Lime Particles Research Articles

Analysis of the Influence of Additions of Flux, SiO2, and Al2O3, on the Desulfurization Efficiency of Hot Metal Using Global Desulfurization Factor

The formation of the solid phases CaS, 3CaO.SiO2 and CaO.Al2O3 around the lime particle decreases the efficiency of desulfurization by the kanbara reactor (KR) process. The addition of fluxes reduces the formation of these phases. The addition of Al and Si can also have this effect, depending on the added levels. In this study, different mixtures based on CaO with different levels of fluorspar, sodalite (Nepheline Syenite), and SiO2 and Al2O3 content were studied and used in the desulfurization process of hot metal. These mixtures were added to a bath of liquid hot metal at 1400 °C. All experiments were performed with mechanical agitation. Samples were taken at times of 5, 10, 15, and 20 min, and analyses were performed to evaluate the variation of sulfur over time. The Thermo‐Calc software was used to determine the formed phases, solid fraction, and liquid fraction of the different mixtures. With this data, different values of the Global Desulfurization Factor (FGDeS) were calculated, which was developed to evaluate and predict the efficiency of hot metal desulfurizing mixtures by the KR process. The results of showed that fluorspar was more efficient than sodalite. The FGDeS had a correlation factor (R2) above 0.9 with the desulfurization efficiency.

Experimental study on improving the performance of imitation earthen site soil in carbon dioxide environment

This study aims to explore the performance of lime-treated soil for repairing the lime soil of the earthen city wall of Kaifeng and to standardize the construction technology of lime-treated soil. The research comprehensively considered factors such as carbonation time, lime particle size, aging conditions, and lime content, and conducted various tests and analyses including triaxial mechanical properties, surface crack analysis, particle size distribution, pH measurement, composition analysis, and electron microscopy on different samples. The results indicate that the significant effect of high-concentration CO2 carbonation enhances the chemical reactions of lime soil, and an appropriate carbonation process can strengthen the bonding and density between soil particles. Under the maintenance condition of 5 % CO2, with increasing carbonation time, the crack ratio, average crack length, and average crack width of the samples decreased. Cohesion and internal friction angle of the samples exhibited an initial increase followed by a decrease, while shear strength of the samples increased by 22.93 %–75.09 %. The lime particle size has a critical impact on the formation of cracks in lime soil. With increasing lime particle size, the crack ratio, average crack length, and average crack width of the samples increased. Cohesion and internal friction angle of the samples gradually increased with increasing lime content. The increase in crack ratio, average crack length, and average crack width during natural curing of lime-treated soil samples was proportional to the lime content. Appropriate carbonation time, smaller lime particle size, and curing conditions with 5 % CO2 contribute to improving the particle size distribution of lime-treated soil samples, reducing surface cracks, and enhancing performance. However, prolonged carbonation may lead to larger lime particle size, resulting in rough and loose particles, disorganized arrangement of CaCO3 crystals, and the inability to form a cross-linked network skeleton, causing a reduction in shear strength of the samples. These research findings provide important theoretical basis and construction technology guidance for the application of lime-treated soil combined with CO2 carbonation in repairing earthen city walls.

Study on the Interaction of Polymeric Chemical Additives with Phase Change Materials in Air Lime Renders.

The interaction of microencapsulated phase change materials (PCMs) with polymeric chemical additives in an air lime binding matrix was studied. These polymer-based additives included an adhesion booster (derived from starch) and a superplasticizer (polycarboxylate ether). Two different PCMs with melting points of 18 °C and 24 °C were assayed. The microcapsules were composed of melamine, with paraffin-based PCM cores. Measurements of zeta potential, particle size distribution, adsorption isotherms, and viscosity analyses were performed to comprehend the behavior of the polymer-based additives within the air lime matrix and their compatibility with PCMs. Zeta potential experiments pointed to the absence of a strong interaction between the lime particles and the microcapsules of PCMs. At the alkaline pH of the lime mortar, the negative charge resulting from the deprotonation of the melamine shell of the microcapsules was shielded by cations, yielding high positive zeta potential values and stable dispersions of lime with PCMs. The polycarboxylate ether demonstrated the ability to counteract the increase in mixing water demand caused by the PCM addition in the lime matrix. The dispersing action of the superplasticizer on the lime particles was seen to exert a collateral dispersion of the PCMs. Conversely, despite the positive values of zeta potential, the addition of the starch-based additive resulted in the formation of large PCM-lime clumps. Air lime renders incorporating 5, 10, and 20% PCMs by weight with various dosages of these chemical additives were experimented with until the optimal formulation for the specific application of the mortars as renderings was achieved. This fine-tuned formulation effectively tackled issues commonly associated with the addition of PCMs to mortars, such as poor adhesion, crack formation, and reduced fluidity.

