Mixture Of CaCO3 Research Articles

Pulse Electrodeposition for Carbonate-Rich Deposits from Seawater

Seawater electrodeposition is gaining renewed interest in the context of sustainable development, both to build climate-resilient coastal infrastructure and for ocean-based decarbonization applications. Most of the applications benefit from CaCO3-rich deposits, but constant-voltage electrodeposition results in a mixture of CaCO3 and Mg(OH)2, especially at higher voltages where precipitation rates are more desirable. The use of pulse voltages can help control interfacial pH that dictates the precipitation reactions. Here, we explore the use of pulse electrodeposition as a function of pulse frequency and duty cycle to control deposit composition. The most CaCO3-rich deposits were obtained under 10 Hz frequency and 10% duty cycle conditions for the voltage window investigated (−0.8 V to −1.2 V vs. SCE). While pulsing the voltage increases the amount of CaCO3 deposited, the energy required per gram of CaCO3 is significantly higher (14.5×) when compared to the base case of applying a constant voltage of −0.8 V vs. SCE. Further optimization of pulse conditions, electrode materials, and system configuration could lead to finding parameters that result in exclusively carbonate deposits without compromising precipitation rates, which may prove to be more useful for corrosion protection, coastal infrastructure, and other applications in sustainable development.

A new strategy for CO2 storage and Al2O3 recovery from blast furnace slag and coal fly ash by employing vacuum reduction and alkali dissolution methods

With the growing awareness of carbon emission reduction and environmental protection, the CO2 storage using industrial solid waste as the storing carrier has recently gained an extensive attention. A new strategy for CO2 storage and Al2O3 extraction from blast furnace slag (BFS) and coal fly ash (CFA) has here been proposed by using vacuum reduction and alkali dissolution methods. The results show that the mullite (Al6Si2O13), gehlenite (Ca2Al2SiO7), and akermanite (Ca2MgSi2O7) in CFA and BFS were converted to Fe–Si alloys and CaO·xAl2O3 during vacuum reduction. Thereafter, the CaO·xAl2O3 was dissolved in a mixed solution of Na2CO3 and NaOH to generate CaCO3 and NaAl(OH)4. Finally, the Fe–Si alloy and CaCO3 mixture in the alkali leaching residue were separated using magnetic separation to realize the CO2 storage and metal recovery. In this process, the CO2 storage capacity attained 241 kg t−1 BFS and the Al2O3 recovery efficiency was 80.61 %, indicating that an efficient storage of CO2 and Al2O3 extraction were achieved simultaneously. In addition, there was almost no generation of waste slag or waste liquid in this process, which indicated that an environmentally friendly and efficient process for CO2 storage, as well as valuable metal recovery from industrial solid wastes was obtained.

Bioinspired Diffuse Reflectance Coatings for Fabric-Based Radiative Coolers

As global temperatures rise due to anthropogenic climate change, thermal comfort becomes an increasingly critical area of research. While most buildings are equipped to cool and heat their interiors, this process is very energy intensive; a smarter approach is to enable personal thermal management using clothing and textiles. In particular, we are interested in the ability to use textiles and clothing to cool bodies in extreme heat, both to maintain comfort and prevent deaths in urban deserts due to heat stroke. One innovative category in this realm is radiative coolers—surfaces adept at manipulating light to passively regulate temperature. These coolers achieve sub-ambient surface temperatures by selectively reflecting or refracting sunlight wavelengths (200nm-2.5µm) while emitting infrared light (8-13µm). This unique capability allows them to maintain cooler temperatures, even when exposed to direct sunlight and the open sky. Coatings facilitating this cooling action typically consist of a porous media filled with refractive gaps, requiring specific substrates and custom production processes, thereby limiting their applications. Furthermore, the necessity of low light transmission presents issues in creating fabrics that radiatively cool while still retaining high breathability and durability. In this study we present a method whereby an optically active coating comprised of a mixture of CaCO3 and BaSO4 microcrystals was applied to multiple fabric substrates to create a radiative cooler. Through the use of photoinitiated chemical vapor deposition (pICVD), a 5 µm thick layer of a hydrophilic polymer polyhydroxyethyleneacrylate (pHEA) was deposited on the fabric substrate. Subsequently, through serial immersion in solutions containing Ca and Ba ions and solutions containing CO3 and SO4 ions, inorganic microcrystals were grown directly on the surface of the fabric. These microcrystals formed with a large polydispersity, endowing the coating with excellent reflective properties in the solar spectrum. Mie scattering calculations confirmed that the CaCO3 and BaSO4 microcrystals were primarily responsible for scattering. Further simulations using finite difference time domain software revealed, surprisingly, that surface-immobilized crystals provided the highest reflection efficiency, indicating that composite fibers with embedded particles are not as efficient. Upon outdoor testing, the device showed a cooling ability of 8°C compared to an uncoated fabric, achieving a maximum cooling of 4°C below ambient temperature. Washing and durability testing of the coating found no degradation in the material's performance, affirming its resilience and long-term effectiveness.

