Model:Morrell HPGR and ball mill - Revision history

Alex Doll at 15:38, 3 August 2023

2023-08-03T15:38:54Z

Alex Doll: /* Discussion */

2022-03-06T18:51:10Z

Discussion

Alex Doll at 18:49, 6 March 2022

2022-03-06T18:49:10Z

Alex Doll: /* Required parameters */

2020-03-09T16:15:17Z

Required parameters

Alex Doll: /* Formulae */

2020-03-07T00:22:14Z

Formulae

Alex Doll: /* Discussion */

2020-03-07T00:21:59Z

Discussion

Alex Doll: /* Discussion */

2016-04-22T18:08:44Z

Discussion

Alex Doll: /* Discussion */

2016-04-22T18:01:07Z

Discussion

Alex Doll: Created page with "category:Models category:Specific Energy Models Category:SMC Model == Morrell SMC HPGR & ball mill Model == This is a secondary cone crusher, High Pressure Grindin..."

2016-04-22T17:43:30Z

Created page with "category:Models category:Specific Energy Models Category:SMC Model == Morrell SMC HPGR & ball mill Model == This is a secondary cone crusher, High Pressure Grindin..."

New page

[[category:Models]]
[[category:Specific Energy Models]]
[[Category:SMC Model]]
== Morrell SMC HPGR & ball mill Model ==
This is a secondary cone crusher, High Pressure Grinding Roll (HPGR) plus ball mill model that estimates the specific energy consumption using the equations of Morrell (GMSG, 2016).

===Testwork Required===
* [[Testwork: Drop weight test|The SMC™ test]], stored in the "DWT" testwork table (SMC is a Drop Weight Test).
* [[Testwork: Bond ball mill work index|Bond ball mill work index]]. The method requires '''all the elements''' of the ball mill work index test to be filled in:
** Ball mill Wi test closing screen size, ''umclosing'', µm
** Ball mill Wi test product size, ''P80'', µm
** Ball mill Wi test feed size, ''F80'', µm
** Ball mill Wi grams per revolution at test conclusion, ''gpr''

===Required parameters===
* '''F80, µm''' is the 80% passing size of the fresh feed to the circuit, ie, primary crusher product (expected to be a Bond-compatible size distribution).
* '''Pc80, µm''' is the 80% passing size of the secondary crusher product (expected to be a Bond-compatible size distribution).
* '''T80, µm''' is the 80% passing size of the HPGR screen undersize, ie. ball mill circuit feed (expected to be a Bond-compatible size distribution).
* '''P80, µm''' is the 80% passing size of the circuit product (expected to be a Bond-compatible size distribution).
* '''Availability''', expressed as a decimal (0.90 = 90% availability) is used to convert t/h to t/d.
* Ball mill '''Operating strategy''' when circuit is SAG-limited (note, fixed speed ball mills can only be ''vary P80'')

===Optional parameters===
* '''Description''' and '''Comment''' are optional text fields
* '''Maximum t/h limit''' is a t/h throughput above which a warning message is displayed (but does not actually limit the throughput).
* '''Conveyor lift height''', used to estimate the specific energy consumption of the conveyors,

===Formulae===
The method is superficially similar to Bond (among other models), but with a variable exponent on size defined by:

<math>f(x) = - 0.295 - \frac{x}{10^6}</math>

Where ''x'' is the particle 80% passing size in µm.

Secondary crushing circuit, assumes secondary crusher operates in closed circuit with a screen:

<math>E_{secCrush} = 55 \times (Pc_{80} \times F_{80})^{-0.2} \times 4 \times Mic \left( Pc_{80}^{f(Pc_{80})} - F_{80}^{f(F_{80})} \right) \times 1.00
</math>[[Bibliography:_Specific_energy_consumption_models|GMSG, 2016]]

High pressure grinding roll circuit, assumes operating in closed circuit with a screen:

<math>E_{hpgr} = 35 \times (T_{80} \times Pc_{80})^{-0.2} \times 4 \times Mih \left( T_{80}^{f(T_{80})} - Pc_{80}^{f(Pc_{80})} \right) \times 1.00

