Sodium polyacrylates permit a higher solids concentration during grinding, reducing the resulting particle size and/or specific energy consumption. Their impact on fine and ultrafine grinding of limestone was studied. Sodium polyacrylate with a low polydispersity index was found to be the most effective grinding aid for limestone and consequently applied for further nano-grinding experiments. Nano-grinding was most energy-efficient with the smallest grinding medium size. These ground nano-sized CaCO3 particles with sodium polyacrylate on the surface accelerated the hydration of ordinary Portland cement cement paste.