Quicklime Research Articles

Geochemical characterization of engineered coal-combustion byproducts (CCBs): Occurrence and mobility of trace elements, implications for interactions with acidic and ambient groundwater

Fixed scrubber sludge (FSS), is a coal-combustion byproduct composed of flue gas desulphurization sludge, fly ash, and quick lime. FSS has potential usages as structural fill and capping materials in mine land reclamation because of its low permeability and acid-neutralization capacity. Sediment cores extracted from an abandoned mine land reclamation site where FSS was used as a hydrologic barrier to groundwater recharge were analyzed in an effort to quantify the chemical phases (both primary and secondary) that constitute the FSS, and to evaluate any evidence of weathering that has occurred during the 18years since emplacement. The primary solid phase is amorphous spheroids. Four different types were identified and their quantitative compositions were obtained, with SiO2, Al2O3, and FeO being the primary components. Of special concern was the occurrence and mobility of trace elements within the solid phases. Sequential extractions using different chemical reagents were conducted to analyze the concentrations of As, B, Ba, Cd, Cr, Cu, Ni, Pb, and Zn in different fractions as indications of mobility. The highest concentration of the trace elements was contained in the residual fraction, which is consistent with the amorphous spheroids being very resistant to chemical weathering. The results also suggest that the mobility of the trace elements decrease in the following order: B, Cu>Cd, Zn, Pb, Cr>Ba>Ni>As. Comparison of samples collected from the weathered edges and unweathered portions of the FSS layer reveal that a more aggressive weathering environment exists at the upper boundary of the FSS, where it is in contact with oxygenated soil water. The quantitative chemical compositions, distribution of trace elements, as well as evidence of how trace elements are released provide background data for the development a reactive transport model to simulate long-term effects of placing FSS in the natural environment; and particularly in areas that are being subjected to abandoned mine land reclamation.

A comparison of neutralization efficiency of chemicals with respect to acidic Kopili River water

Among all the renewable sources of energy, hydropower is the most potential source which is economical, non-polluting and eco-friendly. The efficiency of hydropower plant in the long run depends on many factors like water and sediment quality. Erosive and corrosive wear of machine parts like turbine is a complex phenomenon. The problem becomes more acute if the hydroenvironment is acidic in nature. The wear and tear due to corrosion/erosion caused by acid mine drainage (AMD) from coal mines reduces the efficiency and the life of the equipments. In this work, neutralization of the acidic water of the Kopili River, Assam, India was investigated using a number of basic chemicals and quantitatively estimating their effectiveness and actual requirement. The acidic water of the river, used as the cooling water, has been found responsible for damaging the equipments of the Kopili Hydro Electric Power Project (KHEP), Assam/Meghalaya, India by reducing the life of all metallic parts through corrosion. In this work, use is made of a number of basic materials like calcium carbonate, calcium hydroxide, calcium oxide, sodium carbonate, sodium hydroxide, and ammonia to examine their neutralization efficiency with respect to the acidic water and it was found that quick lime or raw lime (CaO) has the highest neutralization capacity. Suggestions have been made for meeting the problem of acidity of the river water.

Comparative Study of Quick Lime and CaO as Catalysts of Safflower Oil Transesterification

AbstractThis work aimed to contrast the performance of quicklime and CaO reagent grade as heterogeneous catalysts for the safflower oil transesterification reaction. Quicklime was characterized by TGA analysis, XRD, atomic absorption, nitrogen physisorption and by Hammett method. In the safflower transesterification reaction, four main variables were studied: addition reagents order, reagents dosage, type of catalyst and methanol-oil molar ratio. The addition reagents order was not found to be determinant on time for reaching equilibrium or maximum methyl esters yield. On the contrary, reagents dosage was found to negatively affect reaction rate and methyl esters yield. It was found that quicklime performs better than CaO and this was ascribed to an increased basicity found in the former. From the results can also be inferred that the use of quicklime as catalyst of the transesterification reaction allows the decrease of the process cost by reducing both, the reaction time and the required amount of alcohol.

Behavior of Expansive Soil Treated with Steel Slag, Rice Husk Ash, and Lime

AbstractThis paper presents the stabilization of expansive soil (C) with steel slag (SS), rice husk ash (RHA), and quick lime (L). The geotechnical properties, shearing strength characteristics, and dynamic properties of stabilized soil have been studied. The optimum mix is found to be in the proportion of 65C+20SS+5L+10RHA. The unconfined compressive test shows that strength of treated soil increases about 45 and 90% for uncured and cured samples at 30 days. The soaked California bearing ratio (CBR) test shows that the strength increases with increasing curing periods from 7 to 30 days. Laboratory strain-controlled cyclic triaxial tests have been carried out under undrained conditions to study the dynamic properties of stabilized soil for different strain amplitudes and frequencies. The stiffness of stabilized soil increases to 58–78% as compared to clay soil. This study discussed the suitability of stabilized material for subgrade pavement.

