المنتجات الساخنة
Sufficient extraction of Cr from chromium ore
网页2022年10月15日 Chromium ore processing residue (COPR) is a hazardous waste generated during the production of chromate. Currently, approximately 10% of Cr 2 O 3 cannot be extracted after chromite sodium roasting and remains in COPR, wasting
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A cleaner method for preparation of chromium oxide from
网页2022年2月1日 The concentration of total Cr was detected by a spectrophotometer at 540 nm using the oxidation of potassium permanganate and 1,5-diphenylcabohydrazide
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Chrome ore beneficiation challengesopportunities A
网页2011年4月1日 Chromite varies widely in composition according to the chemical formula (Mg, Fe +2) (Cr, Al, Fe +3) 2 O 4. Chromium occurs as chromium spinel, a complex
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Electrochemical enhanced oxidative decomposition of
网页2014年3月1日 Thus the effect of slot current density (SCD) on extraction of chromium from the chromite was initially investigated under the following standard conditions: reaction
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Characterization of Chromium (III) Compounds Isolated
网页2018年9月20日 Quantitative analyses of chromium from the isolated precipitates of SARM 131, UG2 chromite ore, and Merensky Reef mineral ore indicated chromium contents of
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Chromite ore beneficiation: prospects and challenges
网页2023年1月1日 The chrome–iron ratio should be above 1 to 2.5 for the metallurgical grade. Chromium is an important metal, however, the pure metal is neither used by the stainless
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Leaching of hexavalent chromium from young chromite
网页2020年3月18日 Chromium (VI) concentrations in the effluent were determined spectrophotometrically at 540 nm (Lambda 25 UV/Vis spectrometer, PerkinElmer) after
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Extraction of Chromium from Chromite Ore
网页2017年7月20日 The average grade of the metallurgical chromite ore was 43.4 pct Cr2O3, with 52 pct of the ore having a chromium-to-iron ratio of 3:1 or over, 17.6 pct having a ratio between 2:1 and 3:1, and 30.4 pct having
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Chromium Ore an overview ScienceDirect Topics
网页Chromium is the 21st most abundant element in the earth’s crust with an average concentration of 100 μ g/g. Although approximately 40 chromium-containing minerals are
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Leaching mechanisms of Cr (VI) from chromite ore
网页2008年10月23日 The concentration levels for total chromium (Cr) and Cr (VI) in the leaching solutions were virtually identical for pH values >5. For pH values <5, the
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Electrokinetic removal of chromium from chromite ore
网页2018年10月15日 1. Introduction. Chromium, which exists mainly in trivalent and hexavalent oxidation states, has been commonly identified as a contaminant [1], [2].Hexavalent chromium (i.e., Cr(VI)) is considered one of the priority controlled environmental pollutants in China and is known to be highly soluble, mobile, toxic and carcinogenic [3].Chromite ore
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Speciation and spatial distribution of Cr in chromite ore
网页2017年3月13日 The total Cr, Cr (VI) and chromium species were investigated. Results indicated the concentration of total Cr was between 110.5 and 21,774 mg/kg, and the concentration of Cr (VI) was between 0.1 and 1075 mg/kg.
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Chrome ore beneficiation challengesopportunities A
网页2011年4月1日 Most of the chromite reserves in the world are concentrated in Africa and Asia followed by Europe, Australia and Brazil. 2. Sources of chromite Chromium ore occurs exclusively in rocks formed by the intrusion and solidification of molten lava or magma which is very rich in the heavy, iron containing minerals such as pyroxenes and olivines.
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Chromite ore beneficiation: prospects and challenges
网页2023年1月1日 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.
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Mineral processing: leaching process of chromium and
网页2019年5月6日 Chromite roast concentrates a reasonable percentage of approximately 45% with an overall 43% Cr 2 O 3. PGMs in the original ore was petitioned and ends up in Na 2 CrO 4 liquor whereas the liquor and a solid roast residues contained the rest of chromite components (Fe 2 O 3, Al 2 O 3, others).
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A novel reductive alkali roasting of chromite ores for
网页2021年2月5日 The apparent difference in the fraction of alloy phase formed in each ore is attributed to the concentration of iron and chromium oxides and silica, discussed above in Table 3. During reduction reaction, the complex silicates present in chromite combine with alkali above 1000 °C and form a low-melting viscous liquid ( Tathavadkar et al., 2005
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Green metallurgical processing of chromite ScienceDirect
网页2006年8月1日 When the ratio of KOH to ore is 4:1, the influence of reaction temperature on the conversion of chromium to chromate over the temperature range of 260–350 °C is shown in Fig. 3. The optimal parameters for chromium extraction were obtained via applying the shrinking core kinetic model to the experimental results.
