Keywords: 
• 平均凝聚速率、光散射、胶体凝聚、赤铁矿

Abstract: Hematite colloid is an important component of variable charge soil colloids .The interactions of hematite colloids profoundly influence the formation ,stability and dispersion of variable charge soil aggregates ,and then strongly affect the transfer process of soil particles .Under the normal soil pH (pH<8) conditions ,the net charge of hematite surface is positive ,thus the aggregation of hematite colloids is triggered by the anions in the solution . Currently ,there are few reports concerning researches of the aggregation of colloids induced by anions .In this study ,the kinetics of aggregation of hematite affected by Cl -1 in NaCl solution at pH=4 was investigated .T he critical coagulation concentration of hematite colloids in the NaCl solution was found to be 99.2 mmol/L . The exponential function between the activation energy of hematite colloid aggregation and the NaCl con‐centration was observed as ΔE = RTln{[0.35 f0/(0.44 f0 - 8.66)]}.When the NaCl concentration was lower than 99.2 mmol/L ,the reaction of hematite colloid aggregation was slow ,an RLCA cohesion mech‐anism ;in contrast ,when the NaCl concentration was higher than 99.2 mmol/L ,the aggregation showed a rapid diffusion mechanism (DLCA) .The aggregation kinetics of hematite colloids with positive charges ob‐served in the present study would provide a possible direction for the study of the mechanism of the forma‐tion and dispersion of soil aggregates with variable charges .