Kaolin 400mg / Calcium carbonate 75mg tablets

Soda lime silica (SLS) glass waste and granite sludge (GS) waste have been studied as eco-friendly raw materials in ceramic production. Different percentages of SLS or GS (10-30 weight percentage) are added to kaolin powder, pressed, and then sintered at 900, 1000, and 1100 °C. The goal of this research is to comprehend how waste content affects the electrical and physico-mechanical characteristics of ceramics made of silicate. X-ray fluorescence was used to characterize the starting materials (XRF). SEM and X-ray diffraction (XRD) are used to examine the effects of SLS or GS addition on microstructure and phase composition, respectively. Additionally examined are electrical and dielectric characteristics, bulk density, compressive strength, and apparent porosity. Results revealed that GS-containing samples are more porous than SLS-containing samples. Apparent porosity reaches 16.26% after 30 weight percentage of GS addition, while it is 6.50% for 30 weight percentage of SLS addition after sintering at 1100 °C. Maximum compressive strength (180 MPa) is obtained at 1100 °C for the sample containing 10 weight percentages of GS. However, the electrical and dielectric properties are enhanced by SLS addition due to the excellent alkali ionic mobility in the matrix.

Abstract licence: CC BY

• The content of CaO and Fe 2 O 3 in the ash of leather mixed solid waste exceeds 60%. • Kaolin reduces the AFTs of leather mixed solid waste and leads to slagging. • Adding 1.5% CaCO 3 to leather mixed solid waste can significantly increase the AFTs. • Select additives based on B/A ratio, away from 1 to improves melting properties. • At high B/A ratio,the fouling and slagging index are inversely proportional to AFTs. The leather industry produces substantial amounts of solid waste, including tanning sludge and various leather wastes, presenting significant environmental challenges. This study explores the influence of additives (kaolin and CaCO 3 ) on the ash fusion characteristics of leather mixed solid waste (LMSW) during combustion. The effects of these additives on ash fusion temperatures (AFTs) and mineral transformation were systematically investigated using X-ray diffraction, X-ray fluorescence, and thermodynamic equilibrium calculations. The results show that the sum of CaO and Fe 2 O 3 in the ash of LMSW exceeds 60%, increasing the proportion of wet blue leather in the waste slightly elevates the softening temperature (ST). Notably, kaolin—commonly employed to enhance coal ash fusion properties—reduces the AFTs of LMSW, particularly at the base/acid ratio is close to 1. In contrast, CaCO 3 addition significantly improves AFTs, especially when the B/A ratio exceeds 1. Thermodynamic analysis further reveals that kaolin accelerates liquefaction in LMSW, with melting behavior aligning well with experimental AFTs trends. Additionally, this study evaluates the applicability of traditional coal ash fouling and slagging indicators to LMSW, demonstrating a strong correlation between these indicators and AFTs. However, when basicity exceeds 1, the indicators and AFTs exhibit opposing trends. To optimize ash melting behavior, additives should be selected based on the waste ash’s B/A ratio to prevent it from approaching 1.

Abstract licence: CC BY-NC-ND

This work examines the usage of various acid activators, including hydrochloric acid (HCl), sulphuric acid (H2SO4), phosphoric acid (H3PO4), and a combination of them, to improve the thermophysical properties of fired clay-based composite bricks modified-kaolin. To enhance these materials’ insulating capabilities, the main focus is on reducing their diffusivity, specific heat capacity, and thermal conductivity. Whereas, fibrous clays’ surface and catalytic properties were enhanced chemically via the addition of acid-activated kaolinite clay. The mechanical, thermophysical, morphological, shrinkage, density, porosity, microstructure, and shrinkage of each clay–kaolin(acid) composite were thoroughly examined, and the thermal conductivity performance was maximized. All of the peaks’ intensities in the XRD pattern increased in comparison to the untreated peak when varying acid types were added to the kaolin matrix. In the meantime, the addition of these activators caused the compositions’ apparent porosity (i.e., 29.15–29.47%) and compressive strength (i.e., 11.59–12.33 kg/cm2). The results demonstrate that treatment with these acids reduces thermal conductivity (i.e., 0.46–0.44 W/mk), and diffusivity, attributed to the increased porosity and altered microstructure of the bricks. Moreover, combining all three acids (H2SO4/HCl/H3PO4) resulted in the most significant improvements, yielding a composite with superior insulation capabilities. The aforementioned observations are attributed to the formation of two key mineral phases within the fired bricks: mullite and diopside. Mullite strengthens the bonding within the aluminosilicate framework, thereby enhancing the ceramic network and promoting a denser and more mechanically stable microstructure without causing a significant increase in porosity. Meanwhile, diopside also contributes to strength development and is widely recognized for its role in insulation ceramics due to its excellent thermal stability and chemical corrosion resistance.

