ferrochrome slag trivalent and hexavalent chromium
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ferrochrome slag trivalent and hexavalent chromium

Hexavalent chromium removal by ferrochromium slag.

Nov 11, 2005 · Hexavalent chromium removal by ferrochromium slag. Erdem M(1), Altundoğan HS, Turan MD, Tümen F. Author information: (1)Department of Environmental Engineering, Firat University, 23279 Elaziğ, Turkey. The aim of this study is to demonstrate the potential of Cr(VI) generation during jigging operation applied for ferrochrome recovery from slag.

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Hexavalent chromium removal by ferrochromium slag

Chromium contamination of soil and water is a sig-nificant problem since hexavalent form of chromium is highly toxic, mutagenic and potentially carcinogenic to liv-ing organisms [17,18]. The most stable oxidation states of chromium are Cr(III) and Cr(VI) in aqueous systems. The trivalent chromium is quite immobile in the water environ-

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Recovery of Chromium from Ferrochrome Slag - JOCPR

Ferrochrome slag may contain chromium in +3 and +6 oxidation states along with elemental chromium[5].Earlier studies reported the extraction of chromium (VI) [6-8] as well as microbial activity of different metals[9].

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Chromium Compounds - US EPA

Chromium is a naturally occurring element in rocks, animals, plants, soil, and volcanic dust and gases. (1) Chromium occurs in the environment predominantly in one of two valence states: trivalent chromium (Cr III), which occurs naturally and is an essential nutrient, and hexavalent chromium (Cr VI), which, along with

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Chromium adsorption and Cr(VI) reduction to trivalent ...

Chromium as Cr(VI) is a industrially produced pollutant. Hexavalent chromium can be reduced to the trivalent state using various reductive agents or it can be removed from solution by surface-active adsorbents. In this study, both of these methods were evaluated using soya cake. A high efficiency fo

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Toxicological Review of Trivalent Chromium (CAS No. 16065 ...

Chromium (Cr) is a metallic element belonging to the first transitional series of the periodic table. Elemental chromium has a CAS Registry Number of 7440-47-3. The three most stable forms in which chromium occurs in the environment are the 0 (metal and alloys), +3 (trivalent chromium), and +6 (hexavelent chromium) valence states.

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(PDF) Hexavalent chromium removal by ferrochromium slag

Efficient adsorption of hexavalent chromium ions onto novel ferrochrome slag/polyaniline nanocomposite: ANN modeling, Isotherms, kinetics and thermodynamic studies

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Hexavalent chromium removal by ferrochromium slag ...

Nov 11, 2005 · The chromium content in slags is 2–12%, in oxide and metal form. The slag/metal amount ratio in smelting varies from 1.0 to 1.8, depending on raw materials . Slag is discarded as a waste material in enormous quantities during the ferrochrome production.

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Hexavalent chromium removal by ferrochromium slag

The Cr(VI) concentrations of water contacted with ferrochromium slag (W/FS = 10) in a closed cycle after 50 batches were found as 0.61 mg/l. Also, reduction of Cr(VI) to Cr(III) and a subsequent precipitation of Cr(III) by using ferrochrome slag (FS) in a model solution has been aimed.

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MEDICAL EVALUATION OF CHILDREN AND ADULTS OF THE

chromium and other metals. This slag was used as fill dirt at over 100 known locations in Hudson County, including sites in ... trivalent and hexavalent, which occur in a variety of chemical compounds. Serious health effects are linked to exposure to ... and ferrochrome processing (6, 11, 12).

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Controlling Hexavalent Chromium Exposures during ...

Controlling hexavalent chromium levels • Product substitution. Use a less toxic substitute in place of Cr(VI). For example, trivalent chromium is less toxic than Cr(VI). There are a variety of alternatives available that provide similar characteristics to chrome electroplating. •

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Locating and Estimating Sources of Chromium

CHROMIUM L &E. EPA-450/4-84-007G July 1984 Locating and Estimating Air Emissions From Sources of Chromium U.S ENVIRONMENTAL PROTECTION AGENCY ... ferrochrome ..... 43 13 Flow chart for production of chromium-containing basic brick by casting and pressing processes ..... 55 14 Flow chart for production of chromic oxide bricks ...

