This work developed a method for controlling calcium dissolution during leaching operation of lanthanides from phosphogypsum waste. The developed method was carried out in two steps, namely, A - leaching of the phosphogypsum by using mineral acids (HCl and HNO3) with nonyl phenol ethoxylate (NPE) as a leaching solution. B- Addition of a soluble amino acid, e.g., glycine to the leaching solution to precipitate calcium glycinate. The obtained results showed dissolution of about 5 % of calcium content under the leaching conditions: 20 % acid, 25 °C, 0.5 g ml- and 15 min. However, the presence of NPE in a concentration of 4 % decreases the calcium dissolution to about 2.5 %. Also, the kinetics of calcium leaching were investigated and it was found that, the data fitted the shrinking core model, in which both the interface transfer and diffusion through the product layer affected the reaction rate. Moreover, the addition of NPE to the acid leaching solution increases the apparent activation energy from 28 and 29 KJ/Mol to 36 and 50 KJ/Mol for HCl and HNO3, respectively.