Browsing by Author "Hendrickson, David W"

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    Minnesota Ilmenite Processing Using High Pressure Rolls
    (University of Minnesota Duluth, 2001-08-09) Benner, Blair R; Hendrickson, David W
    With funding from the Minnesota Department of Natural Resources through the Minerals Coordinating Committee, a study was undertaken to determine the potential for the use of High Pressure Rolls (HPR) grinding to improve recovery and reduce grinding energy in the processing of ilmenite bearing material from the Duluth Complex. Several deposits in the Duluth Complex have been identified, and the potential ore reserves have been estimated at 50 million tons. Previous work on this material showed the potential for making a low-silica ilmenite concentrate; however, the recovery was only about 50 percent. Relatively low recovery was due to losses in the minus 200 mesh fraction. HPR has been shown to produce less minus 200 mesh material than the conventional rod mill that had been used previously. Two HPR grinding flowsheets were tested. The first involved two stages of HPR, with the first stage being closed by a three mesh screen. The second stage, which treated the minus 3 mesh material from stage one, was closed with a 14 mesh screen. The second flowsheet involved a single HPR stage closed by a 14 mesh screen. Both flowsheets produced significantly less minus 200 mesh material than the rod mill, with the single stage producing the least. Grinding energy for the single stage HPR was 3.28 kWh/mt of new feed, compared to the previous rod mill energy consumption of 13.59 kWh/mt. The minus 14 mesh material from the HPR grinding was concentrated in two stages of spirals with recirculation of the cleaner tails to new feed. The cleaner concentrate was passed through a single drum magnetic separator to remove any magnetite. The nonmagnetic fraction was dewatered in a screw classifier and stored for future upgrading. Ti02 recovery in the nonmagnetics averaged about 61 percent, compared to the average Ti02 recovery of about 50 percent in the previous study. Clearly, the HPR grinding resulted in improved recovery. The amount of Ti02 reporting to the magnetic concentrate was essentially the same for both this study and the previous study using the rod mill; 25. 07 percent and 25 .19 percent respectively. To determine the potential for recovering a portion of the Ti02 in the magnetic concentrate, a series of grinds followed by laboratory magnetic separation tests were run. Even a 90.6 passing 270 mesh grind was not sufficient to produce a magnetic concentrate suitable for pellet production. Elutriation tests run on selected size fractions from the nonmagnetic material from the 84.9 percent passing 270 mesh grind indicated that the Ti02 was well liberated in the plus 500 mesh fractions. A study funded by the Permanent University Trust Fund is currently under way to explore ways of reprocessing the primary magnetic concentrate to increase Ti02 recovery and to produce a suitable pellet feed material.
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    Next Generation Metallic Iron Nodule Technology in Electric Arc Steelmaking – Phase II
    (University of Minnesota Duluth, 2010) Fosnacht, Donald R; Iwasaki, Iwao; Kiesel, Richard F; Englund, David J; Hendrickson, David W; Bleifuss, Rodney L
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    Smart Bioremediation Technology to Achieve High Sulfate Reduction in Mining Waters of NE Minnesota - Phase 1 Report
    (University of Minnesota Duluth, 2015-06) Hendrickson, David W; Hanson, Jeffrey J
    There exists a significant need in northeastern Minnesota to provide a viable solution to the current challenge of maintaining existing iron ore and developing non-ferrous mining industries while simultaneously protecting watersheds from elevated aqueous sulfate concentrations that could prove detrimental to biota, especially wild rice. ”Smart Bioremediation Technology to Achieve High Sulfate Reduction in Mining Waters of NE Minnesota – Phase I” focuses on proof of concept early-stage development of a realistic solution to the aqueous sulfate issue potentially threatening Minnesota’s existing $3 billion/year ferrous mining industry as well as Minnesota’s projected $4 billion/year non-ferrous mining industry (Skurla, 2012). Initial funding was provided for this Phase I work by the Natural Resources Research Institute (NRRI) and an Innovation Grant from the Laurentian Vision Partnership through the East Range Joint Powers Board. The design of the technology included smart sensors and controls which enabled remote operation and monitoring of the pilot scale system. Solar panels mounted on the systems floating bioreactor modules provided DC power to operate embedded pumps, sensors, controls, and data transmitters. The system was designed to enable stand alone, year round remote operation in environmental conditions encountered in either operating or legacy mining operations across the U.S. The modular nature of the technical design allows for practical scale up to accommodate flow requirement needs for the mining industry. The robust system design combined biological sulfate reduction with remediation hydrogeology approaches to remove sulfur from mining impacted waters (Reinsel, 2015). Sulfate reducing bacteria (SRB) from local stream sediments were utilized to provide the sulfate reduction. Preliminary analytical results indicate that the smart bioremediation technology is capable of producing aqueous sulfate reduction in the mining waters flowing through the bioreactor systems. The Phase I project has provided a proof of concept design for remediation of sulfate in mining impacted waters. Additional studies (Phase II study and MN Drive study) are currently under way and will be delivered during summer, 2016. The purpose of these future studies is to deliver a smart technology bioremediation water treatment system that is capable of being commercialized and that can effectively decrease aqueous sulfate levels in impacted waters in a cost-effective manner to concentrations that can be further decreased by other technologies so that stringent aqueous sulfate concentrations can be achieved.