Carbonate Of Lime Research Articles

Influence of relative humidity on carbon sequestration and crystal morphology of air lime: A sustainable building material

This study investigated the carbon sequestration potential of air lime by carbonation in two different relative humidity conditions. The carbonation rate and amount of carbon dioxide captured were quantified using weight gain and various analytical techniques. Samples cured in high relative humidity showed almost complete carbon capture by sequestering 94.8 % of carbon dioxide from atmospheric air within 56 days, with calcite crystal formation and a high crystallinity index. Similarly, samples cured in low relative humidity conditions showed slightly less carbonation around 83.8 % with different calcium carbonate polymorphs like aragonite and vaterite, along with amorphous calcium carbonate. Results demonstrated that carbonation of lime is a promising technology for carbon capture and utilization in buildings as non-load bearing mortars or plasters and could be used to reduce carbon dioxide levels in the atmosphere.

Multi-scale analysis of carbon mineralization in lime-treated soils considering soil mineralogy

Mineral carbonation is emerging as a reliable CO2 capture technology that can mitigate climate change. In lime-treated clayey soils, mineral carbonation occurs through the carbonation of free lime and cementitious products derived from pozzolanic reactions. The kinetics of the reactions in lime-treated clayey soils are variable and depend primarily on soil mineralogy. The present study demonstrates the role of soil mineralogy in CO2 capture and the subsequent changes caused by carbon mineralization in terms of the unconfined compressive strength (UCS) of lime-treated soils during their service life. Three clayey soils (kaolin, bentonite, and silty clay) with different mineralogical characteristics were treated with 4% lime content, and the samples were cured in a controlled environment for 7 d, 90 d, 180 d, and 365 d. After the specified curing periods, the samples were exposed to CO2 in a carbonation cell for 7 d. The non-carbonated samples purged with N2 gas were used as a benchmark to compare the mechanical, chemical-mineralogical, and microstructure changes caused by carbonation reactions. Experimental investigations indicated that exposure to CO2 resulted in an average increase of 10% in the UCS of lime-treated bentonite, whereas the strength of lime-treated kaolin and silty clay was reduced by an average of 35%. The chemical and microstructural analyses revealed that the precipitated carbonates effectively filled the macropores of the treated bentonite, compared to the inadequate cementation caused by pozzolanic reactions, resulting in strength enhancement. In contrast, strength loss in lime-treated kaolin and silty clay was attributed to the carbonation of cementitious phases and partly to the tensile stress induced by carbonate precipitation. In terms of carbon mineralization prospects, lime-treated kaolin exhibited maximum carbonation due to the higher availability of unreacted lime. The results suggest that, in addition to the increase in compressive strength, adequate calcium-bearing phases and macropores determine the efficiency of carbon mineralization in lime-treated clayey soils.

Cradle-to-grave environmental and economic sustainability of lime-based plasters manufactured with upcycled materials

The production of CaO for lime-based plaster and render generates 1.2 t CO2/t CaO, consumes 1.78 t CaCO3/t CaO. This research paper examines the environmental and economic performance of upcycling paper mill sludge (PMS) and carbide lime (CL) as replacements for hydrated lime (HL) in lime-based plasters production. For this, a new Cradle-to-Gate industrial-scale inventory is designed, upscaling recent lab-scale innovations, investigating PMS and CL treatment processes, followed by a Cradle-to-Grave scenario analysis. The results show that incorporating CL in the plaster yields better environmental and economic outcomes compared to PMS. The intermediate treatment for CL is cost-effective and has low carbon emissions. The upcycling of CL eliminates 100% of CO2 emissions, while PMS reduces emissions by 11%. The production of the traditional binder HL is more expensive than upcycling PMS (+69%) and CL (+65%), with carbon taxes accounting for 35%, 44% and 15% of production costs, respectively. The effect of an equilibrated carbon price to ensure fair market competition, considering the natural carbonation of lime (carbon credit) is discussed, and the cost assessment reveals a 47% and 54% reduction for upcycled plasters using PMS and CL, respectively, compared to traditional HL.

