Through the analysis of phase and Mg content variation of samples obtained from different reaction system, we propose that the crystallization of calcium carbonate was mainly the aggregation-mediated process in the ethanol-water mixed solution and the solution-mediated process only in aqueous solution. Solvation of CO₃^2- had obvious influence on the deposition of calcium carbonate. According to XRD and IR of deposits, it was considered that mixed phases of Mg calcite and a transitional phase which bears analogy to dolomite structure were formed. That is to say, magnesium calcite obtained from the mixed solution of ethanol-water demonstrated the dolomitization tendency.

Key words: calcium carbonate, solvation, solution-mediated process, aggregation-mediated process