Quicklime as an alternative in the photodegradation of contaminants

Chemical oxidation is one of the many different methods of removing contaminants that has emerged recently, is an alternative method to traditional techniques. According to this research calcium peroxide is suitable choice for contaminant biodegradation in soil and ground water, but it happens at a very low speed. We hope that the method of synthesis of calcium peroxide in nano size by increased ratio of surface to volume can increase the speed of reaction and solve the problem. In the first synthesis of the material we obtained CaO instead of CaO2. Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound in obtaining hypochlorite and to neutralize acidic soils. In this study we characterize the material by X-ray scanning electron microscopy, and ultraviolet-visible spectroscopy.

Impact of cyprinid herpesvirus 3 (Koi herpesvirus) on wild and cultured fish.

Abstract Common carp is a widespread freshwater fish inhabiting lower and mid streams of rivers and shallow confined waters in Eurasia. Carp aquaculture in shallow, man-made ponds has a long history and now common carp is the most widely cultured freshwater fish species in the world. In many regions, carp aquaculture secures food for the population and carp ponds constitute characteristic elements in the landscape, which contribute to local biodiversity and water balance. Farmed and natural populations of common carp can be threatened by the cyprinid herpesvirus 3 (CyHV-3, syn. Koi herpesvirus (KHV)), the cause of KHV disease. Carp affected by this disease develop severe clinical signs and suffer from high morbidity and mortality. The infection was rapidly dispersed into naive populations by healthy appearing latently infected individuals. During initial outbreaks, the disease killed farmed carp in Europe, Israel and Indonesia as well as a high percentage of carp from natural populations in China, Europe, Japan and the USA. However, in subsequent years the number of carp mortalities declined in affected populations. In carp aquaculture, economic losses related to fish mortalities, reduced stocking density in ponds at risk of infection and trade restrictions incurred upon infected carp populations, are still significantly challenging the economic basis of carp farming. Possible control measures include disinfection of contaminated ponds by quick lime and re-stocking with virus-free fish, the development of effective vaccines and the breeding of disease-resistant carp lines.

Influence of Selected Substrates on The Growth of Common Carp (Cyprinus Carpio)

Present study was undertaken to assess the effect of sugarcane and paddy straw as an artificial substrate on the growth of Cyprinus carpio. These substrates have great potential for microbial colonization compared to other substrates. Experiments were conducted over a period of 60 days in 3 cement cisterns (2 X 5 X 1.2 m). All the three tanks were filled with 0.1 kg of quick lime, 3 kg of cow dung, sugarcane bagassae (T2) and paddy straw (T3). Control (T1) tank was containing quick lime and cow dung without substrates. Some water parameters were estimated during the study period. No significant variation was noticed in water quality between the treatments. Major groups of phytoplankton were observed during the gut content analysis. Percentage of phytoplankton ratio and growth of C. carpio in T2 and T3 tanks were significantly higher than the control. Overall survival and production of fishes were also more in these two treatments. Higher growth of C. carpio in bagassae tank may be due to its feeding on the microbial biofilm that developed on the decaying paddy straw. Percentage of phytoplankton was higher in T3 than T1 and T2 tanks, Phytoplankton is the main source of energy for fishes.

Ettringite Swelling in the Treatment of Sulfate-Containing Soils Used as Subgrade for Road Constructions

In earthworks and road construction, several cases of damage caused by the formation of the mineral ettringite are known. If soils with natural sulfate content were treated with calcium-based binders, the binder may react under certain conditions with sulfate ions to cause the mineral ettringite. Ettringite has a very high crystal water content and is therefore highly voluminous and lightweight. Due to this increase in volume, the mineral reaction may cause uplift damage. Although factors are known for this mineral reaction in the soil, quantitative testing methods and standardized prevention strategies are currently not yet available. The aim of this study is to develop the basis for a practical test specification. With the help of adequate research and testing, in the future it should be possible to avoid damage cases. First, a literature study was conducted. It became clear that the mineral content, the water supply, the chemical environment, the temperature, the pore structure and the overburden pressure in the soil are key factors. In the second step, comprehensive powder-swelling-tests have been carried out on different materials. There is a relation between the sulfate content and the volumetric expansion due to ettringite formation. Critical sulfate contents are strongly dependent on the soil and can be influenced by the choice of the binder. It could be confirmed that treatment with burnt lime caused more heaving under the same boundary conditions, than the use of cement binder.Indications to evaluate the risk of ettringite swelling were developed for engineering practice and recommendations for test methods are proposed.