Mechanical Properties of Concrete that Replace Cement Partly by Using Eggshell Powder

There are many problems due to the cement industry around the world besides the air pollution by greenhouse gas emissions. The issue occurs when a large amount of CO2 is released during the process of converting calcium carbonate lime (CaCO3) into calcium oxide lime (CaO), which is the primary component of cement. This transformation is made in an oven-dry by burning fossil fuels, in a process that releases more carbon dioxide. Substitute materials are usually industrial and municipal wastes .In this study, eggshell powder (ESP) are considered cementitious materials and were added to the cement at different percentages to reduce the cement contents in the concrete industry. Eggshell powder amounts of 0%, 5%, 10%, and 15% by weight were added as ordinary Portland cement (OPC) replacements. The advantages are associated with the high calcium content and good filling effect of eggshell powder. The curing ages were 7, 14, and 28 days. This study evaluates the fresh and hardened properties of concrete. Also, EDX and SEM analyses were conducted on the ESP and concrete to analyze the microstructure. Adding ESP accelerates the concrete setting time compared with the control mix. At the optimal content of 10%, ESC has various advantages compared to conventional concrete. Key Words: Concrete, Eggshell powder, Microstructure characteristics, strength.

A pathway to negative CO2 emissions by 2050: The contribution of the lime industry to a carbon‐neutral Europe

AbstractLime is used for a wide range of processes and in a variety of products that are essential to our quality of life and to a sustainable European economy. This roadmap presents a reference pathway for the European lime sector to achieve negative CO2 emissions by 2050. It is estimated that by 2030, direct CO2 emissions will be achieved through fuel switch to decarbonized/low carbon energy vectors, as well as the first steps in the deployment of carbon capture utilization and storage (CCUS). By 2050, it is estimated that the European lime sector will deliver negative emissions. This will be achieved through full deployment of decarbonization technologies and techniques (crucially CCUS, fuel switch to decarbonized/low carbon energy vectors, and energy‐efficient/electrified kiln technologies) as well as by carbon removal from the atmosphere through lime carbonation during its use phase. The roadmap further explores the key prerequisites that will allow the industry to deliver a reduction in emissions. Altogether, this research demonstrates and quantifies the potential of the European lime sector to deliver net negative emissions by 2050, thus contributing to the overall carbon neutrality of European society.

An investigation of the global uptake of CO2 by lime from 1930 to 2020

Abstract. A substantial amount of CO2 is released into the atmosphere from the process of the high-temperature decomposition of limestone to produce lime. However, during the lifecycle of lime production, the alkaline components of lime will continuously absorb CO2 from the atmosphere during use and waste disposal. Here, we adopt an analytical model describing the carbonation process to obtain regional and global estimates of carbon uptake from 1930 to 2020 using lime lifecycle use-based material data. The results reveal that the global uptake of CO2 by lime increased from 9.16 Mt C yr−1 (95 % confidence interval, CI: 1.84–18.76 Mt C) in 1930 to 34.84 Mt C yr−1 (95 % CI: 23.50–49.81 Mt C) in 2020. Cumulatively, approximately 1444.70 Mt C (95 % CI: 1016.24–1961.05 Mt C) was sequestered by lime produced between 1930 and 2020, corresponding to 38.83 % of the process emissions during the same period, mainly contributed from the utilization stage (76.21 % of the total uptake). We also fitted the missing lime output data of China from 1930 to 2001, thus compensating for the lack of China's lime production (cumulative 7023.30 Mt) and underestimation of its carbon uptake (467.85 Mt C) in the international data. Since 1930, lime-based materials in China have accounted for the largest proportion (about 63.95 %) of the global total. Our results provide data to support including lime carbon uptake into global carbon budgets and scientific proof for further research of the potential of lime-containing materials in carbon capture and storage. The data utilized in the present study can be accessed at https://doi.org/10.5281/zenodo.7896106 (Ma et al., 2023).

