Browsing by Author "Dissanayake, D.M.S."

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    Development Optimisation of Prototype Froth Floatation facility as an advanced physical beneficiation technique to upgrade low grade Sri Lankan vein graphite in Kahatagaha Graphite Lanka Limited
    (Uva Wellassa University of Sri Lanka, 2020) Amarasiri, P.G.S.C.; Chiranjaya, Y.A.S. U.; Dissanayake, D.M.S.; Hewathilake, H.P.T.S.
    Presently, Sri Lanka is the sole Vein Graphite (VG) supplier to the world market. Since the best quality VG has been selected in the sorting procedure, low-quality VG remains while leaving a chance for upgrading. The natural hydrophobicity of graphite has been utilized by the Froth Floatation (FF) which is a physical beneficiation technique uses to separate graphite from gangue minerals. Few studies have been conducted for both flake graphite and VG. Therefore, the present study was forced to set up a prototype FF facility to optimize its cell design and identify the pulp density, frother type, and dosage, collector dosage for the economically feasible installation of the FF plant at KGLL. The cylindrical cell was designed with a height of 20 cm and diameter 12 cm. 150 g of ≤ 72 µm VG powder was mixed with different volumes of water to find optimum solid to liquid (S/L) ratio. The effect of the collector and the frothers were determined by varying the kerosene dosage for 0.01g to 0.10g and both Pine Oil (PO) and 4-Methyl-2-pentanol (TMTP) for 0.01g to 0.05g, respectively, while all other factors were kept constant. Resulted floated VG samples were analysed by Carbon Content (CC) (ASTM-C561) and X-ray Florescence (XRF) analyses. The optimum recovery of 80% of VG was achieved with the pulp density of 10% S/L ratio and further, 0.08g of kerosene, 0.02g of TMTP, and 0.04 g of pine oil. Among the two frothers, TMTP was cost-effective and easy to handle than pine oil. The CC of the obtained floated VG graphite has upgraded from 90.2% to 96.58% and comprehensive elemental analysis was confirmed the removal of iron, silica, and other metallic impurities up to 72%. Therefore, the FF plant can be effectively run with the 10% of S/L ratio together with kerosene collector and TMTP frother. Keywords: Vein graphite, Froth-flotation, Surface science, Value addition
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    Feasibility Study of Sri Lankan Feldspar Using As A Bio Fertilizer
    (Uva Wellassa University of Sri Lanka, 2012) Dissanayake, D.M.S.
    Potassium is one of the three essential elements among, NPK, for the growth and reproduction of the plants and it plays major roles in its nutrition. The crop production in Sri Lanka relies completely on imports to meets its annual requirement of potash fertilizers; the high cost of conventional, water soluble K fertilizers constrains their use by most of the farmers in the country. In order to reduce the dependence on imported potash, feldspar a potash mineral in Kaikawala deposit matale, contains 14% K and therefore it could be a potential K-source for crop production. Novel approaches are needed to unlock K from the silicate structure of this mineral in order to render K more available for plant nutrition. Pure cultures of silicate dissolving bacteria SDB (Bacillus muicilaginosous,Bacillus cereus and Aspergillus niger) were used as bio inoculants. These studies were undertaken to evaluate the effectiveness of bacterial inoculation in combination with different particle sizes of feldspar, and potassium releasing ability was measured to get the best combination of microorganism and the feldspar particle sizes. However, incorporation of feldspar without bio inoculation had little effect on the degradation in controller medium. But bio inoculation has shown different and significant K concentration to the solution. However Bacillus mucilaginosous as a bio inoculant has given the highest K concentration in to the solution at the <125micron particle size of feldspar. According to that the Sri Lankan feldspar has significant ability as a potassium source with Bacillus mucilaginosous inoculation.
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    Microbial Aided Leaching of Potassium from Sri Lankan Feldspar
    (Uva Wellassa University of Sri Lanka, 2012) Dissanayake, D.M.S.; Wijesekara, K.B.; Attanayake, A.N.B.
    Potassium is an essential major plant nutrient and also a non-renewable resource. It plays a vital role in plant nutrition. Majority of the soils of the world are too low in available potassium for production of good yields. Potassium containing agrochemicals remains relatively expensive and supplementing potassium deficiency with agro fertilizers is costly. The uses of alternative indigenous resources such as feldspar and mica which are potassium rich naturally occurring minerals are gaining importance against costly agro fertilizers (Badr et al., 2006). Certain groups of microorganisms including bacteria such as Bacillus mucilaginosus and fungi like Aspergillus niger are known to solubilize potassic minerals into soluble form which can be utilized by the plants (Lin et al. 2002; Han, and Lee, 2006). Microbes can enhance mineral dissolution rate by producing and excreting metabolic by products that interact with mineral surface (Barker et al., 1998). Combination of potassic rock minerals with potassium solubilizing microorganisms could constitute a biofertiziler which provides a sustainable solution to improve plant nutrition and production. This study investigates the potassium solubilizing effect of Bacillus mucilaginosus, Bacillus cereus, and Aspergillus from Sri Lankan potassic rock mineral feldsfar.