The study examines the patterns governing the formation of the structure and properties of construction ceramics when using mechanically activated fly ash from thermal power plants. It is shown that preliminary mechanical activation leads to a significant increase in the reactivity of the ash due to an increase in dispersion and the accumulation of defects in the crystal structure. It has been established that introducing mechanically activated ash into the ceramic mass intensifies sintering processes, helps reduce the firing temperature, and promotes the formation of a denser material structure. Experimental confirmation has been provided for the increase in compressive strength and the reduction in water absorption of the samples at an optimal ash content. The obtained results indicate the high efficiency of using technogenic raw materials in the production of construction ceramics and allow us to consider mechanical activation as a promising method for the targeted control of structure formation. Keywords: fly ash, mechanical activation, construction ceramics, sintering, structure, strength, technogenic raw materials.
Porous carbon was prepared by direct carbonization of tri-lithium citrate tetrahydrate at 800 °C, followed by acid leaching and re-annealing. Pyrolysis produced Li2CO3 and Li2O within the carbonizate; their removal left an oxygen-functionalized disordered carbon with an openwork structure of crumpled sheets, a BET area of 342 m2 g−1 and micropores near 0.9 nm that supply about 40% of the NLDFT surface area. In a symmetric cell with 6 mol L−1 KOH, the carbon delivered a single-electrode capacitance of 91.5 F g−1 at 0.5 A g−1 and retained 80.2 F g−1 at 5 A g−1, with nearly rectangular voltammograms and coulombic efficiencies of at least 98.9%. In concentrated aqueous lithium bis(trifluoromethanesulfonyl)imide (10 mol kg−1), three symmetric coin cells extended the voltage window to 2.0 V and gave a reproducible capacitance of 57.6 ± 0.2 F g−1 at 0.2 A g−1. In batch capacitive deionization with 10 mmol L−1 NaCl at 1.2 V, the electrodes returned a stable charge of 1.4–1.5 C per cycle over 100 cycles and removed 2.54 ± 0.28 mg g−1 of salt in the first five cycles; the decline in salt adsorption on cycling identifies charge efficiency as the next property to improve.
This study presents a comparative analysis of the effect of the structural–mineralogical type of clay matrices on the phase and structure formation in composite aluminosilicate materials within the multi-component Fe-Al-C-Si system. Highly plastic Saryozek montmorillonite clay and moderately plastic Alekseevskaya kaolinite–illite clay were investigated as binding matrices to consolidate iron–aluminosilicate fly ash from the Almaty CHPP-2. The raw materials and binary batches containing 10 to 50 wt.% fly ash were evaluated using XRD, XRF, TG/DTA, and SEM techniques. The results demonstrate that the superior plastic and binding properties of the Saryozek clay ensure enhanced consolidation of the non-plastic, fragmented ash particles. Simultaneous thermal analysis reveals that increasing the compaction pressure from 20 to 30 MPa induces a kinetic shift in the montmorillonite dehydroxylation interval toward higher temperatures (580–720 °C) due to increased partial water vapor pressure within the dense green body. This thermal shift scientifically necessitates introducing an isothermal dwell at 600 °C to mitigate firing defects. The optimal composite properties are achieved at a molding pressure of 30 MPa, a firing temperature of 1050 °C, and a fly ash concentration of 10–20 wt.%, yielding a peak compressive strength of 38.4 MPa. SEM confirmed that under these conditions, the locally formed silicate melt uniformly encapsulates the crystalline mullite and quartz microparticles, whereas increasing the ash content to 50 wt.% results in a loose, highly porous structure that degrades strength down to 17.9 MPa. These findings lay a scientifically substantiated foundation for optimizing composite ceramic synthesis and reducing structural defects.
Бұл мақалада Қазақстанда және бүкіл әлемде қатты өнеркәсіптік қалдықтарды өңдеудің қолданыстағы және қазіргі уақытта қолданылатын әдістері мен тәсілдерінің талдауы ұсынылған. Онда мәселенің негізі мен ұлттық маңызы қарастырылған. Онда ғылыми және технологиялық қажеттіліктер анықталған, нәтижелердің ғылым мен техниканың дамуына әсерін анықтаған және күтілетін әлеуметтік-экономикалық әсер анықталған. Қатты қалдықтарды өңдеудің техникалық және экономикалық бағасы берілген, әсіресе қалдықтарды кешенді өңдеуге баса назар аударылған. Шолу соңында қысқаша қорытынды берілген. Қолданыстағы зерттеулерді талдау кеуекті және жоғары кеуекті керамикалық материалдардың физикалық және механикалық, әсіресе жылулық қасиеттерін жақсартудың әлеуетті ресурстарының бірі олардың құрылымы мен кеуектілігін реттеу екенін көрсетті. Кілт сөздер: экология, қайта өңдеу, жою, қалдықтар, керамика
This study presents a comparative analysis of the effect of the structural-mineralogical type of clay matrices on the phase and structure formation in composite aluminosilicate materials within the multi-component Fe-Al-C-Si system. Highly plastic Saryozek montmorillonite clay and moderately plastic Alekseevskaya kaolinite-illite clay were investigated as binding matrices to consolidate iron-aluminosilicate fly ash from the Almaty CHPP-2. The raw materials and binary batches containing 10 to 50 wt.% fly ash were evaluated using XRD, XRF, TG/DTA, and SEM techniques. The results demonstrate that the superior plastic and binding properties of the Saryozek clay ensure enhanced consolidation of the non-plastic, fragmented ash particles. Simultaneous thermal analysis reveals that increasing the compaction pressure from 20 to 30 MPa induces a kinetic shift in the montmorillonite dehydroxylation interval toward higher temperatures (580 °C –720 °C) due to increased partial water vapor pressure within the dense green body. This thermal shift scientifically necessitates introducing an isothermal dwell at 600°C to mitigate firing defects. The optimal composite properties are achieved at a molding pressure of 30 MPa, a firing temperature of 1050 °C, and a fly ash concentration of 10–20 wt.%, yielding a peak compressive strength of 38.4 MPa. SEM analysis confirmed that under these conditions, the locally formed silicate melt uniformly encapsulates the crystalline mullite and quartz microparticles, whereas increasing the ash content to 50 wt.% results in a loose, highly porous structure that degrades strength down to 17.9 MPa. These findings lay a scientifically substantiated foundation for optimizing composite ceramic synthesis and reducing structural defects.