Tridiagonal Solutions > Tridiagonal Partners FactSage

FactSage Product Portfolio and Services

FactSage 8.3 has been released in October/2023 (latest version)

Free ChemApp for Python license available until end of August 2024 for institutions which license FactSage 8.3

Chemapp for Python & FactSage are developed by and available from GTT-Technologies.

FactSage™, one of the largest fully integrated database computing systems in chemical thermodynamics in the world, was introduced in 2001 and is the fusion of the FACT-Win/F*A*C*T and ChemSage/SOLGASMIX thermochemical packages. FactSage is the result of over 20 years of collaborative efforts between Thermfact/CRCT (Montreal, Canada) and GTT-Technologies (Aachen, Germany).

Because of its high degree of user-friendliness, FactSage provides the proverbial fingertip access to Computational Thermochemistry. A regular upgrade schedule ensures that new technical and user friendly interface features are added.

The calculation features of FactSage are used in diverse areas of applications and provide a flexible platform for the solution of complex thermochemical problems. FactSage is extensively used all over the world. 

The thermodynamic databases integrated in FactSage are based on CalPhaD (Calculation of Phase Diagrams) assessments and span the entire chemical space from oxides to metallic alloys or aqueous systems.

We regularly conduct training courses for FactSage for both beginners and advanced users. 

It is also possible to learn how to use FactSage by the FactSage-Teach self-tuition package.

Further information on the Teach package is available on request directly from GTT (

FactSage Product Portfolio:

  • FactSage – a thermochemical database software(current version 8.3)
  • ChemApp for Python – the thermochemistry library for your software
  • ChemSheet – the spreadsheet tool for process simulation
  • SimuSage – ChemApp-based set of Delphi components for process simulation
  • OLI Systems – FactSage Interface: the link to the OLI Aqueous Databanks
  • METSIM – FactSage Link
  • Database Development and other Consulting Services

Applications of FactSage:-

FactSage has a very broad range of applications, both in the industry and in the academia. It can be used to calculate complex phase equilibria in many systems of interest consisting of a mixture of inorganic substances reacting with each other. This includes oxides and metallic solid phases, aqueous solutions and different types of liquid and gaseous phases. It is the ideal tool for the calculation of high temperature phase equilibria which are relevant for the metallurgical and ceramic industry.

In addition to the calculation of phase equilibria and phase diagrams, it is also possible to simulate the dynamics of reactors or processes by using FactSage.

We divide the main application areas for FactSage in four major groups:

  • Alloy and Material Design- 

    It may be that you wish to design a new material with a certain crystallographic structure or possessing specific chemical, physical, mechanical or electromagnetic properties. Once FactSage can predict which phase forms under specific conditions, one is able to design new materials, i.e. to define the proper ranges for the contents of the different chemical elements, by using FactSage.

  • Microstructure Control:

    A material is not defined only through its chemical composition, but its properties will very much depend on the processing conditions, which in their turn define the details of its microstructure. The same material, in what concerns its chemical composition, may have completely different properties depending on its microstructure. This must include also the consideration of kinetic constrained states and metastable materials. Whenever a material should be optimized by engineering its microstructure, FactSage can be efficiently used as a tool with this objective.

  • Process Metallurgy:

    In the broad area of metallurgical processes, one aims to extract a metal from its corresponding mineral or to refine an impure melt through a variety of methods. This includes pyrometallurgical, hydrometallurgical or electrometallurgical procedures.  In many cases, an analogous process applies also to other industries, e.g. to the ceramic industry.

    In these situations, one is dealing with complex multiphase/multicomponent equilibria, involving gaseous, liquid and solid solution phases. FactSage can simulate the equilibrium in such systems and can also take kinetics into account by using a combination of streams and unit operations in the scope of a flow-sheeting approach.

  • Energy:

    The area of energy generation and conversion has a strong affinity to the broad area of metallurgy, in special to pyrometallurgy. The gasification of all kinds of carbon-containing materials, ranging from coal to biomass can be investigated with FactSage. Also the combustion of different kinds of fuels and of industrial or domestic waste should be optimized for environmental reasons and this optimization can be performed with the help of FactSage.

