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This study proposed and examined a new process flowsheet for treating neutral mine drainage (NMD) from an open-pit gold mine. The process consisted of three sequential stages: (1) in situ hydrotalcite (HT) precipitation; (2) low-cost carbon substrate driven microbial sulfate reduction; and (3) ferrosol reactive barrier for removing biogenic dissolved hydrogen sulfide (H 2 S). For concept validation, laboratory-scale columns were established and operated for a 140-days period with key process performance parameters regularly measured. At the end, solids recovered from various depths of the ferrosol column were analysed for elemental composition and mineral phases. Prokaryotic microbial communities in various process locations were characterised using 16S rRNA gene sequencing. Results showed that the Stage 1 HT-treatment substantially removed a range of elements (As, B, Ba, Ca, F, Zn, Si, and U) in the NMD, but not nitrate or sulfate. The Stage 2 sulfate reducing bioreactor (SRB) packed with 70 % (v/v) Eucalyptus woodchip, 1 % (w/v) ground (<1 mm) dried Typha biomass, and 10 % (w/v) NMD-pond sediment facilitated complete nitrate removal and stable sulfate removal of ca. 50 % (50 g-SO 4 m -3 d -1 ), with an average H 2 S generation rate of 10 g-H 2 S m -3 d -1 . The H 2 S-removal performance of the Stage 3 ferrosol column was compared with a synthetic amorphous Fe-oxyhydroxide-amended sand control column. Although both columns facilitated excellent (95-100 %) H 2 S removal, the control column only enabled a further ca. 10 % sulfate reduction, giving an overall sulfate removal of 56 %. In contrast, the ferrosol enabled an extra 99.9 % sulfate reduction in the SRB effluent, leading to a near complete sulfate removal. Overall, the process successfully eliminated a range of metal/metalloid contaminants, nitrate, sulfate (2500 mg-SO 4 L -1 in the NMD to <10 mg-SO 4 L -1 in the final effluent) and H 2 S (>95 % removal). Further optimisation is required to minimise release of ferrous iron from the ferrosol barrier into the final effluent., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The utilization of municipal solid waste incineration residues in alkali-activated granulated ground blast furnace slag (GGBFS) has garnered substantial interest for its potential in sustainable solid waste management and achieving a low-carbon footprint. However, incorporating these residues often leads to the deterioration of mechanical properties. This study revealed the role of silica fume (SF) and nano-silica (NS) derived from olivine within a sodium carbonate-activated GGBFS system incorporating air pollution control (APC) residues. The dosage of silica additives and APC residues ranges from 0 - 6 wt% and 0-15 wt%, respectively. The mechanical properties, reaction kinetics, phase composition, microstructure and carbonation resistance of the blended binder were investigated. Results indicated that SF slightly improved the early compressive strength with the formation of C-(A)-S-H gel (Ca/Si = 1.47, Al/Si = 0.23), hemicarboaluminate and hydrotalcite; reactive NS retarded the activation of GGBFS and inhibited the formation of hemicarboaluminate and hydrotalcite, while promoting the formation of C-A-S-H gel (Ca/Si = 1.01, Al/Si = 0.23), resulting in an impressive 80.3 % enhancement in compressive strength. Notably, NS-modified samples exhibited decreased carbonation resistance due to increased porosity and C-(A)-S-H gels that are vulnerable to carbonation. Conversely, 2 % SF addition decreased the diffusion rate of CO 2 , and APC residues improved the carbonation resistance by facilitating the formation of C-(A)-S-H gel with a higher Ca/Si ratio. This study provided an alternative management practice for APC residues with favorable early strength development and offered new insights into using silica additives to enhance waste-combined alkali-activated materials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Concerns about the health of the planet have grown dramatically, and the dyeing sector of the textile industry is one of the most polluting of all industries. Nanoclays can clean dyeing wastewater using their adsorption capacities. In this study, as a new finding, it was possible to analyze and quantify the amount of metal ions substituted by anionic dyes when adsorbed, and to determine the optimal amount of nanoclay to be used to adsorb all the dye. The tests demonstrated the specific amount of nanoclay that must be used and how to optimize the subsequent processes of separation and processing of the nanoclay. Hydrotalcite was used as the adsorbent material. Direct dyes were used in this research. X-ray diffraction (XRD) patterns allowed the shape recovery of the hydrotalcite to be checked and confirmed the adsorption of the dyes. An FTIR analysis was used to check the presence of characteristic groups of the dyes in the resulting hybrids. The thermogravimetric (TGA) tests corroborated the dye adsorption and the thermal fastness improvement. Total solar reflectance (TSR) showed increased radiation protection for UV-VIS-NIR. Through the work carried out, it has been possible to establish the maximum adsorption point of hydrotalcite.

