Alumina 3 Bayer Species Model

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Bayer3 Species Model	Species Model Theory	General Discussion

Latest SysCAD Version: 23 April 2024 - SysCAD 9.3 Build 139.35250

Related Links: Precipitation3, Species Models

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General Description

The Alumina3 Bayer species model is used to calculate the properties of fluids within an Alumina project using equations defined in the public domain.

The unit operation Precipitation3 requires Alumina3 Bayer species model to function properly. Please see Precipitation3 for documentation.

Note: The Precipitation Projects and Digestion Projects, which are distributed with SysCAD in the Examples Folder, demonstrate the use of the Alumina 3 Bayer species model in SysCAD projects.

Configuring Bayer3 Species Model

In order for the Bayer3 Species Model to be available in a project, it must included in the configuration file of the project.

Insert into Configuration file

Sort either by DLL or Group.

	DLL:	Alumina3.dll	→	Species Models	→	Bayer3
or	Group:	Alumina3	→	Species Models	→	Bayer3

See Model Selection for more information on adding models to the configuration file.

Required Chemical Compounds

The following species are referenced by the Alumina3 set of models and are required in the species database and configuration file, except for Sodium Fluoride, which is optional. If it is present in the database, its effects will be included in the correlation calculations.

VAPOUR
	H2O(g)	-	Water Vapour
LIQUIDS
	H2O(l)	-	Water
	NaAl[OH]4(aq)	-	Sodium Aluminate
	NaOH(aq)	-	Caustic Soda
	Na2CO3(aq)	-	Sodium Carbonate
	Na2SO4(aq)	-	Sodium Sulphate
	NaCl(aq)	-	Sodium Chloride
	Na2SiO3(aq)	-	Sodium Silicate
	NaF(aq)	-	Sodium Fluoride (Optional)
ORGANICS
	Na2C2O4(aq)	-	Sodium Oxalate
	Na2C5O7(aq)	-	Organic compound representation
SOLIDS
	Al[OH]3(s)	-	Gibbsite (THA)
	Al2O3(s)	-	Alumina Solid
	Na2O(s)	-	Occluded Soda
	NaOH*(s)	-	Bound Soda (Optional) NOTE: This is only used when using the Precipitation3 unit operation.
	Na2C5O7*(s)	-	Bound Organics (Optional) NOTE: This is only used when using the Precipitation3 unit operation.

Note: Sodium Fluoride is not required but will be included in total sodium calculation if present.

Model Theory

Please see Bayer Species Model Theory for the equations used.

All of the properties that are not explicitly calculated by this model are calculated using the Standard Species Model.

Please see General Bayer Data for some general discussion topics.

Bayer Property Calculation Method

Some Bayer properties have different calculation methods, user may select which method to use in the project. Please note that the method selected is Global to the project.

The method and Constants selection can be selected from Plant Model - Global Tab:

Please see Global Properties Calculation Method Selection for more information.

Selecting a Bayer Species Model in a Feeder

The user must have a project that includes a Bayer species model in the configuration file as shown below.

It is then possible to select the Bayer model (either Bayer3 or a client-specific Bayer model).

• On the Feeder access window there is a field 'SpModel.Reqd' where the user may select the model, as shown below:

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
SpModel.Reqd	Inherit	Model used follows upstream units.
	Standard	All the variables are calculated using the Mass Weighted Mean of the species.
	Bayer Species Model	'Bayer Species Model' will be the Bayer model included in the configuration file. In the view above this is 'Bayer3', but may be a client-specific Bayer model. Density, Cp, Boiling Point Elevation, etc. are calculated using the equations defined for that particular Bayer species model.

Bayer Liquor Calculator

When defining a Bayer Liquor stream, it is possible to have SysCAD calculate the feed composition based on user defined Bayer species concentrations and ratios.

This is done in the Feeder unit - but only in a 'True' feeder, i.e. not connected to a sink on a different flowhseet:

• First turn on the Calculator, by ticking the Calculator checkbox () located on the FeederSink Tab,
• Then go to the newly created tab called Calc, and define the required composition.
• NaF_Reqd is only visible if it is selected in the project configuration file.
• OtherLiquidMethod is only visible is there are other liquid species selected in the project configuration file in addition to the Required alumina 3 liquid species.

This is shown in the images below:

For more information on the feed calculator variables, please see Calculator - Bayer Feed Calculator.

