SysCAD + ChemApp for Copper Smelting: A Step-by-Step Guide to Building an Integrated Pyrometallurgical Flowsheet - Part I
Tanai Marin-Alvarado (SysCAD) and Shivani Gonde (GTT-Technologies)
June, 2026
Categories: SysCAD, ChemApp for SysCAD, Process Simulation
Figure 1: Copper primary production from chalcopyrite - SysCAD flowsheet using ChemApp for SysCAD TCE Add-on (Simple Cu Smelter Example)
Copper is one of the most strategically important metals of the modern economy with demand surging, driven by electrification, renewable energy infrastructure, and electric vehicles, yet the ore grades being mined are declining. These puts increasing pressure on smelter operators to process more material and more complex concentrates while improving efficiency and reduce energy use and emissions. Process modelling is one of the most powerful tools available to meet that challenge.
In pyrometallurgical copper extraction, multiple interconnected unit operations - smelting, converting (slag-forming and copper-making), and refining - must be considered together to understand overall process behaviour. Optimising any one stage in isolation risks sub-optimal or even counterproductive outcomes across the full process chain.
A recent post by Shivani Gonde (Part I, GTT Technologies, December 2025) demonstrated how a simple integrated copper smelting flowsheet can be modelled using ChemApp for Python. The same workflow has also been implemented in the FactFlow GUI in the article by Kyota Poeti et al. (Calphad, 88, 2025, 102772). That approach is powerful for engineers and researchers who are comfortable working with Python. This post takes a different path: implementing the same process in SysCAD, a GUI-based steady-state and dynamic process simulation platform widely used in the minerals and metallurgical industries.
By embedding ChemApp for SysCAD directly within SysCAD using SysCAD's ChemApp TCE (Thermodynamic Calculation Engine) Add-on, it is possible to perform the same rigorous Gibbs energy minimisation calculations as in the ChemApp for Python example without writing a single line of code. The result is a fully integrated, graphical flowsheet where stream connections, phase splitting, and solver convergence are handled automatically by SysCAD, making the workflow more accessible to plant engineers and metallurgists who work primarily in a simulation environment rather than a scripting one.
This post is the first in a series that builds progressively in complexity. This post (Part I) introduces a simplified steady-state flowsheet: Smelter_4 → Converter_12 → Converter_19. In the next post (Part II), we will build on this foundation by introducing a more realistic flowsheet that incorporates slag recirculation and multiple slag blow stages.
It is important to note that this is a simplified and intentionally limited first example, designed to introduce the key concepts and SysCAD workflow without unnecessary complexity. The two main performance targets throughout this series are total copper recovered and blister copper purity - the latter typically falling in the 96–98% range and directly determining the metal's suitability for downstream refining.
The example presented here is inspired on the work of Shivani Gonde (Part I, GTT Technologies, December 2025) and Kyota Poeti et al. (Calphad, 88, 2025, 102772), adapted for implementation in SysCAD with the ChemApp TCE Add-on and using SysCAD private theromdynamic database.
The simplified pyrometallurgical copper extraction process from chalcopyrite concentrate in this example consists of three main unit operations, as shown in Figure 1:
- Smelter_4 - converts copper concentrate to a copper-rich matte phase
- Converter_12 (slag-forming) - oxidizes the matte to remove iron as slag
- Converter_19 (copper-making) - further oxidizes the matte to produce blister copper
Each major unit operation (Equilibrium Calculations) is implemented in SysCAD as a ChemApp (CA) TCE Reactor and operates at 1250°C and 2.6 bar, with oxygen-enriched air as the oxidant and SiO2 as the fluxing agent where required. The matte phase output from each stage feeds directly into the next via a Tie unit (Phase_splitter), which separates the condensed matte phase from the outlet gas and slag streams.
The thermodynamic database used across all three reactors is KWA_Cu_Smelting_CST, which contains the Gibbs energy data and interaction parameters for all relevant species and mixture phases in the Cu-Fe-S-O-Si-H-N system. This database file was generated using SysCAD's private thermodynamic solution data and is included with the example project files (see the Accessing the Example Project Files section below). Note that this database differs from the one used by Gonde in the original ChemApp for Python implementation, and as a result the numerical outputs presented here may differ slightly from those reported in that post.
