Before you begin, note that the F10 key is used throughout the program as the acceptance key; it is used once you have edited or chosen an option and would like to proceed. Esc allows you to escape from an operation without implementing any changes.

Pyrosim should now be installed in a directory C:\PYROSIM, as described in the previous section.

Selecting thermodynamic data from Thermo
Thermo is a thermodynamic package used to evaluate individual chemical reactions. Thermo (version 2.09 or higher) can also be used to edit and export thermodynamic data for use by Pyrosim.

Thermo should be installed in a directory C:\THERMO. Type Thermo at the C:\THERMO prompt and select eXport from the main menu. Select the species which you would like to use in your system by pressing enter (which toggles the selection). Using the elements present as a guide you should select most of the species which contain combinations of the elements present, for example if you have Fe, Ca, Mg, and O as elements present you should select all the iron oxides, calcium oxides, magnesium oxides, and complex species like Ca₂Fe₂O₅, CaFe₂O₅, and MgFe₂O₄ species.

Figure 1: The Thermo eXport screen

Don't forget to include gaseous species and all the species present in the feed materials of your process.

Once you have made your selection press F10. The default directory for Pyrosim files is C:\PYROSIM, however, you may edit the default if you wish. Choose a three character identifier and press enter. Thermo will affirm that the data has been sucessfully exported in a Pyrosim format.

Figure 2: Exiting Thermo

If you missed a species you can run Thermo at a later date and add the species to the list. To do this just select the species, and choose the same three character identifier. A message will appear stating that a list with that identifier already exists, press enter to continue. Thermo will append the new species to the bottom of the list.

Using the Pyromake Utility Program
Pyromake is a simple utility to automate the process of gathering thermodynamic data for the initial creation of a set of Pyrosim data files for a particular system. Thermo version 2.09 can now export data in the Pyrosim format, and also add to Pyrosim data files. It is strongly recommended that you use Thermo to manipulate thermodynamic data, if however you do not have Thermo, read on.

All that is involved in using Pyromake is the selection of all species of interest, and the specification of where the files are to be created. A three-character identifier for the set of data files is also required.

To begin constructing a new model use the cursor keys to move around, and press Enter to select a compound.

Select the following compounds:

Compounds present in any feed material.

All compounds that may leave the process as products.

Any complex compound that may account for non-ideal interactions between simple compounds

Any other compound that may be required in your model

Bear in mind that this list forms the basis of a simulation model, and that all feed streams and equilibrium or empirical specifications will be selected from this list.

¤ A rule of thumb to follow when setting up a system is to choose any possible combination of the elements present in the feed streams.

× However, try not to select too long a list, as the memory which Pyrosim uses (the lower 640 kb block) is limited; long lists may result in an Error 7: Out of Memory when you run Pyrosim.

It is crucial to not leave out any species at this stage because, if, at a later stage, you realise that a species is missing you will have to edit your thermodynamic file. This operation is most easily overcome by using Thermo, but editing and adding of thermodynamic data can be performed by running an older version of Pyrosim (called PYRO143.EXE) with your system.

Once you have made your selection press F10. A prompt appears requesting the destination of the Pyrosim files (which Pyromake will automatically create). The default destination is C:>PYROSIM). Choose the default unless the directory into which the files are to be placed is another which already exists. If the directory does not exist an Error 76: "Path not found" will be reported and the Pyromake file will have to be recreated.

Enter a three character identifier for your system (and F10 to accept). Once you return to the DOS prompt type PYROSIM .EXT, (where EXT is your three character identifier), or just PYROSIM.

† A directory listing of files in the PYROSIM directory will show you that a file THERMDAT.EXT has been created from the file THERMO.DAT ( EXT is the three character extension you gave your system). The files ending in SS are files set up for the stainless steel system.

Selecting a System
Once you have constructed the database for your system you will need to run Pyrosim. After typing PYROSIM at the DOS prompt a data set menu, similar to the one displayed below, will appear.

Figure 3: Pyrosim's data set menu that allows for the selection of any predefined system

To select a user defined system move to the desired system and press Enter (all the systems stored in the PYROSIM directory are listed in this menu).
To select the stainless steel system do so from the data set menu as shown above.