The calculated feed composition will be set into the DSp tab. The variables set by the calculator are indicated by the yellow background.

NOTE:

1. If the calculator is enabled, the user may NOT manually change the feed composition on the DSp tab. All changes must be made on the Calc tab.
2. The calculator will calculate the required concentration based on the required alumina 3 liquid species, if other liquid species are present and contain user specified values, the final concentrations might not match the calculator specifications. Please select one of the "OtherLiquidMethod" to help reduce this error.
3. The user may enable the calculator once to get an idea of the values, and then turn the calculator off to manually change the DSp tab values, if required.
4. If the feeder is connected to a sink on another flowsheet, the calculated values are ignored.

Bauxite Feed Composition

When defining the bauxite feed composition, user would often need to convert the lab results (normally presented in Al2O3 and SiO2 basis) to SysCAD species (Al[OH]3, AlO.OH, 2SiO2.Al2O3.2H2O, etc.).

There are a number of ways to convert the data:

1. manipulate the lab results data using external software such as MS Excel, then set the species compositions into SysCAD. If using this method, we recommend using molecular weight data from SysCAD to ensure the calculated data will be matched.
2. manipulate the lab results data using a General Controller. (Please see Bauxite Composition Example for a sample PGM file)
3. define and modify the composition using SysCAD species, then check the results using user defined calculations

Size Data

If the Bayer stream has Alumina Particle Size information for use in Precipitation3 unit model, see the relevant quality model documentation for Specific Surface Area (SSA) or Size Distribution (PSD) for display and configuration information.

Data Sections

Global Properties Calculation Method Selection

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
Menu Command View - Plant Model - Globals Tab - Bayer Properties:
ASatMethod	Rosenberg	Saturated Alumina concentration. See Saturated Alumina Concentration for equations used.
	RosenbergUser	This uses the same equation as above, but user are able to adjust all the constants in the equation manually.
SpecHtMethod	LM_1985	See Heat Capacity Calculations for equations used.
	Mulloy Donaldson	See Heat Capacity Calculations for equations used.
EntropyMethod	Standard	Entropy is calculated by the Standard Species Model using mass weighted mean.
	LM_1985	Based on the LM1985 specific heat. Please see Entropy Calculations for equation used.
SpecHt_UseScale	Tickbox	This allows user to add in a scaling factor for the calculated Bayer Specific Heat value, useful when tuning project to match plant conditions.
SpecHt_Factor	Input	This field is only visible if the SpecHt_UseScale tick box is selected. Used to adjust the calculated Bayer Specific Heat value linearly.
DensityMethod	MulloyDonaldson	See Density Calculations for equations used.
	MulloyDonaldsonUser	This uses the same equation as above, but user are able to adjust all the constants in the equation manually.
Density_UseScale	Tickbox	This allows user to add in a scaling factor for the Bayer Liquor Density value, useful when tuning project to match plant conditions.
Density_Factor	Input	This field is only visible if the Density_UseScale tick box is selected. Used to adjust the calculated Bayer Density value linearly.
BPEMethod	Dewey	This is the original method implemented in SysCAD. This method becomes inaccurate in high caustic concentration range.
	Adamson	This method is more accurate in the high caustic concentration range. See Boiling Point Elevation for equations used.
	Dewey All Liq	This is the same calculation as Dewey option, but using molality for ALL aqueous species present in the stream.
BPE_UseScaleOffset	Tickbox	This enables a global correction (Scale Factor and Offset) to the calculated BPE value. The resulting BPE has a lower limit 0 degrees.
BPE_Factor	Input	This field is only visible if the BPE_UseScaleOffset option is selected. Scale for global correction value for Boiling Point Elevation where final BPE = Calculated BPE * BPE Factor + BPE Offset. Result is limited to a minimum of zero.
BPE_Offset	Input	This field is only visible if the BPE_UseScaleOffset option is selected. Offset for global correction value for Boiling Point Elevation where final BPE = Calculated BPE * BPE Factor + BPE Offset. Result is limited to a minimum of zero.
ViscMethod	EMA1962	Liquid Viscosity. Limitation apply, see Viscosity for equations used.
	Alexandrov	Caustic solution viscosity. See Viscosity for equations used.
OxalateEqMethod	Burnt Island	This is the original method implemented in SysCAD, but should be used with caution.
	Beckham Grocott	This method is based on synthetic liquor and tuned to plant liquor. See Oxalate Equilibrium for equations used.
OxalateEq_UseScaleOffset	Tickbox	This enables a global correction (Scale Factor and Offset) to the calculated Oxalate Equilibrium value. The resulting Oxalate Equilibrium is limited between 0 and 100 g/L Na2C2O4.
OxalateEq_Factor	Input	This field is only visible if the OxalateEq_UseScaleOffset option is selected. Scale for global correction value for Oxalate Equilibrium where final OxEq = Calculated OxEq * OxEq Factor + OxEq Offset. Result is limited to a minimum of zero.
OxalateEq_Offset	Input	This field is only visible if the OxalateEq_UseScaleOffset option is selected. Offset for global correction value for Oxalate Equilibrium where final OxEq = Calculated OxEq * OxEq Factor + OxEq Offset. Result is limited to a minimum of zero.
H2OTestFrac0	Input	This is used to handle very dilute concentration in the stream. If the Water Fraction in the stream is higher than this value, then the stream property will be calculated using the Standard Species Model. The maximum value for this is 99.99%.
H2OTestFrac1	Input	This is used to handle very dilute concentration in the stream. If the Water Fraction in the stream is lower than this value, then the stream property will be calculated using the Bayer3 Species model. For water fraction higher than this value but lower than H2OTestFrac0, a proportional calculation will be performed using both the Standard Species Model and the Bayer3 Species model.
ShowNa2O_Equiv	Input	Selecting this option will add to the display list of Bayer liquor properties variables expressed on Na2O basis.