Optimization of Transesterification Reaction for Biodiesel Production from Refined Palm Oil using Calcined Quick Lime Catalyst

Optimization of Transesterification Reaction for Biodiesel Production from Refined Palm Oil using Calcined Quick Lime Catalyst

Environmental impact assessment of wood ash utilization in forest road construction and maintenance — A field study

The ever increasing use of wood material as fuel for green energy production requires innovative, environmentally safe strategies for recycling of the remaining wood ash. Utilizing wood ash in forest road construction and maintenance to improve mechanical stability has been suggested as a feasible recycling option. To investigate the environmental impact of wood ash application in forest road maintenance, a two-year field experiment was conducted at two Austrian forest sites (Kobernausserwald (KO) (soil pH5.5) and Weyregg (WE) (pH7.7)) differing in their soil chemical properties. Two different ashes, one produced by grate incineration (GA) and the other by fluidized bed incineration in a mixture with 15vol% burnt lime (FBA), were incorporated in repeated road sections at a 15:85% (V/V) ash-to-soil rate. Leaching waters from the road body were collected and analyzed for 32 environmentally relevant parameters over two years. Upon termination of the experiment, sub-road soil samples were collected and analyzed for ash-related changes in soil chemistry. Even though a larger number of parameters was affected by the ash application at the alkaline site (WE), we observed the most pronounced initial increases of pH as well as Al, As, Fe, Mn, Ni, Co, Cu, Mo, and NO2− concentrations in leachates beneath GA-treated road bodies at Kobernausserwald due to the lower soil buffer capacity at this site. Despite the observed effects our results indicate that, when specific requirements are met (i.e. appropriate ash quality, sufficient soil buffer capacity below the road body, and single time-point ash incorporation within several decades), wood ash application in forest road construction is generally environmentally acceptable.

TOXICITY AND BIOACCUMULATION OF CADMIUM CHLORIDE IN NILE TILAPIA (OREOCHROMIS NILOTICUS) AND THE PROTECTIVE ROLE OF QUICK LIME (CALCIUM OXIDE)

The present study was carried out to investigate the toxic effects of waterborne cadmium chloride (CdCl2.H2O) on Oreochromis niloticus and the possible protective role of quick lime (CaO) against Cd toxicity. Fish weighing 44.55±2.96 g were exposed to 1 and 2 mg CdCl2 L-1 individually and in mixture with quick lime 60 mg CaO L-1 for 30 days followed by 15 days recovery. Although, the results revealed a slight decrease in final weight (W) and total length (TL) of Oreochromis niloticus exposed to sublethal concentrations of cadmium (1 and 2 mg CdCl2 L-1) individually and in mixture with quick lime (60 mg CaO L-1) for 30 days in comparison with the control groups, a non-significant differences were recorded in fish condition factor (K) of the different studied treatments. However, there was a significant (p gills>muscles. Moreover, quick lime play a role as a protective agent in eliminating residual Cd from the studied vital organs and improve fish growth indices to levels more or less similar to control groups.

Carbonates in leaching reactions in context of 14C dating

Lime mortars as a mixture of binder and aggregate may contain carbon of various origins. If the mortars are made of totally burnt lime, radiocarbon dating of binder yields the real age of building construction. The presence of carbonaceous aggregate has a significant influence on the 14C measurements results and depending on the type of aggregate and fraction they may cause overaging. Another problem, especially in case of hydraulic mortars that continue to be chemically active for a very long time, is the recrystallization usually connected with rejuvenation of the results but also, depending on local geological structures, with so called reservoir effect yielding apparent ages.An attempt in separating the binder from other carbonaceous components successfully was made for samples from Israel by Nawrocka-Michalska et al. (2007). The same preparation procedure, after taking into account the petrographic composition, was used for samples coming from Poland, Nawrocka et al. (2009). To verify the procedure used previously for non-hydraulic samples determination an experimental tests on carbonaceous mortars with crushed bricks from Novae in Bulgaria were made. Additionally, to identify different carbonaceous structures and their morphology, a cathodoluminescence and scanning electron microscope with electron dispersive spectrometer were applied. The crushed bricks and brick dust used in mortars production process have been interpreted as an alternative use to other pozzolanic materials. The reaction between lime and pozzolanic additives take place easily and affects the rate and course of carbonates decomposition in orthophosphric acid, during the samples pretreatment for dating. The composition of the Bulgarian samples together with influence of climate conditions on mortar carbonates do not allow for making straightforward conclusions in chronology context, but gives some new guidelines in terms of hydraulic mortars application for dating. This work has mainly methodological character, illustrating the special preparation methods used for mortars with complicated (in context of radiocarbon dating) petrographic composition. The local geology combined with finding sources of raw materials for the production of mortars is important issue in final interpretation of the 14C measurement results.

