Waste Limestone Research Articles

Produção e caracterização de pedra artificial para revestimento com resíduo calcário laminado em matriz polimérica

Abstract Exploiting laminated limestone from Cariri Ceará for ornamental and coating purposes has generated about 2.9 million tons of waste, which is discarded of improperly, making it important to search for alternatives to this material. Thus, this work aims to develop artificial stone for wall and floor coating, using laminated limestone waste (Cariri Stone) and a polyester resin. Initially, Cariri stone waste was characterised, and then artificial stone was made with 25% resin and 75% waste, by volume. Water absorption tests and resistance to compression, flexion, abrasion and hard body impact were performed on the composites produced. The results showed that the artificial stone presented water absorption about 5 times lower and abrasion resistance 448% higher than the natural stone, compressive and flexural strength 38.8% and 72.9% lower than the natural stone, respectively, and energy values equivalent to the commercial natural stone in the hard body impact test. It can be observed that the composite produced has a technical potential for use as a coating in civil construction, after adjusting the production process of the artificial stone.

Pemanfaatkan Subtitusi Fly Ash dan Bahan Kapur Alam untuk Peningkatan Mutu Paving Block

Utilization of waste materials as building materials is a solution to reduce waste materials that exist in nature.Fly ash as a waste product from coal combustion contains silica which can be used to increase the compressivestrength of concrete/mortar. Paving Block as a building material made of mortar composition can be increasedits compressive strength by substituting some cement material with fly ash. Fine aggregate material in the formof sand can also be substituted with natural limestone waste material. In this study, paving blocks were madeusing limestone as a substitute for fine aggregate and fly ash as a cement substitute. The ratio of materials formaking paving blocks is 1: 4. For variations of substitution materials, fly ash is used as a cement substitution.The variation of fly ash is 20% and while the limestone waste is used variations of 0%, 10%, 20%, 30% and 40%.The compressive strength test was carried out at the age of 7 days, 14 days, and 28 days. The results of the studyof compressive strength at the age of 7 days obtained a value of 12.24 MPa at a natural limestone substitutionconcentration of 20.7%. For the age of 14 days the compressive strength value is 15.27 MPa with an optimumconcentration of 20.1% at the concentration of natural limestone, while at the age of 28 days the compressivestrength value is 17.11 MPa, with the optimum concentration of natural limestone material being 20. .15%. Theincrease in compressive strength from the optimum mixture to the normal mixture was 28.93%. Based on SNI 03-0691-1996 the paving blocks produced in this study include Quality B.

Recycling of waste limestone powders for the cleaner production of epoxy coatings: Fundamental understanding of the mechanical and microstructural properties

Epoxy resins are very well suited for floor coatings, but their ingredients are harmful to the environment. Therefore, their content in coatings should be reduced, e.g. by adding a filler. In this paper, the fundamental understanding of the behavior of epoxy coatings modified with the addition of waste limestone powder was systematically assessed in terms of viscosity, mechanical properties (hardness, tensile strength, flexural strength, pull-off strength) and microstructure (powder distribution in the coating, porosity of the concrete substrate). The replacement ratio with limestone powder ranged from 0% to 29% of the mass of the epoxy resin. The following research methods were used: a flow cup, a Shore D durometer, a tensile and flexural testing machine, a pull-off tester, and a scanning electron microscope (SEM). It was observed that an increasing amount of waste limestone powder in the epoxy resin resulted in an increased viscosity of the liquid coating by 56%, an increased hardness of the cured epoxy coating by 10%, a decreased tensile and flexural strength by 62% and 59%, respectively, and a decreased pull-off strength of the coating by a maximum of 21%. Although the limestone powder caused a large increase in viscosity, the surface of the coating remained even, and the pull-off strength was still well above the standard minimum values. Microstructural analysis showed that most of the waste limestone was sedimented at the bottom of the sample, which resulted in a local increase of hardness. The novelty of the study is the investigation of the effects of replacing part of the epoxy resin and curing agent in epoxy coatings with limestone powder sourced from the production of coarse aggregate in aggregate quarries. Adding limestone powder to the epoxy coating will reduce the content of harmful substances in it, lower its price, and mean that mineral waste is recycled. The paper presents an analysis of the properties of a modified epoxy resin with regards to its use in floor coatings.

