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Title: Aqueous solubility of Cr(VI) compounds in ferrochrome bag filter dust and the implications thereof

Abstract

The production of ferrochrome (FeCr) is a reducing process. However, it is impossible to completely exclude oxygen from all of the high-temperature production process steps, which may lead to unintentional formation of small amounts of Cr(VI). The majority of Cr(VI) is associated with particles found in the off-gas of the high-temperature processes, which are cleaned by means of venturi scrubbers or bag filter dust (BFD) systems. BFD contains the highest concentration of Cr(VI) of all FeCr wastes. In this study, the solubility of Cr(VI) present in BFD was determined by evaluating four different BFD samples. The results indicate that the currently applied Cr(VI) treatment strategies of the FeCr producer (with process water pH ≤ 9) only effectively extract and treat the water-soluble Cr(VI) compounds, which merely represented approximately 31% of the total Cr(VI) present in the BFD samples evaluated. Extended extraction time, within the afore-mentioned pH range, proved futile in extracting sparingly-soluble and water-insoluble Cr(VI) species, which represented approximately 34% and 35% of the total Cr(VI), respectively. Due to the deficiencies of the current treatment strategies, it is highly likely that sparingly water-soluble Cr(VI) compounds will leach from waste storage facilities (e.g. slimes dams) over time. Therefore, it is criticalmore » that improved Cr(VI) treatment strategies be formulated, which should be an important future perspective for FeCr producers and researchers alike.« less

Authors:
 [1];  [1];  [1];  [1];  [2];  [1]
  1. North-West Univ., Potchefstroom (South Africa). Chemical Resource Beneficiation
  2. Natural Resources Canada, Ottawa, ON (Canada). CanmetMINING
Publication Date:
Research Org.:
North-West Univ., Potchefstroom (South Africa); Natural Resources Canada, Ottawa, ON (Canada); Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Research Foundation (NRF) (South Africa); Natural Sciences and Engineering Research Council of Canada (NSERC)
OSTI Identifier:
1425801
Alternate Identifier(s):
OSTI ID: 1417378
Grant/Contract Number:  
FG03-97ER45628; W-31-109-Eng-38; 101345
Resource Type:
Accepted Manuscript
Journal Name:
Water SA
Additional Journal Information:
Journal Volume: 43; Journal Issue: 2; Journal ID: ISSN 0378-4738
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; hexavalent chromium; Cr(VI); ferrochromium; ferrochrome; bag filter dust; smelter waste

Citation Formats

Du Preez, S. P., Beukes, J. P., Van Dalen, W. P. J., Van Zyl, P. G., Paktunc, D., and Loock-Hattingh, M. M. Aqueous solubility of Cr(VI) compounds in ferrochrome bag filter dust and the implications thereof. United States: N. p., 2017. Web. doi:10.4314/wsa.v43i2.13.
Du Preez, S. P., Beukes, J. P., Van Dalen, W. P. J., Van Zyl, P. G., Paktunc, D., & Loock-Hattingh, M. M. Aqueous solubility of Cr(VI) compounds in ferrochrome bag filter dust and the implications thereof. United States. doi:10.4314/wsa.v43i2.13.
Du Preez, S. P., Beukes, J. P., Van Dalen, W. P. J., Van Zyl, P. G., Paktunc, D., and Loock-Hattingh, M. M. Fri . "Aqueous solubility of Cr(VI) compounds in ferrochrome bag filter dust and the implications thereof". United States. doi:10.4314/wsa.v43i2.13. https://www.osti.gov/servlets/purl/1425801.
@article{osti_1425801,
title = {Aqueous solubility of Cr(VI) compounds in ferrochrome bag filter dust and the implications thereof},
author = {Du Preez, S. P. and Beukes, J. P. and Van Dalen, W. P. J. and Van Zyl, P. G. and Paktunc, D. and Loock-Hattingh, M. M.},
abstractNote = {The production of ferrochrome (FeCr) is a reducing process. However, it is impossible to completely exclude oxygen from all of the high-temperature production process steps, which may lead to unintentional formation of small amounts of Cr(VI). The majority of Cr(VI) is associated with particles found in the off-gas of the high-temperature processes, which are cleaned by means of venturi scrubbers or bag filter dust (BFD) systems. BFD contains the highest concentration of Cr(VI) of all FeCr wastes. In this study, the solubility of Cr(VI) present in BFD was determined by evaluating four different BFD samples. The results indicate that the currently applied Cr(VI) treatment strategies of the FeCr producer (with process water pH ≤ 9) only effectively extract and treat the water-soluble Cr(VI) compounds, which merely represented approximately 31% of the total Cr(VI) present in the BFD samples evaluated. Extended extraction time, within the afore-mentioned pH range, proved futile in extracting sparingly-soluble and water-insoluble Cr(VI) species, which represented approximately 34% and 35% of the total Cr(VI), respectively. Due to the deficiencies of the current treatment strategies, it is highly likely that sparingly water-soluble Cr(VI) compounds will leach from waste storage facilities (e.g. slimes dams) over time. Therefore, it is critical that improved Cr(VI) treatment strategies be formulated, which should be an important future perspective for FeCr producers and researchers alike.},
doi = {10.4314/wsa.v43i2.13},
journal = {Water SA},
number = 2,
volume = 43,
place = {United States},
year = {2017},
month = {4}
}

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