Particle Size of Calcium Hydroxide Prepared by Wet Digestion: Influencing Factors and Mechanism

AbstractThe wet dissolution process of lime is an effective approach for synthesizing calcium hydroxide. Process parameters and additives exert influence on the product particle. Among the process parameters, lime particle size, reaction temperature, and time have a significant impact on product particle size, followed by liquid‐solid ratio and stirring speed. The experiment proved that reaction time affects product particle size by affecting the crystal growth, while other process parameters affect the particle size by affecting the ion diffusion behavior. In terms of inorganic additives, Ca(OH)2 has minimal effect on product particle size; however, NaOH and CaCl2 can significantly enhance it with a greater dose leading to a larger increase. The experiment proved that Ca(OH)2, NaOH, and CaCl2 influence particle size through their impact on ion diffusion behavior. Regarding organic additives, soluble starch exhibits the greatest effect on product size followed by triethanolamine and polyvinylpyrrolidone K30. The experiment proved that soluble starch, triethanolamine, and polyvinylpyrrolidone K30 affect product particle size by influencing its crystallization position. Finally, an ultrafine slurry of calcium hydroxide was prepared using the lime wet digestion method based on the aforementioned research, with particle size distribution characterized by D10, D50, and D90 values of 0.303, 1.750, and 4.534 µm respectively.

CPFD simulation of an electrically heated fluidized bed calciner with binary particles

Electrifying a calciner with clean energy can cut fuel emissions and produce a stream of relatively pure CO2 from the calcination reaction (CaCO3 → CaO + CO2), which can be utilized or stored. A fluidized bed calciner offers a high heat transfer coefficient and requires low gas flow rates for operation. The design of such a reactor is studied in this work. It is not possible to fluidize raw meal directly, so a binary mixture of coarse lime particles and fine raw meal is used. The commercial Barracuda CPFD software is applied. The model was first validated against experimental results and then used to find an optimized design. The results indicate that the suggested pilot-scale fluidized bed calciner can operate between 10 and 16 t/h of raw meal feeding with a calcination degree above 90% and with negligible coarse particle entrainment. The calciner needs 0.05–0.09 kg-CO2/kg-raw-meal for the operation, so the required gas recycling is low. Overall the calciner operation is smooth, and such a design could be used for electrification combined with CCUS.

Investigation of Erosion Corrosion Caused by Drinking Water in the Faucet with Computational Fluid Dynamics

In this study, the reason for erosion-corrosion of drinking or mains water in the faucet was investigated by computational fluid dynamics. Pipes used in homes, the service sector, and industry are responsible for transporting different types of fluids from one place to another. Considering the faucet design, the SolidWorks program was used for 3D studies. In-faucet flow analyses were performed using Ansys Fluent, a computational fluid dynamics program based on the finite volume method. In the analyses, lime particles were chosen. At the end of the analysis, the amount of erosion in the faucet was obtained.

