Authors:P. Ubbrìaco, Angela Traini, and D. Manigrassi
The present research is concerning the characterization of FDR (fuel derived from residues) fly ash and mixtures with lime/brick
hydraulic binder by DTA/TG/DTG thermo-analysis, X-ray diffractometry and chemical analysis. The use of hydraulic binder obtained
from building brick rejects, which is less expensive than the usual solidifiers such as cementitious binder and silicates,
allows us to reutilize, in the meantime, this wreckage material, to the advantage of environmental sustainability. Fly ash
samples investigated in the present study were separated in a thermo-incineration plant. Mineralogical DTA/TG/DTG and XRD
investigations reveal the presence of different phases as well as chemical analysis shows a moderate concentration of heavy
metals and high content of chloride and sulphate. Results obtained from leaching tests with water carried out on hardened
pastes containing fly ash lead to interesting results, which highlight behaviour to the release of contaminants. The whole
of the results obtained in the present study make it possible to regard the objective of disposing such hardened materials
in inert waste landfill sites as achievable.
Authors:Zdenko Loncaric, Domagoj Rastija, Krunoslav Karalic, and Brigita Popovic
benefits of liming. The department of Primary Industries and Resources South Australia.
Lakanen E., Ervio R. (1971): A comparison of eight extractans for the determination of plant available micronutrients in soils
A lime-pozzolan cement was used to make pastes containing different quantities of MSW fly ash. After setting, the pastes were cured in water at room temperature from 1 h to 260 days. The hydration characteristics and the nature of the hydration products of the various pastes were studied by simultaneous TG/DSC thermal analysis and X-ray diffractometry. The MSW fly ash was found to induce a slowing of the hydration process in lime-pozzolan pastes, and after some days an evident acceleration of hydration reactions occurred. Sulphate and chloride in the MSW fly ash yield hydration products forming a cementitious matrix.
Dolomitic lime samples were treated with sodium carbonate solution and the causticizing process was followed at different
temperatures by recording the TG and DTA curves of the solid-phase products that separated after different time intervals.
The chemical reactions occurring during causticization are discussed. From the TG curves, apparent kinetic parameters were
derived. Some aspects of the kinetic compensation effect are discussed.
Authors:A. Bakolas, E. Aggelakopoulou, and A. Moropoulou
Ceramic powder has been used as an artificial pozzolanic addition, in preparing pozzolanic mortars for the historic/traditional
structures’ construction. In order to evaluate the pozzolanic activity of ceramic powder, several pastes were prepared, by
mixing it with hydrated lime, in different ratios. The pastes were stored in standard conditions (RH=99±1%, T=25±1°C) and evaluated using thermal analysis (DTA/TG), X-ray diffraction (XRD), compressive strength tests and mercury intrusion
porosimetry (MIP), in time. The obtained results revealed that the compounds formed were CSH and C4ACH11 (monocarboaluminate) after 270 days of curing. The calcium hydroxide consumption increases as the initial amount of the ceramic
powder in the paste augments. The maximum strength development is obtained for ceramic powder/hydrated lime ratio 3:1.
Authors:A. Bakolas, E. Aggelakopoulou, A. Moropoulou, and S. Anagnostopoulou
to evaluate the pozzolanic activity of metakaolin, several pastes were prepared,
by mixing metakaolin with hydrated lime, in different ratios. The pastes were
stored in standard conditions (RH=991%, T=251C) and evaluated using thermal
analysis (DTA/TG), X-ray diffraction (XRD), compressive strength tests and
mercury intrusion porosimetry (MIP), in time. The obtained results revealed
that the compounds formed are CSH, C2ASH8
while C4AH13 was not detected
up to 270 days of curing. The calcium hydroxide consumption increases as the
initial amount of the metakaolin in the paste augments. The maximum strength
development is obtained for metakaolin/lime ratio:1.
The kinetics of the pozzolanic reaction of enriched kaolin from the “Senovo” deposit (Bulgaria) with lime is the object of
this article. The kaolin contains kaolinite as a major clay mineral as well as admixtures of quartz and illite. The experimental
data of pozzolanic activity at temperatures of 100 and 23 °C are obtained for different reaction times. The reaction degrees
of kaolinite and lime at 100 °C are determined from the pozzolanic activity data using a powder X-ray diffraction analysis.
The kinetic analysis is performed by joint presentation of theoretical and experimental data in dimensionless coordinates
having in mind the influence of particle size distribution on the reaction rate. It is found by the kinetic analysis that
the rate of entire reaction is limited by the rate of chemical reaction on the reaction surface up to degree of reaction near
to 0.4. The rate of penetration of the chemical reaction into the kaolinite particles for this area—from the beginning to
degree of reaction 0.4, is determined to be equal to 2.10−11 m/s.
A thermogravimetric method based on dynamic heating and the use of an internal source of SO2 (metal sulfates with a suitable range of decomposition temperatures) was used to compare the SO2-binding abilities of various lime-containing materials.
By means of this method, furnace and cyclone ashes formed in the combustion of oil-shale in the Baltic Power Station, their
differently activated (grinding, hydrating) forms and some carbonaceous materials were investigated to estimate their suitability
for exhaust gas purification in thermal power stations.
Summary An attempt was made to obtain mineral-carbon sorbents from waste products of petrochemical industry: lime from the decarbonization of river water to be used in technology and hydrocarbon wastes obtained in the treatment of industrial waste waters. The sorbents were prepared by thermal decomposition of mixtures of the mineral and carbon components. In order to optimize the preparation conditions, physicochemical studies were performed of both the mineral matrix and the mineral-carbon sorbents. Adsorption measurements involving nitrogen, water, and benzene as adsorbates were used for determining the parameters of porous structure of the obtained materials and their hydrophilic-hydrophobic properties. The properties influencing the sorptive properties of the organic compounds present in the petrochemical wastes were pointed out.