Pyrosim's Main menu is shown below.

Figure 4: The Main menu

Basic configuration of your system can be performed from this menu.

The following sections describe these basic operations. The next chapter discusses advanced features that are either command line instructions or require specific characters for initialisation.

Choosing a Process Flow Sheet
The flow sheet should contain all the relevant units of the pyrometallurgical stages to be modelled. Pyrosim allows four process models to be connected within a system.

Select option fLowheet from the main menu to configure your system. If a two stage model is to be used the following screen will be displayed.

Figure 5: Screen display for fLowsheet/Flowsheet 2

The interconnections shown at this stage are purely graphical. Until the interconnections between units are specified (Interconnect) no mass flow between units will be reported in the output.

× If you have developed a multi-unit process and wish to revert to a single stage process you must reset the output format. This is done in the main menu, after a single stage unit has been selected, by moving the cursor to the Interconnect command and pressing enter.

Choosing a Model
A number of user definable process models are available. The most frequently used models are the user definable Equilibrium model, and the Heater / Drier. The Empirical model (for performing mass balances) is also becoming more widely used.

Pyrosim was originally developed as a means of simulating the production of crude stainless steel, as described by Rodney Jones1. The original models were developed exclusively for this process however the Stainless Steel models are rarely used; current techniques for describing a mixed phase result in better predictions.

The following sections describe the individual unit models. To select a model use the Models option from the main menu. The Stainless Steel system is described in Appendix B.

Figure 6: Models option from the main menu; the cursor keys can be used to scroll through the list

Heater / Drier
The Heater / Drier model can be used in two configurations, temperature controlled and energy controlled.

As a temperature controlled unit. This is a heater, with Pyrosim calculating the energy requirements. The feed materials are all heated to the specified temperature, and the user can specify a percentage of moisture and volatiles to be removed.

All other species that occur as gases at the operating temperature report to the gas phase.

Combustion is not taken into account in this model.

As an energy controlled unit: This model balances the energy of the feed and product streams (by changing the unit's operating temperature) and predicts a bulk temperature for the unit. For example a hot off-gas stream drying the feed to a furnace. The temperature of the unit would be determined by the enthalpy of the streams entering the unit (and the heat losses of the unit).

The user is prompted for an approximate temperature of the unit to act as a first estimate in the solve routine.

The Equilibrium Model

This model allows any equilibrium specification to be made by you. This requires you to have a good understanding of the chemistry of your process and therefore knowing which species to select.

This model is based on the assumption that the chemistry of the system attains chemical equilibrium.

Thermodynamic modelling of complex systems requires a solution model which adequately describes the excess Gibbs free energies for the solution phases i.e. account for the non-ideality of the solution. A more detailed description of the Ideal Mixing of Complex Components approach may be found in Chapter 5.

If you wish to select one of the five available equilibrium models (six if you include the Multi Stage Equilibrium) you will have to specify the phase chemistry. This is discussed in a later section of this chapter.

Multi Stage Equilibrium Model

This model consists of a user-definable number of coupled equilibrium units connected in a cross-flow arrangement. The solids are passed from unit to unit while other feeds are split between units. The product gas streams are collectively grouped into a single stream.

The following figure illustrates the multi-stage equilibrium model.

Figure 7: The multi-stage equilibrium model

The feeds which are to between the units must be labelled -->Name (Setup/Analysis).

This unit was developed for the modelling of blowing operations where a fresh gas is brought into contact with a liquid which has already been exposed to fresh gas.

Operating Conditions
The following options are available through the Operation choice in the main menu. The screen display is shown below.

Figure 8: Selecting the operating conditions of the system

Select whether your process is to be temperature of energy controlled, the operating temperature and pressure, and the rate of energy loss from you unit (in kW).

A temperature controlled unit will calculate the energy requirements of the process based on your selected operating temperature. An energy controlled unit will balance the energy in the unit by varying the operating temperature, thus predicting a bulk operating temperature if the energy losses of the unit are known.

To select this option select 1 for energy control or 0 for temperature control.

If you have selected the temperature controlled option input the operating temperature in degrees Celsius.

Enter the operating pressure in atmospheres.