Fouling Reduction and Thermal Efficiency Enhancement in Membrane Distillation Using a Bilayer-Fluorinated Alkyl Silane-Carbon Nanotube Membrane.

In this study, we report the robust hydrophobicity, lower fouling propensity, and high thermal efficiency of the 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FAS)-coated, carbon nanotube-immobilized membrane (CNIM) when applied to desalination via membrane distillation. Referred to as FAS-CNIM, the membrane was developed through a process that combined the drop-casting of nanotubes flowed by a dip coating of the FAS layer. The membranes were tested for porosity, surface morphology, thermal stability, contact angle, and flux. The static contact angle of the FAS-CNIM was 153 ± 1°, and the modified membrane showed enhancement in water flux by 18% compared to the base PTFE membrane. The flux was tested at different operating conditions and the fouling behavior was investigated under extreme conditions using a CaCO3 as well as a mixture of CaCO3 and CaSO4 solution. The FAS-CNIM showed significantly lower fouling than plain PTFE or the CNIM; the relative flux reduction was 34.4% and 37.6% lower than the control for the CaCO3 and CaCO3/CaSO4 mixed salt solution. The FAS-CNIM exhibited a notable decrease in specific energy consumption (SEC). Specifically, the SEC for the FAS-CNIM measured 311 kwh/m3 compared to 330.5 kwh/m3 for the CNIM and 354 kwh/m3 for PTFE using a mixture of CaCO3/CaSO4. This investigation underscores the significant contribution of the carbon nanotubes' (CNTs) intermediate layer in creating a durable superhydrophobic membrane, highlighting the potential of utilizing carbon nanotubes for tailored interface engineering to tackle fouling for salt mixtures. The innovative design of a superhydrophobic membrane has the potential to alleviate wetting issues resulting from low surface energy contaminants present in the feed of membrane distillation processes.

Shell Composition Analysis of European Flat Oyster (Ostrea edulis, Linnaeus 1758) From Marmara Sea, Türkiye: Insights Into Chemical Properties

The chemical structure of Ostrea edulis (O. edulis) shells was investigated in this work. The study determined zero charge points (PZC) of Ostrea edulis shells. The shell surface charge status is indicated by the PZC value. It was found that the shell PZC value was 8.30. The shells were subjected to Energy Dispersive X-Ray Spectroscopy (EDS) analyses and scanning electron microscope (SEM) pictures. The main structure of calcium carbonate (CaCO3) is made up of carbon, oxygen, and calcium atoms, which were found in the largest quantities based on the EDS data. The structure of CaCO3 was supported by Fourier Transform Infrared Spectroscopy (FT-IR) analysis. As part of the study, X-Ray Diffraction (XRD) investigations were conducted, and it was found that the shell structures are primarily composed of an aragonite and CaCO3 mixture. As is well known, CaCO3, which makes up roughly 94% of the shell, is the primary constituent of bivalves’ shells. This research offers a thorough examination of the chemical makeup of O. edulis shells. This study is thought to serve as the foundation for further research on the biological and chemical characteristics of marine species.

Electroosmotic permeability in kaolinite and CaCO3 poultice mixtures

Electrokinetic treatment of masonry for desalination or electroosmotic dewatering depends on a poultice, in which the electrodes are placed, which fulfills several purposes. Poultice composed of kaolinite and CaCO3 have been shown to have good workability and high pH buffering capacity. In this work, the electroosmotic (EO) permeability is studied in different kaolinite - CaCO3 mixtures. In addition, the effect on EO of using NaCl as a mixing solution is investigated. A special cell is used to test the EO in the specimens. A phenomenological approach, based on the potential gradient and the flux of solution, was used to calculate the EO flow rate and EO permeability coefficient. Results showed that by increasing the concentration of CaCO3 in the poultice mixture, the EO flow rate decreased and the poultice with 80 % CaCO3 and more did not have any EO flow. Furthermore, the ionic strength in the mixing solution decreases the EO flow rate.

