Preparation of exfoliated Mica using phlogophite

Mica is a generic term for long group of poly-silicates mineral with a unique structure. Mica can be found in nature in the form of sheets connected together by surface force between by layers. Mica has often been used for a wide variety of economical uses including the electronic industry, paints and fillers. The expansion behavior of the natural mica has been studied for industrial use of exfoliated mica. The development of exfoliated mica technology was initiated with a two prolonged approach namely to develop cheaper value added products. Natural mica (Phlogophite) acquired from Feldspar mine at Rattota, Matale, Sri Lanka. The selected mica samples were washed and crushed by using an agate mortar and separated for few minutes to the particle size of 63um and approximately separated in to l-2mm particle size by using a mechanical sieve-shaker. Lithium Nitrate was used for chemical intercalation with mica. The expansion factor (degree of expansion) was determined using the ratio between original volume and maximum volume which was measured. Characterization of the exfoliated mica was carried out with X-ray powder diffractometry (Cu K a, Philips X-Ray generator) and The SEM studies are performed on a JSM 6400 scanning electron microscope. Thickness of the intercalate layers, interplanar distances were studied using 001 diffraction pattern. The exfoliation behavior of the natural graphite mainly depends on the particle size & shape and experimental conditions such as temperature and further it depends on the order of the crystal lattice, the secondary structure; size and shape of the particles, the amount of gangue minerals with the mica and the technological pretreatment of the mica

High tech applications of Sri Lankan vein graphite; future trends

Minerals can play a pivotal role in determining and improving economic performance and the quality of life. Sri Lanka has been well known for processing a variety of economically useful vein type graphite, which are mainly being exported as cheap raw materials but played a main role in modern manufacturing industry internationally. Natural graphite (NG) is an attractive material for Li-ion batteries (LIB) because of its high capacity (372 mAh/g) and low working voltage yields with high energy density (Wh/kg). Introducing performance enhanced cheaper NG electrodes for LIB will definitely reduce their cost and improve the capacity. The objective of the research is to introduce cost effective, time saving, highly economical and more convenient method to convert Sri Lankan vein graphite directly in to the battery grade anode material for Li-ion batteries. Powdered natural graphite sample was treated with mixture of HF, HNO3 and H2SO4 acids at 120 0C till the evaporation of mixture. Results of the Carbon content measurements (ASTM – 561), XRD, SEM and FTIR evidenced that the acid digestion method was successfully purified the Sri Lankan vein graphite over 99.9%. In the preliminary chemical purification study done by acid leaching, revealed the possibility of purifying local graphite using mineral acids with low concentrations at low temperature. It further indicated the ability of surface modification of the vein graphite by mild oxidation. The preliminary investigations on Sri Lankan graphite for rechargeable Li-ion battery (LIB) application and graphite oxide (GO) synthesis has revealed the potentiality of this cheap local mineral for technological applications. Further, it indicated the worthiness of conducting further investigations on the vein graphite to enhance the purity and the properties (homogeneity and particle morphology, electrical conductivity ... etc.) appropriate for the expected high tech applications

Manufacturing of laterite bricks as an environmental friendly alternative row material

There is a deficiency of row materials for housing in Sri Lanka because of population growth. So there is an unfulfilled demand for traditional row materials such as river sand and clay. Serious environmental problems are caused because of over excavation of above row materials. To minimize the environmental problems, it should be focused towards low cost and environmental friendly alternative row materials which are occurring in sufficient amount in Sri Lanka. In order to fulfill the demand of row material for housing and other constructions, laterite soil can be used with quarry dust and cement as additives. Particle size distribution of the laterite was poorly graded and addition of quarry dust corrected this deficiency. The bricks which are made from laterite and quarry dust mixture can be stabilized using low amount of cement while achieving required compressive strength for walling. This material mixture is more economical and environmental friendly for bricks production

