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The reactivity of calcium dialuminate CaAl 4 O 7 refractory cement containing little amount of gehlenite Ca 2 Al 2 SiO 7 , belite Ca 2 SiO 4 , calcium aluminum iron oxide Ca 3 (Al,Fe) 2 O 6 and calcium iron aluminum oxide Ca 3.18 Fe 15.48 Al 1.34 O 28 was studied with and without Li 2 CO 3. The granularity of the cement is d 97 = 112.58 µm, d 50 = 9.72 µm and d 10 = 1.41 µm with water cement ratio W/C = 0.375. Little amount of Li 2 CO 3 from 0.1wt.% to 0.6wt.% was added to the cement paste, and the result from calorimetry showed hydration mean peak time reduced from 17 h to 32 min and showed that the hydration heat of CA 2 cement paste with Li 2 CO 3 was 123 J/g lower than the one without Li 2 CO 3 of 168 J/g. XRD of stabilized hydrates show that CaAl 4 O 7 and Ca 3 (Al,Fe) 2 O 6 participate in the hydration reaction to form C 3 AH 6 , AH 3 and Ca 3 Al 1.54 Fe 0.46 (OH) 12. The results from SEM images show nucleation site with plate-like crystal of CAH 10 and small particles of AH 3 forming a membrane on the cement surface.

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