Developments in Phosphate-rock beneficiation and the problems with Indian phosphorites

Phosphate-rock or more precisely the phosphorites form the repository of phosphate supply for the fertilizer industry for manufacture of elemental phosphorus, phospho- ric acid and innumerable alkali phosphates. It has been universally agreed that phosphorites have some kind of sedimentary marine origin, the source of phosphorous being of organic and/or inorganic origin(1). The principal phos-phate mineral occuring in these deposits is referred by its generic designation as collophane (2), a carbonate bearing variety apatite, whose formula is approximately Cato ( PO4 CO3.H20 with a little of F. It is porous and crypto-crystalline, occuring as compact nodules or pellets as disseminations in calcitic or qurtzitic sedimentary rocks along with clay, sericite, silt, chert, free carbon and invariably associated with a little uranium (0.002 to 0.008% U308 e). The typical apatite [Ca 6(PO4)3 F] is cry-stalline and occurs usually in igneous and metamorphic rocks, pegmatites, granites, and schists. Its chemical composition is more defined and constant compared to the collophane of sedimentary origin. Fertilizer industry, though uses phosphate from both sources; the super phos-phate manufacturers prefer phosphate-concentrates from phosphorite because of the ease with which collophane goes into solution with sulphuric acid. The physical charac-teristics of collophane also have bearing on its flota-bility

Greener One-pot Synthesis of Chromeno Oxazin and Oxazin Quinoline Derivatives and their Antibacterial Activity

An efficient green method for the synthesis of oxazino quinoline-2-amine derivatives, oxazino quinoline derivatives and chromeno oxazin-5-one derivatives have been synthesized through cyclization of aromatic aldehyde, ammonium acetate, substituted amides and 8-hydroxy-quinoline or 4-hydroxy coumarin by one-pot condensation method is described. The synthesized compounds are characterized by FT-IR, 1H NMR and MASS spectral techniques and are screened further for biological activities against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis using cup plate method and disc diffusion method

A NEW ALGORITHM FOR HIGH DENSITY IMPULSE NOISE REDUCTION USING UNSYMMETRIC TRIMMED MEDIAN FILTER

ABSTRACT The filter, Direction index based unsymmetric trimmed median (DIBUTM) filter consists of two steps. In the first step, the detection of impulse corrupted pixels is done based on direction index method. In the second step, the corrupted pixels that are detected using the direction index are filtered using unsymmetric trimmed median filter. It is a technique in which only the noisy pixels are replaced using the concept of trimming, a method in which the noisy pixel values are removed from the selected window to recover the original value of the processing pixel value. The proposed algorithm offers better value of Mean square error (MSE) and Peak signal to noise Ratio (PSNR) compared to other filters like standard median, Center weighted median (CWM) and Pixel wise median of absolute deviations from the median (PWMAD) filters

A study on Variations of pulmonary function tests in different stages of pregnancy

Pulmonary status of women during pregnancy is of great importance. Their efficacy should be assessed for both maternal & fetal well being. In this study, the respiratory functions in various stages of pregnancy along with postnatal status were monitored & compared. Mini Wright Peak Flow Meter (PFM), which is highly effective in assessing the lung functions of a person, has been selected as a means of assessing pulmonary functions of a pregnant woman. Graphs or tables are available of predicted normal values based on person's gender, age & height. We have tested the PEFR throughout pregnancy from 6 weeks onwards till puerperium and effect of mode of delivery and puerperium on it. We have taken study sample size of 300 .It is divided as 60 subjects in 5 groups like Non pregnant, First trimester, Second trimester, Third trimester, Postnatal period till 30 days after delivery in medical teaching institute. Predicted PEFR which depends on age & height of patient is calculated by referring to Wright's scale. In 1st & 2nd trimester the lung functions are relatively normal, while in 3rd trimester the pulmonary function gets compromised with decrease in PEFR, PEFR is not affected by parity and in all modes of delivery it is significantly low, more after caesarean section ( post operative pain might be responsible) and by the end of one month after delivery, the lung functions return back to normal

Phosphorite deposits in India and their beneficiation

The total annual requirements of phosphate rock by the end of fourth plan are expected to be 4.5 million tonnes. India imported in 1967 phosphate rock costing Rs.96 millions in foreign exchange. The intensive search by GSI for new sources has revealed phosphorite deposits at Kanpur, Dakan-kotra, Jhamar-Kotra, Maton, etc., in Rajasthan and at several other localities in Uttar Pradesh and Himachal Pradesh. India has reserves of phosphate rock, according to available data, of about 220 million tonnes as of 1969. Typical chemical analyses of some world's major deposits are compared with that of Indian phosphorites, from the fertilizer manufacturing point of view. Majority of the Indian deposits are below acid-grade (<31.5% P2O5) and are high in the deleterious contents like Fe2O3, Al2O3, MgO and free carbon, needing beneficiation. Suitable methods of beneficiation for Mussourie, Maldeota and Kanpur deposits have been proposed for obtaining acceptable acid grade concentrates. Mussourie rock which has cherty and quartzitic tabling and oleic acid-flotations. But in the case of Rajasthan rocks having calcite gangue, suitable calcination methods have been developed. From a Kanpur rock assaying 16.4% P2O5, concentrates assaying around 34% P2O5 were obtained with good recovery. This concentrate met with the specifications of an acid-grade material. Maldeota rock containing calcite gangue plus some pyrite was found to be not easily amenable to beneficiation. (Ch. Rambabu and K.K. Majumdar, Ore dressing section, Metallurgy Division, Babha Atomic Research Centre, Trombay-85

Three-component coupling of alkynes, Baylis-Hillman adducts and sodium azide: a new synthesis of substituted triazoles

A three-component coupling was used to prepare a series of 1,4-disubstituted-1,2,3-triazoles from the corresponding acetylated Baylis-Hillman adducts, sodium azide and terminal alkynes. This one-pot reaction further increases the efficacy of 'Click' synthesis and diversifies the preparation of multi-functional 1,4-disubstituted-1,2,3-triazoles. Graphical abstract A three-component coupling was used to prepare a series of 1,4-disubstituted-1,2,3-triazoles from the corresponding acetylated Baylis-Hillman adducts, sodium azide and terminal alkynes. This one-pot reaction further increases the efficacy of 'Click' synthesis and diversifies the preparation of multi-functional 1,4-disubstituted-1,2,3-triazoles

Total synthesis of aculeatins A and B via a tethered oxa-Michael approach

A stereocontrolled total synthesis of aculeatins A and B has been achieved in eight steps and in 15% overall yield. The key feature of this synthetic approach is the application of a Marouka allylation and tethered intramolecular oxa-Michael reaction to install the required stereocentres on the tetrahydropyran ring