Production of a syngas and CaO by desorption-enhanced reverse water–gas shift of CaCO3 with H2

A syngas production method is investigated that combines in a single reactor the enhanced decomposition of CaCO3 with H2 and the reverse water–gas shift (RWGS) of part of the CO2 evolved during calcination. The method exploits Le Chatelier’s principle, to overcome RWGS equilibrium limitations by conducting such reactions with an excess of CaCO3 and at sufficiently high temperatures to maintain the partial pressure of CO2 close to the calcination equilibrium. The decomposition and RWGS reactions result in a ‘desorption-enhanced reverse water–gas shift’ (DERWGS) equilibrium of CaCO3 on H2, observed in experiments performed in a packed-bed reactor operated between 1023 and 1123 K and 1 and 5 atm when feeding H2 to a mixture of CaCO3, with or without a RWGS catalyst. Product gases containing over 25 vol% CO, with an H2/CO molar ratio of 2 and below, were obtained. In experiments without the use of an RWGS catalyst, the DERWGS equilibrium was also approached thanks to the catalytic activity of CaO for RWGS. The syngas analogue obtained from these reactions opens the door to new processes for synthetic fuel production from CaCO3 and renewable H2.

Niobium ore genesis in a capsule

Experiments were conducted to test the hypothesis that carbonatite-hosted Nb deposits owe their origin to the metasomatic alteration of K-feldspar-rich fenite by carbonatitic magma. This involved reacting K-feldspar with a synthetic mixture of CaCO3, MgCO3, Mg(OH)2, CaF2, and Nb2O5. At the experimental conditions, a phlogopite-rich calcite-bearing metasomatic rind containing pyrochlore formed on the K-feldspar. This supports the above hypothesis and also explains the origin of fenite-associated glimmerite, the association of glimmerite with calcite carbonatite, and the genesis of the carbonatite-hosted ores that supply the bulk of the world’s niobium.

Performance of inert particles as lubricant additives compared to fully formulated industrial forming oils in sheet metal forming

The increasingly restrictive legislation on the use of hazardous chemicals in lubricant formulation necessitates the use of less hazardous lubricant additives in the sheet metal forming industry. The tribological performance of calcium carbonate (CaCO3) as a green lubricant additive was evaluated in comparison to commercially available forming lubricants used in industry, some of which contain hazardous chemicals such as chlorinated paraffins to enable their function. The lubricants were tested by four-ball wear testing, four-ball weld load testing, and bending-under-tension. The ease of cleaning of surfaces formed with the different lubricants was evaluated by methods used in industry and the viscosity was evaluated using standard methods. The CaCO3 mixtures showed a better performance than commercial lubricants in four-ball wear testing, worse performance in four-ball weld load testing, worse cleanability, and a similar development of drawing force in bending-under-tension over 1000 consecutive strokes. When added to fully formed commercial lubricants, the particles degrade the performance of the lubricant in resisting adhesive wear but improve its capacity for resisting abrasive wear. Surfaces of formed parts after bending-under-tension testing with CaCO3 mixtures were scratched, while parts formed using commercial lubricants showed less scratching. The effect of including particles in a commercial lubricant depended on the application, either degrading it or improving it. It is therefore clear that the use of solid particles as lubricant additives should be constrained to selected applications where abrasive wear is a dominant wear mechanism.

The Effect of Different Particle Sizes of SiO2 in Sintering on the Formation of Ternesite

Ternesite is synthesized through sintering a mixture of CaCO3, SiO2, and CaSO4 in a molar ratio of 4:2:1. Ternesite has a hydration rate between ye’elimite and belite in an aluminum-containing environment, and is considered to be a new material that can be used to enhance the performance of calcium sulphoaluminate cements. This experiment investigated the influence of different particle sizes of SiO2 on ternesite formation. Controlled partial pressure sintering was employed within the temperature range from 1100 °C to 1200 °C, with a 72 h incubation period. The highest purity of ternesite in the samples reached 99.47% (500 nm SiO2 sample). The analysis results from scanning electron microscopy and an energy dispersive spectrometer indicated that the particle size of SiO2 exerted a significant influence on the formation of ternesite. In the preparation of ternesite from 10 μm particle size SiO2, traces of calcium silicate were found in the product. The results of a thermal analysis further demonstrated significant distinctions in the thermal stability of ternesite prepared with SiO2 of different particle sizes. Additionally, the crystallinity of ternesite was influenced by the particle size of SiO2, consequently impacting the hydration performance of ternesite–calcium sulphoaluminate cement.