The configuration file (.cfg) and thermodynamic database file (KWA_Cu_Smelting_CST.cst) are both provided with the example project files - see the Accessing the Example Project Files section below. Users who are new to configuring SysCAD TCE projects are encouraged to refer to the SysCAD Supplementary Tutorial - ChemApp (TD008) for detailed step-by-step guidance.
The key setup steps have already been performed int the distributed example. However, creating a similar project from scratch requires the setup steps as follows:
1. Create a new Project Configuration or select the configuration provided and Enable the ChemApp TCE Add-on (if not already enabled) in the project configuration (Edit | Project Configuration). Under the Model Libraries, select the ScdChemApp.dll group and ensure the Allow Heat Calculations option is enabled. In the Configuration tab, make sure the maximum temperature is above the maximum expected process temperature.
2. Configure the TCE database on the TCEs tab of the project configuration - browse to the folder containing the provided KWA_Cu_Smelting_CST.cst file and select it as the active ChemApp database.
3. Create a new steady-state SysCAD project and select the provided configuration file, which already includes the ChemApp TCE models and species database required for this example.
4. Add a TCE ChemApp Chem Model Configuration (TMC) unit to the flowsheet. Load the KWA_Cu_Smelting_CST.cst database file via the TMC unit and run the species auto-mapping to link ChemApp species to SysCAD species.
5. Build the Flowsheet by inserting ChemApp Reactors, Ties, connecting links and setting up input and equilibrium conditions as required.
6. Solve and Analyse Results by running the simulation, all the results and flow streams and equilibrium results from ChemApp calls are automatically propagated through the model and ready to review and analyse.
Figure 2: SysCAD project configuration - ChemApp TCE database setup
The smelter converts copper concentrate (CuFeS₂ with ~8% H2O) into a copper-rich matte phase by partially oxidizing the feed with oxygen-enriched air in the presence of a SiO₂ flux. Iron preferentially oxidizes and is captured in the slag phase, while copper is concentrated in the matte.
The smelter has three input streams:
- Cu Concentrate - 1000 t/h of CuFeS₂ feed, 92% CuFeS₂ and 8% H₂O, fed at 25°C
- O₂ Enriched Air - 680 t/h of enriched air with 40% by vol O₂, fed at 25°C and 2.60 bar
- Fluxing Agent - 100 t/h SiO₂ fed at 25°C and 1.01 bar
And three output streams:
- Outlet Gas - primarily SO₂ and excess gases, exits to atmosphere
- Slag - furnace slag, mainly fayalite to discard or slag cleaning
- Matte Phase - copper-rich sulfide melt at 67.39% Cu (liquid), carrying 316.29 t/h Cu, passed via a Phase Splitter to Converter_12 (Slag Blow)
The CA reactor unit calls ChemApp at each solver iteration to compute the Gibbs energy minimization and determine the equilibrium phase distribution at 1250°C and 2.6 bar.
The first converter takes the matte phase from the smelter and continues the oxidation process. In this stage, the primary goal is to remove the remaining iron by oxidizing FeS in matte to FeO in slag phase, which then reacts with the SiO₂ flux to form a fayalite slag (2FeO·SiO₂). Copper remains concentrated in the matte.
Converter_12 has three input streams:
- Matte Phase - from the Phase Splitter outlet after the Smelter
- O₂ Enriched Air - 60 t/h of O₂ enriched air (40% enrichment), fed at 25°C and 2.60 bar
- Fluxing Agent - 17 t/h SiO₂ fed at 25°C and 1.01 bar
And three output streams:
- Outlet Gas - SO₂ and excess gases
- Slag to Disposal - iron-rich fayalite slag, removed from the process
- Matte Phase - copper content has risen to 75.68% Cu (liquid), carrying 315.62 t/h Cu, passed via a Phase Splitter to Converter 2
The last converter completes the conversion of the copper-rich matte to blister copper. With most of the iron already removed, the remaining Cu₂S is oxidized to produce metallic copper. This stage is critical for achieving the target blister copper grade.