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Leaching mechanisms of Cr (VI) from chromite ore
网页2008年10月23日 The concentration levels for total chromium (Cr) and Cr (VI) in the leaching solutions were virtually identical for pH values >5. For pH values <5, the concentration of total Cr exceeded that of Cr (VI) with the difference between the two attributed to Cr (III).
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SD0000029 EVALUATION OF CHROMFTE ORE AND THE
网页2004年12月22日 Chromite samples were analyzed using gamma ray spectroscopy in order to estimate the levels of radioactive elements present. It was found that the concentrations of 2?2Th and40K range from 7.62 to 10.98 Bq/kg and 47.38 to
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Concentration of chromite from the Kempersayi deposit
网页The concentration of chromite ore from the Kempersayi deposit according to the above procedure permits a decrease of SiO 2 (from 6.1 to 2.5% and CaO (from 1.3 to 0. 7%) and an increase of Cr 2 O 3 (from 51.7–52.3 to 55.6%). The yield of the concentrate amounted to 82.8% and the extraction of chromium oxide to 89.5%.
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(PDF) Process optimization of a chrome ore gravity
网页2020年4月1日 Existing technologies for chrome concentration like spirals, shaking tables, magnets and flotation have been re-purposed to process chrome slimes with varied success (Çiçek et al. 1998;Dogan et...
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Leaching mechanisms of Cr (VI) from chromite ore
网页2008年10月23日 The concentration levels for total chromium (Cr) and Cr (VI) in the leaching solutions were virtually identical for pH values >5. For pH values <5, the concentration of total Cr exceeded that of Cr (VI) with the difference between the two attributed to Cr (III).
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SD0000029 EVALUATION OF CHROMFTE ORE AND THE
网页2004年12月22日 Chromite samples were analyzed using gamma ray spectroscopy in order to estimate the levels of radioactive elements present. It was found that the concentrations of 2?2Th and40K range from 7.62 to 10.98 Bq/kg and 47.38 to
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A Process Mineralogical Evaluation of Chromite at the
网页2020年8月12日 Three metallurgical samples weighing 4 kg each were representatively collected from each chrome plant, these being the feed (F), concentrate (C) and tailings (T) for a total of six samples for the PCMZ disseminated chromite ore type and the massive chromitite (MCHR) ore type.
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Improving the Quality of Ferruginous Chromite
网页The PSD of the chromite concentrates is given in Figure 1. It is observed that 80% of the particles are below 715, 241, and 62 µm, respectively, for the coarse, fine, and ultrafine concentrates. Similarly, 50% of the particles are less than 345, 120, and 45µm, respectively, for the coarse, fine, and ultrafine concentrates.
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Assessing chromite ore processing residue (COPR) waste
网页2019年7月24日 The depth of the wells is varying from a minimum of 4 m to a maximum of 175 m. Estimated chromium (VI) concentration in the water samples of the region was found to be above the permissible limits (i.e., above 0.005 mg/l) which indicated the presence of contaminated groundwater (Table 1 ).
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Characterization of Chromite Ore Processing Residue
网页2007年10月1日 The manual/dry magnetic separation was able to concentrate iron and chromium oxides in COPR from the former group to 34.9–40.9 and 6.3–8.6%, respectively. The morphology of COPR from a sample containing high iron content revealed that COPR is mainly the remnant of chromite ore.
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Cleaner Production of Chromium Oxide from Low Fe(II)
网页Experimental results indicate that the sulfuric acid concentration (70–90%), dichromic acid/chromite ratio (0.08–0.12), and processing temperature (160–200 °C) have influence on the decomposition of chromite. It can be seen in Table 2 that the extraction yield of Cr falls in the range 50–80%, and it is always lower than that of Fe.
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Chromium Pollution in European Water, Sources, Health
网页2020年7月28日 The main source of Cr (III) in the environment is a natural one and it is related to chromite ore (FeCr 2 O 4) [ 1, 26 ]. This mineral present in mafic and ultramafic rocks is a complex of magnesium, iron, aluminium, and chromium in varying proportions, depending on the deposit [ 27, 28, 29, 30, 31 ].
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Novel Method for Producing Chromic Oxide without
网页2021年9月8日 In this novel process, 97% of the total Cr—in the form of chromium sulfate (Cr 2 (SO 4) 3 )—and Fe are leached from ferrochrome alloy using sulfuric acid. The concentration of Fe in the Cr 2 (SO 4) 3 solution can be reduced to 2 mg/L after precipitating with oxalic acid and extracting with di (2-ethylhexyl) phosphate.
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