Phosphate Amendments for the Inhibition of Acid Mine Drainage Generated from Sidi Kamber Tailings Facility

The aims of this paper was to evaluate the efficiency of phosphates product and by-products from the Djebel Onk mine for the control of acidic mine drainage generated by exposure of Sidi Kamber mine tailings to climatic conditions. Kinetic tests in humidity cells were carried out according to the modified ASTM standard, was used to invistigate the geochemical behaviour of the Sidi Kamber tailings mixed with phosphate materials (phosphatic limestone wastes, raw low grade phosphate ore and phosphate mine tailings) after being characterized. All amendment compositions led to an increase of the pH of the leachate from approximately 3 to circum-neutral values. Humidity cells experiments indicated that the materials were adequate to immobilize Pb, Zn, Cu and Fe by about 99% and prevent their release through the tailings. The tests have also shown that the metals concentrations within the leachate are lower than the limits allowed by Algerian legislation for industrial liquid effluents. Among the tested material amendments, PLW was more effective than other products in immobilizing metals. The results are most probably related to their Ca-carbonate content and/or adsorption capacity.

Assessment of Limestone Waste Addition for Fired Clay Bricks.

Our aim was to investigate the feasibility of using limestone waste resulting from stone processing for the manufacturing of fired clay bricks. Waste materials were considered as a partial replacement for clays to reduce the exploitation of natural resources and as a response to the climate neutrality commitments. The samples were prepared to have a waste content of up to 15% and were fired at a temperature of 900 °C. The chemical and mineralogical composition and the physical analysis of raw materials were investigated by using SEM–EDS and XRD diffraction. The result showed an increase in CaO in the clay mixture due to the presence of limestone, which reduced the shrinkage of the products’ compressive strength, up to 55% for samples with a higher content of limestone (15 wt.%), and influenced the samples’ color by making them lighter than the reference sample.

Kaizer Hill (Modi'in), a pre-pottery neolithic a quarry site - the terraced slopes.

The research of the Kaizer Hill site (the Hilltop and its Terraces), recognized as a Pre Pottery Neolithic A (PPNA) quarry site, involved studies of the rock damage associated with the quarrying activities as well as of the recovered material remains, mostly chipped stone artifacts. We present here the results of our on-site explorations (excavations, surveys and surface-collections), focusing on the findings deriving from the Terraces. Diverse rock damage patterns were identified and described, portraying systematic rock mass-exploitation through quarrying fronts, natural rock joints and fissures enlargement, drilling and chiseling. There are multiple indications that the local bedrock (Bi’na Formation, Turonian) comprising flint and limestone was quarried under a systematic quality evaluation, leaving residual flint unsuitable for exploitation. Of interest to note that nearly all of the flint artifacts excavated and collected on the Terraces were made on raw material transported from the Hilltop (Mishash Formation, Campanian), knapped in-situ, on the quarried rock surfaces of the slopes. The flint tools bear witness to intensive use involving mainly boring and drilling. The dominant tool type is the flint axe for which a variety of waste products related to its production were found in-situ, enabling the reconstruction of axe reduction sequence. Similar axes and waste products were found in many PPN sites indicating that there was a common, widely-used scheme of making flint axes during the PPN. Interestingly, besides the flint waste, there were also limestone waste products typical of the last shaping and thinning stages of axe production, indicating that limestone axes were shaped technologically similar to the flint ones, contrary to what has been assumed before. Rare findings, such as obsidian pieces, originating from much further a-field indicate ties with other PPN communities, near and/or far. Overall, this study provides unique and novel insights on Levantine PPN lifeways.