Calculator - Bayer Feed Calculator

Tag (Long/Short)	Input (Maximum)	Description/Calculated Variables / Options
Bayer Liquor Design Values
DefineLiquor	Check Box	If this box is checked, the Feeder will automatically calculate the make-up of the feed stream, based on the variables supplied below.
Rqd_A/C / A/C_Reqd	Input (0.962003767) (MWAl2O3/MWNa2CO3)	The required ratio of A:C in the Feed stream, where A is Sodium Aluminate NaAl[OH]4 concentration, expressed as grams of Al2O3 /L liquor and C is Caustic Soda concentration in NaOH + NaAl[OH]4, expressed as grams Na2CO3/L liquor.
Rqd_C/S / C/S_Reqd	Input (1.0)	The required ratio of C:S in the Feed stream, where C is Caustic Soda concentration in NaOH + NaAl[OH]4, expressed as grams Na2CO3/L liquor and S is C+ Na2CO3 concentration, expressed as grams Na2CO3/L liquor. A minimum ratio of 0.1 is applied, however depending on other required concentrations a low A/C ratio can result in an unachievable mixture.
Rqd_C / C_Reqd	Input (550.0)	The required Caustic Soda concentration in NaOH + NaAl[OH]4, expressed as grams Na2CO3/L liquor @ 25°C.
Rqd_Na2SO4 / Na2SO4_Reqd	Input (550.0)	Required concentration of Na2SO4 in g/L @ 25°C
Rqd_NaCl / NaCl_Reqd	Input (550.0)	Required concentration of NaCl in g/L @ 25°C
Rqd_NaF / NaF_Reqd	Input (50.0)	Required concentration of NaF in g/L @ 25°C. Only appears if NaF is present as a species.
Rqd_Oxalate / Oxalate_Reqd	Input (550.0)	Required concentration of oxalate in g/L @ 25°C.
Rqd_TOC / TOC_Reqd	Input (200.0)	Required total organics [Na2C5O7(aq) + Na2C2O4(aq)] concentration in the stream expressed as grams of elemental carbon /L liquor @ 25°C. This determines the non oxalate organics. If the specified oxalate organics result in a higher TOC than specified, non oxalate organics are set to zero.
Rqd_SiO2 / SiO2_Reqd	Input (550.0)	Required concentration of Na2SiO3 expressed as grams SiO2 /L liquor @ 25°C
The OtherLiquidMethod droplist is only visible when other liquid species in addition to the Required alumina 3 liquid species are present in the project.
OtherLiquidMethod	Zero Other Liqs	Selecting this method will set all the liquid flows not used by the bayer calculation to zero, this will ensure the output from Bayer DefineLiquor will match the specified concentrations.
	Original	(This method is NOT recommended, it is available only for backward compatibility.) User can manually specify composition for the other liquids, the amount of liquids specified will be added to the Total from the Bayer DefineLiquor Calculation. That means, the end result may not match the specified concentrations.
	Reduce Bayer Liqs	User can manually specify composition for the other liquids. The calculated bayer liquor composition will be adjusted to offset the user specified values. The end result may not match the specified concentrations.
	Reduce Water Only	(This is the recommended method). User can manually specify composition for the other liquids. The calculated water composition will be adjusted to offset the user specified values. The end result will match the specified concentrations.
SolidsDefn	Mass Fraction Solids	The required solids are specified by solids mass fraction.
	Total Solids Conc	The required solids are specified by total solids concentration.
SolFracReqd / Rqd_SolFrac	Input (0.99)	The mass fraction of solids in the feed. The proportion of the different solid species is maintained. If there are no solid species specified then THA is assumed.
SolConcReqd / Rqd_SolConc	Input (1600.0)	The concentration (at 25°C) of solids in the liquor. The proportion of the different solid species is maintained. If there are no solid species specified then THA is assumed.

