WO2014127989A1

WO2014127989A1 - Method for the open-loop control and/or closed-loop control of a grinding system, and grinding system

Info

Publication number: WO2014127989A1
Application number: PCT/EP2014/052132
Authority: WO
Inventors: Andreas Lekscha; Bernd Zehentbauer; Victor Seleznev
Original assignee: Siemens Aktiengesellschaft
Priority date: 2013-02-22
Filing date: 2014-02-04
Publication date: 2014-08-28
Also published as: EP2769769A1

Abstract

The invention relates to a grinding system (2) and a method for the open-loop control and/or closed-loop control of a grinding system (2) comprising a rotational-speed-controllable grinding device (4) for grinding a material (S), a separating device (6) for classifying the ground material (S), and a separator (12) arranged downstream of the separating device (6), comprising the following steps: a) at least one first parameter characteristic of the operation of the grinding system (2) and one second parameter are determined, b) the derivative of the first parameter (P₁) with respect to the second parameter (P₂) is determined, c) the sign of the derivative is determined, d) the grinding system (2) is controlled in an open-loop and/or closed-loop manner in dependence on the sign of the derivative.

Description

description

Method for controlling and / or regulating a grinding plant and grinding plant

The invention relates to a method for controlling and / or regulating a grinding plant and a grinding plant.

Grinding is a mechanical process whose task is to reduce the particle sizes of solids

Overcoming the binding forces in the starting particles is. The grinding process is carried out in a closed grinding circle. In addition to the actual grinding device, such as a ball mill, in which the material is ground, a grinding plant also comprises a separating device, such as a classifier, with which the ground material is separated, ie classified, depending on the grain size or grain size. In this case, sufficiently ground particles (finished grade) leave the separator over the overflow, the insufficiently ground particles in the lower run. The latter are returned to the grinder and thus added to the grinding process again. In addition, especially in the processing of iron ore, the grinding plant comprises a separator in the form of a magnetic separator. This is designed to separate nonmagnetic ferro- magnetic parts of the ground material leaving the separator overflow.

In the existing grinding plants mainly grinding devices are used without speed control. At present, the pulping process is used without speed control of the grinder, which significantly reduces the effectiveness of the grinding processes. At a constant speed of the grinding device, the material comminution process proceeds in one of the following operating modes: - cascade operation / cascade operation (without lifting of the grinding media),

Mixed operation (with unwinding of the grinding media and its partial lifting),

- cataract operation (with predominantly lifting of the grinding media).

For all three types of grinding a dead zone is present in the central part of the ball load. The core of non-moving spheres performs virtually no work of mass reduction, leading to an increase in specific energy consumption. This core represents approximately 30% of the total volume of the grinding media. If the core is made to participate in the crushing work, the productivity of the milling equipment can be improved without increasing the power consumption.

The grinding process depends on a number of factors (ore grinding, drum speed, volume of drum filling with orbital ball load, ratio of solid to liquid in the grinding device, state of wear of the balls and the lining, etc.), which change in real time in a sufficiently broad area.

The task of constant-speed process control is to stabilize the process variables (raw-material throughput, amount of circulating sands, volume of drum loading, percentage solids in the outlet of the grinder, solid or finished-product proportion in the outlet of the classifier, discharge volume).

The variations in the quality of the raw material as well as the change in performance mean that the working range of the system differs from an optimal range. This level leads to an increase in relative energy consumption and has a negative impact on the plant's life cycle. It is therefore an object of the invention to provide a method for controlling and / or regulating a grinding plant and a grinding plant, in which the efficiency is increased. The first object is achieved by a method for controlling and / or regulating a grinding plant with the features of claim 1. Such a grinding plant comprises a variable speed grinder for grinding a substance, a separator for classifying the ground material and a separator downstream separator.

The method comprises the following steps:

a) at least one characteristic of the operation of the grinding plant characteristic first parameter and a second parameter,

b) the derivation of the first parameter is determined according to the second parameter,

c) the sign of the derivative is determined

d) the grinding plant is controlled and / or regulated depending on the sign of the derivative.

Further advantageous embodiments of the invention are specified in the subclaims.

The second object is achieved by a grinding plant with the features of claim 10. According to the invention, such a grinding plant on a milling device for grinding a substance and a separator for classifying the ground material and a control / regulating unit in which a software for performing the inventive Method is implemented.