The value is entered as a rate of energy loss (kW).

This figure is usually a rough estimate depending on the configuration and geometry of the unit. Heat losses are sometimes assumed to be zero for comparison between various process routes, or for determining the theoretical specific energy requirement (kWh/kg) of a certain feed.

Differences Between Operating and Observed Temperatures
For each unit there is allowance to make adjustments for stream temperatures that differ from the process temperature. An example of this is cooling of off-gas stream.

Figure 9: Accounting for differences between the operating and observed temperatures of a stream

Consider an off gas stream which cools when it passes through the burden of a submerged arc furnace. The temperature at which the gas leaves the furnace may be several hundred degrees cooler than the operating temperature of the unit. Thus the gas stream would be given a difference of -500ºC (for example); which would indicate that it is 500 degrees cooler than the temperature of the unit when it leaves the system. The energy balance would thus be corrected to account for this transfer of energy from the gas stream to the burden (feed).

Connecting Units
The Interconnect option from the main menu is only available if more than one process units are selected.

This option accounts for the possibility of a stream changing temperature between units, or for a stream being split before entering the next unit (e.g. 5 % of the gas product from a rotary kiln being carried over to the furnace).

To enter the values use the up/down cursor keys. The interconnection fractions are entered as a fraction of one. The temperatures reflected will be the temperatures of the input streams to the next unit.

Additional feed streams to a following unit are entered from a second Feedrates menu that automatically appears (after F10 has been pressed when selecting the feeds to the first unit). Feed streams are described below.

Feed Streams
Pyrosim requires a number of pre-defined inputs before being able to calculate any results; one of these prerequisites is at least one feed stream.

Defining a Feed Stream
From the main menu select Setup/Analyses. This brings you to the analyses screen. Use the up/down cursor keys to scroll to the option . Press Enter. Type in a name for the feed material.

Figure 10: Entering a new feed analysis.(for this example the name has been entered as Coal and 57% of the material is carbon)

Now, using the up/down cursor keys, scroll through the list of alphabetically listed compounds entering the mass percent of each compound present in the feed material.

When all the compounds shown on the first screen have been selected press F10 to see the next screen; continue making your selection.

Feed stream analyses must total 100 % (within 0.5 %) otherwise the program will report the following message in the lower window:
Analysis total = X (X < 100 %), Press any key to resume editing.
This is a useful check to see if the analysis has been entered correctly (that's why Pyrosim doesn't normalise your input).
After a new feed analysis has been entered correctly Pyrosim will then return to the list of feed materials. Press F10 to return to the Setup menu (Esc will exit without saving changes).
If you would like to enter another feed analysis repeat the above from the Setup menu.

Modifying Existing Feed Streams
To modify the analysis of an existing feed stream choose Setup/Analyses, move the cursor (using the up/down cursor keys) to the material name to be changed and press Enter. You can now change the analyses as in the previous section but remember to exit using F10 and not Esc.

Equilibrium Specifications
Pyrosim's most frequently used model is the equilibrium model. This model relies on chemical equilibrium being attained. Since pyrometallurgy is associated with very high temperatures (and low pressures), this assumption is often valid.

Nickel-copper matte smelting, reverbatory smelting of copper, the processing of platinum bearing concentrates (in a nickel copper system with a high MgO slag), the production of ferrochromium in a plasma arc furnace, cobalt recovery in slag cleaning operations, silico-manganese production, the secondary smelting of lead, the production of ferronickel from laterite ores, are examples of some processes which have been modelled using the equilibrium model.

Each equilibrium model is characterised by the choice of compounds allowed to be present at equilibrium. This choice may be edited by you at any time, this section describes how to set up your first equilibrium file and then edit it at a later stage.

Constructing an Equilibrium File
This is done by choosing the option Setup/Equilib from the main menu.

Figure 11: Selecting a unit to be associated with an equilibrium specification

Select the unit model which is to use this equilibrium file by pressing Enter (this links the file associated with a unit model name to its equilibrium specification). There are five available equilibrium unit models, these are named Equilibrium1 through 5. Each of these are user definable.

Select which phases will be present at equilibrium, move with the up/down cursor; Enter toggles the selection.

