قائمة الطعام
In the present study, the tailings generated from a chromite ore beneficiary plant in India were investigated through a pyro-metallurgical route. The initial characterization confirmed the presence of nickel (0.5–0.9% Ni) in the ore, which led to the interest in smelting the ore to obtain nickel in the metal.
Abstract: Understanding the mineralogical characterization of chromium ore processing residue (COPR) is the basis of soil remediation which is polluted by chromium. Some techniques, such as X-ray fluorescence (XRF), X-ray diffraction technology (XRD) and environmental scanning electron microscopy (ESEM), were …
Chromium (Cr)-hydrogarnet (Ca 3 Al 2 [CrO 4] 0.12 [O 4 H 4] 2.88(s)) is a critical host of hexavalent chromium [Cr(VI)] in cementitious and alkaline solids such as chromium ore processing residue (COPR).Leaching from COPR often results in Cr(VI) contamination of soil and groundwater. Although Cr-hydrogarnet has been synthesized …
A characterization study of chromite ore from South Africa was conducted using bulk assays, X-ray diffraction, optical, scanning electron microscopy (SEM), automated electron probe microanalysis (EPMA) and quantitative evaluation of mineral by scanning electron microscopy (QEMSCAN) mineralogical techniques, and quantitative …
Figure 1—Chrome ore production and applications (ICDA, 2015) Process optimization of a chrome ore gra vity concentration plant for sustainable de velopment. 263 . The Journal of the Southern ...
Abstract: A characterization study of chromite ore from South Africa was conducted using bulk assays, X-ray diffraction, optical, scanning electron microscopy …
This is a consequence of the current lack of standardized and automated methods to characterize particulate materials in 3D. Here, we apply a workflow to characterize a crushed chromite ore with nine particle size classes below 1 mm using X …
Purpose Wastes of unknown composition derived from the production of trivalent chromium (Cr(III)) salts used as tanning agents are deposited in the area of Kanpur, India. The questions of whether these samples are chromite ore processing residue (COPR) and whether Cr occurs in its toxic hexavalent form (Cr(VI)) arise. …
Chromium ore processing residue (COPR) still contains considerable chromate which can lead to groundwater contamination at uncontrolled dumpsites. ... The characterization results of DT-COPR also ...
1. Introduction. Chromium ore processing residue (COPR) is the solid waste obtained from the production of chromium metal and chromium salt, mainly from the process of preparing sodium dichromate by calcium roasting method (Li et al., 2019; Senko et al., 2014; Zhang et al., 2009).For every 1 t of chromium salt and metal, 2–3 t and …
The present investigation focuses on quantitative mineralogy, elemental deportment, and locking-liberation characteristics of the beneficiation of tailings from a …
Chromium (Cr) is widely applied in industry, such as in tanning, electroplating, ore refining, wood preservation and pigmentation 4,5, which inevitably results in the discharge of Cr-containing ...
The important criteria for classifying the chromite ores into dif-ferent industrial grades, such as metallurgical (low- and high-carbon ferrochrome, silico-ferrochrome, and charge …
The leaching behavior of hexavalent chromium (Cr(VI)) and major metal elements relevant to Cr(VI) leaching from chromite ore processing residue (COPR) to HNO3 are investigated by batch leaching tests.
A characterization study of chromite ore from South Africa was conducted using bulk assays, X-ray diffraction, optical, scanning electron microscopy (SEM), automated electron probe microanalysis …
1. Introduction. Chromite ore processing residue (COPR) is a waste of the chromate (CrO 4 2−) extraction roasting process and is still deposited in the environment in large amounts in some newly industrialized countries.In the past, the waste has been produced in several industrial areas, such as Glasgow, Scotland (Farmer et al., 1999) …
Idiomorphic chromite is the only ore mineral appearing in economic quantities. The average content of the ore is 26% Cr 2 O 3 and the Cr/Fe ratio is 1.55. The Kemi chromium mine is an open-pit mine with a waste rock to ore ratio of 5.5:1. At Kemi, the ore from the mine contains 11% iron and 25.5% Cr 2 O 3.
For understanding both the environmental behavior and developing remediation treatments for chromium ore processing residue (COPR) it is important to identify all the potentially soluble sources of Cr(VI). ... Chemical and mineralogical characterization of chromite ore processing residue from two recent Indian disposal …
Modified date: 23/04/2023. Chromium (Cr) ore refers to a natural mineral deposit that contains chromium in its raw form. Chromium is a chemical element with the symbol Cr and atomic number 24. It is a hard, lustrous, …
Batch leaching studies on chromite ore processing residue (COPR) were performed using acids to investigate leaching of hexavalent chromium, Cr(VI), with respect to particle size, reaction time ...
Characterization and Beneficiation of Anka Chromite Ore 100 90 80 70 60 50 40 30 20 10 0 149 7.0 6.0 5.0 4.0 3.0 Cr:Fe Ratio % Cr Recovery Vol.6, No.2 2.0 % Cr Recov Cr:Fe 1.0 0.0 70 100 120 170 Sieve Size 200 250 Figure 2: Variation of Chromium Recovery and Cr:Fe ratio with particle size.
Abstract Chromite ore processing residue (COPR) is a waste derived from the chromate extraction from roasted ores and is deposited in some countries in landfills. ... 2.1 Study site, sampling, and sample characterization. The COPR were sampled in 2011 after the monsoon season from two abandoned, illegally operated landfills in Rania …
Accurate and comprehensive characterization of ore particles carrying the critical elements is crucial to guide mineral process optimization. ... Outokumpu's Kemi chrome mine is the biggest underground mine in Finland and the only chromium producer in European Union. The proven and probable Mineral Reserves of the Kemi Mine are …
The geoenvironmental characterization of COPR at two deposition sites (New Jersey and Maryland) included geotechnical, chemical, mineralogical, and leaching analyses of three main chromite ore processing residue (COPR) types [gray-black (GB), hard brown (HB), clayey (C)]. Quantitative mineralogical analyses were instrumental in the delineation of …
Abstract. This paper summarizes the characteristics of chromite ore processing residue (COPR) in terms of their chemical compositions, phases, and …
A detailed description of ore is given in the characterization section. 2.2 Methods 2.2.1 Characterization. The following characterization was completed for limonitic chromite overburden collected from Sukinda, Odisha. After collecting the sample, the sample was oven-dried to evaporate the moisture content in the ore sample. …
Through kinetic, characterization, and DFT analyses, the effective remediation of Cr(VI) in COPR by CS is a combination of adsorption and reduction. ... Electrokinetic removal of chromium from chromite ore-processing residue using graphite particle-supported nanoscale zero-valent iron as the three-dimensional electrode.
Keywords: Ultra-fine chromite tailings, Magnetic separation, Characterization, Chromite 1. Introduction Chromite recoveries is a major concern particularly in processing of finely disseminated ores due to its inherent complexities. The gravity separation process is the main beneficiation process used to recover chromite mineral. However,
2.1 Chromium in Steel Industry. The only important ore mineral of chromium is the chromite – FeO.Cr2O3 (68% Cr2O3, 32% FeO) which crystallizes in the isometric system. The hardness value is 5.5 ...
The speciation and distribution of Cr(VI) in the solid phase was investigated for two types of chromite ore processing residue (COPR) found at two deposition sites in the United States: gray-black (GB) granular and hard brown (HB) cemented COPR. COPR chemistry and mineralogy were investigated using micro-X-ray absorption spectroscopy and micro …
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