Abstract: To improve the added values of carbide slags，the effects of HCl dosage，extracting temperature，and CO₂ flow rate on the morphology of calcium carbonate micro-particles prepared from carbide slags without crystal controlling agents were investigated.The as-prepared products were characterized by X-ray diffraction and FT-IR.The shapes of particles were ob- served by scanning electron microscopy.Results showed that HCl dosage and extracting temperature were important parame- ters for the control of morphology and shape of CaCO₃.Calcium carbonate was changed from irregular calcite to partially regular vaterite with the increase of HCl content.The vaterite micro-particles can be prepared and the particle size was at 4~5 μm when the leaching agent was completely HCl.In addition， single vaterite micro-particles can be prepared from co-existed cal- cite and vaterite particles，when the extracting temperature was above 30 ℃ from 18 ℃．

Key words: leaching agent, extracting temperature, calcite, vaterite, carbide slag