu, N. X; Kobayashi, MA gaseous chlorination process for hydrometallurgical treatment of a chalcopyrite concentrate was investigated. The overall process is visualized to consist of low temperature chlorination-selective oxidation, followed · by aqueous chloride leaching and SX-EW for producing electrolytic copper, elemental sulfur and ferric oxide. In this article, the chlorination phase of the process is described. Initially, the chlorination behavior of chalcopyrite-concentrate micro-pellets was investigated using a small batch-type fluidized bed reactor. The optimum conditions thereby established were used in continuous chlorination tests. The chlorinated products thus prepared were used in the selective oxidation phase of the investigation.Item Extraction of Copper from Chalcopyrite Concentrates without Sulfuric Acid Generation via Chlorination - II. Selective Oxidation of Chlorinated Products(University of Minnesota Duluth, 1999) Iwasaki, Iwao; Tamagawa, T.; Fu, N. X; Kobayashi, MA low temperature chlorination-selective oxidation, followed by aqueous chloride leaching and SX-EW for producing electrolytic copper, elemental sulfur and ferric oxide was investigated for hydrometallurgical processing of a chalcopyrite concentrate. In this article, the selective oxidation phase of the process is described. The selective oxidation requires a temperature well above the CuCl-FeCl3 eutectic points. The test procedure was developed with a batch reactor and then tested with a continuous reactor. The process was initiated by adding small amounts of chlorinated samples to a fluidizing bed of dead-roasted sulfide concentrate micro-pellets. The selectively oxidized samples thus prepared were shown to fully dissolve copper, while virtually all the iron remained undissolved.Item Geological and Geochemical Reconnaissance for Rare Earth Element Mineralization in Minnesota(University of Minnesota Duluth, 2014) Hauck, Steven A; Heine, John J; Severson, Mark J; Post, Sara P; Chlebecek, Sara; Monson Geerts, Stephen D; Oreskovich, Julie A; Gordee, Sarah MItem Geology and Cr-PGE Mineralization of the Birch Lake Area, South Kawishiwi Intrusion, Duluth Complex(University of Minnesota Duluth, 1997) Hauck, Steven A; Severson, Mark J; Ripley, Edward M; Goldberg, Steven A; Alapieti, TuomoItem Low Temperature Gaseous Chlorination for Sulfur Oxide Free Extraction of Copper from Chalcopyrite Concentrates(University of Minnesota Duluth, 2002) Iwasaki, Iwao; Fu, N. X; Tabaian, S. H; Tamagawa, T.; Kobayashi, MLaboratory investigations of gaseous chlorination-selective oxidation process on primary copper sulfide concentrates are described for producing copper chlorides, elemental sulfur and ferric oxide. The copper chlorides can then be leached, purified and electrolyzed to produce metallic copper and chlorine regenerated for recycle. When a process, originally proposed on a pyrite concentrate analyzing 2.5%Cu using a two-stage reactor, was applied to a Cu, Ni sulfide concentrate analyzing 9%Cu, the process had to be modified to a three-stage reactor by adding a sulfur chloride conversion unit. In this manner, operational problems associated with the formation of Cu-Fe chloride eutectics and sulfur chlorides could be circumvented. When the process was extended to a 29%Cu chalcopyrite concentrate, the use of excess oxygen was found to be necessary to stabilize the operation of the oxidation reactor. A flowsheet was further modified to separate the chlorination and selective oxidation units with separate flow paths of fluidizing gases, thereby preventing the oxidation of sulfide feed in the chlorination reactor. Leaching of selectively-oxidized samples produced solutions analyzing Cu concentrations in excess of 100 g/L with Fe/Cu ratios of less than 0.03 and with Cu extractions of over 99%. Leach residues were readily filterable with cake moisture contents of 20 to 25%.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 Non-ferrous Geology along the Highway 53 Relocation near Virginia, MN(University of Minnesota Duluth, 2015) Heine, John J; Patelke, Marsha Meinders; Post, Sara P; Maly, Craig CThis report outlines the non-ferrous work done in the area of the Highway 53 relocation near Virginia, MN. At the request of the mineral lease holder (Vermilion Gold Inc.), an examination of the gold potential in the area of the new road was completed. Vermilion Gold Inc. located ten exploration diamond drill hole sites which they believed were necessary to characterize the area. Drilling occurred during fall 2013 and was conducted by Idea Drilling. The drilling and subsequent work by Natural Resource Research Institute, University of Minnesota Duluth (NRRI) was funded by the Minnesota Department of Transportation (Mn/DOT) as part of the relocation work for the highway. Logging and sample preparation were completed at the NRRI Coleraine Minerals Research Laboratory (CMRL) in Coleraine, MN.Item A Pot‐Grate Simulator for Experimental Evaluation of Heat Transfer, Drying, Flux Calcination, and Magnetite Oxidation Mechanisms in Pellet Induration Processes(University of Minnesota Duluth, 2005) Englund, David J; Davis, Richard AItem Re-Examination of the Relationship between Davis Tube Data on Drill Core and Actual Plant Operation(University of Minnesota Duluth, 2006) Benner, Blair R