Potential use of ceramic waste as precursor in the geopolymerization reaction for the production of ceramic roof tiles

Use of glass polishing waste in the development of ecological ceramic roof tiles by the geopolymerization process

“…The HP ULTRA brand commercial Metakaulim was also used as a precursor (Figure 1B). For the production of the alkaline solution, Potassium Hydroxide (KOH – Figure 1C) and Sodium Hydroxide (NaOH – Figure 1D) were used together, dissolved in water, with a 24 hour advance of use and control of its pH 8 . The reason for using this combination (KOH + NaOH) in the alkaline solution is due to the fact that precursors activated with KOH have greater resistance to compression compared to geopolymers synthesized from NaOH solutions 19…”

“…Through the PAI. it is possible to determine how much waste and consistency (water/binder) will be used in each test from the material density 8 . Materials that exhibit pozzolanic activity are reactive silica and alumina sources and have the potential to be activated with alkaline solutions, resulting in a product with adequate mechanical strength 20 …”

“…The geopolymeric mass was prepared using a solution/(metakaolin + waste) and solution/metakaolin (reference mixture) ratio of 0.26, varying the molar ratios of the precursors in SiO 2 / Al 2 O 3 in the order of 2.5, 3, 3.5, and 4, based on other studies in the literature 8,21‐23 . The results of the chemical characterization of the glass waste and metakaolin were used to calculate these molar ratios.…”

“…In geopolymeric materials, some problems, such as the difficulty in the operations of the materials due to the use of an alkaline solution with a high basic content, which makes the use dangerous to workers due to the possibility of burns, make a difficult of construction based on alkali‐activated or geopolymeric materials very reduced in view of the potential applications that this material presents. On this issue, it is highlighted that the main uses found in the international literature for these materials are as cement, which can be used for the production of pastes, mortars or concrete, 7 and also in applications replacing ceramic components, such as roof tiles and blocks 8 …”

“…A material that arouses interest in the production investigation via the geopolymerization process are some of the traditional ceramic artifacts most used in civil construction, such as roof tiles, which have a higher added value, but demand sintering at higher temperatures to guarantee their properties and service technical standards, which also increases the production process and energy consumption. For this reason, the production of geopolymer roof tiles is gaining prominence, mainly for its benefits, such as lower associated weight and greater mechanical resistance, in addition to presenting better resistance and emitting 60% less greenhouse gases (CO 2 ) 8,10 …”