Quantitative mineralogical characterization of chrome ore beneficiation plant tailing and its beneficiated products

Mineralogical characterization and liberation of valuable minerals are primary concerns in mineral processing industries. The present investigation focuses on quantitative mineralogy, elemental deportment, and locking-liberation characteristics of the beneficiation of tailings from a chrome ore beneficiation plant in the Sukinda region, Odisha; methods used for the study of the beneficiated tailings are QEMSCAN®, X-ray diffraction (XRD), and mineral chemistry by a scanning electron microscope equipped with an energy-dispersive spectrometer (SEM-EDS). The tailing sample was fine grained (69.48wt% below 45 μm size), containing 20.25wt% Cr₂O₃ and 39.19wt% Fe₂O₃, with a Cr:Fe mass ratio of 0.51. Mineralogical investigations using QEMSCAN studies revealed that chromite, goethite, and gibbsite are the dominant mineral phases with minor amounts of hematite, kaolinite, and quartz. The sample contained 34.22wt% chromite, and chromite liberation is more than 80% for grains smaller than 250 μm in size. Based on these results, it was predicted that liberated chromite and high-grade middling chromite particles could be separated from the gangue by various concentration techniques. The tailing sample was beneficiated by hydrocyclone, tabling, wet high-intensity magnetic separation (WHIMS), and flotation in order to recover the chromite. A chromite concentrate with 45.29wt% Cr₂O₃ and a Cr:Fe mass ratio of 1.85 can be produced from these low-grade chromite ore beneficiation plant rejects.     

Development of carbon composite iron ore micropellets by using the microfines of iron ore and carbon-bearing materials in iron making

Iron ore microfines and concentrate have very limited uses in sintering processes. They are used in pelletization; however, this process is cost intensive. Furthermore, the microfines of non-coking coal and other carbon-bearing materials, e.g., blast-furnace flue dust (BFD) and coke fines, are not used extensively in the metallurgical industry because of operational difficulties and handling problems. In the present work, to utilize these microfines, coal composite iron oxide micropellets (2-6 mm in size) were produced through an innovative technique in which lime and molasses were used as binding materials in the micropellets. The micropellets were subsequently treated with CO₂ or the industrial waste gas to induce the chemical bond formation. The results show that, at a very high carbon level of 22wt% (38wt% coal), the cold crushing strength and abrasion index of the micropellets are 2.5-3 kg/cm2 and 5wt%-9wt%, respectively; these values indicate that the pellets are suitable for cold handling. The developed micropellets have strong potential as a heat source in smelting reduction in iron making and sintering to reduce coke breeze. The micropellets produced with BFD and coke fines (8wt%-12wt%) were used in iron ore sintering and were observed to reduce the coke breeze consumption by 3%-4%. The quality of the produced sinter was at par with that of the conventional blast-furnace sinter.     

Magnetic and flotation studies of banded hematite quartzite (BHQ) ore for the production of pellet grade concentrate

To identify and establish beneficiation techniques for banded hematite quartzite (BHQ) iron ore, a comprehensive research on BHQ ore treatment was carried out. The BHQ ore was assayed as 38.9wt% Fe, 42.5wt% SiO₂, and 1.0wt% Al₂O₃. In this ore, hematite and quartz are present as the major mineral phases where goethite, martite, and magnetite are present in small amounts. The liberation of hematite particles can be enhanced to about 82% by reducing the particle size to below 63 μm. The rejection of silica particles can be obtained by magnetic and flotation separation techniques. Overall, the BHQ ore can be enriched to 65.3wt% Fe at 61.9% iron recovery. A flowsheet has been suggested for the commercial exploitation of the BHQ ore.     

