Environmental pollution with mining waste containing dangerous metal cations necessitates the development of technologies for their disposal. This study proposes the use of blast furnace slag as a geobarrier for binding heavy metal cations. Such parameters as slag mass, temperature and time were used to determine the degree of binding of ferum and zinc cations when they are present together. A central rotatable composite experimental design was used to verify the results. According to the plan, the experiments were performed and the optimal conditions were determined with the help of statistical analysis. It was noted that a simultaneous increase in temperature and treatment time increases the degree of conversion for both ferric and zinc cations. An increase in the mass of slag leads to a decrease in the temperature and interaction time for ferum and zinc cations. However, for zinc cations, the maximum degree of conversion is 43.3% with their simultaneous presence. Experimental results showed that slag was more effective as a base for binding ferum and zinc cations with a conversion rate of 63.3% in concentrated solutions. The resulting regularities allow, by varying the process parameters, to bind metal cations in their joint presence.