Deconvolution of DSC peaks of high-temperature phases in an illite/smectite–CaCO3 mixture

Heat flow curves measured in differential scanning calorimetry (DSC) may contain overlapping peaks corresponding to multiple-step processes. To analyze the individual steps in such a process, a deconvolution of the overlapping peaks into the individual peaks is necessary. Using the Frazer-Suzuki function to describe asymmetric peaks, we apply a nonlinear least squares analysis to perform the decomposition of heat flow curves measured for a mixture of an illite/smectite clay with 19.6 wt.% of CaCO3. The curves contain two overlapping peaks associated with the crystallizations of gehlenite and anorthite in the temperature interval from 900 °C to 1050 °C. Several versions of the decomposition analysis may be used, depending on the number of optimized parameters. These may range from four to all eight parameters (four for either peak). We applied the versions with seven and eight fitting parameters, yielding results that are in very good agreement with the experimental data.

Young’s modulus of illitic clay and CaCO3 mixtures during thermal treatment up to 1100 °C

The dynamic Young’s modulus of samples, made from a mixture of illitic clay and laboratory grade CaCO3 with 6% addition of 3% solution of polyvinyl alcohol in anorthite stoichiometry is studied. The samples with different CaCO3 contents, namely 17.6%, 21.6%, and 25.6% are made by dry pressing. The measurements of the dimensions, mass, and resonance frequency of the samples are performed for the determination of the dynamic Young’s modulus in the temperature interval from 25 °C to 1100 °C. The influence of the amount of CaCO3 on the Young’s modulus of the samples is investigated. During the firing of the studied samples, the values of Young’s modulus increase due to the liberation of physically bound water (up to 250 °C) and sintering (above 850 °C). The values of Young’s modulus after a firing reach 16.7 – 18.4 GPa, which is about 6 – 9 times higher as the values for the raw samples.

PROSES KARBURASI PADAT PADA BAJA KARBON RENDAH DENGAN TEMPERATUR 900 C, 1000 C, DAN 1100 C

This study aims to determine the effect of temperature on the solid carburizing on increasing the hardness value of ST37 steel. This solid carburizing uses temperature variations of 9000C, 10000C and 11000C, with a holding time of 30 minutes. The material used is a mixture of CaCO3 and coconut shell charcoal with mineral water as a cooling medium. The test carried out was the Rockwell hardness test which was carried out in the Mechanical Engineering Materials Testing Lab of Politeknik Negeri Ketapang. From the test results for ST37 steel, the average hardness obtained in the raw material = 48.3 HRB, then in each carbonation treatment at a temperature of 9000C = 48.6 HRB, a temperature of 10000C = 48.9 HRB, a temperature of 11000C = 49.1 HRB. Carburized steel plates with a temperature of 9000C, 10000C and 11000C the test results are harder than the raw material.

Chemical Composition, but Not Specific Surface Area, Affects Calcium Retention of Nanostructured Calcium Compounds in Growing Rats

Background: Low dietary calcium intake and bioavailability may adversely affect bone health. Reducing the size of calcium compounds increases their specific surface area (SSA, expressed as m2/g) and may increase calcium dissolution and bioavailability.Objective: We investigated the influence of SSA and chemical composition on the bioavailability of calcium and compared in vitro calcium dissolution with in vivo absorption.Methods: Calcium dissolution was measured in 0.1 M phosphoric acid, whereas color and pH changes of foods were assessed as indicators for potential sensory performance. Calcium absorption, retention, and fractional retention were measured over a 5-d balance study in growing Sprague-Dawley male rats after 21 d of feeding. Femoral and vertebral bone mineral density (BMD) and extensive tissue histology were assessed at study end. The influence of SSA on calcium bioavailability was assessed by comparing the groups fed pure calcium carbonate (CaCO3) with increasing SSAs of 3, 36, and 64 m2/g (CaCO3_3, CaCO3_36 and CaCO3_64), whereas chemical composition was assessed by comparing the smallest CaCO3_64, a 50:50 wt:wt percent solution mixture of CaCO3 and hydroxyapatite_94, and pure hydroxyapatite_100.Results: In vivo, fractional calcium retention from hydroxyapatite_100 (mean ± SEM: 54.86% ± 0.95%/5 d) was significantly greater than from CaCO3_64 (49.66% ± 1.15%/5 d) (P = 0.044). Increasing SSA of the pure CaCO3 did not significantly improve calcium retention. Across all 5 groups, there were no significant differences in BMD or tissue calcification by histology. In vitro calcium dissolution did not correlate with SSA or calcium absorption. In selected food matrixes, hydroxyapatite_100 caused less color change and/or smaller pH increase than did the other calcium compounds.Conclusions: Our findings suggest that chemical composition rather than SSA is a predictor of nanostructured calcium bioavailability and that in vitro dissolution of nanostructured calcium does not predict in vivo absorption. Although its phosphorus content may limit use in some populations, nanostructured hydroxyapatite may be a promising calcium compound for food fortification.

