Methods of processing phosphogypsum (PG) to recover Radium (e.g., .sup.226Ra), and/or other constituents from PG, are described. PG (stockpiled PG, fresh PG or a combination) is combined with a leach solution, allowed to react for 2-6 hours (e.g., a single leaching step), at a temperature in the range of about 40-70 C. to obtain leachate and leach residue. Further processing by subjecting the leachate and/or the leach residue to one or more separation techniques, such as ion exchange, enables the recovery of one or more constituents of interest. By separating .sup.226Ra, rare earth elements (REE) and/or other constituents from this secondary resource (e.g., waste PG), gypsum can be purified for use in the construction industry, the recovery of .sup.226Ra can be used to produce dedicated isotopes like .sup.223Ra and/or .sup.225Ac for life-saving cancer medication, and raw materials can be provided for the high-tech industry, agriculture and the building industry.