The above-described characteristics, features and advantages of this invention as well as the manner in which they are achieved will become clearer and more clearly understood in connection with the following description of the embodiments. Games, which are explained in more detail in connection with the drawings.

For a further description of the invention, reference is made to the exemplary embodiments of the drawings. Each shows in a schematic schematic diagram:

1 shows a grinding plant, FIG 2 is a diagram with the qualitative dependence of

Power factor S of the grinder of the relative speed of the grinder Vreg according to the formulas of various authors, FIG 3 is a diagram of the qualitative dependence of the intensity for the energy E _ord of the productivity of the milling means according to the initial ore Q _r,

4 shows a diagram with the qualitative dependence of the related feed of the grinder F _ord of the

Productivity according to the starting point Q _r ,

5 shows a diagram with the qualitative dependency of the related mill output on the productivity of the grinder N _ord after the starting point Q _r ,

6 shows a diagram with the qualitative dependence of

Productivity of the grinder according to the starting point Q _r from the ratio "liquid / solid" W / F,

7 shows a diagram with the qualitative dependence of the related energy intensity E _ord on the overflow density of the separating device R _c i, FIG. 8 shows a diagram with the qualitative dependence of the energy intensity E _ord on the ratio "liquid / solid" W / F in the grinding device, 9 shows a diagram with the qualitative dependence of

Productivity of the grinding device according to the starting point Q _x of the circulation load C,

10 shows a diagram with the qualitative dependence of

Productivity of the grinder after the output Q _x of the separator overflow density

11 shows a diagram with the qualitative dependence of the related filling volume F _{ord of} the grinding device on the ratio "liquid / solid" W / F,

12 shows a diagram with the qualitative dependency of the related energy intensity E _ord of the related feed of the grinder F _ord ,

13 shows a diagram with the qualitative dependence of the related filling volume F _{ord of} the grinding device from the pulp density R _m after the grinding device,

14 shows a diagram with the qualitative dependence of the related power of the grinder N _ord of the related loading of the grinder F _ord ,

FIG. 15 shows a diagram with the qualitative dependency of the

Power factor S of the grinder of the relative speed of the grinder Vreg in percent of the critical change of the percentage filling volume of the grinder as a function of the speed of the grinder.

FIG. 1 shows a grinding plant 2 with which a rock S to be ground, such as, for example, iron ore, is ground and classified. The material S to be ground is first fed to a variable-speed grinder 4 and ground. The grinder is driven by an output 5. After the grinding process, the ground substance S enters a separation zone. Device 6 as a classifier, in which the milled substance S is separated depending on the grain size or grain size, that is classified. The separator is driven by a motor 7. In this case, sufficiently ground particles of the substance S leave the separating device 6 via the overflow 8, the particles which have not been ground sufficiently leave the separating device 6 through the underflow 10 and are returned to the grinding device 4. The milling device 4 leaving the overflow 8 particles are then fed to a separator 12, in the embodiment of a magnetic separator. This is designed to separate ferromagnetic parts of the ground substance S from non-magnetic. The ferromagnetic parts leave the separator 12 as an intermediate product at the exit 14. The non-ferromagnetic parts leave the separator 12 in its talling 16.

Furthermore, the grinding plant 2 comprises measuring devices for detecting measured variables 17, which are used for controlling / regulating the grinding plant 2. These are in detail a measuring device 18 for detecting the circulation load C, a measuring device 20 for detecting the power of the drive of the separating device 6 Icl, a measuring device 22 for detecting the water consumption of the separating device 6 Gvk, a measuring device 24 for detecting the Finished-class content after the grinder 4 Rm, Sm, a measuring device 26 for detecting the finished-class content at the overflow 8 of the separating device 6 Let a measuring device 28 for detecting the converter frequency f of the drive 5 of the grinder 4, a measuring device 30 for detecting the speed ndv Grinder 4, a measuring device 32 for detecting the power Pdv of the drive 5 of the grinder 4, a measuring device 34 for detecting the filling volume V of the grinder 4, a measuring device 36 for detecting the filling volume F of the grinder 4, a measuring device 38 for detecting the rotational speed nm the grinder 4, a Mess Device 40 for detecting the weight Qr of the material S to be ground, a measuring device 42 for detecting the water consumption Qvm of the grinder 4. In addition, the grinding plant 2 includes various controllers that regulate the grinding process. It is a controller 44 for feeding the grinder 4 with the material to be ground S, a controller 46 for regulating the ratio liquid / solid in the grinder 4 W / F, a controller 48 for controlling the speed of the grinder. 4 , a controller 50 for controlling the computing class of the overflow 8 of the separator 6. The measured variables 17 are detected by a control / regulating unit 51. This calculates on the basis of the measured variables control variables 52, which forwards them to the controllers mentioned above.