Kovdor to Oldoinyo Lengai—The missing link in carbonatitic magma evolution

Abstract Experiments were conducted to test the hypothesis that interaction of a carbonatitic magma with quartz-rich rocks plays a key role in shaping carbonatite complexes. The host rocks were represented by quartz, and the magma was represented by synthetic mixtures of CaCO3, MgCO3, and Na2CO3. With increasing distance from the quartz, the reaction between the carbonate liquid and quartz produced a domain of Na(Ca)-rich silicate glass, a domain of metasomatic wollastonite, diopside, and forsterite, and a carbonate-rich domain. This zonation reproduces that observed in many carbonatite complexes, e.g., Kovdor, Russia. The experiments provide strong evidence that carbonatitic magma/host-rock interaction controls the evolution of carbonatite complexes and explains how Mg-Ca-carbonatitic magmas from the mantle can evolve to produce the natrocarbonatites and associated alkaline silicate rocks observed at Oldoinyo Lengai, Tanzania.

Effect of soil supplementation with mineral-organic mixtures on the amount of maize biomass and the mobility of trace elements in soil

The application of calcium fertilisers and organic fertilisers or materials is an alternative allowing to reduce soil acidification and increase the organic matter content. Under Polish conditions, where soils belonging to the agronomic category of light and acidic soils predominate, such an approach can bring measurable benefits in improving physical, chemical, and biological properties of soils. However, it should be noted that until now these treatments have usually been applied separately; therefore, the aim of this study was to determine the effect of the combined application of calcium carbonate fertiliser with leonardite (CaLO) and with poultry litter (CaPL) on the amount of maize biomass, the content of trace elements in the biomass, and selected soil properties, including the mobility of trace elements in soil. The study was conducted as a pot experiment. The experimental design included 4 treatments: soil with no fertilisers (Control), soil with mineral fertilisers (NPKS), and soil with mineral fertilisers and the addition of a mixture of CaCO3 and leonardite (NPKS+CaLO) as well as CaCO3 and poultry litter (NPKS+CaPL). The study showed a substantial increase in the amount of mainly aboveground parts of maize biomass after applying mixtures of CaCO3 and organic materials. Despite the lack of significant differences, the relative increase in the chlorophyll a content in NPKS+CaLO and NPKS+CaPL treatments was over 7 % compared to NPKS treatment. The obtained results are inconclusive as to the effect of the applied mixtures on the trace element content in maize biomass. Soil supplementation with CaLO mixture significantly reduced cadmium, copper, and lead contents in maize aboveground parts, while the zinc content was higher compared to the NPKS-fertilised treatment. Soil supplementation with CaPL mixture decreased the zinc content in maize aboveground parts, while the cadmium, copper, and lead contents were higher compared to the NPKS-fertilised treatment. Soil pH significantly improved after applying CaLO and CaPL mixtures. Soil supplementation with CaLO and CaPL was vital for reducing the content of water-soluble forms of Cd and Zn, while for Pb and Cu, we observed an increase in these forms of trace elements in the soil. The treatments with CaLO and CaPL had lower content of NH4EDTA-extracted elements compared to the control.

Mechanical stability and heat transfer improvement of CaO-based composite pellets for thermochemical energy storage

Two types of composite pellets of CaO (non-shelled and shelled) are examined to improve the mechanical stability and heat transfer efficiency of a CaO/H2O/Ca(OH)2 thermochemical energy storage system. To prepare a non-shelled composite pellet, a mixture comprising calcium carbonate (CaCO3) and carboxymethyl cellulose (CMC) is pressed into a cylindrical shape and then calcinated. Subsequently, a shelled composite pellet is obtained by calcinating the pressed mixture of CaCO3 and CMC after embedding it into silicon carbide diesel particle filters. Analyses of the morphology variations of the non-shelled composite pellets in hydration/dehydration operations show that the change in their bulk volume is reduced significantly. CaO crystals pile up layer by layer in a rod-like shape in the pellets, thereby preventing volume expansion. The numerous micropores in the pellets enhance the gas–solid reactivity. The shelled composite pellets attain the advanced performances in mechanical stability, reactivity and output/storage density as thermochemical energy storage materials.

