Utilisation of Waste Plastics in Flexible Pavement Construction Laid on Expansive Soil Subgrade

This paper investigates the performance of model flexible pavement on expansive soil subgrade using gravel / flyash as subbase course with waste plastics as a reinforcing material. It was observed that from the laboratory test results of direct shear and CBR, the optimum percentage of waste plastics is equal to 0.3% and 0.4% for gravel and flyash materials. Cyclic load tests were carried out in the field on the reinforced and unreinforced model flexible pavements laid on expansive soil subgrades. It is observed that the maximum load carrying capacity associated with less value of rebound deflection is obtained for gravel/flyash reinforced subbase compared to unreinforced gravel/flyash subbase

Geochemical assessment of a siliceous limestone sample for cement making

A low grade siliceous limestone sample from the Jayantipuram mine of Andhra Pradesh, India, has been investigated for its suitability for cement making. Petrological as well as X-ray diffraction pattern studies indicated that the limestone sample was crystalline and dominantly composed of calcite and quartz. They are simple in mineralogy, and yet they have variable silica and lime contents. Geochemical analysis results of twenty five hand picked samples indicated that the limestone from the Jayantipuram mine shows a wide range of variations in LOI (29.94% to 40.64%), SiO2 (6.14% to 27.18%), CaO (37.93% to 50.78%), Al2O3 (0.49% to 2.27%) and Fe2O3 (0.28% to 2.4%). MgO, K2O, Na2O, TiO2 and MnO2 are present in traces. CaO with LOI shows a strong positive correlation where as CaO with SiO2 shows a strong negative correlation because of mineralogical factors. The chemical composition of the limestone reflects its mineralogical composition. The distribution of various elements in the acid-soluble fraction has been studied by the factor analysis method in order to interpret in terms of their mineralogy, sedimentary environment and diagenesis. Mineralogy, recrystallization and other diagenetic changes are the main factors affecting the distribution of the elements and their mutual relationships in the limestone. The aim of this paper is also to analyze how significantly the two parameters, silica modulus and lime saturation factor, influence this low grade siliceous limestone sample from the Jayantipuram mine of Andhra Pradesh, India, for the cement making process from the geochemical data

Characterization of Srikurmum and Navaladi Beach Placer Minerals

Two different beach placer samples from Srikurmum of Andhra Pradesh and Navaladi of Tamilnadu were collected and characterized in terms of their total heavy mineral content by heavy media as well as magnetic separation studies. Navaladi beach placer sample contains higher amounts of total heavy minerals than that of the Srikur-mum beadh. Mineralogical analysis on both the samples revealed high amounts of garnet and minor quantities of ilmenite. The particle size of garnet is coarser than that of ilmenite. EPMA results indicated that garnet is of almandine variety. The Eastern Ghats metarnotphic belt, covering both the areas, is considered to be the source of these beach placer minerals

Value Addition of Indian Iron Ore Fines by Column Flotation - Few Case Studies

The Government of India highlighted Processing and utili-zation of iron ore fines as a prerequisite to meet the domestic raw material requirements for the projected 110 million tonnes of domestic steel production by the year 2019-20 in the National Steel Policy announced in Nov-ember 2005. This would require 190 million tonnes of iron ore. The depletion of high grade iron ore and increased generation of fines during mining and handling and demand for high grade iron ore fines for export has necessitated the processing of low to medium grade fines. The R&D efforts undertaken at NML-Madras Centre, India in this direction have been highlighted. Flotation in general and Column Flotation in particular appear to be promising in addressing this problem. This would also mitigate the environmental problem created by the dumping of huge quan-tities of low and medium grade iron ore fines. Three case studies involving iron ore fines of varying silica and alumina content from Goa and Bellary-Hospet regions of India were discussed. The results clearly indicate the feasibility and significance of flotation process in treat-ing the fines to obtain marketable concentrates

Postmastectomy chest wall radiation of left-sided carcinoma breast - a dosimetric comparison between electrons and photons

Background: For carcinoma breast patients requiring post mastectomy radiation therapy (PMRT), tangential photon beam (PB) is commonly used technique. The physical nature of electrons results in sharp dose fall off and reduces organs at risk (OAR) doses. Aim of the present study is to compare the coverage of chest wall and doses received by OARs – heart and lung between electron and photon beam plans in left sided breast cancer patients requiring PMRT.Methods: This study was done in 22 left sided carcinoma breast patients treated at GSL Medical College between May to December 2017. Both tangential PB plans and electron beam (EB) plans were generated on simulation computed tomography (CT) for each patient and both plans were compared. A dose of 50 Gy was prescribed to planning target volume (PTV) in 25 fractions.Results: The PB plans provided superior homogeneity index (HI) and conformity index CI compared to the EB plans (p<0.05). There was significant difference in favour of electron-beam plans for mean heart dose (p=0.0312), V25 Gy (p=0.029), V45 Gy (p=0.001) and V20 Gy of left lung (p=0.042). There was no significant difference in mean lung dose.Conclusions: Dosimetric data from this study suggests that PMRT with the electron beam can reduce doses to the heart and left lung with acceptable target coverage. It needs further research in the clinical setting

Alteration characteristics of manavalakurichi beach placer illmenite, Tamilnadu.