Optimization of biodiesel production from a calcium methoxide catalyst using a statistical model

Calcium methoxide catalyst was synthesized from quick lime and methanol, and further characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and energy dispersive X-ray spectroscopy (EDX). Response surface methodology (RSM) with a 5-level-3-factor central composite was applied for the calcium methoxide catalyzed transesterification of refined palm oil to investigate the effect of experimental factors on the methyl ester yield. A quadratic model with an analysis of variance (ANOVA) obtained from RSM is suggested for the prediction of methyl ester yield, and reveals that 95.99% of the observed variation is explained by the model. The optimum conditions obtained from RSM were 2.71 wt% of catalyst concentration, 11.5: 1 methanol-to-oil molar ratio, and 175 min of reaction time. Under these conditions, the produced biodiesel met the standard requirements for methyl ester yield.

Controllable Preparation of Al2O3‐MgO·Al2O3‐CaO·6Al2O3 (AMC) Composite with Improved Slag Penetration Resistance

Compact Al2O3‐MgO·Al2O3‐CaO·6Al2O3 (AMC) composite was obtained by melting technology using industrial alumina, light‐burned magnesia, and quick lime as raw materials based on the Al2O3‐MgO‐CaO ternary phase diagram. The results show that the phases of MgO·Al2O3 and Al2O3 are formed as the main framework with plate‐like CaO·6Al2O3 crystals mainly discontinuously embedded in MgO·Al2O3. The bulk density of AMC composite is up to 3.42 g/cm3, equivalent to 90.5% of the theoretical density. The synthesized compact AMC composite in the work also exhibits better slag penetration resistance than the castable based on tabular corundum due to the formation of liquid phase.

Autoclaved Aerated Concrete based on Fly Ash in Density 350kg/m3 as an Environmentally Friendly Material for Energy - Efficient Constructions

In recent years the evaluation of U-value for buildings materials has been seen. Since 1st January 2014 U-value can’t be higher than 0,25 [W/m2K], but since 2017 this value will be 0,23 and 0,20 from 2021. Therefore, a good solution to fulfill mentioned conditions is using buildings material with better thermos insulation. One of the best construction materials, which have very low λ value [W/mK] is an autoclaved aerated concrete (AAC). It's the reason why AAC is the most popular buildings material from years. AAC could be produced with using various aggregates, like sand or fly ash. Test results of thermal conductivity clearly shown that AAC based on siliceous fly ash have better λ value than sand AAC in the same density. Polish energy policy is based on coal and production AAC based on siliceous fly ash is a great solution to utilization this waste. Autoclaved aerated concrete has better λ value than other available construction materials in polish market. Lower density have good impact on environment, because lower weight caused possibility to transport more products by the same truck and also it means less waste from buildings made from AAC in the future. This waste can be used again in normal production process of AAC. Due to these facts were undertaken studies of possibility of production AAC in 350 [kg/m3] density in PGS process technology. The PGS process technology is a very specific because in a production cement is not used. As a binder are used only: quick lime, gypsum and some part of fly ash. The most important properties of AAC were tested, like: compressive strength, density, λ value or phase composition. Production AAC in lower density could be the next step to improve that it's an environmental friendly material for energy-efficient constructions.

Performance of Lime Kiln Dust as Cementitious Material

Lime Kiln Dust (LKD) is the by-product of Quick Lime (QL) production which is mostly disposed off into landfills globally. Therefore, LKD needs to be reused to reduce environmental problems and promote sustainability. This paper presents preliminary investigations on the use of LKD as a cementitious material in mortar. LKD was added to mortar mixtures to study its effect on the strength by replacing ordinary Portland cement (OPC) up to 60% by weight with LKD. Experimental results on physical and engineering properties, and compressive strengths of mortar samples containing LKD are reported. Results indicated that the initial and final setting time of the LKD mortar tested ranged from 1.08 to 2.3h and 4.58 to 5.8h respectively, and the strength values from 36.35 to 68.08MPa for 90 days strength. Furthermore, addition of LKD reduced the strength of the mortar but with a faster setting time. It can be concluded that there is a good potential for the use of LKD as a cementitious material with accelerated hydration rates.