Research on the properties of wet-ground waste limestone powder as foam stabilizer in foamed concrete

Two unavoidable problems of lightweight foamed concrete: low strength and low stability. The low stability of the foams was the main reason. Recently, the particle-stabilized foams (PSF) have been proposed because of its high stability. However, most PSF had to use nanoparticles, such as nano-silica, carbon nanotubes, which will lead to high foam density and cost. In this study, waste limestone powder (WLP) was processed by the wet grinding process (i.e., WGWLP, D50 = 281 nm), and WGWLP was used as foams stabilizer to prepare high stability foams for the preparation of high-stability and high-strength foamed concrete. The foaming agent and foams properties was investigated, and the mechanism of foams stabilization was revealed by foams microstructure, SEM and EDS; the properties of WGWLP or WLP stabilized foams in foamed concrete was revealed by compressive strength, Micro-CT and foamed concrete stability and homogeneity. Results showed that the adsorption of WGWLP on the liquid film increased the liquid flow resistance and limited the discharge of the liquid, thereby improving foams stability. In addition, WGWLP absorbed a large amount of free energy of the liquid film and limited the decreased of surface tension, thereby leading to the homogeneity and high strength of foamed concrete. Such results suggested that WGWLP was expected to as a foams stabilizer, and the foamed concrete with the WGWLP stabilized foams showed a considerable performance.

Strategies for Waste Recycling: The Mechanical Performance of Concrete Based on Limestone and Plastic Waste

Recycling is among the best management strategies to avoid dispersion of several types of wastes in the environment. Research in recycling strategies is gaining increased importance in view of Circular Economy principles. The exploitation of waste, or byproducts, as alternative aggregate in concrete, results in a reduction in the exploitation of scarce natural resources. On the other hand, a productive use of waste leads to a reduction in the landfilling of waste material through the transformation of waste into a resource. In this frame of reference, the paper discusses how to use concrete as a container of waste focusing on the waste produced in limestone quarries and taking the challenge of introducing plastic waste into ordinary concrete mixes. To prove the possibility of reaching this objective with acceptable loss of performance, the mechanical characteristics of concrete mixed with additional alternative aggregates classified as waste are investigated and discussed in this paper through the presentation of two experimental campaigns. The first experimental investigation refers to concrete made with fine limestone waste used as a replacement for fine aggregate (sand), while the second experimental program refers to the inclusion of three types of plastic wastes in the concrete. Different mixes with different percentages of wastes are investigated to identify possible fields of application. The experimental results indicate that use of limestone quarry waste and use of plastic waste are possible within significant percentage ranges, having recognized a limited reduction of concrete strength that makes concrete itself appropriate for different practical applications.

Replacement of lime with industrial wastes in hot metal desulfurization mixtures

The steel production enhancement in recent decades has increased the solid waste generation in the steel plants. Due to the increase in the environmental policies stringency, efforts have been made to give them a more appropriate destination. In this context, the internal reuse of these materials is a solution often applied by the industry to reduce production costs and to decrease slag generation. Therefore, the aim of this research is to replace calcitic lime by limestone waste and KR slag in hot metal desulfurization, which are wastes from steel production. The KR slag is the waste generated by the desulfurization process in Kambara Reactor. Experimental desulfurization tests were carried out in a resistance furnace at a temperature of 1350?C, in an inert atmosphere with constant stirring of 500 rpm. Along with the tests, simulations were carried out with FactSage 7.0 software in order to obtain the phases present in each mixture at the working temperature and compare them with the practical results. It was found that the tricalcium silicate phase (3CaO?SiO2) was present in mixtures with lower desulfurization efficiency, which shows its kinetic limitation. The use of limestone waste proved to be more efficient than the use of KR slag.

Effect of waste limestone powder on properties and sulphate-carbonate corrosion of autoclaved silicate materials

Effect of waste limestone powder on properties and sulphate-carbonate corrosion of autoclaved silicate materials

Use of Off-ASTM Class F Fly Ash and Waste Limestone Powder in Mortar Mixtures Containing Waste Glass Sand

