Activity (consumption) of sulphuric acid is the prominent factor in hight-temperature leaching. This factor determines not only speed and deepness of the process (without dependence of cation liquid phase composition) but also natures of the process itself, where kinetic functions of mineral decomposition is not invariant relating to H₂SO₄ consumption. Leaching is divided into two periods: initial active period with sulphuric acid participation and S⁰ formation, and final slow period without sulphuric acid participation and sulphur oxidation to sulfate form. Amount (part) of concentrate, oxidated during active period depends on sulphuric acid consumption. Average leaching rate is growing together with increase of this part, without dependence on other factors. During dual-stage leaching the part of concentrate oxidated during active period is higher than during single-stage process. It is shown that selectivity of zinc extraction in the solution grows up relating to copper and iron.