Long term solution for flood in Malala Lagoon, Hambantota

The lagoon systems play a major role in maintaining the balance of the organisms as well as the physical environment. The lagoon resources were misused due to unavailability of a proper management plan, environment pollution and lagoons converted into lands and polluted due to natural disasters. Therefore, the research was focused to find the vulnerable area and vulnerable communities to the flood; to carry out a scientific study to assess the hydrological, ecological, and biological impacts of the increased inflow into the lagoon; to study how the above problems affect the fishing community who depend on the lagoon for their livelihood , the farmers community who rely on paddy fields of vulnerable area and the other organisms who depend on the lagoon and surrounding area for their livelihoods; to find a long term solution for the flood in Malala and Embilikala lagoons, situated inside the Bundala conservation area of Hambanthota district. Considering the biological environment and the inundation affects the divert water directly to the sea from a canal through the reserved area is the best alternative to be acceptable by both farming and fishing communities and the environment

Chemical intercalation of potassium into natural graphite

The potassium binary graphite intercalation compound [GIC (K)] was prepared using classical double bulb chemical method and compared with different types of natural vein graphite from Sri Lanka and natural flake graphite of Madagascar. The first stage GIC (K) was always obtained for natural vein and flake graphite. These result indicated that the potassium intercalation does not depend on the graphite‘s physical texture or their morphology

Natural hazards and vulnerability in South Eastern coastal region of Sri Lanka: a case study in Maruthamunai area

Sri Lanka has experienced several disasters including cyclone, typhoons, tornadoes, flood, drought, landslide, epidemics, lightening, accident related disaster and tsunami. Tsunami occurred on 24th December 2004 which was the biggest catastrophic disaster in Sri Lanka, affected entire north, east and south coastal belt and killing people and destroying properties. Maruthamunai in Ampara district in the south eastern coastal region was severely affected than other coastal regions of Sri Lanka. A questionnaire survey was carried out on hazard awareness in Maruthamunai area. The purpose of this study was to identify the community perception on hazards and vulnerability by mapping at community level. The study describes the factors or constraints of economic, social, physical or geographic nature, which reduce the ability to prepare and to cope with the impact of hazards. Throughout the study it was found that people are not aware about all the hazards around them and hazard mapping. More than 95 percent of residents lacked tsunami knowledge prior to the 2004 tsunami. People consider the reason for flooding as heavy rainfall and inadequate drainage system, but not aware that water disposal into marshy lands too contribute to flood the area. All the people who are living in the coastal area are vulnerable to the hazards, and it is recommended to educate the people on disaster and its management and also to develop a land use plan by authorities with the support of the community. Adequate drainage network systems have to be developed and implemented by the local authority

Determination of Zn2+ ion adsorption capacity of montmorillonite clay

Drinking water contaminated with heavy metals is a serious problem in Sri Lanka in the recent years. Therefore to provide safe drinking water, it is compulsory to remove heavy metals and we should have to use water filters. montmorillonite, which is a mineral from the smectite group and considered as a great candidate as an adsorbent material for heavy metal ions such as Zn2+in aqueous solution due to its typically elevated surface area, high availability and low cost. In this study, removal of heavy metals from water was investigated by studying adsorption of them onto montmorillonite clay material. Properties of the clay have been stabilized by a thermal treatment. The montmorillonite clay material was characterized by applying different techniques of Fourier transformation infrared spectroscopy and also the surface properties of the clay material, Scanning electron microscopy were also used to study the morphology of the samples. The obtained results showed that the raw clay has a maximum removal efficiency of 97.84 %. Among the heat treated samples, the sample heat treated at 400 ºC showed a maximum removal efficiency of 96.72 %. Further, the removal efficiency continuously decreased with the increasing treatment temperature above 400 ºC

Upgrading Sri Lankan natural vein graphite by purification and surface modification