The grinding plant 2 is now controlled / regulated by means of the method according to the invention. To do this, the following steps are performed:

c) the sign of the derivative is determined

The following implementation method is proposed:

In real time, the monitoring of: relative speed of the grinder 4 ndv taking into account the mains frequency control for the drive 5, in this case an electric motor, raw material throughput of the grinder 4 Qr, filling volume F, V of the grinder 4 with the material to be ground S, in this case, ore mass and ball load, power consumption Pdv of the drive 5, water consumption of the grinder 4 Qvm and separator 6 Qvk, current load Icl of the motor 7 of the separator 6, pulse density in the outlet of the grinder 4 Rm and separator 6 Rcl. By calculation are determined: dimensionless power factor S, relative speed of the grinder 4 no, liquid-solid ratio W / F, energy consumption taking into account the motor power E, proportion of finished class in the outlet of the grinder 4 Sm and separator 6 Be, circulation load C for "grinder 4 - separator 6" and their derivatives.

To determine the control limits for the speed of the grinding device 4, taking into account the frequency change in the supply network, the rated speed of the motor no, the critical speed of the grinder 4 nkrit, loading the Mahleinrichtungsvolumens for the power demand No taking into account the frequency change of the inverter fo Right.

The control / regulation of the grinding plant 2 takes place by means of a control circuit of the relative speed of the grinder Vrel as a function of the optimum net power (of the dimensionless power factor S).

The regulation of the optimum motor power takes place in the predetermined range of the relative speed of the grinder 4 and predetermined range of the filling of the grinder 4 with Roherz.

The search for zones with optimum useful power as a function of different filling volumes and relative rotational speeds of the grinding device is based on the nonlinear dependencies North = f (F) (see FIG 14) and S = f (V) (see FIG.

The control unit 51 receives and calculates the measured quantities 17 from the raw-mass weight measuring devices Qr, water consumption of the grinder GVM, water consumption of the separator 4 Gvk, load volume of the grinder 4, power of the drive 5 of the grinder 4 Pdv, currents of the spirals 1. 2 of the separator 6 Icl, outlet density of Separator 6 Rcl, density of pulp outlet of grinder 4 Rm, sand circulation C, mass of sands in circuit "Grinder 4 - separator 6" Sp, product grain in the separator outlet for computational class Sei *, speed of the grinder 4 nm, speed of the drive 5 nd, Inverter frequency f, ore-water ratio

Qr / Qv, liquid / solid ratio in the grinder 4 W / F, relative speed of the grinder 4 of the critical Vrel, derivations of the dependencies.

The process control is realized in the following way:

to increase the speed of the grinding device to the controller 48 (when limiting the relative speed of the grinder 4 in the range of 64 to 100% of the critical),

- to the controller 44 in the range of 30 to 50% taking into account the correction factor for the change in the relative speed corresponding to the filling volume of the ore ball - load and taking into account the deviation of this parameter from the base value (see FIG.

Increasing the speed of the grinder 4 at:

- Positive value of the ratio of the derivative of the relative drum speed Vreg of the grinder 4 for deriving the power factor S, taking into account the change in the filling volume of the grinder with Roherz (see.

FIG. 15), as well as the increase in the filling volume F of the grinder when the raw-material load is increased,

if the ratio of the derivative of the drawn power North to the value of the filling volume Ford is positive (see FIG.

Reduction of the speed of the grinder 4 at:

negative value of the ratio of the derivative of the relative drum speed Vreg of the grinder 4 to the derivation of the power factor S taking into account the change of the filling volume of the grinder with Roherz (see FIG. in the case of a negative value of the ratio of the derivative of the drawn power north to the value of the filling volume Ford (see FIG. Stabilization of process variables for cycle control:

- At zero values of the ratio of the derivative of the relative drum speed Vreg of the grinder 4 for deriving the power factor S taking into account the change in the filling volume of the grinder with Roherz (see FIG 15).

at zero values of the ratio of the derivative of the drawn power north to the reference value of the filling volume Ford (see FIG. In addition, there is a control of the grinding plant 2 with a control loop for optimal energy consumption for crushing in relation to Roherzendurchsatzsatz, internal mill filling of the grinder 4 with orb-ball load, water channels in grinder 4 and separator 6.

