Flotation Cell
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Navigation: Models ➔ Mass Separation Models ➔ Flotation Cell
| Flotation Cell | Solids Recovery Unit |
|---|
General Description
The flotation cell assumes perfect mixing of all incoming feed streams. Based on the user configuration, it calculates the flow rate, temperature, and composition of material reporting to each product stream.
The Concentrate Launder (Conc Launder) stream is not mixed with the feed or air streams; instead, it is added to the Concentrate stream after all flotation cell calculations have been completed.
The flotation cell model does not support a third outlet stream (e.g. a Middlings stream). To model a Middlings stream, users may either configure two flotation cells arranged in series or use the Solids Recovery Unit model.
Diagram
The diagram shows the default drawing of the Flotation Cell, with all of the streams that can be connected to the unit. The physical location of the streams connecting to the unit is unimportant. The user may connect the streams to any position on the unit.
Notes:
- For a process where the concentrate reports to the float stream in the actual plant, e.g. for the recovery of sulphur minerals, then the Float stream is the Concentrate stream. The Sinks stream is the Tailings stream in this case.
- For Reverse Flotation, where the concentrate reports to the sinks, the Sink stream is the Concentrate stream. The Float stream is the Tailings stream.
- When drawing the links, the concentrate stream may be shown coming from either the top or bottom of the unit. For example, for normal flotation the concentrate stream may be shown coming from the top and for Reverse Flotation the concentrate may be shown coming from the bottom.
Inputs and Outputs
| Label | Required Optional |
Input Output |
Number of Connections | Description | |
| Min | Max | ||||
| Feed | 1 Required | In | 1 | 20 | The slurry feed/s to the unit |
| Conc Launder | Optional | In | 0 | 10 | The stream going to the Concentrate Launder of the unit. |
| Air | Optional | In | 0 | 5 | The air feed/s to the unit. |
| Concentrate | Required | Out | 1 | 1 | Concentrate outlet from the unit. |
| Tailings | Required | Out | 1 | 1 | Tailings outlet from the unit. |
| Vent | Optional | Out | 0 | 1 | Vent Stream (Vapour only). |
Behaviour when Model is OFF
If the user disables the unit, by un-ticking the On tick box, then the following actions occur:
- All streams connected to the 'Feed' inlet will flow straight out of the 'Tailings' outlet;
- All streams connected to the 'Conc Launder' inlet will flow straight out of the 'Concentrate' outlet;
- All streams connected to the 'Air' inlet will flow straight out of the 'Vent' outlet if connected otherwise to the 'Tailings' outlet;
- No separation will occur.
- No sub-models will occur.
So basically, the unit will be 'bypassed' without the user having to change any connections.
Model Theory
The Flotation Cell is based on user defined variables that define the solids / liquids split.
Terminology used
Mass Pull is defined as the percentage of the total feed solids mass that reports to the concentrate stream:
- [math]\displaystyle{ \text{Mass Pull (%)} = \frac{\text{Mass of solids in Concentrate}} {\text{Mass of solids in Feed}} \times 100 }[/math]
Solids Recovery to Concentrate
There are several Recovery methods available in this model:
| Recovery Method | Input Parameters | Calculated Parameters | Comments |
|---|---|---|---|
| Grade & Recovery |
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Primary species can be defined either by selecting specific solid species or by applying Primary / Secondary / Excluded elemental rules. A species is considered recoverable if it contains the Primary and Secondary elements and does not contain the Excluded element. To ensure the unit can be solved, avoid over‑specifying recoveries. At least one species must remain unspecified to retain the necessary degree of freedom. |
| Mass Pull & Recovery |
|
| |
| Size Recovery |
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Only available when size distribution modelling is enabled and feed solids have size distributions. Recovery is set for each size fraction independently. |
Feed Liquid Split to Concentrate
Users can specify how the feed liquid is distributed between the output streams:
- Fraction of Feed Liquids - The user defines the fraction of liquid in the feed to the flotation cell that reports to the concentrate stream.
- Liquid in Concentrate - The user specifies the required fraction of liquid in the concentrate stream.