Developing sustainable concrete with less ordinary Portland cement is a growing issue in the construction industry. Incorporating industrial by-products (such as fly ash or slag) or municipal solid wastes (such as waste glass or recycled concrete aggregate) into the concrete becomes an effective way to reduce the consumption of natural sources and carbon dioxide emission if a proper mix design is provided. The present study examines the influence of the combined use of off-ASTM Class F fly ash (FFA) and waste limestone powder (LSP) on flowability, compressive strength, and expansion characteristics of mortar mixtures containing waste glass sand (WGS). FFA and LSP were used as cement replacement while WGS was used as partial reactive siliceous river sand replacement. Material variables included different WGS replacement ratios (25%, 50%, and 75%) with river sand, LSP contents (25%, 50%, and 75%), FFA contents (15%, 30%, and 45%), and different combinations of FFA-LSP (15–10%, 15–15%, 15–30%, and 15–35%). It is shown that the single use of FFA or LSP reduces both compressive strength and flowability of mortar mixture as its replacement level increases. However, mixtures combined with FFA and LSP provide higher or comparable strength to the single LSP or FFA mixture. For the expansion characteristics due to alkali-silica reaction, the single-use of more than 30% FFA or 75% LSP has less than 0.1% expansion, which is a non-reactive aggregate criterion based on the C1260/C1567 when the test period is extended to 56 days. Moreover, the combination of FFA and LSP has a considerable reduction in expansion rate compared to the single FFA or LSP mixture.

Transition Zone Enhancement with Waste Limestone Powder as a Reason for Concrete Compressive Strength Increase.

Modification of concrete with waste materials is an increasingly common process, and they are primarily used as a partial substitution for cement. In the case of inert or nearly inert additions according to EN 206, the effectiveness of such a modification mainly concerns ecological aspects and, only to a small extent, mechanical properties. This article analyses the effect of modifying cement concrete with waste limestone powder as a partial substitution for fine aggregate. The analysed waste arises as a result of the accumulation of dust produced during the initial preparation of aggregate for the production of hot mix asphalt (HMA). In order to analyse the effect of waste on compressive strength, an experimental design was prepared with variable substitution levels and variable water/cement ratios. Compressive strength tests were performed after 28 to 90 days. Statistical analysis of the results was performed. Microscopic evaluation of the fractures of the samples was carried out to clarify the mechanism of transition zone enhancement, which resulted in an increase of compressive strength of the composite.

Using Waste Limestone Powder as Filler in a Toxic Epoxy Resin Coating and Its Influence on Adhesive Properties

Epoxy resin is very harmful to the environment, e.g. it affects aquatic organisms, irritates the skin and eyes and causes allergic reactions. Because, the epoxy resin is an expensive building material, this study presents research on reducing its mass needed to make a floor coating, through the use of waste limestone powder as a filler. This additionally supports the recycling of the mineral waste. The main aim of the research was to find the amount of waste limestone powder that would not adversely affect the adhesive properties of the epoxy resin coating. The tests were carried out on a concrete element, with two differently prepared substrate surfaces using grinding and left raw after concreting. The epoxy resin coating contained waste limestone powder in an amount of 0 to 29% was examined. The pull-off strength of the coating was examined at three points for each coating composition on both types of the surfaces. The aim of the research was achieved by obtaining the satisfactory results of the pull-off strength for epoxy resin filled with the waste limestone powder.

Passive treatment of acid mine drainage from the Sidi-Kamber mine wastes (Mediterranean coastline, Algeria) using neighbouring phosphate material from the Djebel Onk mine

Passive abiotic treatment of acid mine drainage (AMD) was investigated using phosphate mining residuals (raw low-grade phosphate ore, phosphatic limestone wastes, and phosphate mine tailings) from the Djebel Onk mine, Algeria. Laboratory batch tests were performed using the main expected lithologies of phosphate materials in contact with synthetic AMD, which had a low pH (3.08) and contained high concentrations of Fe (600 mg/L), Mn (40 mg/L), Mg (10 mg/L), Zn (20 mg/L), Cu (25 mg/L), As (50 mg/L), and sulfate (3700 mg/L). Phosphate materials were used as an oxic limestone drain to evaluate the increase in the pH of the AMD and metal removal by sorption and precipitation mechanisms. The results showed that all phosphatic lithologies were efficient in the passive treatment of AMD. The pH rapidly increased from 3.08 to 8.47 during water-rock interactions. The neutralization potential comparisons also showed that the phosphatic limestone wastes neutralized more acid than other lithologies. In addition, metals were efficiently removed (95.5% to 99.9%) by all materials. The results of batch sorption tests showed that the concentrations of metals in residual leachates did not exceed the Algerian criteria for industrial liquid effluents. Overall, these findings indicate that passive systems using phosphatic materials from the Djebel Onk mine can be effective for AMD treatment. The use of these mine wastes for passive treatment of AMD would allow the development of integrated management strategies for these residual materials in the context of sustainable development of phosphate mining.