To know more about FactSage, please visit :

FactSage – System Requirements:-
Recommended System Requirements:
Operating System: Microsoft Windows 10 or above
CPU: Intel Core i5 (or an equivalent AMD processor) or better
RAM: 16 GB or more
Storage: 7200 RPM or better HDD or SSD

Latest Version

In addition, also add the following information concerning GTT thermochemical databases:

GTT-Technologies develops its own Factsage thermochemical databases. Presently, the GTT databases are the following ones:

a) GTT Oxides Database (GTOx) – GTOx includes a better description for some combinations of oxides, e.g. high Na2O- and K2O-containing systems like biomasses (2016-2019) or Vanadium oxide-containing systems (2019-). In 2023, the so-called unified liquid phase model (SLIQ) was introduced in GTOx. This describes the liquid sulfide, the liquid oxide and the liquid metallic melt with a single liquid solution model.

b) aiMP (ab initio Materials Project) and aiOQ (ab initio OQMD) – these databases are based on ab-initio data calculated at 0K by using quantum-mechanical approaches (DFT). We at GTT have upscaled the thermodynamic stability of hundred of thousands of compounds from 0K to relevant temperatures.

ChemApp – the thermochemistry library for your software

ChemApp provides the powerful calculation capabilities of the ChemSage Gibbs energy minimiser (the same one that powers the FactSage modules Equilib, Phase Diagram and OptiSage) in the form of a programmer’s library. It consists of a rich set of subroutines which provides all the necessary tools for the calculation of complex multicomponent, multiphase chemical equilibria and the determination of the associated thermodynamic properties of the system, its phases, and their constituents. Potential applications for the use of ChemApp are almost limitless and can cover an extremely diverse range of applications. Two distinctly different groups of applications of ChemApp are possible:

  • using it for the development of application-specific programs; for example, for handling repetitive complex equilibrium calculations, for analysis, and for process control in well-defined technological areas,
  • linking it to third-party process simulation packages for modelling new or optimising existing processes; for example, commercial CFD programs such as Fluent®, CFX®, general simulation programs, including Aspen Plus®, PRO II®and also a company’s own process simulation program.

ChemApp is available for a wide variety of programming languages (e.g. Fortran, C, C++, Visual Basic®, Delphi®) and hardware platforms/operating systems (e.g. Windows, Linux, Unix). ChemApp reads ChemSage (.dat and .cst) thermochemical data files (note, .cst files can be generated by the FactSage Equilib module). For detailed information on ChemApp features, ChemApp “light” versions available for download, publications and ongoing projects together with an online version of the programmer’s manual, with complete references to all ChemApp subroutines and dozens of code examples in both FORTRAN and C, plus several worked examples, consult the ChemApp section on GTT-Technologies’ web site.

ChemSheet – the spreadsheet tool for process simulation

ChemSheet combines the flexibility and practicality of spreadsheet applications with rigorous, multi-phase thermodynamic calculations. It was developed in a co-operation between GTT-Technologies and VTT Chemical Technologies in Espoo, Finland. ChemSheet is an add-in for Microsoft’s EXCEL™. It provides a link between ChemApp, the programmer’s library for thermochemistry (using the same ChemSage Gibbs energy minimiser as in the FactSage modules Equilib, Phase Diagram and OptiSage) and an EXCEL spreadsheet. Each application is defined as an independent worksheet in which the entire simulation can be done. Interaction with ChemSheet is done through easy to use dialog boxes which provide the user with a tool to link values of variables with cells in the spreadsheet. The graphical capabilities of EXCEL are available for the visualisation of the results. One of the major strongholds of ChemSheet is its applicability to systems with kinetic inhibitions such as the production of TiO2 reaction of TiCl4 with O2. Although the equilibrium of this reaction is on the TiO2 side it is kinetically retarded. The effect of this constraint on the global equilibrium with all other chemical species of the system being fully equilibrated has been successfully modelled using ChemSheet. ChemSheet requires ChemSage (.dat or .cst) thermochemical datafiles. (.cst files can be generated by the FactSage Equilib module.) For the inclusion of the data that permit the kinetic calculations referred to above it is necessary to modify the standard .dat file. A software called ChemSage File Administration Program is available for that purpose. A free demo version of ChemSheet, called ChemSheet-light, is available. For more details on ChemSheet including animations of ChemSheet applications and a download of the demo version click on ChemSheet Information.