Bayer Properties Data

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
Bayer Liquor Values @ 25°C
A | AluminaConc	Calc	NaAl[OH]4 concentration expressed as Al2O3 @ 25°C. (g/L liquor)
C | CausticConc	Calc	NaOH + NaAl[OH]4 concentration, expressed as grams Na2CO3/L liquor @ 25°C.
S | SodaConc	Calc	NaOH + NaAl[OH]4 + Na2CO3 concentration, expressed as grams Na2CO3/L liquor @ 25°C.
A/C	Calc	Ratio of A to C
C/S	Calc	Ratio of C to S
Cl/C	Calc	Ratio of Cl to C
TOC@25	Calc	Total Organic Carbon concentration, as carbon equivalent. Grams of [Na2C5O7*5 + Na2C2O4*2] / L liquor @ 25°C.
SodiumCarbConc	Calc	Sodium Carbonate concentration
SolidConc25	Calc	Expressed as grams of solids / L Slurry @ 25°C.
FC | FreeCaustic	Calc	Free Caustic, Caustic Concentration excluding the amount asscoiated with NaAl[OH]4, expressed as g/L of Na2CO3.
Sulphate*@25	Calc	Sodium Sulphate concentration @ 25°C
Chloride*@25	Calc	Sodium Chloride concentration @ 25°C
Oxalate*@25	Calc	Oxalate Concentration @ 25°C
Silica*@25	Calc	Silicate Concentration as SiO2 @ 25°C
Silica/C	Calc	Silica to Caustic ratio times 1000.
Concentration @ 25°C, as Na2CO3 equivalent
Organate@25	Calc	Grams of organic Na2C5O7(l) / L liquor @ 25°C.
Oxalate@25	Calc	Grams of oxalate Na2C2O4(l) / L liquor @ 25°C.
NaCl@25	Calc	Grams of NaCl(l) / L liquor @ 25°C.
Na2SO4@25	Calc	Grams of Na2SO4(l) / L liquor @ 25°C.
TotalNa@25	Calc	Total sodium as per TNa Equation in Model Theory section, but expressed as g/L liquor @ 25°C.
Other properties @ 25°C
LRho25 | LiquidDensity@25	Calc	The liquor density @ 25°C.
SLRho25 | SlurryDensity@25	Calc	The slurry density @ 25°C.
LQv25 | LVolFlow25	Calc	Liquor Volumetric Flowrate @25°C.
SLQv25 | SLVolFlow25	Calc	Slurry Volumetric Flowrate @25°C.
Bayer Liquor Values @ 25 °C, as Na2O Equivalent NOTE: This group of variables is only visible if the View | PlantModel |Globals - ShowNa2O_Equiv tickbox is selected.
C_Na2O	Calc	NaOH + NaAl[OH]4 concentration, expressed as grams Na2O/L liquor @ 25°C.
S_Na2O	Calc	NaOH + NaAl[OH]4 + Na2CO3 concentration, expressed as grams Na2O/L liquor @ 25°C.
TotalNa@25_Na2O	Calc	Total Sodium, expressed as grams Na2O/L Liquor @ 25°C.
RP | A/C_Na2O	Calc	Ratio of A : C expressed as Na2O.
RPSat | A/C_Sat_Na2O	Calc	Ratio of ASat : C@25 expressed as Na2O.
Bayer Liquor Values @ Temperature
A@T | AluminaConcT	Calc	Al2O3 concentration @ Temperature (g/L liquor)
C@T | CausticConcT	Calc	NaOH + NaAl[OH]4 concentration, expressed as grams Na2CO3/L liquor @ Temperature.
S@T | SodaConcT	Calc	NaOH + NaAl[OH]4 + Na2CO3 concentration, expressed as grams Na2CO3/L Liquor @ Temperature.
TOC@T	Calc	Total organic carbon concentration as Carbon equivalent. Grams of [Na2C5O7*5 + Na2C2O4*2] / L liquor @ Temperature.
SodiumCarbConc@T	Calc	Sodium Carbonate concentration @ Temperature.
SolidConc@T	Calc	Expressed as grams of solids / L Slurry @ Temperature.
