Modified hydrocycloning for effective elimination of stubborn slimes

The present paper deals with the skillful exploitation of the extremely high shear fields inside a hydrocyclone to effectively eliminate a sticky slime from a phosphate ore before beneficiating the coarser fraction using con¬ventional mineral processing techniques. Earlier studies on samples of the same ore at NML and abroad established that it was necessary to pass the ore through a series of three stages of desliming, each consisting of a step of rigorous attrition scrubbing followed by hydrocycloning, for effective elimination of the slime. With the new approach,by innovative modifica¬tions on the standard hydrocyclone design, it was possible to eliminate all the stages of attrition scrubbing while minimising the stages of hydrocycloning. It could be established that the modified technique not only yielded concentrate of grade comparable to that obtained by employ¬ing the earlier more complex flowsheet, it also improved the P205 recovery

Salvaging the values from the rejects of a by-product recovery plant

Two samples of table tailings (-147 pm and -74 pm in size) from refrac¬tory linings of the precious metal recovery (PMR) plant of Indian Copper Complex (ICC), Ghatshila were received to study the possbility to re¬cover residual values of precious metals from them. Analyses, as reported by ICC, were 0.021% Au and 0.39% Ag for the -147 pm sample and 0.023% Au and 0.47%Ag for the -74 pm sample. Multi-Gravity Separator (MGS) studies, with varying design and operating variables, showed three fold upgradation - assay of Au improved from 0.023% to 0.076% and assay of Ag improved from 0.47% to 1.53%. The -74 pm sample yielded better results with MGS than the -147 pm sample

Gravity separation at variable 'g' for management of mineral wastes and pollution

The treatment of mineral wastes in the form of slimes and its utilisation, for management of pollution and conservation of mineral wealth, have become very important now-a-days. Multi Gravity Separator (MGS) is the latest inclusion to various gravity separation machines developed far the treatment offines and ultrafines. In this paper, results of recent studies carried out at NML with MGS using slimes of chromite ore, iron ore, phosphatic soil etc. are discussed to evaluate the effectiveness of the equipment for the treatment of slimes. In most of the cases, three to four fold upgradations have been achieved even at very fine sizes

On the Long Lasting “C‐Type” Structures in the Sodium Lidargram: The Lifetime of Kelvin‐Helmholtz Billows in the Mesosphere and Lower Thermosphere Region

In order to understand the characteristics of long‐lasting “C‐type” structure in the Sodium (Na) lidargram, six cases from different observational locations have been analyzed. The Na lidargram, collected from low‐, middle‐, and high‐latitude sites, show long lifetime of the C‐type structures which is believed to be the manifestation of Kelvin‐Helmholtz (KH) billows in the Mesosphere and Lower Thermosphere (MLT) region. In order to explore the characteristics of the long‐lasting C‐type structures, the altitude profile of square of Brunt‐Väisälä frequency in the MLT region has been derived using the temperature profile collected from the Na lidar instruments and the SABER instrument onboard TIMED satellite. It is found to be positive in the C‐type structure region for all the six cases which indicates that the regions are convectively stable. Simultaneous wind measurements, which allowed us to calculate the Richardson numbers and Reynolds numbers for three cases, suggest that the regions where the C‐type structure appeared were dynamically stable and nonturbulent. This paper brings out a hypothesis wherein the low temperature can increase the magnitude of the Prandtl number and convectively stable atmospheric region can cause the magnitude of Reynolds number to decrease. As a consequence, the remnant of previously generated KH billows in nearly “frozen‐in” condition can be advected through this conducive region to a different location by the background wind where they can sustain for a long time without much deformation. These long‐lived KH billows in the MLT region will eventually manifest the long‐lasting C‐type structures in the Na lidargram

The Ionospheric Impact of an ICME-Driven Sheath Region Over Indian and American Sectors in the Absence of a Typical Geomagnetic Storm