SimuSage – the component library for rapid process modelling


is a ChemApp-based set of Delphi components for process simulation (flowsheeting) tasks. SimuSage has originally been developed by SMS Demag as an internal tool. Subsequent development work at GTT-Technologies has turned it into a commercial product. With SimuSage you can develop a model for a process using a set of “unit operations”. These are comprised of stream splitters, mixers, equilibrum reactors, iterators and others. Build your entire model using the unit operations in basic configurations such as by-passes or split equilibria (to include kinetic inhibitions into your process), or use recycle streams with (or without) internal equilibrium in order to handle output from one stage as input to a previous stage. Simple process simulations can be set up using visual programming alone, no coding is required. When the demands in the complexity of your simulations increase, Delphi with its technologically advanced programming concepts and tools offers you everything necessary to produce highly customized applications. The highlights of SimuSage are:

  • Rapid process modelling: assemble process models involving complex thermochemistry in a minimum amount of time
  • Modern development environment: use state-of-the-art Borland Delphi visual programming tools
  • Fast, custom-made programs: create standalone executables for internal or external distribution
  • Limitless extensibility and customization: all Delphi features are available to extend SimuSage and customize your own applications

ChemApp reads ChemSage (.dat and .cst) thermochemical data files (note, .cst files can be generated by the FactSage Equilib module). For more information, consult the SimuSage section on GTT-Technologies’ web site.

FactSage – OLI Systems Interface – the link to the OLI Aqueous Databanks

The FactSage – OLI Systems link is no longer supported.

METSIM – FactSage Link

The FactSage – METSIM link is no longer supported.

Database Development and other Consulting Services

We offer extensive database development and other consulting services. For more information please contact us at

Pravin, one of the five members of Board of Directors in Tridiagonal Solutions has proven his expertise in creating, positioning and managing high growth companies. Mr. Jain has completed his Bachelors in Computer Engineering from University of Mumbai and Masters in Computer System Engineering from Northeastern University, Boston. He has also completed the Executive Program for Growing Companies at Stanford University Graduate School of Business. He has over 17 years of experience in Technology Entrepreneurship, Business Development and Delivery of Customer Centric Solutions. Pravin’s experience includes acquiring as well as divesting companies. Pravin lived and worked for 14 years in the US, and shifted back to India in the summer of 2006. He has driven, and been accountable for Sales, Marketing, Technology, Delivery and Strategy functions at his previous ventures. Pravin’s previous company grew by over 40x in 6 years and was subsequently divested to Wipro.

Ashish heads the software development activities at Tridiagonal Solutions. He has Post graduate degree in Fluid Mechanics and Thermal Sciences from IIT, Kanpur. Ashish is also a founder member of Tridiagonal and his interests include Computational Fluid Dynamics, Turbulence Modeling, Technical Training and Mentoring along with Open Source Software Development. Before founding Tridiagonal, Ashish worked with Fluent for seven years where he looked after product management responsibilities for Catia and FlowLab products.

Dr. Damodaran Vedapuri heads the North American Operations of Tridiagonal Solutions. He obtained his doctorate from Ohio University. Dr. Vedapuri has wide experience in Computational Fluid Dynamics, Flow Accelerated Corrosion and solving Multiphase Flow Problems of interest to the oil and gas industry. Before joining Tridiagonal, he was employed with SwRI, a premier research lab in the US and at Fluent Inc.

Dr. Damodaran Vedapuri heads the North American Operations of Tridiagonal Solutions. He obtained his doctorate from Ohio University. Dr. Vedapuri has wide experience in Computational Fluid Dynamics, Flow Accelerated Corrosion and solving Multiphase Flow Problems of interest to the oil and gas industry. Before joining Tridiagonal, he was employed with SwRI, a premier research lab in the US and at Fluent Inc.

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