Leaching stage is one of the main ones in the production of alumina and its effectiveness depends on the quality of the final product and its technical and economic indicators. Leaching is а process of maximizing the transfer of aluminum oxide from cake into solution with minimal loss. The paper describes the research conductivity of aluminate solution based on the laboratory test set of vertical leaching tank. The conductivity can be used as a criterion of efficiency in the process of leaching. On the basis of experiments possible to construct a mathematical model of vertical leaching tank, which will become part of the automatic control and regulation of the process of leaching in vertical leaching tank.