Highlights
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Potassium acetate-intercalated kaolinite (CSK-K) is prepared in a simple way.
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Kaolin calcined below 400 °C cannot be alkali-activated to form a geopolymer.
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CSK-K calcined between 350 and 400 °C can form a geopolymer by alkaline activation.
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The geopolymer prepared in this way has a high compressive strength.