Select the phases you would like to be present. In the figure below gas, slag, and metal were selected.

Figure 12: The screen display for specifying the equilibrium phases, gas, slag and metal have been selected as the phases

After selecting the required phases press F10. A list of chemical compounds is presented for the first phase (in this example the gas phase).

Figure 13: The screen display showing the list of species available for possible insertion into the equilibrium phases

Using the up/down cursors move through the list selecting the species that you expect to be present in this phase. Press Enter to toggle the asterisk that indicates a selection made.

Shown below is a typical specification for a system which contains three phases, viz. gas, slag, and metal. This model was used to simulate the smelting of titaniferous magnetite. Notice the complex components specified in the slag phase.

Table 1: Example of an equilibrium file specification

Gas CO, CO₂, H₂, H₂O, Mg, N₂, SiO

Slag Al₂O₃, Al₂SiO₅, Al₂TiO₅, C, Ca₂Al₂Si, Ca₂SiO₄, Ca₃Ti₂O₇, CaAl₂O₄, CaAl₂Si, CaAl₂SiO, CaAl₄O₇, CaMgO₂,
CaMgSi₂O, CaMgSiO₄, CaO, CaSiO₃, CaTiO₃, Fe₂O₃,
Fe₃O₄, FeAl₂O₄, FeO, FeSi, FeTiO₃, Mg₂SiO₄, MgAl₂O₄,
MgO, MgSiO₃, MnO, SiO, SiO₂, Ti₂O₃, Ti₃O₅, Ti₄O₇,
Ti₅O₉, Ti₆O₁₁, Ti₇O₁₃, Ti₈O₁₅, TiO, TiO₂, V₂O₃, V₂O₅,
VO, VO₂

Metal C, Fe, Fe₃C, Fe₃Si, FeSi, Mn, Si, SiC, Ti, TiC, V, V₂C, VC

Once you have selected the compounds expected to be present in a phase press F5 to check your entry. A list of the selected compounds is presented; this is shown below for a slag phase.

Figure 14: An example of a slag phase equilibrium specification

†This list from which you made your selection was obtained from the file THERMO.EXT containing the list that you selected using either Thermo, or the Pyromake utility.

†A file called EQUIL00*.EXT is being formed containing the selected species for your Equilibrium unit.

If too many species have been selected (>70) for a phase a message will be reported. You will have to decrease the number of species selected (by using the up/down cursor keys and Enter) before you can proceed.

Editing an Existing Equilibrium File
Choose Setup/Equilibrium from the main menu. Select the equilibrium unit to be modified. Press F10 to bypass the changing of phases or Enter to toggle the selection of a phase.

For each phase scroll through the list of species and select or remove using Enter to toggle selection. Press F5 to check the selection and F10 to exit to the Setup menu.

¤ To move quickly to a desired species, type the name. (this operation is case specific, for example, to move to Fe₂O₃ type Fe2O3).

× If the situation arises where a species required in the equilibrium file is not selected in the Pyromake facility you will have to add the thermodynamic data to your list. The preferred way of doing this is by using Thermo; using the e_Xport feature from Thermo's main menu, just select the specie, specify the three character identifier, and add the species to the bottom of the list.

However, you could also run PYRO143.EXE and use the Setup/Thermo Data option (this option has been disabled in Pyrosim version 1.50). In order to use PYRO143.EXE you will need to have a printout of the thermodynamic data available. This can be obtained by selecting the species you wish to add using Pyromake, then, using Pyrosim choose Document/Thermo Data and print the thermodynamic data coefficients of these species. Finally run PYRO143.EXE, choose Setup/Thermo Data and add it to your list.

Pyrosim's Costing Option
Pyrosim contains a costing option to calculate the operating costs of a process. To select the costing option from the main menu select Setup/Costs. You will be prompted for the electricity costs and presented with a list of the feed materials. Simply follow the prompts.

In the following figure the price of chromite has been entered as $100/ton. The coal as $0.00/ton (tonnes used are metric).

Figure 15: The costing menu

Calculate
This command in the main menu initialises Pyrosim's solve routine. An active screen is displayed which provides some information about the convergence of the system.