Magnesium hydroxide is commonly used as a coagulant for treating reactive dyes wastewater. However, the flocs are relatively small and coagulation process needs longer sedimentation time. Large flocs and short operation time are important for good coagulation performance. Coagulation floc formation and growth processes using magnesium hydroxide and polyacrylamide (PAM) dual-coagulant were investigated with controlled experiments through flocculation index (FI), floc size distribution, zeta potential, scanning electron microscopy and Fourier transform infrared spectroscopy. The final average floc size reached 58.5 and 4.96 μm with and absence of PAM addition during slow mixing periods. PAM feeding time and magnesium hydroxide formation time can affect the floc formation and growth processes. The results showed that floc formed rapidly during magnesium hydroxide generation within 90 s and flocs aggregated together by PAM bridging function. Reactive orange removal efficiency reached 99.3% with rapid mixing 250 rpm at 90 s during 100 mg/L magnesium ion addition, then adding 6 mg/L PAM at the beginning of slow mixing period in dual-coagulant system.

The environmental impact of amino acids on the release of SeO 4 2- immobilized into hydrotalcite (Mg 2 Al-LDH) which belongs to the layered double hydroxides (LDHs) family was investigated by experimental study and the observed layer structure of hydrotalcite was verified through density-functional theory (DFT) calculations. Glycine, l-cysteine, and l-aspartic acid, which have smaller molecular sizes, can release SeO 4 2- largely due to intercalation, unstabilization of Mg 2 Al-LDH and simple dissolution, while l-tryptophan and l-phenylalanine caused limited SeO 4 2- release due to their larger sizes and aromaticity. XRD patterns for the solid residues after intercalation of amino acids revealed that the layer distance of Mg 2 Al-LDH was partially expanded. The main peaks and shoulder features corresponding to d 003 diffraction were well explained by DFT simulations using glycine as a model: the layer spacing of the main peak is responsible for the remaining SeO 4 2- and singly stacked glycine molecule and the layer spacing of the shoulder peak was well explained by doubly stacked glycine molecules. Hydrogen bonds between amino acids and hydroxyl ions in the metallic layers of Mg 2 Al-LDH were responsible for the stable configuration of the intercalated Mg 2 Al-LDH. This study indicates potential limitations to the stability of low-level radioactive wastes of 79 Se in repositories which are affected by smaller molecules of amino acids released through degradation of organic matters in the pedosphere., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Hydrotalcite-like compounds are a group of layered double hydroxides widely studied as sorbents to remove organic and inorganic contaminants under laboratory conditions. This study is a proof-of-concept of the long-term fate of hydrotalcite compounds under natural environmental conditions, to bridge the gap between laboratory studies and their field application as sorbents. Hydrotalcite (HT) with intercalated carbonate species (HT-CO 3 ) and dodecyl sulphate (HT-DS) were synthesised and placed in two groundwater monitoring wells in Denmark, one contaminated with chlorinated hydrocarbons and another with uncontaminated groundwater. To assess the structural and surface compositional changes of hydrotalcite compounds upon prolonged exposure to groundwater, the material was analysed with powder X-ray diffraction (PXRD), Fourier-transformed infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The results showed that the stability and dissolution behaviour of hydrotalcite compounds under groundwater conditions depended on the intercalated anion (CO 3 2-  > DS) and groundwater dynamics (static flow > dynamic flow), while the hydrotalcite aggregate size only had a minor effect. Groundwater geochemistry influenced the precipitation of insoluble species (CaCO 3 , and adsorbed sulphate) on the hydrotalcite surface. The instability of hydrotalcite compounds, especially in the case of HT-DS, may constitute a significant limiting factor on their future application as sorbents under dynamic flow conditions.