Surface analyses of low carbon steel and stainless steel in geothermal synthetic Na-Ca-Cl brine saturated with CO[formula omitted

In a geothermal power plant, certain precautions should be taken to ensure a good efficiency. Indeed, it is important to avoid degassing of the geothermal fluid and to prevent corrosion issues. To address these problems, the gas–liquid equilibrium has to be controlled and the characteristics (composition, temperature…) of the fluid known as well as the nature of the material used.For this reason, in this paper, a laboratory-scale device was developed in order to simulate natural like conditions and achieve corrosion tests. The corrosion behaviour of two materials, a carbon steel (DC01) and a stainless steel (304 L), has been investigated. The testing materials have been exposed to a synthetic brine which composition is similar to the Upper Rhine Graben water formation. The brine was saturated with 2 MPa of CO2 and heated up to 50 °C and 100 °C.Surfaces of tested metals were analysed by spectroscopic (XPS) and microscopic (SEM) methods in order to characterize corrosion products and to get more information onto the corrosion mechanisms process.The use of the laboratory prototype coupled with surface analysis methods allowed to better understand CO2 corrosion in geothermal environment. The role of the brine chemistry and the impact of temperature and CO2 dissolved concentration have been studied in this work. Indeed, different natures of corrosion products regarding the material composition and microstructure have been highlighted. A mixture of CaCO3 and FeCO3 scale is identified on the carbon steel whereas the stainless steel exhibits a mixture of Cr(OH)3 and FeCO 3 on its surface.

Mixture of CaCO 3 Polymorphs Serves as Best Adsorbent of Heavy Metals in Quadruple System

This study compares and analyzes removal of Pb (II), Cu (II), Mn (II), and Zn (II) from aqueous solution as individual ions (monometal system) or as mixed ions (quadruple system) by commercial laboratory-grade calcium carbonate (C–CaCO3) and as-synthesized CaCO3 (S–CaCO3) as adsorbents. This was performed to determine whether heavy metal ion adsorption can be influenced by the polymorphic phases of CaCO3. C–CaCO3 and S–CaCO3 were equally efficient in the removal of Pb (II) and Cu (II) from a monometal system. However, S–CaCO3 exhibited only 49.3% ± 0.14 heavy metal removal when compared with 96.7% ± 0.08 by C–CaCO3 in a quadruple system. FTIR and HR-SEM analysis revealed C–CaCO3 consisted of a mixture of calcite and aragonite polymorphs, whereas S–CaCO3 was pure calcite polymorph. These results indicated the importance of identification of the polymorphic phase and phase transformation in any experiment while utilizing CaCO3 as adsorbent.

Transformation of Cr under sintering of Ca-rich solid waste with kaolin: Analysis of multi-element coupled interactions

The high toxicity of Cr–Ca compounds generated during the heat treatment of solid waste will heavily threat the environment. In this work, a kind of Ca-rich river sludge which is bound with Ca and heavy metals was combusted with kaolin under 900 °C for 3 h in a muffle to study the transformation of Cr. The effects of kaolin on Cr transformation were investigated through sequential extraction, the risk assessment of heavy metals, and constant pH leaching test, also combined with crystal phase analysis of Ca–Al–Si minerals. The experimental results showed that the formation of Ca10(SiO4)3(SO4)3Cl2 was inhibited by the addition of 10% (mass fraction) kaolin and the released Cl promoted the evaporation of target elements in priority while 30% kaolin addition further inhibited the solidification of Cr. Furthermore, the effect of NaCl and CaCO3 on the Cr solidification by kaolin were also explored by leaching procedure or XRD analysis of calcination products of their mixtures. It should be noticed that the addition of kaolin in Cr2O3–CaCO3 mixture will directly react with CaCrO4 and fixed the generated Cr2O3 into internal layered structure, preventing its re-oxidization by the free CaO. This work aims to help illustrate the Cr transformation with existence of Ca during sintering of Ca-rich solid wastes and reduce the Cr contamination in future.