The Investigation of the Addition of Sodium Lignosulfonate to Lime Column Used For Improving the Expansive Soils

The lime column (LC) technique has been commonly used for the improvement of expansive soils. The achievement of this technique depends on the lime diffusion into the expansive soils, but lime diffusion into the expansive soil is generally a slow process due to the low permeability of these soils. In this study, sodium lignosulfonate, which is used as a superplasticizer in the concrete industry, was added to lime columns to accelerate the diffusion of lime particles. First, treated expansive clay specimens with thirty-seven 4.5 mm diameter columns were prepared in an oedometer ring. These columns were filled with two different mixtures: water-lime and water-lime-sodium lignosulphonate to investigate the effect of the addition of sodium lignosulphonate. Free swell tests were done on these treated expansive clay specimens that were subjected to different curing periods, it was observed that the treated specimens with sodium lignosulphonate lime columns (NaLS-LC) are more effective than the treated specimens with lime columns (LC). A treated expansive clay specimen (in a 30cmx30cm mold) with seven pieces of 45 mm diameter sodium lignosulphonate lime columns were prepared to observe the alteration of engineering properties of untreated expansive clay specimen (US) located between the columns. Free swell and unconfined compressive strength tests were done on the undisturbed expansive clay specimens taken from the mold between the columns. SEM-EDX analyses were made to investigate whether the ettringite mineral, which leads to swelling of the expansive soil during lime stabilization, forms or not. While the ettringite mineral formed during the curing period in the lime column stabilization method, the addition of sodium lignosulphonate to lime columns blocked the formation of the ettringite mineral. It can be stated that sodium lignosulphonate lime columns (NaLS-LC) show better performance than lime columns (LC), in the treatment of expansive clays.

Influence of Exposure Conditions and Particulate Deposition on Anodized Aluminum Corrosion

Anodizing is commonly used for corrosion protection of aluminum and its alloys in the construction industry. The anodic aluminum oxide (AAO) coating has a high ability to prevent the development of extensive pitting corrosion in aluminum substrates, particularly in marine sites, as was observed during a 10-year atmospheric corrosion study carried out in several marine and industrial sites. However, this study also evidenced that this coating can be highly affected by the deposition of particulate material in industrial polluted environments, sometimes in unexpected ways. This study presents information on the atmospheric corrosion of anodized aluminum exposed at two different chemical industrial complexes: a fertilizer production plant and a pulp and paper mill. Visual assessment of surface changes, pitting depth and mass variation with exposure were determined to quantify the degradation suffered. Additionally, SEM/EDS analyses were carried out on the exposed surfaces. Based on the results obtained, the role played by the deposition of airborne particles present in the two environments with respect to the type and level of damage observed is discussed. Deposits of roasted pyrite ash and phosphates or of wood chips and lime particles enhanced pitting corrosion or caused dissolution of the AAO coating.

Influence mechanism of alkaline environment on the hydration of hemihydrate phosphogypsum: A comparative study of various alkali

• The influence of various alkali on hydration and microstructure of HPGP was investigated. • Two opposite effects of alkali resulted by neutralization effect and ion strength effect on hydration of HPGP were observed. • Gypsum crystal morphology was significantly affected in alkaline environment except of excessive lime. • The influence effect of alkaline environment is related to its alkalinity and the impurity content in HPG. Although lime neutralization is widely recommended for raw phosphogypsum pretreatment, the influence mechanism of alkaline environment on hydration of hemihydrate phosphogypsum (HPG) is not clear. In the present paper, effect of alkaline environment created by different kinds of alkali including Mg(OH) 2 , NH 3 ·H 2 O, NaOH and Ca(OH) 2 with variable contents on hydration and microstructure of HPG were investigated. Abnormal setting and strength degradation were observed in the low-alkaline environment, while the setting time was normalized and crystal size developed in the high-alkaline environment regardless of the alkali category. Interestingly, the strength of HPG in the alkali environment only increased with excessive Ca(OH) 2 . It is verified that the formation of Ca 3 (PO 4 ) 2 from neutralization reaction in the low-alkaline environment served as retarder, and the excessive alkali beyond the threshold value of neutralization reaction played as accelerator in the high-alkaline environment, while only excessive lime particles promoted the development of gypsum crystal at c axis probably due to its absorption of Ca 3 (PO 4 ) 2 . This finding would promote the application of HPG in an alkaline environment and thus improve the utilization rate of phosphogypsum.

