Instrumental neutron activation analysis (INAA) based on a nuclear reactor and proton induced X-ray emission (PIXE) based on a 2 Me V Van de Graaff accelerator were used to analyse different environmental samples including coal, sawdust, fly ash and landfill materials. These samples represent a large component of the solid waste being buried in the ground, and may be a potential source of toxicity which can have not only adverse effects on the soil and ground water, if diffused during leaching processes, but may also be transferred to humans through the food chain. Both techniques were employed to determine trace element concentrations in these matrices. The concentration of 30 elements were detemined, namely Na, Mg. Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Cd, Ba, La, Sm, Eu, Tb, Ho, Yb, Hf, Ta and Th. The detection limits in the various sample matrices were calculated and a comparison was made for those elements commonly detected by both techniques.
A simple and rapid laser fluorometric determination of trace and ultra trace level of uranium in a wide variety of low uranium
content materials like soil, basic and ultra basic rocks, plant ash, coal fly ash and red mud samples is described. Interference
studies of some common major, minor and trace elements likely to be present in different, geological materials on uranium
fluorescence are studied using different fluorescence enhancing reagents like sodium pyrophosphate, orthophosphoric acid,
penta sodium tri-polyphosphate and sodium hexametaphosphate. The accurate determination of very low uranium content samples
which are rich in iron, manganese and calcium, is possible only after the selective separation of uranium. Conditions suitable
for the quantitative single step extraction of 25 ng to 20 μg uranium with tri-n-octylphosphine oxide and single step quantitative
stripping with dilute neutral sodium pyrophosphate, which also acts as fluorescence enhancing reagent is studied. The aqueous
strip is used for the direct laser fluorometric measurement without any further pretreatment. The procedure is applied for
the determination of uranium in soil, basalt, plant ash, coal fly ash and red mud samples. The accuracy of the proposed method
is checked by analyzing certain standard reference materials as well as synthetic sample with known quantity of uranium. The
accuracy and reproducibility of the method are fairly good with RSD ranging from 3 to 5% depend upon the concentration of
microorganisms include decomposition of organic matter, nutrient mineralization, crop pest’s suppression and its protection. Flyash is a residue of burning of coal/lignite in thermal power plant has traditionally been considered as a waste product. The high
Investigations of physico-chemical properties
of three kinds of fly ash and their influence on cement hydration were performed
in this work. Thermal analysis, microcalorimetry, infrared absorption and
others were used. It was confirmed that the kind of coal and combustion conditions
essentially influence physico-chemical properties of fly ash and in consequence
influence cement hydration. Investigated fly ashes show in cement system so-called
pozzolanic activity. Fly ash from combustion of brown coal in fluidized furnace
revealed better activity compared to other investigated ones. This work is
an introduction to more extensive investigation of fly ash activation.
Three bio-fuels with or without additives and their fly ash samples were characterized using simultaneous Thermogravimetry-Differential
Thermal Analysis-Fourier Transform Infrared Spectrometry-Mass Spectrometry (TG-DTA-FTIR-MS), X-ray Diffraction (XRD), X-ray
Fluorescence (XRF), and Scanning Electron Microscopy-Energy Dispersive Spectrometry (SEM-EDS). The results show that the additives
increase the reactivity of the bio-fuel during combustion. The additives also significantly decrease the amount of unburned
carbon in the fly ash. The additives affect the compounds formed in the fly ash sample, and consequently the thermal behaviour
of the fly ash. The fly ash samples are thermally stable in air up to 100C. The fly ash samples contain fine particles with
irregular shape, small round particles, and large hollow spherical particles with entrapped gases.
The effect of oxydation of particulate carbon as a part of fly ash has been studied by mean of differential scanning calorimetry
(DSC) and simultaneous thermal analysis/mass spectrometry (TA/MS). The results from different carbon modifications added to
fly ash were discussed and compared to those of the pure samples.
Thermogravimetric (TG) analysis was applied to the characterisation of the pozzolanic reaction in mortars containing the supplementary
cementitious materials (SCMs) pitchstone fines (PF) and fly ash (FA) as partial replacements for Portland cement (PC). TG
analysis was used to determine the proportion of calcium hydroxide (CH) present from the hydration of the PC based on the
dehydroxylation of the CH present in the blended PC-SCM mortars. The consumption of CH indicated that both SCMs underwent
the pozzolanic reaction and that PF was found to compare favourably in its pozzolanic reactivity of FA, the industry and globally
accepted standard artificial pozzolan.
The self-hardening activity of fly ashes was investigated looking for the possibility of their chemical reactions with water without additives. A method had to be developed for separation of the structural water from the adsorbed or free one. The decomposition of the chemically bound water was measured by thermogravimetry. The‘I’ dimensionless number proved to be applicable for the quantitative characterisation of the measured data with more DTG peaks. The examined reaction depends on the chemical composition and the physical structure of the fly ashes and the time of interaction with water. The SO3 content seems important, but the characteristics of the formed compounds differ deeply from the CaSO4·2H2O. The observed and examined reaction is an important factor of the self-hardening process of fly ash deposits.