To study the influence factors of calcined layer-like Mg-Al hydrotalcites nanosheets adsorbing perfluorooctanoic acid (PFOA) in aqueous solution, Mg-Al hydrotalcite (HMA) nanosheets were prepared by one-step hydrothermal synthesis. The effect of calcination temperature on adsorption properties and structure of HMA (CHMA-x, x means different calcination temperature) was investigated. The prepared samples were systematically characterized by the Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), X-ray diffraction (XRD), scanning electronic microscopy (SEM), and nitrogen adsorption-desorption isotherms. The adsorption isotherms and kinetics showed the adsorption equilibrium reached within 2 h, and the factors, such as adsorption dosage, pH, and cycles were investigated. It was found that CHMA with 600 °C displayed a uniformly morphology, higher surface area about 106.3 m 2 /g, and excellent adsorption properties (1969 mg/g). The equilibrium adsorption data perfectly fitted to the pseudo-second-order kinetic model (R 2  = 0.999) and the Freundlich model (R 2  = 0.994). The main mechanism of CHMA adsorbing PFOA might be the "memory effect." This study provided a new insight to prepare highly effective adsorbents in water treatment.

The impact of Ce on SO 2 adsoption and oxidation was studied over a series of flower-like hydrotalcite-based CeNiAl mixed oxides. Combined with XRD, BET, pyridine chemisorption, CO 2 -TPD, XPS and H 2 -TPR results, it revealed that introduction of Ce into NiAlO generates new centres for oxygen storage and release, promotes the enhancement of Lewis acid strength, increases weakly and strongly alkaline sites, and increases ability for SO 2 adsorption and oxidation. Furthermore, in situ Fourier transform infrared spectroscopy revealed that adsorbed SO 2 molecules formed surface bidentate binuclear sulfate. Taken together, we propose that the addition of Ce 4+ to NiAlO acts to improve this compound as major adsorbent for SO 2 .

The objective of this study was to evaluate ADMI color removal from a biologically treated textile mill effluent by heterogeneous photocatalysis with UV-visible irradiation (UV-vis) using a novel catalyst composed of TiO 2 supported on hydrotalcite and doped with iron oxide (HT/Fe/TiO 2 ). Simulated biological treatment of solutions of the dyes (50 mg/L) used in the greatest amounts at the mill where the textile effluent was collected resulted in no color removal in reactive dye solutions and about 50% color removal in vat dye solutions, after 96 h, indicating that the secondary effluent still contained a large proportion of anionic reactive dyes. Photocatalytic treatments were carried out with TiO 2 and HT/Fe/TiO 2 of Fe:Ti molar ratios of 0.25, 0.5, 0.75 and 1, with varying catalyst doses (0-3 mg/L), initial pH values (4-10) and UV-vis times (0-6 h). The highest ADMI color removal with unmodified TiO 2 was found at a dose of 2 g/L and pH 4, an impractical pH value for industrial application. The most efficient composite was HT/Fe/TiO 2 1 at pH 10, also at a dose of 2 g/L, which provided more complete ADMI color removal, from 303 to 9 ADMI color units (96%), than unmodified TiO 2 , from 303 to 37 ADMI color units (88%), under the same conditions. Hydroxyl radicals were responsible for the color reduction, since when 2-propanol, an OH scavenger, was added color removal was very low. For this reason, the HT/Fe/TiO 2 1 composite performed better at pH 10, because the higher concentration of hydroxide ions present at higher pH favored hydroxyl radical formation. COD reductions were relatively low and similar, approximately 20% for both catalysts after 6 h under UV-vis, because of the low initial COD (78 mg/L). Secondary effluent toxicity to Daphnia similis (EC 50  = 70.7%) was reduced by photocatalysis with TiO 2 (EC 50  = 95.0%) and the HT/Fe/TiO 2 1 composite (EC 50  = 78.6%). HT/Fe/TiO 2 1 was reused five times and still lowered secondary effluent ADMI color below local discharge limits. Benefits of the HT/Fe/TiO 2 1 catalyst compared to TiO 2 include its lower bandgap energy (2.34 eV vs 3.25 eV), higher ADMI color removal and its magnetic nature that facilitated its recovery and would reduce treatment costs., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The objective of this study was to investigate the removal of bacteriophages in Mg/Al layered double hydroxide (LDH). Batch experiments were performed with bacteriophage MS2 in a powder form of Mg/Al LDH under various LDH doses. Column experiments were also performed under flow-through condition with bacteriophages MS2 and phiX174 in Mg/Al LDH immobilized on sand surfaces. Batch tests demonstrated that the powder form of Mg/Al LDH was effective in removing MS2 with the removal capacity of 2.2 × 10(8) plaque forming unit (pfu)/g under the given experimental conditions (LDH dose = 2 g/L; initial MS2 concentration = 4.61 × 10(5) pfu/mL). Column experiments showed that the log removal of phiX174 was 4.40 in columns containing 100% Mg/Al LDH-coated sand while it was 0.05 in 100% quartz sand. These findings indicated that Mg/Al LDH-coated sand was effective in removing bacteriophages compared with sand. A more than 4 log removal (=5.44) of MS2 was achieved in 100% Mg/Al LDH-coated sand. This study demonstrates the potential application of Mg/Al LDH for virus removal in water treatment.