Cement–ash concrete with the addition of lime kiln dust

The article is devoted to the study of the effect of lime kiln dust (LKD) on the properties of concrete mixtures and concrete using Portland cement and fly ash. A possible mechanism for the formation of the structure of cement–ash paste with the addition of LKD is analyzed in detail. The positive effect of LKD on hydration (an increase in the content of hydration water by 40.50%) and structure formation due to an increase in the alkalinity of the cement–ash paste is shown. Using the method of the experiment mathematical planning, experimental–statistical polynomial models of the concrete component (Portland cement, fly ash, dust, superplasticizer, and aggregates) content influence on the workability of the concrete mixture and the strength of concrete at different ages were obtained. The introduction of lime–carbonate components into concrete mixtures increases the strength of concrete by 27%–54%. At the same time, with the consumption of cement up to 200 kg/m3, ash 100.150 kg/m3, and LKD 50.100 kg/m3, it seems possible to obtain concrete with a compressive strength of 20.30 MPa. The obtained models were analyzed, which made it possible to establish the positive effect of LKD additive on the compressive strength of concrete at the age of 7–180 days.

Gas-solid carbonation of lime produced by thermal decomposition of dolomite

Gas-solid carbonation of lime produced by thermal decomposition of dolomite

Effects of sticky rice on the carbonation reaction of lime-treated soil in earthen sites

Earthen sites with important historical, artistic, social, cultural, and scientific values have suffered serious damage due to long-term influences from various natural factors. The sticky rice and lime composite shows the potential to be applied to the protection of earthen sites. The carbonation of lime has a significant impact on the engineering properties of earthen sites. The main purpose of this study is to investigate the effect of sticky rice on the carbonation reaction of lime-treated soil in earthen sites. The results indicated that sticky rice can inhibit the carbonation reaction of lime, resulting in a reduced calcium carbonate content. The inhibition effect of sticky rice on carbonation reaction of lime could be attributed to the limitation of gaseous water and CO2 gas diffusion. Sticky rice had both binding effect and inhibition effect on lime-treated soil, and its mechanical properties depended on the dominant effect after these effects cancelled each other. When the lime content was ≤6%, the addition of sticky rice can increase the strength of soil. When the lime content was >6%, however, the addition of sticky rice resulted in a decrease in strength. In addition, the carbonation of the outside of the cylindrical sample was higher than that of the inside. These findings can increase the understanding of protecting earthen sites with sticky rice and lime composite, and optimize the application of sticky rice and lime composite.

Effect and mechanism of two different types of waterproof admixtures and silica fume on the hydration and mechanical properties of natural hydraulic lime

In this study, the effect and mechanism of two different types of waterproof admixtures, silica fume and their composite usage on the hydration and mechanical properties of natural hydraulic lime were evaluated. Specifically, X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy and scanning electron microscopy were utilized to investigate the phase composition, micromorphology, and chemical state in-depth. The results showed that, combination of two waterproof admixtures with cementitious matrix via forming Si-O-Si bond and calcium-containing compound weakened the contact between water and cementitious matrix, leading to retardation of hydration. However, silane impregnant more or less promoted formation of hydrated product thanks to the reaction between polycondensated silane and Ca(OH)2, and improved mechanical strength of natural hydraulic lime-based mortars. Hydration and carbonation of natural hydraulic lime was inhibited by bulk modification with silicone-acrylic latex. Partial substitution of natural hydraulic lime by silica fume promoted the hydration and hardening process of cementitious system, leading to improvement of mechanical strength. What is more important, composite modification compensated strength weakening which was the common shortcoming caused by bulk modification of cementitious system with waterproof admixtures.

Phase transition and morphology evolution of precipitated calcium carbonate (PCC) in the CO2 mineralization process

The indirect CO2 mineralization by using Ca/Mg-containing industrial alkaline by-products or wastes is a promising way for mitigation of CO2 emissions and valorization of wastes, although plagued by the utilization of precipitated calcium carbonate (PCC) if low-value product is obtained. It is difficult to acquire specific PCC with targeted morphology for commercial use since many parameters change in the gas–liquid carbonation process. In this work, the phase transition and morphology evolution behavior of PCC precipitated during carbonation of 0.1 mol·L−1 NH4Cl Ca-rich solution were studied. Results show that the polymorph transformation from rhombohedral calcite to spherical vaterite was found during the gas–liquid carbonation process, which is different from the traditional carbonation process (aqueous carbonation of lime). A promising result is that pure spherical vaterite of industrial interest was obtained under the studied conditions. In addition, to achieve conversion of CO2(g) into desired morphology of PCC, the feasibility of introducing additives (ethylene glycol and citric acid) into the gas–liquid carbonation system was also evaluated in terms of CO2(g) adsorption and PCC polymorphs control. Finally, the mechanism of additives on the growth and morphology of crystalline CaCO3 was investigated by FTIR and interpreted at the atomic level.