Relationship between the microstructure and properties of thermomechanically processed Fe-17Mn and Fe-17Mn-3Al steels

Two austenitic Mn steels(Fe-17 Mn and Fe-17 Mn-3 Al(wt%, so as the follows)) were subjected to thermomechanical processing(TMP) consisting of forging followed by solutionization and hot rolling. The rolled samples were annealed at 650 and 800°C to relieve the internal stress and to induce recrystallization. The application of TMP and heat treatment to the Fe-17 Mn/Fe-17 Mn-3 Al steels refined the austenite grain size from 169 μm in the as-solutionized state to 9–13 μm, resulting in a substantial increase in hardness from HV 213 to HV 410 for the Fe-17 Mn steel and from HV 210 to HV 387 for the Fe-17 Mn-3 Al steel. The elastic modulus values, as evaluated by the nanoindentation technique, increased from(175 ± 11) to(220 ± 12) GPa and from(163 ± 15) to(205 ± 13) GPa for the Fe-17 Mn and Fe-17 Mn-3 Al steels, respectively. The impact energy of the thermomechanically processed austenitic Mn steels was lower than that of the steels in their as-solutionized state. The addition of Al to the Fe-17 Mn steel decreased the hardness and elastic modulus but increased the impact energy.     

Essential role for the peroxiredoxin Prdx1 in erythrocyte antioxidant defence and tumour suppression

Reactive oxygen species are involved in many cellular metabolic and signalling processes and are thought to have a role in disease, particularly in carcinogenesis and ageing. We have generated mice with targeted inactivation of Prdx1, a member of the peroxiredoxin family of antioxidant enzymes. Here we show that mice lacking Prdx1 are viable and fertile but have a shortened lifespan owing to the development beginning at about 9 months of severe haemolytic anaemia and several malignant cancers, both of which are also observed at increased frequency in heterozygotes. The haemolytic anaemia is characterized by an increase in erythrocyte reactive oxygen species, leading to protein oxidation, haemoglobin instability, Heinz body formation and decreased erythrocyte lifespan. The malignancies include lymphomas, sarcomas and carcinomas, and are frequently associated with loss of Prdx1 expression in heterozygotes, which suggests that this protein functions as a tumour suppressor. Prdx1-deficient fibroblasts show decreased proliferation and increased sensitivity to oxidative DNA damage, whereas Prdx1-null mice have abnormalities in numbers, phenotype and function of natural killer cells. Our results implicate Prdx1 as an important defence against oxidants in ageing mice.     

Inhibitory effects of flavonoids on several venom hyaluronidases.

In vitro studies showed that the flavonoid aglycones apigenin, luteolin and kaempferol inhibited the hyaluronidase activity of five different venoms dose-dependently. They were also able to delay the venom action when injected into mice. Naringenin, catechin and flavonoid glycosides had no effect. The flavonoids with unsubstituted hydroxyl groups at C-positions 5, 7 and 4', a double bond between carbons 2 and 3, as well as a ketone group at position 4, exhibited potent inhibitory actions on the venom hyaluronidases.     

Mutation of PAX9 is associated with oligodontia

Pheromones elicit specific behavioural responses and physiological alterations in recipients of the same species. In mammals, these chemical signals are recognized within the nasal cavity by sensory neurons that express pheromone receptors. In rodents, these receptors are thought to be represented by two large multigene families, comprising the V1r and V2r genes, which encode seven-transmembrane proteins. Although pheromonal effects have been demonstrated in humans, V1R or V2R counterparts of the rodent genes have yet to be characterized.     

Lethal effect of electrolysis on nematodes (Meloidogyne incognita)

Summary Electrolysis of salt solutions produces mortality of a plant-parasitic nematodeMeloidogyne incognita. The mortality depends on the nature and amount of the, products of electrochemical reactions and is enhanced in presence of Cu-electrodes. Application of magnetic fields on electric fields alters nematode mortality in ferro-magnetic electrolytes.     

Antifungal activity of some constituents ofMurraya koenigii spreng

Zusammenfassung Es wird über die antifungale Wirksamkeit der Murrayanine, Girinimbine und Mahanimbine, drei ausMurraya koenigii Spreng. isolierte Carbazolderivate, berichtet.