Hydrotalcite nanoparticles were synthesized by co-precipitation of aqueous Mg(NO(3))(2)·6H(2)O and Al(NO(3))(3)·9H(2)O in the presence of urea and subsequent microwave-hydrothermal treatment. The nanoparticles were activated with saturated aqueous Ca(OH)(2), and used to hydrolyze cellulose. A maximum hydrolysis yield of 47.4% with high glucose selectivity (85.8%) was achieved at 423 K. The nanocatalyst was stable and leached little as confirmed by ICP, XRD, and neutral effluent aqueous solution after reactions. It can be concluded that hydrotalcite nanoparticles activated with Ca(OH)(2) were a highly active, selective and stable catalyst for hydrolysis., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

This paper reports on the adsorption of different organic pesticides by hydrotalcite, hydrotalcite heated to 500 degrees C and organo-hydrotalcite in aqueous medium by employing adsorption isotherms, and using X-ray diffraction and infrared spectroscopy techniques. The results suggest that the adsorption capacity of the different materials depends on their nature as well as on the structure, polarity and hydrophobic or anionic nature of the pesticides. The results also show that hydrotalcite, both natural and after calcination at 500 degrees C, is not a good sorbent of hydrophobic pesticides. The data demonstrated that both types of hydrotalcite, however, are very good sorbents of glyphosphate. Furthermore, the organo-hydrotalcites may be as good sorbents as organo-montmorillonites for hydrophobic pesticides.

We investigate the method for the determination of an appropriate mixing region of three kinds of antacid, magnesium hydroxide, dried aluminum hydroxide gel and calcium carbonate using triangular coordinates. Using the triangular coordinates, the appropriate mixing region of satisfying the following categories was determined; 1) acid neutralizing capacity (200 ml), 2) immediate action (pH 6-8 range obtained 10 min after pouring an antacid into 50 ml of 0.1 mol/l HCI (aq) sol.), 3) bowel property (mol ratio of Mg/Al = 1-3), and 4) quantities of combination of three antacids (under 700 mg of total quantities). Modified Fuchs Test was performed at some points which met the above conditions. The durability of the combination of these three antacids was evaluated. The following regions have long durability of antacids (about 60 min for persisting pH 3.5-5); magnesium hydroxide 40-60%, dried aluminum hydroxide gel 30-50% and calcium carbonate 10%. In the cases of changing the above mentioned conditions, and of using different kinds of antacid, the determination of the appropriate mixing region using triangular coordinates is effective for the pharmaceutical technology. In this study we emphasize the following striking features; utilization of triangular coordinates, fixing the combination of antacid, and incorporation of three kinds of antacid with aluminum, magnesium and calcium.

The effect of a Hungarian Al-Mg-containing drug, called Tisacid was studied using of 2.0, 1.0 and 0.5 gram doses. Two administration forms, suspension and tablet were compared. Ten informed, adult hyperacid volunteers were included into the program and three times 5-hour intragastric pH-metry was carried out in a randomized, self-controlled open clinical study (Control, after administration of tablet or suspension). Both forms were found effective in gastric acid reduction at doses of 2.0 and 1.0 g. Tisacid suspension revealed a more pronounced efficacy at the dose of 2.0 g in comparison to the same dose of tablet form. The 0.5 g dose seemed insufficient in reduction of gastric acidity in hyperacid patients applied in tablet or suspension forms. The authors emphasize the role of continuous intragastric pH-metry in clinical practice and investigation of antacids and antisecretory drugs.

