• MATERIALS

    Geopolymers based on natural zeolite clinoptilolite with addition of metakaolin

    Machines. Technologies. Materials., Vol. 16 (2022), Issue 2, pg(s) 82-85

    Geopolymers based on natural zeolite clinoptilolite and addition of up to 50% metakaolin were synthesized using binary sodium/potassium alkali activator. The influence of metakaolin addition was evaluated on apparent density, water absorption, relative mass loss after watering and microstructure (XRD) of the prepared geopolymers. The addition of metakaolin greatly influenced the physical and mechanical properties of the obtained geopolymers. Minimal/optimal metakaolin addition was estimated to 30% in the respect of sufficient strength (11 MPa) and the high price of metakaolin. The resulted geopolymer based on natural zeolite and metakaolin (30%) contained residual unreacted clinoptilolite which could be beneficial for properties of future geopolymer products. Potential applications of obtained geopolymer-clinoptilolite agglomerates are: waste or radioactive water decontamination, passive cooling systems, plasters in residential buildings, etc.

  • MATERIALS

    Alkali and acid activated geopolymers based on iron-silicate fines – by-product from copper industry

    Machines. Technologies. Materials., Vol. 14 (2020), Issue 1, pg(s) 37-39

    Geopolymer based on iron-silicate fines (fayalite slag) were synthesized in alkaline and acidic media using activation solution
    comprised of respectively alkali silicate and phosphoric acid solutions. The raw material consists of fayalite, magnetite and pyroxene which could be a conglomerate in some particles. The alkali activation occurs very slow at room temperature, while acid activation take place very rapid. The acid activated geopolymer binder phase include cracks probably formed by thermal gradient because of the rapid exothermal reaction. The morphology of the alkali activated geopolymers were presented by porous structure.