Behavior of geopolymer concrete deep beams containing waste aggregate of glass and limestone as a partial replacement of natural sand

The geopolymer concrete has outstanding physical properties and positive impact on environment compared to conventional concrete. Present endeavor highlights a strategy for management of glass and limestone waste to recycle them in geopolymer concrete deep beams. In this study, 126 geopolymer concrete samples were made for investigating the mechanical properties of geopolymer concrete with the sand replacement ratio of 0–15% by weight in increments of 5%. In addition, seven Reinforced geopolymer concrete deep beams of 600,150,150 mm were casted with respect to the concrete mix and their performance was examined in four-point bending test as per ASTM C78/C78M considering sand replacing ratio of 0–15%. Moreover, proper material constitutive relationships were selected to simulate the performance of geopolymer concrete incorporating waste aggregate. Consequently, a nonlinear finite element solution in ANSYS 11.0 was developed using these constitutive models to predict the behavior of beams. Experimental observations revealed that the use of waste lime and waste glass aggregates reduced the compressive and tensile strength of geopolymer concrete. Furthermore, the loss in strength using waste glass aggregate was less than 15% when compared to geopolymer concrete with waste limestone. Whereas, 5–15% sand replacing with waste aggregate resulted in an average reduction of 19% in loading capacity of the deep beams. The degradation in the ultimate load of the beams with limestone aggregate was 46.6% lower than that for members containing waste glass aggregate. The strain energy of the deep beams containing waste limestone was enhanced by increasing the waste aggregate content from 5% to 15%. Whilst increasing the ratio of replacement for glass mixes led to a decrease in final compressive strain. The outputs of the numerical analysis, in terms of loading capacity of the geopolymer concrete deep beams, were in good matching with the experimental results.

Structurally controlled synthesis of synthetic gypsum derived from industrial wastes: sustainable approach

AbstractBACKGROUNDThe article demonstrates the possibility of processing spent sulfuric acid and limestone waste into high‐quality synthetic calcium sulfate dihydrate.RESULTSA comprehensive technological scheme for the production of synthetic gypsum from industrial waste was proposed. Mathematical models of the main technological stages were obtained. In the process of acid processing, at the stage of separating gypsum from the mother liquor, a filtrate was formed containing ions such as Na+, K+, Mg2+ and SO42−, which are some of the main ions necessary for plant growth. A positive effect was found when using the filtrate as fertilizer.CONCLUSIONSOptimal values of synthesis parameters that allow one to obtain crystals of the maximum size were determined. A positive effect when using the filtrate as fertilizer was found. These results mean that it is possible to obtain a technology for gypsum with a closed production cycle (waste‐free technology) derived from waste limestone and spent sulfuric acid. © 2021 Society of Chemical Industry (SCI).

Efficient reclaiming phosphate from aqueous solution using waste limestone modified sludge biochar: Mechanism and application as soil amendments

A novel limestone-modified biochar derived from sewage sludge was prepared to reclaim phosphorus (P) from aqueous solution, and the potential application of P-laden biochar as soil amendments was also investigated. The limestone-modified biochar demonstrated excellent performance on phosphate recovery from aqueous solution in a wide range of pH (2.0–11.0), with maximum adsorption capacity of the biochar (Limestone/sludge mass ratio of 3:1) up to 231.28 mg P/g, which was 10.7 times that of the original sludge biochar. The adsorption was well described by the pseudo second-order model and Langmuir isotherm model. According to the adsorption thermodynamic parameters, the phosphate adsorption was spontaneous (ΔG0 < 0) and endothermic (ΔH0 > 0) so that increasing the temperature was beneficial to adsorption. Characterization analysis by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope-energy dispersive spectrometer (SEM-EDS) proved that electrostatic attraction, surface complexation and brushite (CaHPO4.2H2O) precipitation were the dominant mechanism. The P-laden biochar exhibited an excellent ability to be reused as a new slow-release P fertilizer for soil. Pot experiment results showed that the treatment of P-laden LB 3:1 (P content of 22.8%) addition (1 wt%) significantly promoted Indian Lettuce germination (increasing by 14.4%), plant height (increasing by 18.6%), and dry biomass (53.0%) compared with the control, though it underperformed compared to commercial fertilizer.