The mineralogy and alteration characteristics of beach placer ilmenite from the Manavalakurichi coast were investigated by optical microscopy and electron probe microanalysis. Mineral chemistry by electron probe micro-analysis indicated ;enrichment of TI02, MgO, AI203, Cr203, Si02. K20, V205,. CaO and Na20 in the altered products ofilmenitc:. while there was a loss of iron oxide, maganesc oxide and zinc oxide from the ilmenite grains during weathering leading to leucoxen

Beneficiation of a Low Grade Limestone by Flotation Column

Beneficiation of a Low-grade limestone sample from Salem, Tamilnadu was carried out by pilot scale flotation column. Mineralogical studies have revealled that quartz, freldspar, pyroxene and biotitic as gangue minerals while pyrite, in trace quantitiew, appear as opaque along with dominating calcite. Reverse flotation was tried using two different commercial amines viz. Chem750F and Flotamine-D. The studies clearly suggest that it is possible to produce a limestone concentrat assying around 96-97% of CaCO3 with less than 1% SiO2

Mineralogy and Geochemistry of a low grade iron ore sample from Bellary-Hospet sector, India and their implications on beneficiation.

Detailed studies were conducted on iron ores of Bellary-Hospet sector using microscope, XRD, TG, and EPMA techniques. The results indicate that hematite is the major iron oxide mineral with minor amounts of goethite, magnetite, martite and limonite with quartz and clay as major gangue. There is no evidence of the presence of any iron silicate and iron carbonate minerals. Trace amounts of pyrite were observed under the microscope and is the only iron sulphide phase. Microscopic studies also indicated that most of the quartz grains are present as inclusions within the hematite and magnetite grains. XRD studies revealed hematite as the major mineral with subordinate amounts of goethite, quartz and kaolinite confirming to the microscopic findings. Qualitative mapping and quantitative EPMA studies on these ores indicated the presence of gibbsite as the only alumina bearing phase and apatite as phosphorous bearing mineral. Traces of alumina, present as solid solution in the iron oxide minerals, has also contributed Al2O3 to the ores. Electron microscopic studies revealed that gibbsite grains are in the size range of 10 to 50 microns and are intimately and intricately associated with the iron oxide phases. Major elemental analyses of 47 representative iron ore samples of various types were analyzed to deduce the source of silica and alumina’s contributing phases in the ore and their interrelationships. The geochemistry data revealed negative correlation of Fe2O3 with silica and alumina thus indicating there is no iron silicatephase as well as alumina contribution from iron oxide minerals in the form of solid solution is insignificant. Positive correlation of silica with alumina indicates that the clay is the major contributing mineral for both the silica and alumina phase and presence of gibbsite. The role of gangue minerals and the interrelationship of silica, alumina and iron oxide, with reference to beneficiation are discussed. Jigs and heavy media cyclones for this type of ores can be used but at the cost of poor yield because of complex nature of alumina distribution. As long as alumina and silica mineralization is not too fine and the ore composed of magnetite/hematite with coarse grained quartz, magnetic route is the most effective. Since the quartz grains are too fine and their distribution is very complex for the Bellary-Hospet sector ores, flotation in general and column flotation in particular seems to be more effective

Reverse flotation studies on an Indian low-grade iron ore slimes

The present investigation deals with the recovery of iron values from the screw classifier overflow slimes from an iron ore washing plant by means of reverse cationic flotation as an alternate to direct anionic flotation. Selectivity index, an indicator of separation efficiency, was chosen as the response parameter for optimizing the quantity and evaluating a series of generically same but chemically different cationic collectors used in reverse flotation and for further optimization of other flotation process parameters. In the optimization, the main variables investigated were percent solids, collector and depressant dosage. An increase in the iron content of the concentrates is obtained with concomitant reduction in Si02 and Al203levels

Processing of iron ore fines by column flotation – Part I & part II

The Government of India highlighted Processing and utilization of iron ore fines as a pre-requisite to meet the domestic raw material requirements for the projected 110 million tonnes of domestic steel production by the year 2019-20 in the National Steel Policy announced in November 2005. This would require 190 million tonnes of iron are. The depletion of high grade iron are and increased generation of fines during mining and handling and demand for high grade iron are fines for export has necessitated the processing of low to medium grade fines. The R&D efforts undertaken at NML-Madras Centre, India in this direction have been highlighted. Flotation in general and Column Flotation in particular appear to be promising in addressing this problem. This would also mitigate the environmental problem created by the dumping of huge quantities of low and medium grade iron are fines. Three case studies involving iron ore fines of varying silica and alumina content from Goa and Bellary-Hospet regions of India were discussed. The results clearly indicate the feasibility and significance of flotation process in treating the fines to obtain marketable concentrates