Investigation of Reaction Mechanism on the Lime-Free Roasting of Chromium-Containing Slag

Yu, Kaiping; Zhang, Hongling; Chen, Bo; Xu, Hongbin; Zhang, Yi

doi:10.1007/s11663-015-0428-5

Cited by 4 publications

(2 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, almost no carcinogenic calcium chromate is found in the residue from the non-calcium roasting process [23]. However, the basic chemical reactions of the non-calcium roasting process are roughly the same as the calcium-roasting process, hence Cr(VI) compounds are still generated [32,33]. In summary, the non-calcium roasting process cannot completely solve the problem of Cr(VI) pollution, even though the amount of toxic residue is significantly reduced [34].…”

Section: Chromium Salt Preparation Technologymentioning

confidence: 99%

Advances towards a Clean Hydrometallurgical Process for Chromite

2016

View full text Add to dashboard Cite

Abstract:Because of the acute toxicity of Cr(VI)-bearing substances, the pollution problem caused by chromite process residue has become a worldwide concern. In the view of relevant studies, the technologies based on the alkali treatment cannot fundamentally resolve the pollution problem, because the oxidation of Cr(III) to Cr(VI) is unavoidable during chromite decomposition. In contrast, the oxidation of Cr(III) to Cr(VI) can be controlled by the sulfuric acid treatment of chromite, and the Cr(VI) pollution can be eliminated from the original source of production. Many research studies focusing on the resolutions of the key obstacles hindering the development of the sulfuric acid treatment process have been carried out, and significant progress has been achieved. In this study, a clean hydrometallurgical process without the generation of hexavalent chromium is demonstrated. First, the chromite was decomposed and leached by sulfuric acid solution in the presence of an oxidant. Then, iron was hydrothermally removed from the acid solution as the precipitate of jarosite. Finally, chromium salts were obtained by adjusting the basicity of the solution, separation and drying. With the aim of realizing industrialization, future research emphasis on the development of the sulfuric acid treatment process is proposed in this study.

show abstract

Section: Chromium Salt Preparation Technologymentioning

confidence: 99%

Advances towards a Clean Hydrometallurgical Process for Chromite

2016

View full text Add to dashboard Cite

show abstract

“…The contamination of groundwater by Cr may be derived from industrial activities, such as in the Czech Republic (a highly industrialized country in Central Europe) [17], at the area of Friuli Venezia Giulia (northern Italy) [18], the Assopos Basin (Oinofyta or Inofyta, near the Assopos river) in Greece, exhibiting as high as 8000 μg/L Cr(VI) in shallow groundwater [19]. Additionally, ferrochromium (FeCr), which is a critical alloy in the production of stainless steel, is produced in several European countries (Finland, France, Italy, Norway, Sweden, the nations formerly comprising Yugoslavia, Germany, Italy, Switzerland, and the U.K.) generating Cr-bearing wastes [7,20].…”

Section: Introductionmentioning

confidence: 99%

The Cr(VI) Stability in Contaminated Coastal Groundwater: Salinity as a Driving Force

Eliopoulos

Economou-Eliopoulos

2021

Minerals

View full text Add to dashboard Cite

Chromium concentrations in seawater are less than 0.5 μg/L, but the Cr(VI) in contaminated coastal groundwater affected by Cr-bearing rocks/ores and/or human activities, coupled with the intrusion of seawater may reach values of hundreds of μg/L. A potential explanation for the stability of the harmful Cr(VI) in contaminated coastal aquifers is still unexplored. The present study is an overview of new and literature data on the composition of coastal groundwater and seawater, aiming to provide potential relationships between Cr(VI) with major components in seawater and explain the elevated Cr(VI) concentrations. It is known that the oxidation of Cr(III) to Cr(VI) and the subsequent back-reduction of Cr(VI) processes, during the transport of the mobilized Cr(VI) in various aquifers, facilitate the natural attenuation process of Cr(VI). Moreover, the presented positive trend between B and Cr(VI) and negative trend between δ53Cr values and B concentration may suggest that seawater components significantly inhibit the Cr(VI) reduction into Cr(III), and provide insights on the role of the borate, [B(OH)4]− ions, a potential buffer, on the stability of Cr(VI) in coastal groundwater. Therefore, efforts are needed toward the prevention and/or minimization of the contamination by Cr(VI) of in coastal aquifers, which are influenced by the intrusion of seawater and are threatened by changes in sea level, due to climate change. The knowledge of the contamination sources, hotspots and monitoring of water salinization processes (geochemical mapping) for every coastal country may contribute to the optimization of agricultural management strategies.

show abstract