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Chromium - PubMed

Chromium occurs primarily in the trivalent state (III), which is the most stable form, or in the hexavalent state (VI), which is a strong oxidizing agent. Elemental chromium (0) does not occur naturally on earth. Trivalent chromium (III) is an essential trace metal necessary for the formation of glu

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Journal of Cleaner Production - Oulu

1.2. Relevance of hexavalent chromium Chromium can occur in several oxidation states, but only trivalent chromium, Cr(III), and hexavalent chromium, Cr(VI), are common in near surface environments, while metallic chromium, Cr(0), is mainly produced by human intervention (Motzer and Engineers, 2004; Bartlett, 1991).

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Processes affecting the remediation of chromium ...

May 01, 1991 · Kassem T (2010) Kinetics and thermodynamic treatments of the reduction of hexavalent to trivalent chromium in presence of organic sulphide compounds, Desalination, 10.1016/j.desal.2010.03.011, 258:1-3, (206-218), Online publication date: 1-Aug-2010.

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(PDF) Treatment of Hexavalent Chromium in Chromite Ore ...

Treatment of Hexavalent Chromium in Chromite Ore Processing Solid Waste Using a Mixed Reductant Solution of Ferrous Sulfate and Sodium Dithionite. Environmental Science & Technology, 2005. Chunming Su. Ralph Ludwig. Chunming Su. Ralph Ludwig. Download PDF. Download Full PDF Package. This paper.

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Long-term leaching characterization and geochemical ...

Dec 09, 2019 · Chromium released from the AOD slag was primarily presented as trivalent chromium (Cr(III)). The eluate exhibited low hexavalent chromium (Cr(VI)) concentration. As the L/S ratio increased to 115 L kg-1, the accumulated release quantity of Cr(III) and total chromium per AOD slag mass reached 1549.68 and 1613.67 μg kg-1, respectively.

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Hexavalent Chromium - niehs.nih.gov

May 14, 2020 · Hexavalent chromium is a form of the metallic element chromium. Chromium is a naturally occurring element found in rocks, animals, plants, soil, and volcanic dust and gases. It comes in several different forms, including trivalent chromium and hexavalent chromium. Trivalent chromium is often referred to as chromium (III) and is proposed to be ...

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Erin Brockovich - Wikipedia

The case (Anderson, et al. v. Pacific Gas & Electric, file BCV 00300) alleged contamination of drinking water with hexavalent chromium (also written as "chromium VI", "Cr-VI" or "Cr-6") in the town of Hinkley, near Barstow in southern California.At the center of the case was a facility, the Hinkley compressor station, built in 1952 as a part of a natural-gas pipeline connecting to the San ...

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Chromium: a review of environmental and occupational ...

Europe PMC is an archive of life sciences journal literature. The following topics are covered in this brief review on the environmental and occupational toxicology of chromium: occurrence, production and uses of chromium and chromium compounds; experimental toxicology; chromium toxicity for man; hygienic and ecologic aspects of chromium contamination of the environment.

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In situ bioremediation of hexavalent chromium in presence ...

May 15, 2019 · Stability of chromium in the ferrochrome slag dumps and leachate are affected by pH, redox potential and the presence of other metallic species in the slag. It is desirable to keep chromium in slag dumps in the trivalent [Cr(III)] state because trivalent chromium is 1000 times less toxic to living organisms than the hexavalent form [Cr(VI)].

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Recovery of Chromium from Ferrochrome Slag

Recovery of chromium from ferrochrome slag is 64% by treatment of slag with lime at 973K in solid phase. The soluble chromium ion was extracted with water. The chromium from liquid extract is separated with fly ash based zeolite which has 3000 mmol/gram and it

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Recovery of Chromium from Ferrochrome Slag | Open Access ...

• Recovery of chromium from ferrochrome slag is 64% by treatment of slag with lime at 973K in solid phase. • The soluble chromium ion was extracted with water. • The chromium from liquid extract is separated with fly ash based zeolite which has 3000 mmol/gram and it can be regenerated to recover chromium.

