Model:Bond HPGR and ball mill - Revision history

Alex Doll at 18:49, 6 March 2022

2022-03-06T18:49:52Z

Alex Doll: Alex Doll moved page Model:HPGR and ball mill to Model:Bond HPGR and ball mill: distinguish Bond HPGR model from Morrell HPGR model

2016-04-22T16:31:15Z

Alex Doll moved page Model:HPGR and ball mill to Model:Bond HPGR and ball mill: distinguish Bond HPGR model from Morrell HPGR model

Alex Doll: /* Formulae */

2015-10-16T15:04:32Z

Formulae

Alex Doll: /* Recommended Usage */

2015-04-25T18:34:11Z

Recommended Usage

Alex Doll: /* HPGR and ball mill circuit */

2015-04-25T18:29:36Z

HPGR and ball mill circuit

Alex Doll: /* Default Parameter Values */

2015-04-25T18:27:18Z

Default Parameter Values

Alex Doll: /* HPGR and ball mill circuit */

2015-02-15T19:10:05Z

HPGR and ball mill circuit

Alex Doll: /* Formulae */

2014-10-06T17:24:59Z

Formulae

Alex Doll: /* Formulae */

2014-05-26T17:36:23Z

Formulae

Alex Doll: /* HPGR and ball mill circuit */

2014-05-26T17:34:14Z

HPGR and ball mill circuit

← Older revision		Revision as of 18:49, 6 March 2022
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		+	[[Category:P80 adjustment]]
	== HPGR and ball mill circuit ==		== HPGR and ball mill circuit ==

← Older revision		Revision as of 15:04, 16 October 2015
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−	The crusher specific power consumption is calculated from the sum of the power drawn in all crushers (which is manually set in the crusher settings) divided by the circuit throughput (which is set by the ball mill circuit). You will need to manually adjust the crusher mechanical efficiency to achieve the E<sub>crushers</sub> observed in the pilot plant. Secondary cone crushers normally consume 50% to 60% of their name-plate power (set the mechanical efficiency to between 0.5 and 0.6). The HPGR mechanical efficiency should be entered such that the E<sub>crushers</sub> indicated equals the sum of the pilot plant E<sub>HPGR</sub> plus E<sub>sec.crushing</sub>.	+	The crusher specific power consumption is calculated from the sum of the power drawn in all crushers (which is manually set in the crusher settings) divided by the circuit throughput (which is set by the ball mill circuit). You will need to manually adjust the crusher mechanical efficiency to achieve the E<sub>crushers</sub> observed in the pilot plant. Secondary cone crushers normally consume 50% to 65% of their name-plate power (set the mechanical efficiency to between 0.5 and 0.65). The HPGR mechanical efficiency should be entered such that the E<sub>crushers</sub> indicated equals the sum of the pilot plant E<sub>HPGR</sub> plus E<sub>sec.crushing</sub>.

	<math> E_{crushers} = \frac{\sum{\text{crusher kW drawn}} }{tonnes/hour} </math>		<math> E_{crushers} = \frac{\sum{\text{crusher kW drawn}} }{tonnes/hour} </math>

← Older revision		Revision as of 18:34, 25 April 2015
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	This is a highly simplified HPGR model that does not consider the volumetric throughput constraints of the crushers. It is suitable for high level comparisons of the likely difference in "energy efficiency" versus SAG milling circuits. It is not intended as a HPGR circuit sizing calculation; factors such as m·dot, pressing pressure and roll speed are not considered.		This is a highly simplified HPGR model that does not consider the volumetric throughput constraints of the crushers. It is suitable for high level comparisons of the likely difference in "energy efficiency" versus SAG milling circuits. It is not intended as a HPGR circuit sizing calculation; factors such as m·dot, pressing pressure and roll speed are not considered.
		+
		+	The throughput of an HPGR plant, once calibrated to a plant or pilot plant test, can be predicted based on drill core Bond testwork. This also allows geometallurgy calculations – drilling an orebody, combined with testing using off-the-shelf Bond test gear (crushing, rod mill & ball mill) can be used for future production forecasting of an HPGR circuit.

	== Default Parameter Values ==		== Default Parameter Values ==

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 The high pressure grinding roll (HPGR) and ball mill circuit can be thought of as a variation on the classical single stage ball mill (SSBM) circuit with the final stage of cone crushing replaced by an HPGR.  Simulating HPGR has two differences from a classical SSBM circuit with cone crushers: first is that the crusher product tends to be finer (~4 mm versus 9 mm) and the nature of the product is different.
-To simulate an HPGR and ball mill circuit, choose the '''HPGR - BM''' flowsheet and the '''Bond/Rowland single stage ball mill model'''.
+To simulate an HPGR and ball mill circuit, choose the '''HPGR - BM''' flowsheet and the '''Bond/Rowland single stage ball mill model'''.  The model assumes that the circuit is always ball mill limited, and that the crushers have neither volumetric nor power limitations.  Engineers (that's you!) must do off-line checks of crusher & HPGR power draw and volumetric limitations to confirm that these assumptions are valid.
 ===Testwork Required===

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 It is necessary to change the SSBM circuit default parameters to simulate an HPGR circuit:
-* '''Crushing circuit P80, µm''' : set to the observed HPGR screen product size (typically 3000 to 5000 &micro;m).
+* '''T80: Crushing circuit product, µm''' : set to the observed HPGR screen product size (typically 3000 to 5000 &micro;m).
 * '''Essbm calibration factor''' : set to the reduction in ball mill operation work index observed in the HPGR test (typically -0.05 to -0.10 for a 5% to 10% reduction).
-* HPGR crusher model '''mechanical efficiency''' : adjust until the E<sub>crush</sub> matches the HPGR test specific energy.
+* HPGR crusher model '''mechanical efficiency''' : adjust until the E<sub>crush</sub> matches the HPGR test specific energy.  Typical number is 0.3 (suggesting 30% energy is consumed in breakage).