On 13 April 2013, the ACE spacecraft detected arrival of an interplanetary shock at 2250 UT, which is followed by the passage of the sheath region of an interplanetary coronal mass ejection (ICME) for a prolonged (18‐hr) period. The polarity of interplanetary magnetic field Bz was northward inside the magnetic cloud region of the ICME. The ring current (SYM‐H) index did not go below −7 nT during this event suggesting the absence of a typical geomagnetic storm. The responses of the global ionospheric electric field associated with the passage of the ICME sheath region have been investigated using incoherent scatter radar measurements of Jicamarca and Arecibo (postmidnight sector) along with the variations of equatorial electrojet strength over India (day sector). It is found that westward and eastward prompt penetration (PP) electric fields affected ionosphere over Jicamarca/Arecibo and Indian sectors, respectively, during 0545–0800 UT. The polarities of the PP electric field perturbations over the day/night sectors are consistent with model predictions. In fact, DP2‐type electric field perturbations with ∼40‐min periodicity are found to affect the ionosphere over both the sectors for about 2.25 hr during the passage of the ICME sheath region. This result shows that SYM‐H index may not capture the full geoeffectivness of the ICME sheath‐driven storms and suggests that the PP electric field perturbations should be evaluated for geoeffectiveness of ICME when the polarity of interplanetary magnetic field Bz is northward inside the magnetic cloud region of the ICME

Mutation D816V Alters the Internal Structure and Dynamics of c-KIT Receptor Cytoplasmic Region: Implications for Dimerization and Activation Mechanisms

The type III receptor tyrosine kinase (RTK) KIT plays a crucial role in the transmission of cellular signals through phosphorylation events that are associated with a switching of the protein conformation between inactive and active states. D816V KIT mutation is associated with various pathologies including mastocytosis and cancers. D816V-mutated KIT is constitutively active, and resistant to treatment with the anti-cancer drug Imatinib. To elucidate the activating molecular mechanism of this mutation, we applied a multi-approach procedure combining molecular dynamics (MD) simulations, normal modes analysis (NMA) and binding site prediction. Multiple 50-ns MD simulations of wild-type KIT and its mutant D816V were recorded using the inactive auto-inhibited structure of the protein, characteristic of type III RTKs. Computed free energy differences enabled us to quantify the impact of D816V on protein stability in the inactive state. We evidenced a local structural alteration of the activation loop (A-loop) upon mutation, and a long-range structural re-organization of the juxta-membrane region (JMR) followed by a weakening of the interaction network with the kinase domain. A thorough normal mode analysis of several MD conformations led to a plausible molecular rationale to propose that JMR is able to depart its auto-inhibitory position more easily in the mutant than in wild-type KIT and is thus able to promote kinase mutant dimerization without the need for extra-cellular ligand binding. Pocket detection at the surface of NMA-displaced conformations finally revealed that detachment of JMR from the kinase domain in the mutant was sufficient to open an access to the catalytic and substrate binding sites

Efficacy of multi-gravity separator in recovery of values from waste using experimental design

The recovery of values from mineral waste and their utilisation, for the conservation of mineral wealth and protection of environment, is gaining increasing importance. Multi-Gravity Separator (MGS) is the latest inclusion to various gravity separation machines developed for the treatment of very fine particles (less than 75 microns). The separation process inside MGS is extremely complicated and its operation is generally controlled by different design and operating variables. In the present paper, a mathematical modelling technique, using experiments and statistics, has been presented. It has been observed that it is possible to optimise design parameters of MGS to achieve best possible assay value from the wastes, composite material from flue ash and sludge, using 'design of experiments' technique which involves the selection of a strategy to obtain an adequate model with a minimum of experimentation

Effect of grinding on beneficiation of a low grade limestone sample

Beneficiation studies were conducted on a low grade limestone sample from Gola area. Hazaribagh District, Bihar. The sample assayed 42'()'1;. CaO. 4,()% MgO, 2.66 % AIP" 3.20% FeO and 21.38% insoluble. Mineralogical studies indicate that the sample was fine grained variety of limestone containing calcite as the chief mineral with quartz as the principal gangue. The calcite being intimately associated with quartz. it is necessary to have fine grinding of the sample in order to have fine liberation for high concentration. The object of the studies was to optimise the grind condition and to develop a process to produce a concentrate with 54% CaO and <2.0% insoluble. Detailed flotation studies were conducted on the sample using anionic collector. Grind variation studies were conducted to fix the optimum grind of the sample for notation. The optimum grind was found to be 60%-74. Flotation studies were conducted with the sample ground to different fineness. The results indicated that at optimum grind, a rougher concentrate weighing 67% and assaying 51.5% CaO and 5.7% insoluble with a recovery of 82.3% CaO could be obtained. The grade of cleaner concentrate varied from 53.8% CaO and 2.4% insoluble to 54.0% CaO and 1.8% insoluble with the variation of number of cleaning from one to three