Abstract The description of the metal evaporation process in the condition of an atmospheric pressure has got a special significance in the alloys smelting technologies as well as in the metallurgical waste materials treatment. The quantity of metals evaporated in the process depends on many factors from which the most important are: a kind of applied apparatus, conditions of the process, a metal bath composition and a kind of applied atmosphere. In order to state which factors have got the biggest influence on the evaporation rate it is necessary to carry out the experiments. The obtained results can be the base of a piece of information about the nature of phenomena occurring in an open system including condensate and gaseous phase. The results and their analysis lead to conclusion that the Pb evaporation process from Cu-Pb alloys in an inert atmosphere is determined by a mass transport in the gaseous phase. In the experiments of Pb evaporation from Cu-Pb alloys have been applied the following atmospheres: helium, argon and carbon monoxide in the temperature range from 1398 K to 1543 K. On the base of the obtained results has been determined a kinetic process factor-a mass transfer coefficient. It is confirmed by a considerable influence of the kind of an applied atmosphere and lack of distinct influence of Pb concentration on the process rate.