Effects of Titration Rate, pH, and Drying Process on Cation Exchange Capacity Reduction and Aggregate Size Distribution of Montmorillonite Hydroxy‐Aluminum Complexes

Abstract The effects of rate of titration of montmorillonite + AICI 3 with NaOH, and of drying on CEC reduction, C‐axis spacing, and aggregate size distribution of montmorillonite hydroxy‐Al complexes at the pH range of 5–10, were studied. The CEC reduction was found to be influenced by the titration rate. While the CEC of the montmorillonite was 0.92 meq/g, the CEC of the clay hydroxy‐Al complexes was 0.27, 0.31, 0.39, and 0.45 at titration rates of 0.025, 0.1, 0.4, and 0.8 meq NaOH/min, respectively. The mean aggregate size and the C‐axis spacing of the clay hydroxy‐Al complexes decreased as the pH of the suspensions increased. The CEC of the montmorillonite hydroxy‐Al complexes after drying was higher than the nondried systems at a pH above 7.5, whereas no difference was observed at the lower pH range (pH 5–6). The CEC and the C‐axis spacing for both the dried and nondried systems were highly correlated.