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Hexavalent Chromium Factsheet

Hexavalent Chromium. What is hexavalent chromium? Hexavalent chromium is a form of the metallic element . chromium. Chromium is a naturally occurring element found in rocks, animals, plants, soil, and volcanic dust and gases. It comes in several different forms, including trivalent chromium and hexavalent chromium. Trivalent

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Conversion of Chromium Ore Processing Residue to Chrome

and 1150ºC under an oxidizing environment. Trivalent chromium in chromite ore was oxidized to hexavalent chromium. The highly soluble hexavalent chromium was then removed from the COPR (left over Chromium Ore Processing Residue) leaving un-oxidized trivalent chromium and slow-dissolving hexavalent chromium compounds [Burke et al., 1991].

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Chromium in Environment, Its Toxic Effect from Chromite ...

Jul 06, 2018 · The ferrochrome slag consists mainly of silica, alumina and magnesia, in different phases such as spinel, (MgO·Al 2 O), and fosterite, (MgO·SiO 2), but also of smaller amounts of CaO, chromium and iron oxides, and metal fragments. The chromium content in slag

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(PDF) Utilization of ferrochrome wastes such as ...

Ferrochrome slag (FS) is another residue that is obtained as a solid waste by the smelting process during the production of stainless steel in Ferroalloy industries. ... etc. Trivalent chromium ...

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Case Study: Chromite mining and processing

hexavalent chromium.8 Sources of chromium emissions to air include coal and oil combustion (primarily trivalent), chrome plating (hexavalent) and industrial cooling towers (hexavalent).8 Chromium is removed from the atmosphere by fallout and precipitation over about 10 days.8 Smoking can contribute to chromium levels in indoor air as tobacco

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3. - cfile219.uf.daum.net

Slag is separated from the liquid ferrochrome and tapped into ladles for further processing. ... or trivalent chromium are required in the human body to metabolise lipids and sugar. ... kilns in Europe and North America due to the regulations and costs of disposal of the used bricks which may contain hexavalent chromium as a result of the ...

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Kinetics and pH Dependence of Chromium(VI) Reduction by ...

Apr 29, 1997 · Iron(II) is one of the most important reductants of chromium(VI), a severe, toxic contaminant of natural waters, sediments, and soils. We studied the reaction kinetics between pH 2 and pH 7.2 with UV−VIS and multicomponent fitting, a method without the interference of added reagents. The reaction rate was minimal around pH 4. A rate increase with decreasing pH below 4 is

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Health Consultation - TN

From 1952 to 1980, Chromium Mining and Smelting Corporation produced alloys of ferrochrome, ferrosilicon, and ferromanganese. Chromasco used coke, gravel, chrome ore, and manganese ore as principal raw materials. Although furnace operations ceased in 1980, from 1981 to 1983, the plant operated as a ferrochrome slag concentrator.

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Chromium(III) oxide | Cr2O3 - PubChem

The intestinal absorption of trivalent and hexavalent chromium (Cr) given orally (experiment I) or infused in the intestine (experiment II) was investigated in rats. The nonabsorbable form of chromium ((51)Cr2O3) and water-soluble and more absorbable Na2(51)CrO4 (the hexavalent form of Cr) were compared.Total retention of chromium given orally ranged around 15 percent of the dose, regardless ...

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Magnetic Separation To Make Granulated Slag Less ...

Mar 14, 2020 · The density of the ferrochrome slag is between 2.5- 3g/cm3 and that of ferrochrome 6.8 g/cm3. But slag particles associated with metal droplets shown density between 3

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Biological Reduction of Hexavalent Chromium: A Field Study

trivalent form (Cr3^), but with a minor fraction as hexavalent chromium (Cr6+). Chromium is leached when rainwater percolates through the deposit. The leachate is collected in a pond of approximately 10 000 m3, where the concentration of Cr6+ varies between 5 and 120 mg/L. Currently, excess leachate is evaporated on hot slag, but this is ...

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