I am developing geopolymers with kaolinite clay and calcium hydroxide activated with sodium carbonate solution. The alkalinity of the mix is too high to handle.. what can I do to bring it down?

  • 1
    $\begingroup$ Try neutralizing part or all of the Ca(OH)2 (with CO2), and employ more of the mildly alkaline Na2CO3. $\endgroup$
    – AJKOER
    Aug 9, 2020 at 14:50
  • $\begingroup$ Geopolymers are synthesized at very high pH. You are not supposed to use glassware. What is it corroding?? $\endgroup$
    – AChem
    Aug 9, 2020 at 16:34
  • $\begingroup$ It is Na2CO3 that turns into caustic soda when mixed with water which makes it corrosive.. Also i believe the silicates in the kaolinite also turns caustic at when mixed to this.. i want to make it a material which can be handled by workers.. hence i need to bring the pH to less than 12 i guess.. $\endgroup$
    – Ak Ash
    Aug 10, 2020 at 10:23
  • $\begingroup$ Add sodium bicarbonate. The pH will soon go down under 9. $\endgroup$
    – Maurice
    Aug 17, 2021 at 20:29
  • $\begingroup$ When creating sodium hydroxide from sodium carbonate, I would not wonder why it is so much alkaline. $\endgroup$
    – Poutnik
    Aug 17, 2021 at 21:10


Browse other questions tagged or ask your own question.