Preparation method for calcium carbonate whiskers extracted from limestone

The invention relates to specifically relates to a preparation method for calcium carbonate whiskers extracted from limestone, belonging to the field of inorganic micropowder. According to the preparation method, natural limestone is subjected to fragmentation and crushing and then mixed with a proper amount of water and a surface modifier, and the calcium carbonate whiskers with structured morphology can be directly obtained through the processes of generation, dissolving, decomposition and crystallization of calcium bicarbonate. The preparation method comprises the following key technical steps: (1) introducing high-pressure CO2 gas into limestone dust suspension with the proper amount of the surface modifier so as to convert calcium carbonate into water-soluble calcium bicarbonate; and (2) controlling decomposition of water-soluble calcium bicarbonate under proper reaction conditions so as to allow the calcium carbonate whiskers mainly of aragonite structures to be precipitated. The preparation method has low requirement on raw materials and completes both purification and crystallization in the process of preparation; and the calcium carbonate whiskers have hydrophobic surfaces, show good dispersibility in matrixes like organic solvents and high-molecular resin and are applicable to the industrialization fields of paint, plastics, polymer composites, etc.