Browsing by Author "Rao, Shashi"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Continuous Pilot-Scale Demonstration of Ilmenite Processing Technology
    (University of Minnesota Duluth, 2021-05) Hudak, George J; Rao, Shashi; Peterson, Dean M; Chen, Jonathan; Lakshmanan, V.I.; Sridhar, Ram; Gluck, Eugen
  • Thumbnail Image
    Item
    Mobile Water Treatment Demonstration System for Sulfate Reduction
    (University of Minnesota Duluth, 2022-08) Cai, Meijun; Rao, Shashi; Post, Sara P; Hanson, Adrian; Chun, Chan Lan; Johnson, Lucinda B; Hudak, George J; Weberg, Rolf
    The State of Minnesota adopted a sulfate standard of 10 mg/L for wild rice waters in 1973. Although under review, current technology for achieving this standard is a challenge for small industries and municipalities. Membrane-based technologies such as nanofiltration and reverse osmosis are capable of treating water to reach the Minnesota wild rice water sulfate standard; however, they typically require high capital and operation costs. Therefore, there is a need to develop cost-effective sulfate treatment alternatives. The Natural Resources Research Institute (NRRI) has developed a treatment system based on barite chemical precipitation reactions to reduce sulfate levels in water from 60-200 mg/L to below 10 mg/L. This system was demonstrated at bench-scale batch and continuous tests. The data collected from these lab tests were used to scale up the process to a trailer-based modular demonstration treatment system. This study highlights the outcomes of field pilot tests conducted by NRRI using this treatment system. The objectives of the field pilot trials were to: (1) Evaluate the efficacy of the chemical precipitation process when scaled up from 200 ml/min to 2 GPM; (2) Study the effect of co-existing chelating organics of the raw wastewater on barite precipitation reactions; (3) Optimize the chemical reagent dosage levels; (4) Investigate the potential of reusing process sludge to promote precipitation reactions; (5) Identify strategies to minimize scale formation on process equipment; and (6) Estimate the chemical reagent costs. The pilot tests were conducted using effluent from two municipal wastewater treatment plants (WWTP)—the Virginia WWTP and the Grand Rapids WWTP in northeastern Minnesota—from June 2021 until October 2021.
  • Thumbnail Image
    Item
    Opportunities Offered by Emerging Hydrometallurgical Technologies
    (University of Minnesota Duluth, 2022-08) Rao, Shashi; Mlinar, Matthew A; Hudak, George J; Kangas, Kevin W; Peterson, Dean M
    Minnesota has abundant mineral resources, including deposits of iron, iron manganese, copper-nickel- cobalt-platinum group elements, titanium-vanadium, copper-zinc, gold with and without silver, sand, and aggregate. Commercial and industrial byproducts such as mine tailings, industrial residues, and waste electrical and electronic equipment also contain valuable mineral resources. To address significant environmental impact concerns associated with mining, collection and processing of these materials, new processing technology approaches with reduced water and energy consumption and minimal environmental footprints are needed to support production of value-added products. Emerging hydrometallurgical processing technologies offer promising opportunities. Hydrometallurgy techniques have a range of applications from extraction of high-value products from mineral and recycled materials to water remediation to generating secondary products for carbon sequestration. To evaluate the technical, economic, and environmental resiliency of emerging hydrometallurgical innovations, the Minnesota Legislative-Citizen’s Commission on Minnesota Resources (LCCMR) provided funding to the Natural Resources Research Institute (NRRI) to evaluate how to best support the development of emerging hydrometallurgical technologies in the state. To support this effort, NRRI evaluated: 1) A summary of perceived current and future hydrometallurgical needs of stakeholders based on a “voice of customer” (VOC) survey. 2) A discussion of how to apply hydrometallurgical capabilities to Minnesota-specific mineral and waste resources to maximize long-term economic, environmental, and social benefits and resilience. 3) A vision developed to advance Minnesota’s research capabilities in mineral characterization, mineral processing, extraction, and refining via hydrometallurgy that will lead to more efficient and effective utilization of Minnesota minerals and waste resources in the future. This research digs deeper into emerging applications of hydrometallurgical techniques in the production of value-added materials from a range of primary and secondary resources. The report also explores how application of these techniques to regional resources could potentially foster a more diversified minerals economy in Minnesota, develop treatment technologies to protect water resources, utilize regional resources for carbon mineralization, and supply materials required to build clean energy technologies.
  • Thumbnail Image
    Item
    Pilot-Scale Demonstration of Ilmenite Processing Technology
    (University of Minnesota Duluth, 2017-05-24) Mlinar, Matthew A; Rao, Shashi; Petersen, Tom S