Note: the material entering the unit via the 'Conc Launder' inlet is NOT included in these calculations, but basically bypasses the unit and reports straight to the concentrate launder.
Example
Example: Using Grade & Recovery - Elemental
The feed stream to the flotation cell contains the following solid species:
- Cu2S(s), Cu5FeS4(s), CuFeS2(s), CuO(s), Cu2O(s), SiO2(s), CoO(s) and Ore(s)
The user sets the following:
- The Primary element = Cu
- The Secondary element = S
- The Exclude element = O
- The Recovery = 50% and Grade = 65%.
Then the model will recover to the concentrate 50% of all solid species containing both Cu and S, but not O:
- Cu2S(s), Cu5FeS4(s), CuFeS2(s) will be classified as Primary species.
The remaining solids species will mainly be sent to the tailings, with sufficient material to the concentrate to ensure a grade of 65% Cu in the concentrate.
Flowchart
The following shows the sequence of events. See next heading for more information.
Data Sections
Summary of Data Sections
- FlotationCell tab - Contains general information relating to the unit.
- Recovery - Optional tab, only visible if the Size Recovery Method is chosen.
- PC - Optional tab that is visible if EB.Solubility.On and/or [email protected] is enabled in the Evaluation Block.
- RB - Optional tab, only visible if the Reactions are enabled in the Evaluation Block.
- EHX - Optional tab, only visible if the EnvironHX is enabled in the Evaluation Block.
- Evap - Optional tab that is visible if Evaporator is enabled in the Evaluation Block.
- MU - Optional tab, or multiple tabs if more than 1 Makeup is selected. Only visible if one or more Makeups are enabled in the Evaluation Block.
- DB - Optional tab, or multiple tabs if more than 1 Discard Block is selected. Only visible if one of more Discard Blocks are enabled in the Evaluation Block.
- QConcentrate - Optional tab, visible if ShowQConcentrate is enabled. This and subsequent tab pages, e.g. QConcentrate.. and Sp, shows the properties of the Concentrate stream. The tags in the QConcentrate tab are valid even when the ShowQConcentrate option is not selected.
- QTailings - Optional tab, visible if ShowQTailings is enabled. This and subsequent tab pages, e.g. QTailings.. and Sp, shows the properties of the Tailings stream. The tags in the QTailings tab are valid even when the ShowQTailings option is not selected.
- Info tab - Contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
- Links tab, contains a summary table for all the input and output streams.
- Audit tab - Contains summary information required for Mass and Energy balance. See Model Examples for enthalpy calculation Examples.
Flotation Cell Page
Unit Type: FlotationCell - The first tab page in the access window will have this name.
| Tag (Long/Short) | Input / Calc | Description/Calculated Variables / Options |
| Tag | Display | This name tag may be modified with the Change Tag option. |
| Condition | Display | "OK" if no errors/warnings, otherwise lists errors/warnings. |
| ConditionCount | Display | The current number of errors/warnings. If condition is OK, returns 0. |
| GeneralDescription / GenDesc | Display | An automatically generated description for the unit. If text is entered in the 'EqpDesc' field on the Info tab (see below), this is displayed here. Otherwise, SysCAD will display the UnitType or SubClass. |
Requirements | ||
| On | Tickbox | If the model is switched off then no separation occurs and all the feed is sent to the tailings stream. If any vapour is present it is sent to the vent stream if it exists, otherwise it is also sent to the tailings stream. |
| TrackStatus | Tickbox | Enable warning messages if requirements are not met. |
| RecoveryMethod | Grade & Recovery | The user sets the recovery and grade of the required solid species in the concentrate stream. This does not require any Size distribution data. |
| Mass Pull & Recovery | The user sets the recovery of the required solid species as well as the mass pull of solids to the concentrate stream. This does not require any Size distribution data. | |
| Size Recovery | The user sets the fractional recovery to the concentrate stream for each individual size interval for all species that do have size distributions. The project must contain Size distribution data. | |
| Primary Solid | ||
| Method | Solid Species | User may choose a solid species as the primary species for the recovery calculations. |
| Element | The user may choose to base the recovery to concentrate calculations on an elemental basis. | |
