The dissolution of calcium carbonates in water Kindly help out. It is generally know that calcium carbonates has poor solubility in distilled water. Hence its ability to form slurry becomes difficult. Studies have shown that eggshells contain basically calcium carbonates.  I conducted an experiment in modification of eggshell powders with anionic surfactant in order to improve its solubility in water.  I carried out solubility and dissolution test on the modified eggshell powder. This was compared against the raw eggshell in order to confirm its solubility rate.  ICP was used to calculate the calcium  content in the solvent filtrate.  The reusults is showing that the calcium content in filtrate was higher than that of the modified eggshell.  Please who can assist in explaining this phenomenon. Thanks.
Regarding the slurry statement, you can only make slurries with insoluble compounds or they would dissolve and your slurry would go away leaving you with a clear solution!  

Your attempt to alter the eggshell composition by extracting with the surfactant should have had little effect.  You didn't give any quantitative results from your ICP analysis, but I think one or both of two things happened:
1) There was residual Ca from the surfactant remaining on your eggshell
 and/or
2) You may have extracted the few percent of protein that makes up eggshells, leaving a more "concentrated" $\ce{CaCO3}$ residue as compared to the untreated shells.