Behavior of cadmium during roasting of zinc concentrate
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Behavior of cadmium during roasting of zinc concentrate

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Published by U.S. Dept. of the Interior, Bureau of Mines in Pgh. [i.e. Pittsburgh], Pa .
Written in English

Subjects:

  • Zinc -- Metallurgy.,
  • Roasting (Metallurgy),
  • Cadmium.

Book details:

Edition Notes

Bibliography: p. 16-17.

Statementby Arne Landsberg ... [et al.].
SeriesReport of investigations ;, 8543, Report of investigations (United States. Bureau of Mines) ;, 8543.
ContributionsLandsberg, Arne.
Classifications
LC ClassificationsTN23 .U43 no. 8543, TN796 .U43 no. 8543
The Physical Object
Pagination17 p. :
Number of Pages17
ID Numbers
Open LibraryOL4239846M
LC Control Number80607819

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Refining of zinc and its cadmium content, can be accomplished by treating the zinc concentrates and/or zinc-bearing secondary materials using either a hydrometallurgical or pyrometallurgical process. In both processes, the concentrate is converted from zinc sulfide to zinc oxide by roasting, and at the same time most of the sulfur is removed as. During the first 4 hr. of the roasting period, when the sulfur-dioxide concentration exceeded 2 per cent., 82 per cent, of the zinc was oxidized. During the later period, and while the sulfur-dioxide concentration averaged so low that one could breathe the roaster gas without serious discomfort, an added 17 per cent, of the zinc was oxidized. Zinc is a chemical element with the symbol Zn and atomic number Zinc is a slightly brittle metal at room temperature and has a blue-silvery appearance when oxidation is removed. It is the first element in group 12 of the periodic some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn 2+ and Mg 2+ ions are of. The zinc plant residue is a hazardous waste which is produced in the hydrometallurgical zinc plant and it contains considerable amounts of metals such as zinc, cadmium and nickel.

During the roasting process the sulfur in the concentrate is removed at a temperature of about – °C, wherein zinc sulfide is oxidized mainly to zinc oxide. The following zinc containing phases: ZnSO 4, ZnFe 2 O 4, Zn 2 SiO 4, are also obtained with a small quantity of unreacted ZnS. The origin of the zinc ore and the manufacturing process of the supplement, will determine how much cadmium will be present in the different supplements Cite 5 Recommendations. Roasting is a high-temperature process that converts zinc sulfide concentrate to an impure zinc oxide called calcine. Roaster types include multiple-hearth, suspension, or fluidized bed. The following reactions occur during roasting: 2ZnS 3O2 → 2ZnO SO2 (1) 2SO2 O2 → 2SO3 (2). After posting the article Cadmium Levels in Vegans, Zinc Supplements and Alzheimer’s Disease, Ginny Messina let me know that there is a concern about cadmium contamination of zinc supplements.. I researched the issue and added the following section to ’s article Cadmium. In , Krone et al tested six zinc supplements from Seattle area health food stores to see if they.

CHARACTERISATION AND CONTROL OF THE ZINC ROASTING PROCESS Academic Dissertation to be presented with the assent of the Faculty of Technology, University of Oulu, for public discussion in Kuusamonsali (Auditorium YB), Linnanmaa, on December 17th, , at 12 noon. OULUN YLIOPISTO, OULU Cadmium has many chemical similarities to zinc and is often recovered from the primary zinc ore sphalerite. The single most important use of cadmium is in the production of nickel-cadmium (Ni-Cad) batteries. Relation to Mining. Cadmium rarely appears in nature and is most commonly sourced by its removal from zinc metals during the refining process. Bastnaesite in a mixed rare earth concentrate can be easily broken down to release CO 2 during roasting (Burmaa et al., , Huang et al., ), after which most of the rare earths can be leached by acid; however, REF 3 and monazite cannot be dissolved and go into the slag (Jha et al., ). During the fluid-bed roasting of zinc sulfide concentrates, the sulfur in the sphalerite (Zn,Fe)S diffuses out of the particles, whereas the associated zinc and iron are converted to (Zn,Fe)O. The iron from the (Zn,Fe)O phase migrates outward to the peripheries of the particles, forming ZnFe2O4. The resulting porous ZnO+ZnFe2O4 particles agglomerate to form large, spherical masses.