Figure 16: The active screen for the example used in this manual

Interpreting this active screen is discussed in more detail in Chapter 3. After the system has converged Pyrosim displays a Results menu that's discussed in the following section.

If the system doesn't converge there are a number of possible causes. Check to see if a mixed phase is disappearing (if one of the numbers beneath Convergence becomes greater than 1). This can be corrected by adding trace quantities (<0.1kg/h) of an inert substance to that phase, like argon to a gas stream or platinum to a metallic stream. This would involve specifying such a compound (Setup/Equilib) in the phase, and defining feeds containing these dummy compounds.

Printing
Before you begin make sure that you have selected the correct printer to be present. This should be done under Setup/Printer (where the setting will be permanent) or may also be done from the Report menu (temporary).

This section briefly describes the printing options available as well as the option of saving your output to a text file.

Figure 17: The report menu

Summary produces a screen display of the complete report. Press Pause to halt the scrolling screen.
Report gives you a hard copy of the output in a fixed format.
floWsheet, Flowrates, Operation, Energy, Analyses, eLements, and Date. These options allow certain sections of the Report to be printed separately and are useful for saving paper.

The output can be saved to a text file in the ASCII format by selecting this option (Setup/Printer) and then using the DOS utility PRN2FILE.EXE (also supplied with Pyrosim).

A copy of the report output supplies all the information necessary to reconstruct a model.

Analysing the Results
The analyses output reports the status of the compounds present in the system in both the feed and product streams. This output is useful for determining which species are responsible for certain partitions, e.g. the carbides accounting for carbon in the metal.

If any compounds have been selected in the equilibrium file and don't form in the product stream remove them from the equilibrium specification by editing the equilibrium file. This will have no bearing on your results and make Pyrosim run faster for the defined system.

In the elemental analyses summary slag analyses are reported as their common oxides. For example Al in a slag is usually reported as Al₂O₃. Pyrosim calculates percent Al₂O₃ in slag = X * (MW_Al₂O₃ / (2*MW_Al)) where MW_Al and MW_Al₂O₃ are the molecular weight of aluminium and alumina respectively.

The default settings for flow rate and energy requirements in Pyrosim are kg/h and kW. If you choose to work with other units for flow rate remember to convert your energy values accordingly.

Document
It is possible to obtain hard copies of the system's thermodynamic data, equilibrium specification and the feed material analyses. This is done through the Document option from the main menu.

A screen display of the document menu is shown below.

Figure 18: The document menu: for thermodynamic data, feed analyses, and equilibrium specifications

You should now have a good grasp of Pyrosim. The following chapter discusses the more advanced (and more obscure) features which are available to you.

Contact Information
Pyrometallurgy Division, Mintek,
200 Hans Strijdom Drive, Randburg, 2125, South Africa
Private Bag X3015, Randburg, 2125, South Africa.

Phone: +27 (11) 709-4642
Fax: +27 (11) 793-6241

ABOUT MINTEK- - - DIVISIONS- - - BULLETIN- - - BUSINFO
PYRO HOMEPAGE- - - PYRO E-MAIL- - - PILOT PLANTS- - - PYRO INDEX

Gas	CO, CO₂, H₂, H₂O, Mg, N₂, SiO
Slag	Al₂O₃, Al₂SiO₅, Al₂TiO₅, C, Ca₂Al₂Si, Ca₂SiO₄, Ca₃Ti₂O₇, CaAl₂O₄, CaAl₂Si, CaAl₂SiO, CaAl₄O₇, CaMgO₂, CaMgSi₂O, CaMgSiO₄, CaO, CaSiO₃, CaTiO₃, Fe₂O₃, Fe₃O₄, FeAl₂O₄, FeO, FeSi, FeTiO₃, Mg₂SiO₄, MgAl₂O₄, MgO, MgSiO₃, MnO, SiO, SiO₂, Ti₂O₃, Ti₃O₅, Ti₄O₇, Ti₅O₉, Ti₆O₁₁, Ti₇O₁₃, Ti₈O₁₅, TiO, TiO₂, V₂O₃, V₂O₅, VO, VO₂
Metal	C, Fe, Fe₃C, Fe₃Si, FeSi, Mn, Si, SiC, Ti, TiC, V, V₂C, VC