Improvement of dissociation efficiency of limestone fines using vibration pneumoseparation

This paper presents the results of research into dissociation of minerals on a vibro-pneumatic separator composed of a series of cascade sections through which the classified material passes. Formation of the two-phase air flow in the working space of the separator is examined, and the causes of settling of small particles on the walls of the separator housing are analyzed. From the theoretical findings and experimental proof, dissociation efficiency of fines increases exponentially with growing frequency and amplitude of vibration effect on the body of the pneumatic separator. With the increasing amplitude and frequency of vibrations of the separator housing walls, the speed of particle settling on the walls decreases, which enhances the separation efficiency. The greatest effect is achieved when the vibrator is mounted on the front wall of the separator. This can be explained by turbulization of gas flow in the wall area due to the vibration effect exerted on it by the front wall. Vibration of the walls of the pneumatic separator leads to leveling of concentration of particles along the channel section and, consequently, to reduction in the number of fine particles settled. It is established that the maximum efficiency of separation of limestone waste from the Khomyakovsky Deposit by the boundary size of 1 mm is achieved with the following combinations of vibration parameters of the separator body: vibration amplitude A = 2.5 mm; vibration frequency &omega; = 250 s&ndash;1.

Research on sustainable development of fine-grained material cement slurry

Sustainability has become a major focus of the cement industry, largely due to the carbon dioxide emissions associated with Portland cement production. In grouting engineering, ordinary cement slurry has high viscosity, poor fluidity and groutability and is prone to blockage. In this study, a cement slurry was designed using superfine cement (SC). Fine-grained ultrafine fly ash (UFA) waste was used, part of which is used to replace cement, and a certain amount of nontoxic mSiO2·nH2O (SH) is extracted from limestone waste and mixed with the commonly used admixture polycarboxylic acid water reducer (PAWR) to ensure its physical properties in practical engineering applications while reducing its viscosity, increasing its fluidity, and reducing the occurrence of clogging. To determine the optimal mix ratio of the cement slurries mixed with various materials, the characteristics of each material were analyzed through the single-factor test of the multiperformance test, and the orthogonal test mix ratio was designed based on the single-factor test results. Through the Taguchi grey correlation analysis method, the orthogonal test data were analyzed to find the optimal mix ratio. A performance test of the cement slurry with the optimal mix ratio was carried out, and its sustainability was analyzed. Combined with the Discrete Element Method (DEM) and the Voronoi Calculation Method (VCM) methods, UDEC numerical simulation software is used to simulate and analyze the general laws of cement slurry fluidity. The results show that the cement slurry with the optimal mix ratio of SH, SC, PAWR and UFA materials has good fluidity and groutability, has the characteristics of sustainable development, and can be applied to practical projects.

Effects of alternative ecological fillers on the mechanical, durability, and microstructure of fly ash-based geopolymer mortar

In this research, the performance of fly ash/GGBS geopolymer mortars made with different quarry waste powder as filler materials by substituted the river sand fine aggregate with different ratios was evaluated based on the mechanical, physical, durability properties and microstructural analysis. Limestone waste, marble waste and basalt waste powder were used as filler materials developing eco-friendly and economical geopolymer from industrial waste as a promising sustainable area of research. A series of tests were conducted such as on strength properties, ultrasonic pulse velocity (UPV), physical properties, abrasion resistance test, splitting tensile strength and microstructure analysis (SEM). The samples were elevated at the high-temperatures of 200 °C, 400 °C, 600 °C and 800 °C. Results conducted that the use of limestone waste powder and marble waste powder up to 50% ratio improved the geopolymer composite's strength. The three filler geopolymer composites positively affected water absorption, strength properties and abrasion ratio results. The current article’s finding has indicated a potential solution, presenting another geopolymer class followed by the successful use of fly ash and quarry waste as significant asset materials. The output of this study is commercially expected to be effective intercession for waste recycled and friendly environmental management conclusions.