<p>This dissolution inhibitor is characterized by comprising a calcination product which was obtained by calcining minerals containing magnesium carbonate (MgCO3) and calcium carbonate (CaCO3) as major components and which comprises MgCxOy (wherein 0<x≤1 and 0<y<3 are satisfied) yielded by decarbonation of the MgCO3 and further comprises MgCO3 and CaCO3.</p>