Effects of sugarcane bagasse ash and nano eggshell powder on high-strength concrete properties

There are many problems due to the cement industry around the world besides the air pollution by greenhouse gas emissions. The problem arises when a dense quantity of CO2 is emitted through the conversion of calcium carbonate lime (CaCO3) into calcium oxide lime (CaO), the main ingredient in cement. This transformation is made in an oven-dry by burning fossil fuels, in a process that releases more carbon dioxide. In this study, sugarcane bagasse ash (SCBA) and nano eggshell powder (NEP) are considered cementitious materials and were added to the cement at different percentages to reduce the cement contents in the concrete industry. Sixteen high-strength concrete (HSC) mixtures experimented with in this investigation contain SCBA and NEP other than the control mix. The SCBA and NEP were added to cement content by 5 %, 10 %, 15 %, and 20 % for SCBA, and 2.5 %, 5 %, and 7.5 % for NEP. This study evaluates the fresh and hardened properties of HSC. Also, EDX and SEM analyses were conducted on the SCBA, NEP, and HSC concrete to analyze the microstructure. The experimental results exhibited that the setting time of HSC is delayed by increasing the SCBA ratio by 25 % of the control mix. Adding NEP accelerates the HSC setting time compared with the control mix. The best mixture result includes 5 % NEP with 15 % SCBA, which exhibited a dense form, no pores, and no cracks, as analyzed in the microstructure.

Carbon Capture Potential in Waste Modified Soils: A Review

Carbonation of lime modified soil could capture carbon dioxide (CO_2) alongside strength improvement for road pavement materials. Due to large amounts of 〖CO〗_2 emissions and increasing cost of primary soil stabilizers such as lime and cement, the use of lime-based wastes have been encouraged. This paper reviews waste materials based on separate potential for 〖CO〗_2 capture and strength improvement of soils. Such wastes include cement kiln dust (CKD), saw dust ash (SDA), steel slag, basic oxygen steel (BOS) slag, ground granulated blast furnace slag (GGBS), coal fly ash (CFA) and cattle bone powder (CBP). Based on separated considerations of 〖CO〗_2 capture and strength improvement, CKD, SDA, BOS and GGBS have shown to have both high 〖CO〗_2 capture and strength improvement potential for weak soil. Future laboratory studies on lime-based waste (such as CKD and SDA) treated soil for combined 〖CO〗_2 capture and strength improvement need to be conducted.

Thermodynamic modelling of hydrogen production in sorbent‐enhanced biochar‐direct chemical looping process

AbstractHydrogen (H2) has been widely considered the clean energy carrier of choice for emerging renewable energy generation technologies. However, H2 is a secondary fuel mainly derived from natural gas. Over the past decades, research on developing H2 production technology that reduces carbon emissions has gained momentum due to increasing atmospheric levels of carbon dioxide (CO2). This study proposed a new sorption‐enhanced (SE) and biochar‐direct (BD) integrated chemical looping system for hydrogen production from biomass gasification, using iron oxide as an oxygen carrier, calcium oxide (CaO) as a CO2 adsorbent, and biochar as a reducing agent. In this study, a thermodynamic model with the proposed sorbent‐enhanced biochar‐direct (SE‐BD) chemical looping hydrogen production (CLHP) process has been developed using an Aspen Plus simulator. The effect of important process parameters, including the reactor temperature, the syngas composition, and the molar feeding ratios of iron oxide/syngas, biochar/syngas, and CaO/syngas on the performance in terms of product gas composition, iron oxide conversion, H2 yield, H2 purity, and reactor heat demand has been evaluated. The simulation results show that the addition of biochar significantly enhances the overall hydrogen yield compared to the conventional CLHP process; whereas the addition of CaO‐sorbent was found to significantly improve the H2 purity. Moreover, the exothermic lime carbonation further reduced the thermal requirements of the process. In addition, this thermodynamic simulation demonstrates that the sorbent‐enhanced biochar‐direct chemical looping hydrogen production (SE‐BD‐CLHP) process can achieve a wide operating window for complete iron oxide (Fe3O4) reduction by adjusting the CaO and biochar feeding ratio.