The search of the zones with optimal energy requirement as a function of the different values of the parameters: raw heart throughput of the grinder (see FIG 3), filling volume of the grinder 4 taking into account the corrections of the Mahleinrichtungsfüllung (see FIG 12), water flow in the grinder ( 2) as well as water guidance in the separating device 6 (see FIG 7) takes place on the basis of nonlinear dependencies E = f (Q) (see FIG 3), E = f (F) (FIG 12), E = f (Rclk) (see FIG 7), E = f (W / F) (see FIG 8).

Underload / Overload control is realized in the following way:

- The control unit 51 receives the measured variables 17 from the measuring devices for Roherzgewicht Qr, water consumption of grinder 4 GVM, water consumption of the separator 4 Gvk, load volume of the grinder 4 F, power of the drive 5 of the grinder 4 Pdv, outlet density of the separator 6 Rcl , Density of pulp outlet of Grinder 4 Rm, speed of grinder 4 nm, speed of motor 5 nd, converter frequency f,

- The relative speed of the grinder 4 as a function of the critical Vrel, the energy demand E, the liquid / solid ratio W / F, the product grain in the overflow 8 of the separator 6 for the computational class Sei *, the circulation load of the system grinder 4 - separator 6 C and the derivations of the dependencies are determined.

The task is set for increasing the raw material throughput and reducing the energy requirement:

To the controller 44 for feeding the grinder 4 with the material to be ground S:

in the case of a positive value, the derivative of the energy demand Eord over time and the negative value of the derivative of the throughput Qr over time (see FIG.

if the ratio of the derivative of the energy demand Eord is negative, then the derivative of the fuel filling Ford is derived (see FIG. 12).

To the controller 46, taking into account the optimization of the liquid / solid ratio in the grinder 4 when increasing the water consumption of the grinder 4:

With a negative value of the ratio of the derivative of the energy demand Eord for deriving the liquid / solid ratio W / F (see FIG. To the controller 50 at a given Roherzdurchsatz the grinder 4 by reducing the water consumption in the separator 6:

When the arithmetic class decreases, the derivation of the energy demand Eord over time and the negative value of the derivative of the pulse density in the overflow 8 of the separation device 6 over time (FIG. 7) are positive. To reduce the raw material throughput while increasing the energy requirement, the task is carried out:

in the case of a negative value, the derivative of the energy requirement Eord over time and the positive value of the derivative of the throughput Qr over time (see FIG.

if the value of the derivative of the energy demand Eord is positive, this is used to derive the in-filler filling Ford (see FIG.

To the controller 46, taking into account the optimization of the liquid / solid ratio in the grinder 4 with reducing the water consumption of the grinder 4: When the value of the derivative of the energy demand Eord is positive for deriving the liquid-solid (W / F) ratio ( see FIG 8). To the controller 50 in the output reduction by increasing the water consumption in the separator 6:

When increasing the arithmetic class for a negative value of the derivative of the energy demand Eord over time and positive value of the derivative of the pulse density in the overflow 8 of the separator 6 Rcl over time (see FIG 7).

Stabilization of the parameters for the cycle control:

at zero value of the ratio of the derivative of the energy demand Eord for the derivation of the internal filler filling Ford (see FIG 12),

at zero value of the ratio of the derivative of the energy demand Eord for deriving the liquid / solid ratio W / F (see FIG.

- Upon reaching the arithmetic class in the pulp in the overflow 8 of the separator 6, taking into account the pulse density (see FIG 7). Control circuit for raw material throughput of the grinding device 4 as a function of the parameters for the comminution process, classification and water flows in the cycle when the speed of the grinding device is controlled.

