Formation of hexavalent chromium in Cr-containing steelmaking slag

• Autorzy: Sato Y. , Ijima K. , Shibayama A. , Inoue R.

Identyfikatory

DOI

10.5604/01.3001.0012.7802

• Języki publikacji: EN

Abstrakty

EN

Purpose: In present work, the mineral phases in chromium-containing slags were identified, and the formation mechanisms of Cr(VI) in Cr2O3-containing mineral phases were discussed. Design/methodology/approach: In steelmaking slag containing chromium, chromium is mainly present as spinel phases such as MgCr2O4 and (Mg,Fe)Cr2O4. When these Cr(III) oxides are oxidized to Cr(VI) oxide, the Cr(VI) is easily eluted from the slag due to its high solubility in water. Findings: The Cr (VI) adversely affects the human health and the environment. In this study, the influence of cooling rate, quenching temperature and oxidation/reduction condition during cooling on the Cr(VI) amount eluted from synthesized MgCr2O4, (Mg,Fe)Cr2O4 and CaCr2O4 were investigated. Research limitations/implications: The formation of Cr(VI) oxide in MgCr2O4 and CaCr2O4 compounds during heating under air was considered to be indispensable. The amounts of Cr(III) and Cr(VI) dissolved from MgCr2O4 were smaller than those from CaCr2O4. Since the formation of CrO3 in MgCr2O4 started at around 1400 K during cooling, slag should be cooled rapidly from the high temperature above 1400 K, or cooled in inert atmosphere in order to minimize Cr(VI) formation. FeO in (Mg,Fe)Cr2O4 solid solution suppressed Cr(VI), Cr(III) and Mg elution. Originality/value: The development of prevention method of Cr(VI) formation in the slags containing chromium is urgent in order to utilize the slags to land-fill and civil engineering works.

Słowa kluczowe

EN

stainless steelmaking slag; hexavalent chromium; elution test; chromium compound

PL

żużel ze stali nierdzewnej; sześciowartościowy chrom; test wymywania; związek chromu

• Wydawca: International OCSCO World Press
• Czasopismo: Archives of Materials Science and Engineering
• Rocznik: 2018
• Tom: Vol. 94, nr 1
• Strony: 5--10
• Opis fizyczny: Bibliogr. 12 poz.

Twórcy

autor

Sato Y.

• Material Eco-Refining Co. Ltd., 3-1-18, Barajima, Akita 010-0065, Japan; Formerly, Graduate School of Engineering and Resource Science, Akita University, 1-1, Tegatagakuen-machi, Akita 010-8502, Japan

autor

Ijima K.

• Graduate School of International Resource Sciences, Akita University, 1-1, Tegatagakuen-machi, Akita 010-8502, Japan

autor

Shibayama A.

• Graduate School of International Resource Sciences, Akita University, 1-1, Tegatagakuen-machi, Akita 010-8502, Japan

autor

Inoue R.

• Graduate School of International Resource Sciences, Akita University, 1-1, Tegatagakuen-machi, Akita 010-8502, Japan

Bibliografia

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• [4] H. Suito, R. Inoue, Immobilization of Fluorine and Chromium in Steelmaking Slag and Sludge, Sanyo Technical Report 10/1 (2003) 9-18 (in Japanese).
• [5] H. Hatada, Chemical state and Dissolution Character¬istics of Cr in Steel-making Slag, Bulletin of the Ad-vanced Materials Processing Building, IMRAM, Tohoku University 63/1-2 (2007) 27-33.
• [6] H. Suito, R. Inoue, Behavior of Fluorine dissolution from Hot Metal Pretreatment Slag, Tetsu-to-Hagane 88/6 (2002) 340-346 (in Japanese).
• [7] Ministry of the Environment (Ed.), Environmental Quali¬ty Standards for Groundwater Pollution, Tokyo, Available from: http://www.env.go.jp/en/water/gw/gwp.html.
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• [10] H. He, H. Suito, Immobilization of Hexavalent Chro¬mium in Aqueous Solution through the Formation of 3Ca0 (Al,Fe)203 Ca(0H)2 xH20 phase, Ettringite and C-S-H gel, ISIJ International 42/2 (2002) 139-145.
• [11] J.W. Mellor, A Comprehensive Treatise on Inorganic and Theoretical Chemistry, Vol. XI, Longmans, Green and Co. Ltd., London, 1930, 274.
• [12] A.M. Alper, R.N. McNally, R.C. Doman, F.G. Keihn, Phase Equilibria in the System Mg0-MgCr204, Journal of the American Ceramic Society 47/1 (1964) 30-33.

Uwagi

Opracowanie rekordu w ramach umowy 509/P-DUN/2018 ze środków MNiSW przeznaczonych na działalność upowszechniającą naukę (2019).