20 research outputs found
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