The search of the zones with optimum throughput in dependence on the different values of the parameters: related engine power (see FIG 5), water flow in the grinder 4 (see FIG 6) and in the separator 6 (see FIG 10), circulation load C. (see FIG 9) is based on the nonlinear dependencies: Qr = f (north) (see Figure 5), Qr = f (Rcl) (see Figure 10), Qr = f (W / F) (see FIG 6), Qr = f (C) (see FIG 9). Underload / Overload control is realized in the following way:

- The control unit 51 receives the measured variables 17 from the measuring devices for Roherzgewicht Qr, water consumption of grinder 4 GVM, water consumption of the separation device 6 Gvk, loading volume of the grinder 4 F, power of the drive 5 of the grinder 4 Pdv, outlet density of the separator Rcl, grinding speed 4 nm, speed of drive 5 nd, converter frequency f,

the relative speed of the grinder 4 as a function of the critical Vrel, the energy requirement E, the liquid-solid ratio W / F, the product grain in the overflow 8 of the separator 6 for the computational class Sei *, the circulation load of the system grinder 4 - Separator 6 C and the derivatives of dependencies are determined.

Task for increasing the raw material throughput and reducing the energy requirement: To the controller 44:

In the case of a negative value, the derivative of the power North over time and the negative value of the derivative of the throughput Qr over time (see FIG. Regarding the optimization of the liquid / solid ratio W / F in the grinder 4 with the increase of the water in the grinder 4 to the controller 46: If the ratio of the derivative of the flow rate Qr is negative, to derive the liquid / solid ratio W / F (see FIG 6).

To the controller 50 at the maximum possible specification of the raw-metal throughput of the grinder 4 by reducing the water consumption in the separator 6 when reducing the computational class:

With a negative value of the derivative of the flow rate Qr over time and negative value of the derivative of the pulse density in the overflow 8 of the separator 6 Rcl over time (see FIG 10).

To the regulator for circulation load, taking into account their optimization for the cycle grinder 4 - separator 6 when increasing the water in the grinder 6 or deterioration of erosion in the grinder 6, taking into account the mechanical-physical properties of the raw ore, its grain composition when placed in the grinder 6 and other parameters:

With a positive value of the ratio of the derivative of the flow rate Qr for deriving the circulation load C (see FIG.

Task for the reduction of the raw tube throughput: To the controller 44:

With a positive value of the derivative of the power North over time and a positive value of the derivative of the flow rate Qr over time (see Figure 5). To the controller 46 taking into consideration the optimization of the liquid / solid ratio W / F in the grinder 4 when reducing the water in the grinder 4: With a positive value of the ratio of the derivative of the flow rate Qr to the derivative of the liquid / solid ratio W / F (see FIG. To the controller 50 at the maximum possible specification of the Roherz - throughput of the grinder 4 by increasing the water consumption in the separator 6 in increasing the computational class:

With a positive value of the derivative of the flow rate Qr over time and positive value of the derivative of the pulse density in the overflow 8 of the separator 6 Rcl over time (see FIG 10).

To the regulator for circulation load taking into account its optimization for the cycle grinder 4 - separator 6 with reduction of the water in the grinder 4 or deterioration of ore crushing in the grinder 4 taking into account the mechanical-physical properties of the raw ore, its grain composition at Task in the grinder 4 and other parameters:

With a negative value of the ratio of the derivative of the flow rate Qr to the derivative of the circulation load C (see FIG. Stabilization of the process variables for the shredding cycle:

at zero value of the ratio of the derivative of the throughput Qr for deriving the power of the drive 5 of the grinder 4 (see FIG.

at zero value of the ratio of the derivative of the flow rate Qr for deriving the liquid-solid ratio W / F (see FIG.

Control circuit for the volume of the milling device inside filling of the grinder 4 with ore ball -Belastung with respect to raw heart rate, water flow in the grinder and related motor power at speed control of the grinder. In order to control the comminution parameters taking into account the speed control of the grinder, the related parameters are used analogously to the above control loops.

The search of the zones with optimal loading of the filling volume of the grinder 4 is carried out in dependence on pulse density in the outlet of the grinder 4 Rm, related filling of the grinder 4 with ore ball load Ford (see.

FIG. 13), water supply in the grinder F = f (W / F) (see FIG. 11), raw-product throughput of the grinder 4 Qr (cf.

FIG 4), related power north (see FIG 14) based on the non-linear dependencies Ford = f (Qr) (see Figure 4), Ford = f (Rm) (see Figure 13), Ford = f (W / F) (see FIG.

Ford = f (north) (see FIG 14).