| PrimarySolid | List | Only visible if the user has selected Solid Species for Method. List of solid species in the current project which can be chosen as the primary solid. |
| PrimaryElement | List | Only visible if the user has selected Element for Method. List of elements in the current project which can be chosen as part of the primary solids species (based on all solid species in the project). |
| The following two fields are only visible if the user has selected Grade & Recovery or Mass Pull & Recovery for Recovery Method AND selected Element for Method. | ||
| SecondaryElement | List | Optional: List of elements in the current project which can be chosen to restrict the primary solid species. If a Secondary Element is chosen, then only solid species that contain BOTH the Primary AND Secondary elements will be classified as Primary Solids. |
| ExcludeElement | List | Optional: List of elements in the current project which can be chosen to restrict the primary solid species. If an Exclude Element is chosen, then only solid species that contain the Primary (and Secondary, if selected) element, but NOT the Excluded element will be classified as Primary Solid Species. (Please see the example in Model Theory above) |
| PrimaryRecoveryReqd | Input | Only visible if the user has selected Grade & Recovery or Mass Pull & Recovery for Recovery Method. Mass Recovery of the primary solid, or element, from the Feed stream to the Concentrate stream. |
| PrimaryGradeReqd | Input | Only visible if the user has selected Grade & Recovery for Recovery Method. Mass Fraction of the primary solid, or element, in the Concentrate stream. |
| MassPullReqd | Input | Only visible if the user has selected Mass Pull & Recovery for Recovery Method. Mass Fraction of all solids in the Feed stream, which report to the Concentrate stream. |
| Additional Solid Species to Concentrate (Only visible if the user has selected Grade & Recovery or Mass Pull & Recovery for Recovery Method) | ||
| SolidSpeciesCount / SolSpCount | Input | Optional: The number of additional solid species to be specified with recoveries or grades. Up to 25 may be specified. |
| SecondaryMethod | Recovery to Concentrate | The user can specify the recovery of additional solid species to the Concentrate stream. |
| Grade in Concentrate | The user can specify the grade of additional solid species in the Concentrate stream. | |
| For each additional solid species: | ||
| SolidSpecies / SolidSp | List | List of solid species in the current project which can be chosen as an additional species. |
| RecoveryReqd | Input | Only visible if the user has selected Recovery to Concentrate for Secondary Method. Mass recovery of the additional species to the Concentrate stream. |
| GradeReqd | Input | Only visible if the user has selected Grade in Concentrate for Secondary Method. Grade (mass fraction) of the additional species in the Concentrate stream. |
| Concentrate Liquid Split | ||
| LiquidSplitMethod | Fraction of Feed Liquids | User can specify the fraction by mass of liquid in the Feed that is recovered to the Concentrate stream. |
| Liquid in Concentrate | User can specify the fraction by mass of liquid in the Concentrate stream. | |
| LiquidToConcentrate | Input | Only visible if user has selected Fraction of Feed Liquids for LiquidSplitMethod. Fraction by mass of liquid in Feed that is recovered to the Concentrate stream. |
| ConcentrateLiqFracReqd | Input | Only visible if user has selected Liquid in Concentrate for LiquidSplitMethod. Fraction by mass of liquid in the Concentrate stream. Please do note that if a stream has been connected to the 'Conc Launder' connection, any material in this stream will NOT be included in these calculations. Therefore, the final liquid fraction in the Concentrate stream may be different to the value set here. |
| OperatingP - NOTE: this pressure is applied to the (combined) feed, before sub-models (if any). DirectLink feeds, for example from Makeup Blocks, are excluded in determining the pressure. | ||
| Method | AutoDetect | If there are any liquids AND no vapours present in the feed, outlet streams will take the highest pressure of the feeds. Else (e.g. some vapours present) outlet streams will take the lowest pressure of the feeds. |
| LowestFeed | Outlet streams will take the lowest pressure of the feeds. | |
| HighestFeed | Outlet streams will take the highest pressure of the feeds. | |
