Browsing by Author "Fu, N. X"

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    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, M
    A 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.
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    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, M
    A 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.
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    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, M
    A 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.
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    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, M
    Laboratory 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%.