Converter_19 has two input streams:
- Matte Phase - from the Phase Splitter outlet after Converter 1
- O₂ Enriched Air - 201 t/h of 40% by vol O₂ enriched air, fed at 25°C and 2.60 bar
And two product streams contained in Output_21:
Outlet Gas - SO₂ and excess gases
Blister Copper - the primary product at 98.08% Cu (liquid), carrying 315.45 t/h Cu
Figure 3: Smelter (CA Reactor) - TCE unit configuration in SysCAD
A key advantage of SysCAD is the ability to directly connect unit operation outlets to subsequent inlets using stream objects, creating a fully integrated flowsheet. Between each reactor stage, a Tie unit representing the Phase Splitter unit of FactFlow is used to separate the condensed matte phase from the outlet gas and slag - the matte is then routed forward as feed to the next reactor.
This means that when any upstream condition changes - such as feed composition or oxygen flow rate - the effects propagate automatically through the entire flowsheet through the automatic iterative SysCAD Solver mechanism. No manual transfer of intermediate results is needed, which is a significant practical advantage over scripted or spreadsheet-based approaches. This advantage will become even more important in the next Part of the series, where additional slag blow steps will be added and full slag recirculation to furnace and crust from copper blow to slag blows will be demonstrated, showing how SysCAD automatically handles, initialise and converge such a process configuration.
The table below summarises the key operating conditions and copper outputs from the three reactor stages as reported in the SysCAD model:
| Unit | T (°C) | P (bar) | Matte/Metal Cu (t/h) | Cu % (liquid) |
|---|---|---|---|---|
| Smelter_4 | 1250 | 2.60 | 316.29 | 67.39% |
| Converter_12 | 1250 | 2.60 | 315.62 | 75.68% |
| Converter_19 | 1250 | 2.60 | 315.45 | 98.08% |
As shown in Figure 1, similar tables summarizing key results can be inserted directly in the SysCAD Graphics page as Annotation Tables that update automatically after the model is solved.
The progressive enrichment of copper across the three stages - from 67.39% in the smelter matte to 98.08% blister copper - demonstrates the effectiveness of the integrated flowsheet model. The small reduction in copper mass flow between stages (316.29 → 315.62 → 315.45 t/h) reflects minor copper losses to slag and gas phases, consistent with expectations for this type of process.
It is worth noting that this simplified model does not yet account for heat losses, reaction kinetics, or slag copper entrainment - all of which will be introduced in subsequent parts of this series as the model becomes progressively more realistic.
The SysCAD project files for this example are available through two channels. First, the project is distributed as a built-in example with the SysCAD installation - users can find it in the examples directory after installing or updating SysCAD. Second, the files are hosted in the GTT Technologies ChemApp Examples repository on GitHub, where they can be browsed, downloaded, or cloned directly (ChemApp for sysCAD).
The repository also contains examples for other tools and workflows in the ChemApp ecosystem, making it a useful reference point as you work through subsequent parts of this series.
License requirements: To open and reproduce this example, the following licenses are required:
- SysCAD Steady State Solver, with Energy Balance, Integrated Libraries and TCE Add-on
- ChemApp for SysCAD license from GTT Technologies
While this first example has demonstrated the core SysCAD and ChemApp TCE workflow using a simplified flowsheet, it does not yet capture the full complexity of an industrial copper smelting process. In the coming parts of this series, the model will be progressively extended to reflect more realistic process conditions:
In the next post (Part II), we will build on this foundation by introducing a more realistic flowsheet that incorporates slag recirculation and multiple slag blow stages.
- Part II will introduce slag recirculation, where slag streams are recycled back into the process to recover dissolved and entrained copper - a common and important feature of real smelting operations.
Part II will build on the foundations established here, so if you are new to SysCAD and also interested in Thermodynamic Calculation Engines (TCE), this is the right place to start. Stay tuned!
This example is based on: Shivani Gonde, (Part I, GTT Technologies, December 2025) and Kyota Poeti et al. (Calphad, 88, 2025, 102772).
For more information on SysCAD and the TCE Add-on with ChemApp for SysCAD, visit SysCAD and GTT Technologies.