Abstract licence: CC BY

Increasing water scarcity in arid regions has prompted the mining industry to develop strategies to maximize water recovery and reuse, especially in tailings treatment processes. In this context, the present investigation evaluated the effects of sodium polyacrylate (NaPA) on the compressibility and viscoelasticity of clayey tailings in the presence of hard water containing calcium and magnesium. To this end, clayey slurries were analyzed using rheological tests (rheograms and oscillatory viscoelasticity), zeta potential measurements, and compressibility tests using batch centrifugation. The yield stress was determined using the Herschel–Bulkley model, while the compressive yield stress (Py(Φ)) was calculated as a key indicator to characterize the degree of sediment consolidation. The results showed that NaPA, due to its anionic nature and high degree of ionization at pH 8, induces effective particle dispersion by increasing electrostatic repulsion and decreasing the interaction force between particles, which reduces both rheological parameters and compressive yield stress. For the 70/30 quartz/kaolin mixture, the yield stress decreased from 70.54 to 61.64 Pa in CaCl2 and from 57.51 to 52.95 Pa in MgCl2 in the presence of NaPA. It was also observed that suspensions in the presence of magnesium ions presented greater compressibility than those with calcium, attributable to the greater hydration radius of magnesium (10.8 Å), which favors less dense and more easily deformable network structures. Furthermore, a higher proportion of kaolin in the mixture resulted in higher yield stresses, a product of the clay’s laminar structure, colloidal size, and high surface area, both in the absence and presence of NaPA. Overall, the results show that incorporating NaPA significantly improves the compressibility and rheology of clayey tailings in hard water, offering a promising alternative for optimizing water recovery and improving tailings management efficiency in the context of water restrictions.

Abstract licence: CC BY

Addressing the need for cost-effective alternatives to activated carbon (AC) for chlortetracycline (CTC) removal, this study developed sustainable kaolin–alginate composite beads (KN@Alg). The adsorption performance of KN@Alg was systematically evaluated compared with pristine KN and AC through kinetics, isotherms and thermodynamics. Regeneration cycles and X-ray photoelectron spectroscopy analysis were employed to assess reusability and elucidate mechanisms. Results demonstrated that incorporating of KN into the alginate matrix significantly enhanced the adsorption capacity to 68.74 mg g −1 , surpassing that of KN (42.76 mg g −1 ) and approaching that of AC (102.96 mg g −1 ). KN@Alg achieved 93.7% removal efficiency in dynamic experiments, demonstrating practical applicability. Thermodynamics confirmed a spontaneous and exothermic process. Mechanistic studies revealed that CTC uptake onto KN@Alg involves multifunctional mechanisms, including n–π interactions, hydrogen bonding, electrostatic attraction, cation exchange and calcium ion-bridging. Notably, KN@Alg exhibited superior renderability, retaining approximately 76% efficiency after four cycles, outperforming both AC and KN. Compared with the high cost of AC, KN@Alg integrates the rigid framework of KN with the functional advantages of alginate, addressing the limitations of low adsorption capacity and instability of pure components while achieving comparable removal efficacy. These findings highlight KN@Alg as a sustainable, cost-effective alternative for CTC-contaminated water treatment.

Abstract licence: CC BY