Performance Evaluation of Lateritic Subgrade Soil Treated with Lime and Coir Fibre-Activated Carbon

The subgrade layer’s stability considerably influences the long-term performance of pavement systems. This study investigates the influence of lime as a traditional stabiliser and activated carbon with coir fibre (ACF) as waste materials and an environmentally friendly binder to stabilise lateritic subgrade soil. Experiments, including the one-dimensional consolidation and unconfined compressive strength (UCS) tests, have been conducted to investigate the geotechnical properties of stabilised soil in various percentages of additives 3%, 6%, 9%, and 12% lime and 1%, 2%, and 3% ACF. The results demonstrate that 3% ACF and 12% lime can significantly improve the strength parameters and decrease the void ratio and permeability in the stabilised soil. Furthermore, microstructural analysis was performed before and after stabilisation for optimum content. The microstructural analysis proves that AC and lime particles fill soil voids, and gel formation binds the soil particles in the stabilised soil matrix. The results show that 3% ACF stabilised soil is comparable with 12% lime in UCS value and decreasing void ratio. Furthermore, both are suitable for subgrade of low-volume road stability according to Malaysian standards.

A novel approach for treating acid mine drainage by forming schwertmannite driven by a combination of biooxidation and electroreduction before lime neutralization

Acid mine drainage (AMD) contains abundant iron, sulfates, and various metal ions, and it causes environmental pollution. The traditional AMD lime neutralization forms a layer of iron hydroxide and gypsum on the surface of the lime particles, preventing continuous reaction and leading to excessive lime addition and neutralized sludge production. In this study, an approach for treating AMD using a cyclic process of biooxidation and electroreduction before lime neutralization was proposed, in which the Fe2+ in AMD was oxidized to Fe3+ and induced to form schwertmannite through Acidithiobacillus ferrooxidans. The remaining Fe3+ was reduced to Fe2+ using an electric field. After three biooxidation and two electroreduction cycles, 98.2% of Fe and 62.4% of SO42− in AMD precipitated as schwertmannite (Fe8O8(OH)5.16(SO4)1.37). The yield of schwertmannite reached 33.98 g/LAMD, with a high specific surface area of 112.59 m2/g. The lime dosage and sludge yield of the treated AMD in the subsequent neutralization stage (pH = 7.00) decreased by 85.0% and 74.5%, respectively, than those of raw AMD. The pilot test results showed that the integrated treatment of biooxidation–electroreduction cyclic mineralization and lime neutralization has practical applications.

The Consistency, Setting Time and Compression Strength of Pozzolanic Materials: A Taguchi Gray Validation

Currently, the focus of research is on biocement mortar and concrete. To lower the cement substance by up to 40%, lime, fly ash, metakaolin, and silica fume are utilised. The major purpose of this study was to see if adding pozzolanic materials to biocement mortar may increase its setting time, consistency, and compressive strength, as well as the interaction of these pozzolanic components with cement mortar and concrete. The pozzolanic particles by sieving interaction to affirm the uniform molecule size equivalent to 1 µm. The compressive strength, consistency, and final setting time were estimated after the fruitful maturing of concrete blocks for around 28 days. As indicated by Taguchi investigation, the exploratory arrangement Level 10 gives the general best position among other trial designs with the GRG of 0.805. Besides, the weight level of metakaolin straightforwardly impacts the general exhibition of concrete substantial shapes rather than silica smoke, lime, and fly debris particles. The affirmation concentrates on uncovered improvement in the dark social grade of 1.92%, which is equivalent to the high compressive strength of 51.285 MPa, consistency territory between 29.5 to 38.5, and final setting time is 525 min. the impact of different pozzolanic substances on the concrete's consistency and setting time. It uncovered that by supplanting the 40% normal Portland concrete (OPC) with bio concrete, the concrete's consistency improves and the level of pozzolanic materials comparative with the level of OPC can build the concrete consistency restricts and lessen the use of bio concrete with minimal expense.