Three-hundred and ninety-five cases of massive upper gastrointestinal haemorrhage were treated in the Surgical and Anaesthesiological Departments of the University Hospital in Linköping over a 5-year period. The mortality was 13%, or 10% when oesophageal varicosities are excluded. Results of a consistent policy concerning surveillance, diagnostic measures, and different forms of therapy are described. From the surgeon's point of view, emphasis is laid on the importance of endoscopy as a means of decreasing the number of exploratory gastroduodenotomies and increasing the proportion of patients in whom surgery is directed against a known source of bleeding. This leads to an enhancement of surgical expediency.

The effects of hydrochloric acid on mixed gels of aluminum and magnesium hydroxide and on magaldrate have been examined using quasi-elastic light scattering. Particles of magaldrate and mixed gels behave differently. The magaldrate particles initially decrease in size in response to increasing amounts of hydrochloric acid up to that sufficient to neutralize all the magnesium hydroxide present, then increase in size to approximately 2 microns. The composition of the mixed gels appears to be particularly important in determining the reaction with limited amounts of acid. For these particles, which are thought to consist of a magnesium hydroxide core surrounded by an aluminum hydroxide sheath, slow erosion of the aluminum hydroxide was apparently followed by complete disintegration of the particles. Particles which remain grow in size to approximately 3 microns.

The effect of freeze-thaw cycles on the physical stability of aluminum hydroxycarbonate and magnesium hydroxide gels was studied. Coagulation following a freeze-thaw cycle, leading to the formation of visible aggregates, affected the content uniformity of both gels. The freeze-thaw cycles did not affect the crystal form or surface characteristics of the gels as determined by X-ray powder diffraction and point of zero charge, but caused a slight reduction in the rate of acid neutralization and a large increase in the rate of sedimentation. The greatest effect was observed after the first freeze-thaw cycle. While the duration of freezing was not a factor, the rate of freezing was important and was inversely related to the aggregate size. The aggregates which formed following a freeze-thaw cycle were not redispersed by shaking, but were reversed by ultrasonic treatment or homogenization. The adsorption of polymers or surface-active agents prior to freezing reduced and, in some cases, prevented the formation of aggregates. The physical instability produced by a freeze-thaw cycle was explained by the modified DLVO theory. The force exerted on the particles by the growing ice crystals forced the particles into the primary minimum, producing strong interparticle attraction. On thawing, simple agitation did not provide enough force to overcome the attractive force of the primary minimum. Adsorption of polymers or surface-active agents increased the steric repulsive force and prevented the particles from reaching the primary minimum.

Fifteen cases of intractable chronic esophagitis due to gastroesophageal reflux were treated with a continuous intraesophageal antacid drip. A proprietary antacid preparation, Gelusil or monalium hydrate (Riopan), in a concentration of one part of antacid to nine parts of water, was infused into the mid-esophagus through a polyethylene tube with an internal diameter which admits a No. 18 blunted needle. Patients are not confined to bed while the drip is in progress. If the flow is constant and the end of the tube is below the cricopharyngeal sphincter, patients do not experience discomfort even if the drip is administered continuously for several days.Results indicate that remission of symptoms can be achieved in almost every patient, even those who have previously failed to respond to oral antacid therapy.