← Older revision	Revision as of 16:31, 22 April 2016
(No difference)

← Older revision		Revision as of 19:10, 15 February 2015
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	== HPGR and ball mill circuit ==		== HPGR and ball mill circuit ==
		+
		+	'''This is a highly experimental model. Use at your own risk!'''

	The high pressure grinding roll (HPGR) and ball mill circuit can be thought of as a variation on the classical single stage ball mill (SSBM) circuit with the final stage of cone crushing replaced by an HPGR. Simulating HPGR has two differences from a classical SSBM circuit with cone crushers: first is that the crusher product tends to be finer (~4 mm versus 9 mm) and the nature of the product is different.		The high pressure grinding roll (HPGR) and ball mill circuit can be thought of as a variation on the classical single stage ball mill (SSBM) circuit with the final stage of cone crushing replaced by an HPGR. Simulating HPGR has two differences from a classical SSBM circuit with cone crushers: first is that the crusher product tends to be finer (~4 mm versus 9 mm) and the nature of the product is different.

← Older revision		Revision as of 17:24, 6 October 2014
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−	The crusher specific power consumption is calculated from the sum of the power drawn in all crushers (which is manually set in the crusher settings) divided by the circuit throughput (which is set by the ball mill circuit).	+	The crusher specific power consumption is calculated from the sum of the power drawn in all crushers (which is manually set in the crusher settings) divided by the circuit throughput (which is set by the ball mill circuit). You will need to manually adjust the crusher mechanical efficiency to achieve the E<sub>crushers</sub> observed in the pilot plant. Secondary cone crushers normally consume 50% to 60% of their name-plate power (set the mechanical efficiency to between 0.5 and 0.6). The HPGR mechanical efficiency should be entered such that the E<sub>crushers</sub> indicated equals the sum of the pilot plant E<sub>HPGR</sub> plus E<sub>sec.crushing</sub>.

	<math> E_{crushers} = \frac{\sum{\text{crusher kW drawn}} }{tonnes/hour} </math>		<math> E_{crushers} = \frac{\sum{\text{crusher kW drawn}} }{tonnes/hour} </math>

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 <math> E_{ball} = E_{ssbm} \times (1+CF) -  Wi_{C} \times \left ( \tfrac {10}{\sqrt{ 9400 }} - \tfrac {10}{\sqrt{ T_{80} }} \right )  </math>
-where ''CF'' is the calibration factor for ball mill operating work index versus laboratory ball mill work index.  A value of zero means use the Bond/Rowland SSBM formula to predict E<sub>ball</sub>, a value of '''-0.05''' means use 5% less than Bond/Rowland SSBM formula to predict E<sub>ball</sub>.  ''CF'' is a negative number if Wi<sub>O</sub> is less than the laboratory work index.
+where ''CF'' is the '''Essbm calibration factor''' (in the Circuit Settings) for ball mill operating work index versus laboratory ball mill work index.  A value of zero means use the Bond/Rowland SSBM formula to predict E<sub>ball</sub>, a value of '''-0.05''' means use 5% less than Bond/Rowland SSBM formula to predict E<sub>ball</sub>.  ''CF'' is a negative number if Wi<sub>O</sub> is less than the laboratory work index.
 The circuit throughput is calculated using the ball mill (the circuit is assumed to be ball-limited).

@@ Line 2: / Line 2: @@
 The high pressure grinding roll (HPGR) and ball mill circuit can be thought of as a variation on the classical single stage ball mill (SSBM) circuit with the final stage of cone crushing replaced by an HPGR.  Simulating HPGR has two differences from a classical SSBM circuit with cone crushers: first is that the crusher product tends to be finer (~4 mm versus 9 mm) and the nature of the product is different.
 ===Testwork Required===
@@ Line 10: / Line 12: @@
 === Formulae ===
-See the base formulae in the [[Model:BondSSBMModel|Bond SSBM model]].
+The ball mill specific power consumption E<sub>ball</sub> is determined by deducting a cone crushing component from the Bond/Rowland E<sub>ssbm</sub> specific power consumption.  See the base formulae in the [[Model:BondSSBMModel|Bond SSBM model]].
 <math> E_{ball} = E_{ssbm} \times (1+CF) -  Wi_{C} \times \left ( \tfrac {10}{\sqrt{ 9400 }} - \tfrac {10}{\sqrt{ T_{80} }} \right )  </math>
@@ Line 18: / Line 18: @@
 where ''CF'' is the calibration factor for ball mill operating work index versus laboratory ball mill work index.  A value of zero means use the Bond/Rowland SSBM formula to predict E<sub>ball</sub>, a value of '''-0.05''' means use 5% less than Bond/Rowland SSBM formula to predict E<sub>ball</sub>.  ''CF'' is a negative number if Wi<sub>O</sub> is less than the laboratory work index.
 <math> \frac{tonnes}{hour} = \frac{\sum{\text{ball mill kW drawn}} }{E_{ball}}  </math>