</math>[[Bibliography:_Specific_energy_consumption_models|GMSG, 2016]]

Ball mill circuit:

<math>E_{ball} = 4 \times Mia \left( 750^{f(750)} - F_{80}^{f(F_{80})} \right) + 4 \times Mib \left( P_{80}^{f(P_{80})} - 750^{f(750)} \right)
</math>[[Bibliography:_Specific_energy_consumption_models|GMSG, 2016]]

===Discussion===
* This model requires that the product of the secondary crusher and HPGR be coarser than 750 µm. This is reasonable as no HPGR circuit operates anywhere near that size range (as of early 2016).
* There is a minor correction required for open circuit secondary crushing (the 1.0 factor becomes 1.19). I

← Older revision		Revision as of 18:51, 6 March 2022
Line 58:		Line 58:
	* The estimation of conveyor specific energy is based on [https://www.sagmilling.com/articles/23/view/?s=1 Doll, 2015]:		* The estimation of conveyor specific energy is based on [https://www.sagmilling.com/articles/23/view/?s=1 Doll, 2015]:

−	<math>E_{conveyor} = (Height \times 6) \times 2.724 \times 1.22 \times 1.85 / 1000</math>	+	<math>E_{conveyor} = (Height,m \times 6) \times 2.724 \times 1.22 \times 1.85 / 1000</math>

@@ Line 50: / Line 50: @@
 Ball mill circuit:
-<math>E_{ball} = 4 \times Mia \left( 750^{f(750)} - F_{80}^{f(F_{80})} \right) + 4 \times Mib \left( P_{80}^{f(P_{80})} - 750^{f(750)} \right)
+<math>E_{ball} = 4 \times Mia \left( 750^{f(750)} - T_{80}^{f(T_{80})} \right) + 4 \times Mib \left( P_{80}^{f(P_{80})} - 750^{f(750)} \right)
 </math><sup>[[Bibliography:_Specific_energy_consumption_models|GMSG, 2016]]</sup>

@@ Line 54: / Line 54: @@
 ===Discussion===
-* This model requires that the product of the secondary crusher and HPGR be coarser than 750 µm.  This is reasonable as no HPGR circuit operates anywhere near that size range (as of early 2016).
+* This model requires that the product of the secondary crusher and HPGR be coarser than 750 µm.  This is reasonable as no HPGR circuit operates anywhere near that size range (as of 2020).
 * There is a minor correction required for open circuit secondary crushing (the 1.0 factor becomes 1.19).  In theory, open circuit operation would change the particle size distribution of the cone crusher product affecting the load on the HPGR.  The change in cone crusher specific energy consumption should be, for all practical purposes, completely offset by a change in the HPGR specific energy consumption.
 * The estimation of dust collection is based on Doll, 2015 where E<sub>dust</sub> = 0.5 kWh/t.

@@ Line 57: / Line 57: @@
 * There is a minor correction required for open circuit secondary crushing (the 1.0 factor becomes 1.19).  In theory, open circuit operation would change the particle size distribution of the cone crusher product affecting the load on the HPGR.  The change in cone crusher specific energy consumption should be, for all practical purposes, completely offset by a change in the HPGR specific energy consumption.
 * The estimation of dust collection is based on Doll, 2015 where E<sub>dust</sub> = 0.5 kWh/t.
-* The estimation of conveyor specific energy is based on Doll, 2015:
+* The estimation of conveyor specific energy is based on [https://www.sagmilling.com/articles/23/view/?s=1 Doll, 2015]:
 <math>E_{conveyor} = (Height \times 6) \times 2.724 \times 1.22 \times 1.85 / 1000</math>

@@ Line 2: / Line 2: @@
 [[category:Specific Energy Models]]
 [[Category:SMC Model]]
 [[Category:P80 adjustment]]
 == Morrell SMC HPGR & ball mill Model ==

@@ Line 20: / Line 20: @@
 * '''P<sub>80</sub>, µm''' is the 80% passing size of the circuit product (expected to be a Bond-compatible size distribution).
 * '''Availability''', expressed as a decimal (0.90 = 90% availability) is used to convert t/h to t/d.
 ===Optional parameters===