For obtaining flame retardant, oil resistance, high strength, and softness EVA/POE‐g‐MAH composites for cables, multifunctional modified magnesium hydroxide (MH‐KH570), and aluminum hydroxide (ATH‐KH570) were prepared by grafting γ‐(methacryloyloxy) propyltrimethoxysilane (KH570) onto the surface of MH and ATH. The successful grafting was confirmed by Fourier‐transform infrared spectrometer, scanning electron microscope, thermogravimetric analysis, and contact angle test. The hydrophobicity of MH and ATH was enhanced and the decompose time was extended, called the "sustained release" effect. The ethylene‐vinyl acetate copolymer (EVA)/maleic anhydride grafted polyolefin elastomer (POE‐g‐MAH) composites containing 62.5 wt% the mixture of MH‐KH570 and ATH‐KH570 in a 1:1 mass ratio was prepared. The vertical combustion test, limited oxygen index (LOI), and cone calorimetry proved the flame retardancy performance of the EVA/POE‐g‐MAH composites were enhanced, because of the homogeneous dispersion and the "sustained release" effect of MH‐KH570 and ATH‐KH570. The vertical combustion and LOI reached V‐0 and 38.1%. Importantly, the "crosslinking" effect of MH‐KH570 and ATH‐KH570 further enhanced the tensile strength after the composites crosslinked, and reached 19.9 MPa. In a word, a simple method for preparing flame retardant EVA/POE‐g‐MAH composites with high tensile strength was provided. [ABSTRACT FROM AUTHOR]

In order to systematically study the suppression effect of Aluminum hydroxide[Al(OH)3] and Magnesium hydroxide[Mg(OH)2] on the explosion of flour, Hartmann experiment system was used to carry out the explosion flame propagation experiment, and the influence of adding different proportions of Al(OH)3 and Mg(OH)2 powder on the morphology and propagation speed of flour combustion flame was studied. Combined with the thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) curves of Al(OH)3 and Mg(OH)2 powder, the inhibition mechanism of Al(OH)3 and Mg(OH)2 powder on flour explosion was analyzed. The results showed that with the increase of Al(OH)3 and Mg(OH)2, the flame propagation speed gradually decreases. After adding 40%wt Mg(OH)2, when t = 182 ms, the flame reaches the top of the glass tube. When 60 wt% Mg(OH)2 and 60 wt% Al(OH)3 powder were added, the maximum flame propagation velocity of flour decreased from 13.86 m/s to 5.78 m/s and 1.62 m/s, respectively, and Al(OH)3 was superior to Mg(OH)2 in inhibiting flame propagation. Both inhibitors can inhibit flour combustion by adsorption of H and OH radicals. [ABSTRACT FROM AUTHOR]

Natural fiber composites offer a sustainable alternative to synthetic polymer composites, addressing the environmental concerns associated with traditional materials. This study aims to investigate the effect of flame‐retardant additives (magnesium hydroxide Mg(OH)2 [A] and aluminum hydroxide Al(OH)3 [B]) on hemp fiber‐based epoxy composites with a different fire retardant (FR) loading, that is, 0%, 8%, 12%, and 24%. An evaluation of flame‐retardant effectiveness on composites was carried out using thermogravimetric analysis, limited oxygen index (LOI), UL‐94 horizontal burning, morphological analysis scanning electron microscopy (SEM), and char residue analysis. The results show that introducing the flame retardants in the hemp–epoxy composites improved the thermal stability and flame retardancy of hemp–epoxy composites When composites were incorporated with flame retardants, the Horizontal burning rate was decreased, and LOI was increased. The lowest Horizontal burning rate of prepared composites was recorded as 11.6 mm/min, and the highest LOI was 25.3%. SEM shows uniform distribution of FR particles in the prepared composite. It is concluded that adding flame‐retardant additives efficiently improves the flame retardancy properties of the prepared composites. Highlights: The mechanical and flammability behavior of developed composites were investigated after adding magnesium hydroxide and aluminum hydroxide to composites.An enhancement in flame retardancy and a slight reduction in mechanical properties are observed in composites.The purpose of this study is to expand the area where flame‐retardant ramie fabrics may be applied. [ABSTRACT FROM AUTHOR]

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Layered magnesium aluminum hydroxide Mg4Al2(OH)12CO3⋅3.85H2O with the hydrotalcite structure is obtained by the solid-phase interaction of AlCl3⋅6H2O and MgCl2⋅6H2O with (NH4)2CO3 at room temperature. The change in the phase composition of the products of its heat treatment in the temperature range 180–600°C is studied. It is determined by DSC/TG that the thermal decomposition occurs in two stages: the first stage occurs in the temperature range 180–215°C; the second, in the range 400–440°C. The apparent activation energies Ea of both stages of thermal decomposition are found by the model-free Kissinger method to be 62.85 and 141.86 kJ/mol, respectively. The obtained Ea values agree well with the literature data and indicate that both stages are single-step kinetic processes. [ABSTRACT FROM AUTHOR]