Moreover, in these tanks there are specific areas called dead spots where only diffusion takes place. In general, an increase in the momentum of the flow leads to a decrease in dead spots in the volume of the tank, leading to a decrease in mixing time. Therefore, in order to reduce the dead zones and intensify the rate of mixing, baffles are distributed on the tank walls for directing the flow, breaking vortices and contributing to energy dissipation [3; 6]. The improvement of stirred tanks aims to decrease the mixing time and energy cost. Fluid mixing is characterized by tracking the dissipation of a passive scalar injected into the volume of the fluid [7]. This approach has been recommended for predicting the mixing time for miscible liquids since it does not require a solution for the phase interface between the fluids [8]. Important studies have been performed to improve the comprehension of the phenomenology of the problem as well as the influence of impellers on power for the tank and mixture of the flow. For instance, ref. [9] presented numerical simulations to investigate transient power consumption characteristics in a stirred tank without baffles. The transient power number was analyzed based on the predicted impeller torque. The results showed that the power number undergoes four stages: plateau value, sharp falling, slow falling and stable stages, which are affected by the velocity of the impeller. [PERSON] et al. [10] studied the mixing characteristics in a stirred tank with two six-blade Rushton turbines. The mixing efficiency was predicted using a scalar transport model that accounted for the local and global mixing time in the stirred tank. The flow pattern was affected by changing the tank configurations (e.g., with/without baffles, impeller size and velocity of the impeller), which also had a significant influence on the mixing process and overall mixing time. [PERSON] et al. [11] numerically studied turbulent mixing of a passive scalar in a stirred tank by a six-blade Rushton turbine. The mixture simulation was performed by injecting an inert tracer at a location on the upper surface of the tank. The predicted evolution of the tracer concentration over time and mixing times were analyzed at various points inside the tank. The results showed that the concentration of the tracer exhibited initial fluctuations that decreased with time and eventually reached a steady state value that represented the concentration of the fully mixed tracer. Considering that mixing time is defined as the time required for the concentration variance to reach a predetermined value, the results indicated that full mixing was achieved between 3.1 s and 4.8 s. Furthermore, some advances have also been made towards the most representative phenomenological conditions for turbulent flow. For example, ref. [12] numerically evaluated the mixing characteristics and the mixing time for a tank with a Rushton turbine using large eddy simulation (LES) to approach turbulent flow. Recently, ref. [13] developed a computational fluid dynamics (CFD) code with a Euler-Euler model to tackle two-phase flow and mixing of liquid and bubbles in a stirred tank reactor. A sliding mesh approach was also used to simulate the effect of the impeller on fluid flow. The authors concluded that the fluid dynamic behavior and the mixing of both phases around the two blades and in the main tube of the reactor were physically plausible. The influence of the geometric configuration of the impellers has also been investigated. In this realm, ref. [14] evaluated the position of the impeller from the bottom of the tank and disc thickness, as well as the influence of the Reynolds number on the flow field and energy consumption using a Rushton turbine. [PERSON] et al. [15] presented a numerical simulation of the mixing process in a stirred tank and considered the effects of impeller speed, type, spacing, blade tilt angle and blade shape. The authors found an impeller spacing and impeller blade tilt angle most appropriate for the solid-liquid suspension process.