The shock-induced dispersal of particle curtains with varying material density

We present results from experiments within Sandia National Labs’ multiphase shock tube on the shock-induced dispersal of dense particle curtains. The curtain spread rate was measured by tracking the position of the upstream and downstream fronts using high-speed schlieren images. The effect of particle density on the curtain spread rate was examined by comparing curtains comprised of soda lime, stainless steel, and tungsten particles at volume fractions φp=9% and φp≈20%. Various incident shock strengths were investigated, with shock Mach numbers ranging from 1.4 to 1.7. Non-dimensionalized time scales of the spreading process were generated using two scaling methods from literature; one related to the pressure ratio across a reflected shock and the other to the incompressible drag through a grid. Both scaling methods successfully collapse the spread rate of curtains with different particle densities, while only the drag-based scaling properly accounts for variation in volume fraction. A new scaling based on a simple force balance and the experimentally measured pressure differential across the curtain achieves the tightest collapse of all methods tested. Correlations are introduced for the pressure upstream and downstream of the curtain which incorporate the effect of volume fraction and successfully collapse the curtain spread rate when used with the simple force balance scaling. These results expand the parameter space over which the examined scaling methods are valid and introduce correlations that accurately estimate the pressure behind the transmitted and reflected shocks.

Technology of primary water purification

The polluted wastewater treatment is one of the main issues in agro-industrial complex. This article is devoted to the primary water purification research for its further treatment with ferrate technology. The technology implies the wastewater treatment from household and industrial waste resulting from agricultural enterprises. The ferrate technology provides a high efficiency of pretreated water purification, in comparison with other existing methods. The article substantiates such an advantage accordingly. The waste generated as a result of wastewater treatment is non-toxic and disposal. The article proposes a new method of preliminary water purification based on its treatment between a galvanic couple in the presence of the calcium hydroxide. This method can be used at water treatment plants and at enterprises carrying out industrial activities in agriculture. The method is applicable only after mechanical filtration at the stage of primary water treatment. The proposed method provides water treatment from a wide range of various origins contaminants. The article also describes an experimental equipment specially designed for the proposed method’s implementation and further research. The equipment provides continuous water treatment consuming electricity, quicklime and compressed air. To maintain the lime particles in suspension condition the airflow is supplied through an aerator. The article applies the turbidimetric analysis method to conduct an in-depth analysis of the water treatment processes and determine the relative reagent concentration in the working area. The article also proves the absence of interface formation between water and milk of lime when subjected to air flow.

Chemical injury with “packet of chunna” (lime) in children: A major ocular health concern in central rural India

Purpose: The purpose of the study is to report the hazardous effect of chunna packet (lime) on ocular surface in terms of pattern of presentation and visual outcome in children. Materials and Methods: Children of age <16 years with definitive history of chemical injury with chunna packet were analyzed. Ocular chemical injury was graded according to Modified Roper Hall grading system. Best corrected visual acuity (BCVA) and anterior segment examination evaluation were compared at time of presentation and at 3 months and categorized on the basis of WHO visual disability classification. Likelihood ratio of BCVA with time of presentation and grade of injuries were calculated using Pearson's correlation coefficient. Results: Eighty eyes of 74 children with a history of ocular burns resulting from lime were included in the study. Of these, 6 patients had bilateral burns. Mean age at the time of injury was 8.44 ± 4.29 years. Many children presented late after 3 weeks of injury (n = 24, 32.4%). The most common grade of injury was Grade 4 (n = 31, 38.8%). Clinical presentations were corneal haze (55%), limbal ischemia (65%), lime particle in fornix (36.2%), corneal scar (33.7%), and symblepharon (22.5%). Surgical intervention was advised in 54 eyes (67.5%) in the form of amniotic membrane grafting, symblepharon release, limbal stem cell transplantation, and tectonic keratoplasty. Mean BCVA at presentation was 1.65 ± 0.99 and at 3 months was 1.39 ± 1.03. Conclusion: Grade of injury and time of presentation were strongly associated with visual outcome in cases of chemical injury with chunna packet.

Effects of Aging on the Dry Shrinkage Cracking of Lime Soils with Different Proportions

In this study, the reasonable aging time of lime soils with different ratios was determined to investigate the effect of aging on the internal mechanism of the dry shrinkage cracking of lime soil. To this end, the effects of aging time, lime content, and particle size on the volume crack rate, expansion and shrinkage rate, particle size distribution, and pH were analyzed using a dry–wet cycle, screening, and pH tests. In addition, the changes in the particle structure of the samples and the formation of new substances were analyzed. The results revealed that the volume crack and expansion shrinkage rates of the sample initially decreased, and then stabilized with increasing aging time. In addition, the aging time of the sample increased with increasing lime content and particle size. Further, at the initial aging stage, the volume crack and expansion/shrinkage rates of the sample increased with increasing lime content and particle size. With an increase in the aging time, the pH increased and then decreased significantly to 0.57–1.1% at the reasonable aging time. These indicate that the pH exhibited a significant effect on the reasonable aging time, and this will provide useful insights for the restoration of lime soil sites.