Sri Lanka is well known for high quality vein graphite, containing about 95-98% of pure carbon. Vein graphite in Sri Lanka have been categorized into four structurally distinct graphite varieties, shiny-slippery-fibrous graphite (SSF), needle-platy graphite (NPG), coarse striated-flaky graphite (CSF) and coarse flakes of radial graphite (CFR). Impurity content in different structural type varies depending on the mode of occurrences and nature of graphite vein. Both chemical and physical methods are employed for removing impurities from the graphite. Among them, flotation is a versatile and selective mineral processing technique, which can be used to achieve specific separations from complex ores. Therefore the present study focuses on purification of Sri Lankan natural vein graphite by froth flotation, HCl leaching and alkali roasting followed by surface modification suitable for advance electrical applications. Graphite powder (<75 μm) from Needle Platy Graphite (NPG) and Shiny Slippery Fibrous (SSF) morphological types were used for this study. Initially 200g from both varieties were subjected to froth flotation. For HCl leaching under the chemical purification study, 3g of each graphite sample was treated with 10 vol. % HCl at 650C for 75 minutes. For the alkali roasting, 3g from each graphite sample was mixed with 35vol. % NaOH (solid: liquid = 1:2) separately and roasted at 250 0C under air for one hour. Selected graphite samples having carbon content about 99.9% were used for surface modification. Thermal oxidation was performed at 550 0C in a box furnace under air for 6 hours. Under the chemical method, graphite powder (3 g) was treated with 69% HNO3 (100 ml) under stirring at 60 0C for 24 hours. Carbon percentage of graphite was determined according to ASTM - 561 and weighing the residues. Filtrates were taken from both chemical purification techniques and analyzed by the Atomic Absorption Spectroscopy (AAS) technique. Both purified and modified graphite samples were characterized by Fourier Transform Infrared (FTIR) spectrophotometer (Nicolet 6700). The electrical conductivity measurements were performed by the d.c. four probe technique. The results revealed that the froth flotation could not make a considerable influence on purification, in contrast, both the acid leaching and alkali roasting methods revealed that Sri Lankan natural vein graphite can be purified over 99% carbon content. The surface modification study shows the formation of oxidized species on the graphite surface and the surface modification by chemical oxidation has a higher effect than the thermal oxidation. Both of the investigated graphite varieties reveal the possessing of electrical conductivity in the semi-conductivity range. Further the purification process improves the electrical conductivity, though it slightly decreases with surface modification

A web GIS based study for managing mangroves of Krishna Delta, Andhra Pradesh, India

Mangroves are one among the most productive ecosystem which provide a wide range of services to the coastal people, which includes the provision of food and timber products and coastal defense services by reducing risk from coastal hazards. Several research found that mangrove forests have been degraded throughout the world since 80s onwards due to anthropogenic factors and India is no exception for the same. The current study was conducted in the Krishna’s wetland, which is located in Krishna district of Andhra Pradesh (AP), South India, India. The Mangroves of Krishna is second largest mangrove ecosystem in AP, fifth in East coast, eighth in India and it is rich in biodiversity but highly vulnerable because of anthropogenic and natural factors which makes this study area very scared. Information on Krishna mangroves and their geospatial information are owned by different institutions to build this geospatial dataset as open to access everyone. The WebGIS is a latest advancement and hybrid of GIS and Internet technologies for the dissemination of the geospatial datasets and its variations through the web. The main objective of the current study is to develop and demonstrate a WebGIS using open source software and integrate geospatial datasets of the mangroves of Krishna into WebGIS platform and to analyse and assess areas that are degraded by influenced parameters and in need of sustainable management.The result revealed that the area of mangroves in Krishna was decreased from 2,454 ha in 1990 to 1,363 ha in 2000 to 1,339 ha in 2011. On the other hand the areas of mangroves in the Krishna delta were increased to about 678 ha from 1990 to 2000 and 2,230 ha from 2000 to 2011. It may be pointed out that the variation in mangrove covers in the study area due to land use conversion for different purposes and mangroves provides coastal defense services by reduce risk of coastal hazards. It is may be concluded that this WebGIS study is very useful and unique because it is sharing data through internet to everyone as it save money, time and data duplication, which are needed to different stakeholders such as researchers, decision makers, planners for the sustainable management of mangrove ecosystem