Optimization of an Iron Ore Washing Plant

AbstractThe sustainable viability of a mineral enterprise depends on improving the concentrate quality, generating readily salable by-products, improving recovery, throughput, and reduction of unit cost rate and maximize the unit income rate and thereby unit profit rate. Closing down of iron ore mines due to environmental constraints spurred the captive iron ore washing plants to workon a custom plant mode and also recover the values from their slimy tails. This paper enumerates the difficulties faced by a captive iron ore fine washing plant [treating iron ore fines assaying Fe∼58% yielding sands assaying Fe>60%] due to raw material change yielding unsalable sands and discuss the importance of process plant audit for improving the mineral processing plant performance. Based on the base line study, laboratory tests on typical samples followed by short term modifications, retrofitting of downstream slime concentrating wet high intensity magnetic separators and dewatering of products could produce readily salable sinter grade [Fe>60%] and pellet grade[Fe>62.5%] with an overall increase of concentrate yield by 11.5%. Even the previous wash plant tails [which assayed Fe > 45%] may be reprocessed in the retrofitted slime processing VPWHIMS plant. The final tails assayed 38.60% Fe at weight % yield of 28.5. Efforts are on for utilizing the above tails in bricks- tiles manufacture. Also, R&D efforts to concentrate Fe values from above 38.60% Fe tails by Magnetizing roast followed by magnetic separations in bench scale has given encouraging results. Thus auditing not only improved the quality, quantity and rate of production of concentrate but mitigated the problem of tailing disposal. The investments were repaid within a year of operation and unit operating costs reduced by 20% with reference to base line data

Swyer’s syndrome: a rare cause of primary amenorrhoea

This is a rare case of pure gonadal dysgenesis, the exact incidence of the condition is unknown but can be estimated at 1:80 000 births. The patient presented with primary amenorrhoea , after complete evaluation it was diagnosed as Swyer’s syndrome, which is 46,XY complete gonadal dysgenesis (46,XY CGD) characterized by a 46,XY karyotype, normal female external genitalia, completely undeveloped (”streak”) gonads, no sperm production, and presence of normal müllerian structures

Controllability of Matrix Sylvester System and Sylvester Integro-differential System

In the present article, Sylvester matrix first order differential system and matrix first order integro-differential system are studied. A set of sufficient conditions for controllability and complete controllability of the system is presented. As a necessary tool, a variation of parameter formula is developed for the non-linear Sylvester system.Исследованы дифференциальные и интегро-дифференциальные матричные системы Сильвестра первого порядка. Представлен набор достаточных условий управляемости и полной управляемости систем. Как необходимый инструмент для нелинейной системы Сильвестра получена разновидность параметрической формулы.Досліджено диференціальні та інтегро-диференціальні матричні системи Сильвестра першого порядку. Наведено набір достатніх умов керованості та повної керованості систем. Як необхідний інструмент для нелінійної системи Сильвестра отримано різновид параметричної формули

Variational Calculations for 3^3He Impurities on 4^4He Droplets

Variational Monte Carlo method is used to calculate ground state properties of $^4$He droplets, containing 70, 112, 168, 240, 330, and 728 particles. The resulting particle and kinetic energy densities are used as an input in the Feynman-Lekner theory for $^3$He impurities. The kinetic energy density of $^4$He atoms and the energy of the $^3$He surface states are compared with the results of previous phenomenological calculations.Comment: 12 pages, in revtex 3.0, with 5 .ps figure

Pseudogap phase of high-Tc compounds described within the LDA+DMFT+Sigma approach

LDA+DMFT+Sigma_k approach was applied to describe pseudogap phase of several prototype high-Tc compounds e.g. hole doped Bi2212 and LSCO systems and electron doped NCCO and PCCO, demonstrating qualitative difference of the Fermi surfaces (FS) for these systems. Namely for Bi2212 and LSCO the so called "hot-spots" (intersection of a bare FS and AFM Brillouin zone (BZ) boundary), where scattering on pseudogap fluctuations is most intensive were not observed. Instead here we have Fermi arcs with smeared FS close to the BZ boundary. However for NCCO and PCCO "hot-spots" are clearly visible. This qualitative difference is shown to have material specific origin. Good agreement with known ARPES data was demon strated not only for FS maps but also for spectral function maps (quasiparticle bands in cluding lifetime and interaction broadening).Comment: 4 pages, 4 figures, 1 table, SNS2010 proceedings (24-28 May 2010, Shanghai, China

Evidence for the In‐Situ Generation of Plasma Depletion Structures Over the Transition Region of Geomagnetic Low‐Mid Latitude

On a geomagnetic quiet night of October 29, 2018, we captured an observational evidence of the onset of dark band structures within the field-of-view of an all-sky airglow imager operating at 630.0 nm over a geomagnetic low-mid latitude transition region, Hanle, Leh Ladakh. Simultaneous ionosonde observations over New Delhi shows the occurrence of spread-F in the ionograms. Additionally, virtual and peak height indicate vertical upliftment in the F layer altitude and reduction in the ionospheric peak frequency were also observed when the dark band pass through the ionosonde location. All these results confirmed that the observed depletions are indeed associated with ionospheric F region plasma irregularities. The rate of total electron content index (ROTI) indicates the absence of plasma bubble activities over the equatorial/low latitude region which confirms that the observed event is a mid-latitude plasma depletion. Our calculations reveal that the growth time of the plasma depletion is ∼2 h if one considers only the Perkins instability mechanism. This is not consistent with the present observations as the plasma depletion developed within ∼25 min. By invoking possible Es layer instabilities and associated E-F region coupling, we show that the growth rate increases roughly by an order of magnitude. This strongly suggests that the Cosgrove and Tsunoda mechanism may be simultaneously operational in this case. Furthermore, it is also suggested that reduced F region flux-tube integrated conductivity in the southern part of onset region created conducive background conditions for the growth of the plasma depletion on this night

Density functional calculations for 4He droplets

A novel density functional, which accounts correctly for the equation of state, the static response function and the phonon-roton dispersion in bulk liquid helium, is used to predict static and dynamic properties of helium droplets. The static density profile is found to exhibit significant oscillations, which are accompanied by deviations of the evaporation energy from a liquid drop behaviour in the case of small droplets. The connection between such oscillations and the structure of the static response function in the liquid is explicitly discussed. The energy and the wave function of excited states are then calculated in the framework of time dependent density functional theory. The new functional, which contains backflow-like effects, is expected to yield quantitatively correct predictions for the excitation spectrum also in the roton wave-length range.Comment: 15 pages, REVTEX, 10 figures available upon request or at http://anubis.science.unitn.it/~dalfovo/papers/papers.htm