Underload / Overload control is realized in the following way:

- The control unit 51 receives the measured variables 17 from the measuring devices for Roherzgewicht Qr, water consumption of grinder 4 GVM, load volume of the grinder 4 F, power of the drive 5 of the grinder 4 Pdv, density of the pulp outlet of the grinder 4 Rm, speed of the grinder 4 nm, speed of drive 5 nd, converter frequency f,

- The relative speed of the grinder as a function of the critical Vrel, the energy requirement E, the liquid / solid ratio, the product grain in the outlet of the grinder 4 for the computational class Sm *, the derivations of the dependencies are determined.

Task to increase the Roherzherzadung the filling volume of the grinder 4: To the controller 44 at:

positive value of the ratio of the discharge of the filling volume Ford for the derivation of the pulse density in the outlet of the grinder 4 Rm (see FIG. negative value of the derivative of the filling volume of the grinding device 4 Ford over the time and negative value of the derivative of the power of the drive 5 of the grinder 4 North over time (FIG. 14),

- negative value of the derivative filling volume of the grinder 4 Ford over the time and negative value of the derivation of the raw material throughput of the grinder 4 Qr over time (see FIG 4). Taking into account the regulation of the water flow in the grinder 4 according to the liquid-solid ratio W / F in the grinder 4 with increasing the water in the grinder 4 to the controller 46

Negative value of the derivative of the filling volume Ford over the time and positive value of the derivative of the liquid-solid ratio W / F over time (see FIG 11).

Task for the reduction of the raw heart loader grinding device 4:

To the controller 44:

negative value of the ratio of the discharge of the filling volume Ford for the derivation of the pulp density in the outlet of the grinder 4 Rm (see FIG.

positive value of the derivative of the filling volume of the milling device Ford over the time and positive value of the derivative of the power of the drive 5 of the grinder 4 North over time (see FIG.

- positive value of the discharge of filling volume of the grinding device 4 Ford over the time and positive value of the derivation of the raw material throughput of the grinding device 4 Qr over time (see FIG.

Taking into account the regulation of the water guide in the grinder 4 according to the liquid-solid ratio W / F in the grinder 4 when the water in the grinder 4 is reduced, Positive value of the derivative of the filling volume Ford over the time and negative value of the derivative of the liquid-solid ratio W / F over time (see FIG 11). Stabilization of parameters for the control of the shredding cycle:

At zero values of the ratio of the discharge of the filling volume Ford of the grinder 4 for the derivation of the pulp density in the outlet of the grinder 4 Rm (see FIG 13).

Although the invention has been further illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Claims

claims

1. A method for controlling and / or regulating a grinding plant (2) comprising a variable speed grinder (4) for grinding a substance (S), a separating device (6) for classifying the ground material (S) and one of the separating device (6) downstream Separator (12), with the following steps:

a) at least one characteristic for the operation of the grinding plant (2) characteristic first parameter and a second parameter,

b) the derivative of the first parameter (Pi) is determined according to the second parameter (P ₂ ),

c) the sign of the derivative is determined

d) the grinding plant (2) is controlled and / or regulated depending on the sign of the derivative.

2. The method according to claim 1,

in which a magnetic separator is used as the separator (12).

3. The method according to any one of the preceding claims, wherein the first parameter, the relative speed (Vreg) of the grinder (4) and the second parameter of the power factor (S) is used.

4. The method according to any one of the preceding claims, wherein as the first parameter that the power used (north) of the grinder (4) and as the second parameter, the related filling volume (Ford) of the grinder (4) is used.

5. The method according to any one of the preceding claims, wherein the first parameter of the energy requirement (Eord) and as a second parameter, the throughput (Qr) of the grinder (4) is used.

6. The method according to any one of the preceding claims, wherein the first parameter of the energy requirement (Eord) and as a second parameter, the mill device internal filling (Ford) is used.

7. The method according to any one of the preceding claims, wherein the first parameter of the energy requirement (Eord) and as a second parameter, the liquid / solid ratio (W / F) is used.

8. The method according to any one of the preceding claims, wherein the first parameter, the power (north) and as a second parameter, the throughput (Qr) of the grinder (4) is used.

9. The method according to any one of the preceding claims, wherein the first parameter of the throughput (Qr) of the grinder (4) and as a second parameter, the liquid / solid ratio (W / F) is used.

10. grinding plant (2) with a variable speed grinder (4) for grinding a substance (S), a separating device (6) for classifying the ground material (S), one of the separating device (6) downstream separator (12) and a ner Control unit (51), in which a software for

Implementation of the method according to one of the preceding claims is implemented.