Model-Based Optimization of Industrial Gas-Solid Reactors

Heterogeneous non-catalytic gas-solid reactors are commonly used in the production of chemicals, metals and metal oxides, for example, rotary drum reactor for producing quick lime; blast furnace, a moving bed reactor for producing iron, etc. Industrial processes involve multicomponent mixtures of solids as most of the naturally occurring materials such as minerals are multicomponent in nature. Generally the raw materials are heterogeneous and their physical and chemical characteristics vary from one source to another. The solid particles are also usually moist, the moisture content varying from season to season. The physico-chemical phenomena that take place in these reactors include flow of gases through porous media, heat transfer between the gases, solids, equipment and the environment, evaporation and condensation of moisture, reactions between gases and solids and within a single phase, melting and solidification depending on the temperatures inside the reactor, etc. The flow of particles is also of great importance especially in rotary drum and moving bed reactors. General features of the mathematical models for non-catalytic reactors are described along with models for the phenomena mentioned above. Case studies from the iron and steel industry on model-based optimization of production of direct reduced iron in a rotary kiln and induration of wet iron ore pellets on a moving packed bed reactor are discussed here.

Improvement of the decarburization rate in austenitic stainless steelmaking

In order to enhance the decarburization rate at low carbon content region during the decarburization of molten stainless steel in argan oxygen decarburization, inert gas was blown into top slag and molten steel through a top lance. The carbon content at the end point of the decarburization process was found to reach lower values than conventional levels without the inert gas top blowing. The decarburization rate might be improved, probably due to the disturbance of the slag/metal interface and the dilution of CO gas. The influence of slag in decarburization step on the decarburization and the reduction reactions of chrome oxides in the slag were also experimentally and theoretically investigated by establishing a kinetic model of the decarburization of molten stainless steel under the existence of slag containing chrome oxide. The liquid fraction of the slag appears to be essential for a more effective decarburization reaction. Countermeasures were also proposed to prevent carbon pickup from burnt lime for better slag control.

Shedding light onto the spectra of lime: Raman and luminescence bands of CaO, Ca(OH)2 and CaCO3

In microscopy studies of 19th‐century cement stone, we found free lime in the form of darkened spherical structures, as they were described in the literature already. When trying to determine their phase composition by Raman spectroscopy, we encountered contradictive assignments in literature spectra of the lime phases CaO, Ca(OH)2 and CaCO3 and observed strong spectral features that have been ignored or erroneously assigned so far. In this study we present Raman spectra of pure lime phases and of a naturally grown calcite crystal, burnt limestone (quick lime, mainly CaO), aged slaked lime putty (mainly Ca(OH)2), and carbonated lime putty (mainly CaCO3). Based on the results, we shed light mainly onto these two questions: (1) Does CaO have a Raman spectrum? (2) Which features in the spectra are luminescence bands that could be (and already have been) misinterpreted as Raman bands? We proof our assignment of luminescence bands in lime phases by using three different laser wavelengths for excitation, and give hypotheses on the origin of the luminescence as well as practical advices on how to identify these misleading features in Raman spectra. This article is mainly addressed to users of Raman spectroscopy in different fields of material analysis who might not be aware of the presence of interfering bands in their spectra. Copyright © 2014 John Wiley & Sons, Ltd.

Fluorine Gypsum Modification and Preparation of Self-Leveling Material

The fluorine gypsum was used as research object in this paper. In order to recognize the basic properties of fluorine gypsum fully, the physical and chemical properties were analyzed through different testing means. The chemical modification (additive A, sodium sulfate, quick lime) on the activity of fluorine gypsum excitation effect were studied. The best way to compound modification was determined and the mechanism of the admixture was analyzed. On this basis, the fluorine gypsum base self-leveling mortar materials was prepared and its performances were tested. Research shows that, the optimal ratio of: additive A content 2.0% (mixed), sodium sulfate content 0.8%, quick lime content 1.5%, the fluorine gypsum self-leveling material initial setting time is 2.4h, the final setting time is 5.3h, 24h flexural strength of 2.60MPa, compressive strength of 6.05MPa, the dry flexural strength of 7.68MPa, compressive strength of 22.89MPa, the performance indicators have reached the JC/T1023-2007《Gypsum based self-leveling mortar》 requirements.