BPE@T | BoilPtElev	Calc	Boiling Point Elevation calculated as a function of stream temperature. Note: this differs to the BPE value displayed under the Saturation section as BPE is calculated as a function of pressure. The two values and BPE@P will be the same if the stream is at saturated conditions.
BPE@P | BoilPtElev@P	Calc	Boiling Point Elevation calculated as a function of stream pressure. Note: this is the same as the BPE value displayed under the Saturation section. BPE@T will be the same as BPE@P if the stream is at saturated conditions.
Molality	Calc	Molality of the liquor using ALL liquid species. [math]\displaystyle{ \frac{n_{solute}}{m_{solvent}} }[/math], where: [math]\displaystyle{ n_{solute} }[/math] = total moles of liquid species (excluding water) [math]\displaystyle{ m_{solvent} }[/math] = mass of water
ViscL | ViscosityLiquor	Calc	Viscosity of the liquid phase. Based on selected Viscosity method.
ViscSL | ViscositySlurry	Calc	Viscosity of the combined liquid and solid phases (slurry). Based on selected Viscosity method.
Bayer Liquor Values @ T, as Na2O Equivalent NOTE: This group of variables is only visible if the View | PlantModel |Globals - ShowNa2O_Equiv tickbox is selected.
CausticConc@T_Na2O	Calc	NaOH concentration, expressed as grams Na2O/L liquor @ Temperature.
SodaConc@T_Na2O	Calc	NaOH plus Na2CO3 concentration, expressed as grams Na2O/L liquor @ Temperature.
TotalNa@T_Na2O	Calc	Total Sodium, expressed as grams Na2O/L Liquor @ Temperature.
Bayer Liquor Solubility Properties @ T
ASat | A_Saturation	Calc	The saturated Alumina concentration @ stream temperature. (Note: As described in Model Theory, concentrations used in the correlation are referenced to 25°C).
AConcEquil | AConcEquilibrium	Calc	Alumina Concentration (A) at Equilibrium, i.e. accounting for changes in composition to liquor if equilibrium saturation is reached.
CConcEquil | CConcEquilibrium	Calc	Caustic Concentration (C) at Equilibrium, i.e. accounting for changes in composition to liquor if equilibrium saturation is reached.
A/CSat | A/C_Saturation	Calc	The ratio of ASat : C. (Note: Concentrations used in ASat correlation are referenced to 25°C, so ratio is ASat : C@25).
SSN_Ratio	Calc	The ratio of A : ASat which is the same as ratio of fields 'A/C' : 'A/CSat'. (Note: Concentrations used in ASat correlation are referenced to 25°C, so ratio is A@25 : ASat).
SSN_Ratio1	Calc	= SSN_Ratio - 1
A_ASat_Diff	Calc	The difference between Alumina Concentration @ temperature and Alumina Saturation Concentration. So result is fields 'A@T' - 'ASat'.
I | IonicStrength	Calc	The Ionic strength. See model theory under Alumina Saturation for equation.
OxalateEq | OxalateEquilibrium	Calc	The Oxalate Equilibrium value. See Model Theory for equation.
THA.Qm | THAMassFlow	Calc	The mass flowrate of THA - Al[OH]3(s).
THA.Rho | THADens	Calc	The density of THA - Al[OH]3(s).

Individual Component Volume Flow/Fraction Displays for Bayer streams

See General Bayer Data