| Atmospheric | Outlet streams will be at Atmospheric Pressure. The atmospheric pressure is calculated by SysCAD based on the user defined elevation (default elevation is at sea level = 101.325 kPa). The elevation can be changed on the Environment tab page of the Plant Model. | |
| RequiredP | Outlet streams will be at the user specified pressure. | |
| IgnoreLowMassFlow / IgnoreLowQm | Tick Box | This option is only visible if the AutoDetect, LowestFeed or HighestFeed methods are chosen. When calculating the pressure and temperature of the mixture, SysCAD will ignore the low flow feed streams should this option be selected. The low flow limit is set in the field below. |
| LowMassFlowFrac / LowQmFrac | Input | This field is only visible if the IgnoreLowQm option is selected. This is the amount required for any stream to contribute to the total flow when calculating the mixture pressure. For example, if the total feed to the unit is 10 kg/s, and this field is set to 1%. Then any feed streams with less than 0.1 kg/s will be ignored in the pressure calculations. |
| PressureReqd / P_Reqd | Input | This field is only visible if the RequiredP method is chosen. This is user specified pressure. |
| Result | Calc | The actual pressure used for the sum of the feeds which will also be the outlet pressure (unless further model options change the pressure). |
EB (Evaluation Block) | ||
| Solubility.On | Tickbox | Only visible if Solubility has been defined for at least one species in the project. Allows the user to switch on any predefined solubility curve to adjust the composition of material in the unit. |
| [email protected] | Tickbox | Only visible if Phase Change at Temperature has been defined for at least one species in the project and Plant Model - Species Tab - PhaseChange@T = OFF. Allows the user to switch on any predefined phase changes at temperature in the unit. |
| Makeups | Input | The number of Makeup Blocks required. Extra dropdown options Makeup1, Makeup2, etc. will be added to allow these to be switched on and off and prioritised in relation to the other sub-models. |
| MakeupX | List | This can be used to switch the Makeup Block (MU) on or off and prioritise it in relation to the other sub-models. If this is 'On' then the associated page, MUX becomes visible and may be configured. Note: This field is only visible if the entry for 'Makeups' is greater than 0. If there is one makeup then X=1. If there are two makeups, then X=1 and X=2, etc. |
| Reactions | List | Reaction Block (RB) - Enable or disable Reactions and set the sequence in relation to the other sub-models. If this is 'On' then the associated page, RB becomes visible and may be configured. Note: The user does not have to configure a reaction file, even if this block is checked. |
| EnvironHX | List | Environmental Heat Exchanger (EHX) - Enable or disable Environmental Heat Exchange and set the sequence in relation to the other sub-models. If this is 'On' then the associated page, EHX becomes visible and may be configured. Note: The user does not have to configure an environmental heat exchange, even if this block is checked. |
| Evaporation | List | Evaporation Block (Evap) - Enable or disable the Evaporator and set the sequence in relation to the other sub-models. If this is 'On' then the associated page, Evap becomes visible and may be configured. Note: The user does not have to configure an evaporator, even if this block is checked. |
| VLEquilibrium | List | Vapour Liquid Equilibrium (VLE) - Enable or disable Vapour Liquid Equilibrium and set the sequence in relation to the other sub-models. If this is 'On' then the associated page, VLE becomes visible and may be configured. Note: This option may automatically adjust the species make-up. |
| Discard | Input | The number of discard blocks required. Extra dropdown options Discard1, Discard2, etc. will be added to allow these to be switched on. |
| DiscardX | List | This can be used to switch the Discard Block (DB) on or off and prioritise it in relation to the other sub-models. If this is 'On' then the associated page, DBX becomes visible and may be configured. Note: This field is only visible if the entry for 'Discards' is greater than 0. If there is one discard then X=1. If there are two discards, then X=1 and X=2, etc. |
Options | ||
| ShowQConcentrate | Tickbox | When selected, the QConcentrate and associated tab pages (e.g. Sp) will become visible, showing the properties of the Concentrate stream. See Material Flow Section. Tags in the QConcentrate tab can be used for controllers (e.g.: PGM files) and reports even when this option is not selected. |