Pemanfaatan Teknologi Mikoriza di Tanah Karst Petani Desa Karangasem Kabupaten Gunung Kidul Yogyakarta

The community of Karangasem Village works as farmers. The land condition in Karangasem village dry land , high content of lime carbonate and shallow soil solum so that the percentage of plant life is low. To overcome these problems, it is necessary to increase knowledge of land management that is suitable for karst areas. Prior to the application of new technology, it is necessary to measure the level of knowledge of farmers towards technology and changes in attitudes that occur after understanding the technology. These factors encourage Community Service (PkM) with assistance to farmers which aims to foster farmer changes that include the level of knowledge, skills, abilities, attitudes, and motivation for farming activities carried out. The PkM method is done by focus group discussions , counseling, training and assistance for mycorrhizal applications on woody plants, icons of rare tree conservation and land management. The implication of the activity is that 92% of farmers who do not know about mycorrhizal inoculation technology and its benefits for soil and plants become 100% aware and know the benefits of mycorrhizal application.. Changes in farmers' attitudes have implications for the pattern from chemical agricultural changes to organic farming and environmentally friendly agriculture.

Triaxial Tests on Hempcrete for Prefabricated Blocks Production

Nature-based solutions are sustainable building materials produced recovering and enhancing agricultural biomasses which are by-products or waste of crops as, for example, rice, flax or hemp. Specifically, this research investigates the properties of hempcrete which is produced mixing lime, which acts as binder, and hemp shives, as vegetal aggregate. Hempcrete is characterized by breathability and excellent insulating properties, moreover it is a sustainable material due to the introduction of vegetal material and due to the carbonation of lime which gives further carbon dioxide sequestration. The mechanical properties of the material are largely variable and, in this research, triaxial tests have been performed to evaluate this experimental methodology as a technique applicable to evaluate the mechanical behavior of this material. The tests have been performed on samples produced with the same mix design developed by an Italian manufacturer for the production of prefabricated hempcrete blocks. These building components are used as non-loadbearing blocks, they are introduced in building envelopes or in indoor partition walls as insulating elements.

Swertia Chirata: A Comprehensive review of its abundant medicinal properties

Swertia chirata (S chirata), (Family Gentianaceae) is a well-known herbaceous plant. It is very popular in traditional systems of medicine like Unani, Ayurveda, and Siddha. It is commonly used in Unani medicine, for several pharmacological effects including Musaffi-i-Dam (blood purifier), Muqawwi-i-Mida (stomachic), Muhallil-i-Awram (anti-inflammatory), Muqawwi-i-Qalb wa Jigar (tonic to heart and liver), Mulattif (demulcent), Mudir (diuretic), Mulliyin (laxative) properties. It is used for chronic fever, malaria, anemia, liver disorders, hypertension, dyspepsia, gastritis, ulcers, constipation, and skin diseases, and is included in many pharmacopoeial and non-pharmacopoeial preparations. The entire plant contains ophelic acid, two bitter glycosides chiratin, and amarogentin. It also contains resins, tannin, gum, carbonate, and phosphate of potash, lime, and magnesia. Extensive studies on S. chirata have been carried out by various researchers and a wide spectrum of its pharmacological actions have been explored which includes anti-inflammatory, anti-diabetic, antimicrobial, and antioxidant properties. The present review is an effort to provide a detailed survey of the literature, scientific researches of pharmacognostical characteristics, chemical composition, and pharmacological activities of this plant.

