In this Multi-Cell Copper Electrorefining CFD Analysis tutorial, we provide comprehensive training on simulating the industrial process used to produce high-purity copper (99.99%). In a real refinery, hundreds of impure copper anodes and pure cathodes are submerged in a tank filled with an electrolyte mixture of Copper Sulfate (CuSO4) and Sulfuric Acid (H2 SO4). When voltage is applied, copper ions migrate to the cathode. To ensure the deposited metal is smooth and free of nodules, engineers add precise amounts of leveling agents like Thiourea. However, managing the flow and current distribution across many parallel plates is incredibly difficult. If the flow is uneven, impurities ruin the product. Therefore, engineers rely on CFD simulation to visualize the internal physics without disrupting production. In this ANSYS Fluent training, we simulate the complex interaction between the electric field, chemical species transport, and fluid dynamics. This Multi-Cell Copper Electrorefining fluent simulation teaches you how to optimize tank designs for uniform deposition and energy efficiency.

In this lesson, we simulate a multi-cell geometry using the Species Transport Model. We track five specific components, including critical additives like Thiourea () and the primary electrolyte species. We also calculate the Potential Field to ensure the current density is uniform. Unlike our previous product which focused on single-cell electrorefining, this tutorial expands to a Multi-Cell configuration, allowing us to analyze the “shunt current” effects and flow distribution discrepancies between neighboring plates. For more chemical processing lessons, please explore our Chemical Engineering tutorials.

Figure 1: 3D Geometry model of the Multi-Cell Copper Electrorefining system showing alternating anode and cathode plates arranged in a series configuration.

Simulation Process: Electrochemistry and Species Modeling in ANSYS Fluent

For this CFD – Multi-Cell Copper Electrorefining training, we developed a 3D geometry representing a slice of an industrial tank containing multiple electrode pairs. We generated a high-quality Polyhedral Mesh containing 1,632,433 cells. We specifically chose polyhedral cells for this ANSYS Fluent simulation because they handle the complex gradients of chemical species better than tetrahedral meshes while keeping the cell count manageable.

We configured the Species Transport Model to track a mixture of five components: Copper Sulfate (CuSO4), Sulfuric Acid (H2 SO4), Thiourea (CH4 N2 S), a generic additive (C2H9NOX), and Water (H2O). Modeling Thiourea is critical because it acts as an inhibitor; it adsorbs onto high-current areas to prevent roughness. We enabled the Potential Equation to solve for the electrostatic field, setting the electrolyte Electrical Conductivity to 1 S/m.

Figure 2: Polyhedral Mesh Grid (1.63 million cells) with fine refinement in the narrow inter-electrode gaps to capture steep electrochemical gradients.

Post-processing: Multi-Cell Copper Electrorefining CFD Analysis of Species & Potential

This section teaches you how to interpret the simulation contours to evaluate cell performance. We perform a detailed analysis of the Potential, Acid, and Copper Sulfate distributions. First, we analyze the Electric Potential Distribution in Figures 5 and 6. The contours display a perfect alternating pattern essential for a multi-cell system. The red zones represent the anodes at 0.3 Volts, and the blue zones represent the cathodes at 0.0 Volts. The gradient between them is linear and smooth. Engineering Insight: This smooth transition confirms that the primary current distribution is uniform. There are no short circuits or localized hot spots at the edges of the plates. In a Multi-Cell Copper Electrorefining CFD Analysis, verifying this linear voltage drop is the first step to ensuring that every copper plate will grow at the same rate.

Next, we examine the Species Distribution, specifically Sulfuric Acid (H2 SO4) in Figure 4 and Copper Sulfate () in Figure 3. The mass fraction varies slightly between 0.136 (13.6%) and 0.140 (14.0%). This variance of less than 0.4% proves the electrolyte is Well-Mixed. This is a critical finding. If the acid concentration were higher at the bottom due to gravity (stratification), the electrical conductivity would change vertically, causing the copper to plate unevenly (thicker at the bottom). Our simulation proves the flow rate is sufficient to keep the acid chemically homogeneous.

Figure 3: Copper Sulfate (CuSO4) Mass Fraction Contours, visualizing the ion depletion near the cathodes and accumulation near the anodes.

Figure 4:  Sulfuric Acid ((H2 SO4) Mass Fraction Contours (0.136 – 0.140) showing a highly uniform acid distribution across the multiple cell gaps.

Figure 5: Electric Potential Contours on vertical planes, illustrating the linear voltage drop from the anodes (0.3V, red) to the cathodes (0V, blue).

Figure 6: Horizontal Potential Distribution showing the smooth electric field gradient through the electrolyte between the electrode pairs.

Figure 7: Velocity Magnitude Contours highlighting the slow, laminar flow in the gaps (<0.05 m/s) compared to the faster circulation zones near the bottom inlets (0.25 m/s).

Finally, we correlate this with the Velocity Contours in Figure 7. The flow speed in the narrow gaps is Laminar and slow (< 0.05 m/s), while the bottom of the tank shows circulation zones up to 0.25 m/s. This flow profile is ideal. The slow, stable flow between plates ensures that the Thiourea (CH4 N2 S) additive is not washed away too quickly, allowing it time to adsorb onto the cathode surface and smooth the copper deposition. Meanwhile, the higher velocity at the bottom prevents anode slime (impurities) from settling and clogging the inlets. This ANSYS Fluent tutorial confirms that the multi-cell design successfully balances chemical transport with electrical efficiency.