Abstract: A hydro-metallurgical method 80 for the removal of uranium, thorium, radium, lead, bismuth and polonium and/or other radionuclides from a radioactive copper concentrate to produce an upgraded copper concentrate having lowered emission levels. The method comprises the step of: subjecting the copper concentrate to an acidic leaching process (NONOX leach) 120 using a sulfate and chloride containing lixiviant under electrochemically controlled conditions, to allow at least partial removal of one or more of the radionuclides to produce the lowered emission upgraded copper concentrate, wherein the leaching process is conducted at elevated temperature and under pressure to suppress boiling in the leaching process.