Characterization and durability assessment of fibre-reinforced tung oil lime putties for restoration

As a traditional organic-inorganic hybrid binding material, tung oil lime putty has a prospective application in ancient architecture restoration. In this paper, we prepared nine mixtures by adding hemp fibre to tung oil lime putties. The physical-mechanical characteristics, pore structure, mineralogy, infrared spectra and micromorphology of the curing-aged pastes were first determined. Then, the resistance of the specimens to the action of freeze-thaw and salt crystallization cycles was assessed. Tung oil acted as a modifier for lime carbonation and imparted water repellence. Paste-enriched oil exhibited a more compact microstructure and a significant reduction in water absorption. The fibre addition converted lime pastes to fibre-reinforced composites and promoted the carbonation progress of lime. Fibre reinforcement further hampered the development of cracks and pores, macroscopically characterized by the bending ductility in curing and a slight compressive strength increment after frost ageing of the salt solution. The composite with 1.0% fibre and 5% tung oil addition presented favorable resistance towards freeze-thaw cycles and salt crystallization degradation.

A petrochemical study of Mughal plasters of Quila-I-Ark, Aurangabad with respect to technology and repair

This paper reports the mineralogical composition of western India's 16-17th century Mughal plasters of Quila-I-Ark, Aurangabad to prepare compatible repair mortar and document ancient Indian lime technology. Analytical studies were undertaken for aggregate grain size distribution, thin section analysis, Fourier Transform Infrared Spectrometer (FTIR), X-ray diffraction (XRD), and chemical composition of the plasters by x-ray fluorescence (XRF analysis). The analysis revealed the inclusion of large size basaltic aggregate grains mostly sourced from the water channel of nearby Harsullake. Some of the plaster works show prominent inclusion of small size grains pointing different periods of construction. Creamy white zeolites were found specifically added in the mortar mix to maintain a certain level of humidity during the dry season. The zeolite is highly porous and breaks easily both in dry and wet conditions. The calcite rich limestone with traces of magnesium was sourced as raw material for the plasters. Based on mineralogical composition and binder/aggregate ratio, three phases of historical constructions were documented. FTIR and thin section analysis showed the mixing of some proteinaceous adhesive juice in the lime for improvement in rheological and waterproof properties. The high quantity of large size aggregate grains ensured better carbonation of lime and the source of aggregates remained the same for all phases of historical constructions. The cementation index (C.I.) and hydraulicity index (H.I.) vary between 0.10 to 0.96 and 0.20 to 3.43, respectively showing the plaster is aerial lime with traces of magnesium. The plaster is feebly hydraulic as the hydraulic component calculated varies between 0.88 to 6.10 percent in different samples. A moderate strength plaster with a lime/silica ratio close to 0.33 was prepared for most phases of construction except a few isolated locations. The analytical data will now help to prepare compatible mortar with identical additives for a major repair.

Effects of carbonation on chemo-mechanical behaviour of lime-treated soils

In the paper, a multi-scale experimental investigation on the occurrence of carbonation and its effect on chemo-mechanical behaviour of lime-treated soil has been presented. Carbonation affects chemo-mineralogical evolution of lime-treated soils depending on the time scale at which reaction mechanism takes place. In the short term, a progressive carbonation of portlandite is responsible for the formation of calcium carbonate with consumption of available lime for pozzolanic reactions (lime carbonation). In the long term, carbonation of the secondary phases resulting from pozzolanic reactions weakens the bonding effects induced by hydrated compounds (carbonation of secondary reaction products). Mineralogical and microstructural features of lime-treated and carbonated samples have been monitored at increasing curing times by means of microstructural analyses. Triaxial drained compression tests have been performed on treated samples cured in different conditions for short and long term. Mineralogical investigations showed precipitation of calcium carbonate for lime-treated samples exposed to atmospheric CO2 since the very short term. Exposure of lime-treated sample to CO2 after precipitation of hydrated phases favoured decalcification of cementitious compounds and formation of calcium carbonate. In both cases, precipitation of calcite relevantly affects the mechanical behaviour of lime-treated samples. From the observed behaviours, it will be possible to take into account relevant factors for performing the best practice finalized to efficient and durable soil treatment.