Browsing by Author "Dissanayaka, DMDOK"

Now showing 1 - 5 of 5

item: Conference-Full-text
Economic feasibility of copper extraction from Seruwila copper magnetite deposit.
(2014-07-09) Abinav, R; Chamara, HAKM; Dinojan, J; Sampath, HKT; Dissanayaka, DMDOK
Sri Lanka is endowed with a variety of industrial minerals such as graphite, quartz, mica; brick and tile clay, ball clay, kaolin, dolomite, calcite, feldspar, miocene limestone, mineral sands (Ilmenite, Rutile , Garnet and Zircon), apatite (phosphate rock), silica sand, magnetite and also gem minerals: Contribution to the GDP from mining and quarrying industries including gems is within the range of 1.8-2% over the last two decades. However, Government has banned export of minerals used for ceramic, construction and agricultural industries considering the limited availability of such mineral resources in Sri Lanka. Some export limitations were also imposed for other export minerals as well without value addition. However, high energy cost for processing is a drawback to value addition of industrial minerals. Considering the above fact and the country's needs, this research was carried out to evaluate economic viability of manufacturing of copper metal from Seruwila Copper magnetite. A detailed literature survey has been 'done initially and field investigations were carried out to collect ore samples. The chemical analysis revealed that average copper concentration of the surface sample collected in Arippu area was 1.1%. Copper concentration of finely-ground ore samples could be increased up to 15- 20% using a Potassium Amyl Xanthate in a laboratory scale flotation cell. Concentrated copper sample taken from froth flotation was dissolved in concentrated hydrochloric acid and the filtered solution was used for copper electrowinning. Extraction of copper was directly related to the applied current density. However, current density varies with other factors mainly the distance between electrodes, temperature, pH, concentration of electrolyte, area of the electrode, stirring speed and applied potential etc. Conducting several trial runs for laboratory made copper sulphate solution by varying a single parameter at a time, the optimum parameters for electrowinning were identified. Unit cost for electrowinning of copper metal was calculated by applying identified optimum current density and other parameter values to actual chalcopyrite solution and average cost of copper extraction was calculated as Rs.I01.7/kg considering the average electrical tariff for industrial application in Sri Lanka is to Rs.15/kwh.
item: Conference-Extended-Abstract
The flow behavior of mineral particles through glass funnels
(2007) Rohitha, LPS; Dissanayaka, DMDOK; Fernando, WLW
In industry the flow of mineral particles in silos playa very important role in the recovery of these particles into containers for bagging and transport. The silo design parameters and particulate properties are restricting the flow behavior in silos thereby controlling the rate of packing into containers as a finished product or else in the utilization of these particles for subsequent unit operations down the processing line. Further, telescopic silos have been introduced recently in mining industry [1] for dust suppression in quarries, gravel pits by minimizing the distribution of dust and fines in to the surrounding areas. There are factors affecting the flow behavior in silos [2] such as particle size, angle of repose. moisture content, static electric charges of powders and so on. In order to simulate the behavior of mineral particulates in silos, glass funnels of different dimensions have been chosen due to their transparency.
item: Conference-Abstract
Flow Behavior Of Mineral Particles Through Silos
(2008) Rohitha, LPS; Dissanayaka, DMDOK; Fernando, WLW
Flow behavior of dry minerals in silos has been investigated initially with glass funnels with different orifices. Thereafter, funnel was scaled up to a pilot plant (Silo) with adjustable orifices at its discharge end. The flow rates vs particle size were investigated with beach mineral sands and quartz grains of varying sizes obtained from river sand. Zero flow rates were observed at d/D ratio of 1/5-1/4 for large size sand grains. For small grains of size about 200 microns zero flow rate was observed for orifice diameters 1.5, 2.0 and 3.5cms respectively due to 'floc' effect arising probably from static electrical charges of the powder and the humidity of air prevailing at the time of investigation.
item: Conference-Abstract
Resource recovery from photographic waste by electro-winning
(2006) Wijeyekoon, SLJ; Rohitha, LPS; Fernando, WLW; Dissanayaka, DMDOK; Karunarathna, S
Industries such as mining and industrial minerals, metallurgical, photographic, textile, leather and chemical produce wastewater containing heavy metals that are hazardous to man and the environment. Indiscriminate discharge of these effluents pollutes natural resources and disturbs vital eco systems. On the other hand most heavy metals in these effluents are rare in nature and hence are expensive industrial raw materials. Therefore a sustainable pollution control option for these industries should aim at resource recovery. Successful isolation of heavy metals from wastewaters will not only render such effluents non hazardous but also make waste management an attractive proposition, thus leading to multiple benefits in terms of resource conservation, pollution control and treatment cost savings. Photographic waste effluents arise from X-ray, lithographic and photographic operations. The photosensitive medium used in these operations is an emulsion of fine Ag halide matrix in gelatin. During fixing, the Ag+ is removed by the fixer solution. The developer and bleach solutions also contain the Ag heavy metal. The recovery of Ag" from such wastewater may be done by electro-winning, metallic replacement, evaporation, ion exchange, reverse osmosis and electro-dialysis. However many process parameters of these methods are not readily available and opportunities exist for optimization of methods to improve removal efficiencies. The aim of this research was to investigate the application of electro-winning technique for selective removal of Ag metals from photographic wastewater. The advantages of the application of electro-winning technique are no hazardous sludge generation, isolation of pure elements, no pretreatment requirement and l
item: Conference-Extended-Abstract
Study on the suitability of cation selective membrane and the effect 011 current density for electrodialitic removal of heavy metal joils
(2003) Dissanayaka, DMDOK; Jaaweera, MW; Gunawardhana, WDDH; Wijekoon, SLJ
Heavy metal pollution of the environment is a major environmental problem facing the modem world. Their persistence in the environment and the difficulty in removal from wastewaters make them available for aquatic and terrestrial fauna. This would enable the transfer of heavy metals up in the food chain causing severe damages in the higher organisms due to bioaccumulation.