| ShowQTailings | Tickbox | When selected, the QTailings and associated tab pages (e.g. Sp) will become visible, showing the properties of the Tailings stream. See Material Flow Section. Tags in the QTailings tab can be used for controllers (e.g.: PGM files) and reports even when this option is not selected. |
Results | ||
| PrimariesFound | Calc | List of all solid species in the project that meet the criteria specified for the primary solid species. When using the Element Method, the primary solids may consist of multiple solid species. The Primary Recovery and Primary Grade calculations are based on all species listed here. |
| PrimaryRecovery | Calc | The actual percentage recovery achieved for the primary species. |
| PrimaryGrade | Calc | The actual percentage grade achieved for the primary species. When using solid species, the primary grade is defined as the combined solids fraction of all primary species in the concentrate. When using the Element Method, the primary grade is defined as the elemental solids fraction in the concentrate. |
| ConcMassPull | Calc | The actual percentage solid mass pull to the concentrate stream. See Mass Pull. |
| AdditionalSolids | Calc | List of all solid species in the project specified as additional species. |
| GangueSpecies | Calc | List of all solid species in the project which have not been specified as either primary or additional species. |
| Concentrate.SolidFrac / Concentrate.Sf | Calc | The percent solids fraction of the concentrate stream. |
| Concentrate.SolidConc | Calc | The solids concentration of the concentrate stream. |
| Concentrate.SolidConc25 | Calc | The solids concentration of the concentrate stream measured at 25°C. |
| Tailings.SolidFrac / Tailings.Sf | Calc | The percent solids fraction of the tailings stream. |
| Tailings.SolidConc | Calc | The solids concentration of the tailings stream. |
| Tailings.SolidConc25 | Calc | The solids concentration of the tailings stream measured at 25°C. |
Recovery Page
If the user selects Size Recovery as the Recovery Method, then an additional tab will be visible, called Recovery. This will display a table of the size intervals for all solids species in the project which has its own size distribution. The user must enter the recovery to Concentrate for each size interval, as shown below:
In the example shown above, the flotation cell is used to recover PbS(s) - as can be seen by the higher recoveries specified for this species. The other species are gangue solids that are recovered to the flotation concentrate in smaller fractions.
Adding this Model to a Project
Add to Configuration File
Sort either by DLL or Group:
| DLL: | Separation.dll |
→ | Units/Links | → | Separation: Flotation Cell | |
| or | Group: | Mass Separation |
→ | Units/Links | → | Separation: Flotation Cell |
See Model Selection for more information on adding models to the configuration file.
Insert into Project Flowsheet
| Insert Unit | → | Separation | → | Flotation Cell |
See Insert Unit for general information on inserting units.
Hints and Comments
- If there are some solids species which the user does not want to send to the concentrate at all, then include them as additional compounds/solid species with a recovery of 0%.
- It is possible to over-specify the problem, i.e. if the user sets Additional Solid Species to recover to the concentrate, this may prevent the Required Grade or Mass Pull from being met.
- Note: The Required Recovery will always be achieved, but the Grade/Mass Pull do depend on feed conditions and the user defined parameters.
- If the Size Recovery Method is selected and there is no PSD Quality data in the feed then the model does not perform any calculations and behaves as if it was off.
- If a stream is connected to the 'Conc Launder' input then any material in this stream will report directly to the concentrate stream and will NOT be included in the calculations in the Flotation unit. Therefore, if the user selects 'Liquid in Concentrate' the actual concentrate liquid fraction will be different if material (usually water) is added in the stream connected to the 'Conc Launder' input.
- If an air stream is connected but there is no vent stream, then the user will get a warning but the model will still function.
- If there is no vent stream, all vapours will be sent to the concentrate stream.
- The user cannot choose the same species as both a primary solid species and an additional solid species or twice as an additional compound/solid species. In either of these cases the model will not run and the user will be given an error message.