The Influence of Casein Protein Admixture on Pore Size Distribution and Mechanical Properties of Lime-Metakaolin Paste

Biopolymers based on proteins are applied in the building materials technology to modify and improve their selected properties. These polymers are designed as natural admixtures that improve the workability of materials. Casein is an example of a protein-based organic polymer. It is a protein obtained from cow’s milk. The paper aimed at investigating the prospects of enhancing the strength properties of a binder prepared on a basis of metakaolin and hydrated lime. The mix was modified with powdered technical casein at 0.5%, 1%, 3%, and 5% as a partial replacement for the binder mix by mass. The study involved investigating the effect of the applied natural admixture on the flexural and compressive strengths, as well as pore size distribution. The average pore diameter decreased in the recipes with casein in the amount of 0.5% and 1%, while it increased when the amount of casein equaled 3% and 5%. Only the 0.5% casein admixture caused a decrease in the total porosity. The results show a clear dependence of the strength parameters on porosity. The admixture of casein significantly increased the flexural strength of the pastes, and decreased the compressive strength. The highest increase in flexural strength (by 205.7%) was caused by the admixture of 0.5% casein, while the greatest decrease in compressive strength (by 28%) was caused by the 3% casein admixture. The flexural strength was enhanced, i.a., due to the improved adhesion and mutual bonding of lime particles, resulting from the application of a sticky admixture. No notable difference was indicated during carbonation by the phenolphthalein test. The lime binder is characterized by a slow setting process and low mechanical strength. The results of the research showed the possibility of improving the flexural strength using small amounts of natural admixture, which may broaden the scope of application of this binder.

The Influence of Dry Hydrated Limes on the Fresh and Hardened Properties of Architectural Injection Grout.

Dry hydrated lime is an air binder often used in architectural injection grouts. This study compared the influences of three commercially available dry hydrated limes on the injection grouts’ workability and mechanical properties. The main differences between the limes were in their chemical and mineralogical composition and Blaine specific surface area. The grouts were composed of dry hydrated lime, finely ground limestone filler, water, and super plasticiser. Subsequent results obtained revealed that the Blaine specific surface area is not directly related to the fresh grout properties. Grain size distribution and shape of lime particles and their aggregates in the water suspension are key parameters influencing the following fresh grout properties: fluidity, injectability, the mixture’s stability, and water retention capacity. However, the lime injection grouts’ mechanical strengths were higher in relation to an increase in the content of portlandite and the Blaine specific surface area of the dry hydrate.

Numerical Investigation of Lime Particle Motion in Steelmaking BOF Process

Numerical Investigation of Lime Particle Motion in Steelmaking BOF Process

Effects of natural and accelerated carbonation on the properties of lime-based materials

This work aims at evaluating the influence of curing conditions on the carbonation process of lime-based mortars and pastes and on the resulting mineralogical, macro- and microstructural properties. To this end, lime-based materials (mortars and pastes) were subjected to natural (0.05 % CO2) and accelerated (5 % CO2) carbonation. The influence of factors such as water/binder ratio, lime (agglomerated) particle size (surface area) and presence of admixtures on the carbonation process was also addressed. The materials cured under the CO2-rich atmosphere carbonated faster and reached a higher degree of carbonation after only 7 days than those cured naturally for 3 years, even though total carbonation was not achieved. Nevertheless, due to the high conversion rate, the evolution of the properties of the tested materials after being subjected to accelerated carbonation for 7 days is expected to be minimal (stable properties were reached). Portlandite was mostly converted into calcite that precipitated as rhombohedral and scalenohedral crystals regardless of the curing environment. The crystals appeared to be larger and better developed in the specimens subjected to accelerated carbonation, which contributed to the higher mechanical strength displayed by these mortars.