SU1678454A1 - Method for autmatic control of wet grinding machine with closed cycle - Google Patents

Abstract

The invention relates to controlling the operation of a closed cycle grinding unit. It can be used in non-ferrous and mining metallurgy, construction and chemical industries and other industries where drum mills are used to grind raw materials. Improves control accuracy. To achieve this goal, the performance of the unit, the stock of the material in the unit, the density of the finished grinding product, the power consumed by the mill motor, the large class content of the crushed ore are measured, and the aggregate performance, the stock of the material in the unit, and the density of the finished product are stabilized at given values Search for the optimal performance of the unit by incrementally changing the set values of the material stock in the unit and the density of the finished product at times Changing the type of ore with fixing unit starts overload torque to achieve not less than double the rate of change exceeding power as compared with the rate of change of the grinding zone noise. The mineralogical composition and the content of the valuable component in the final grinding product, concentrate and tails are measured, the concentrate yield and the grinding of the valuable component in the concentrate are determined, the content of the determining grain size in the crushed ore is determined, and the optimum performance is calculated corresponding to the size of crushed ore. according to the large size class of the finished grinding product and the grindability of ore Compare the obtained value of the optimal performance with the current value of n level of performance of the mill, fixed start searching for an optimal performance values are calculated required grind size depending on the contents of a large class of crushed ore and adjusting the setpoint 5ml density. sl VI 00 SL

Description

The invention relates to controlling the operation of a closed-cycle grinding unit at concentrating mills and can be used in nonferrous and mining metallurgy, construction and chemical industry and other industries where drum mills are used to grind raw materials.

The purpose of the invention is to improve the accuracy of control.

The control method is as follows.

Measure the performance of the unit, the stock of the material in the unit, the density of the finished grinding product, the power consumed by the mill motor, the content of a large class in the crushed ore and stabilize the unit performance, the stock of the material and the density of the finished product at a given value, step by step change of the set values of the material in the unit and the density of the finished product at the moments of changing the type of ore with fixation of overloading the unit by the time it reaches not less than the rate of change in power compared to the rate of change in the grinding zone noise, the mineralogical composition and content of the valuable component in the finished grinding product, concentrate and tailings are measured, the concentrate output and the extraction of the valuable component in the concentrate are determined, the content of the determining grade size in the crushed ore and calculate the optimal performance corresponding to the size of the crushed ore by large class, the size of goth of the ore grinding product according to the determining class and ore grindability and compare the obtained optimal performance value with the current mill productivity, record the beginning of the search for the optimal performance value, calculate the required grinding size depending on the large class content in the crushed ore and correct the specified the density value, with the beginning of the search for the optimal performance value carried out in case of discrepancy of the optimal producer value and the current value of productivity, and the correction of the target density value is carried out depending on the calculated grinding size required.

FIG. 1 shows a device that implements the proposed method; in fig. 2 dependences of the content of the determining class (-0.16 ± 0 mm) in crushed .1b),% of the nepheline content in the ore (),% with different content of the large class

(+25 mm) in crushed ore (charts 1, 2, 3); in fig. 3 - dependence by which it is possible to predict the maximum specific productivity of mills according to the determining class (-0.16 + 0 mm) by the known grindability of ore, estimated by the content of the most durable mineral (for example, nepheline); in fig. 4 - dependence of the content of the class + 0.16 mm in the flotation concentrate on the grinding size; in fig. 5 - dependence of the grinding size on the density (solid content) in the discharge of a hydrocyclone.

The device contains a sensor 1 unit performance (for example, scales

LTM), controller 2 unit performance, actuator 3 material feed, sensor 4 material presence in the mill, controller 5 material feed in the mill, computing unit 6, sensor 7

active power consumed by the mill motor, sensor 8 of a large class content in crushed ore, sensor 9 of the density of the finished grinding product, regulator 10 for stabilizing the density of the finished grinding product, actuator 11, analyzer 12 of mineralogical composition and material composition, samplers 13-15 of the finished grinding product, concentrate and tailings, hopper 16 (RDU) crushed ore conveyor-feeder17, conveyor-weight gauge 18, hydrocyclone 19 and ball mill 20

The device works in several modes.

I. The mode of recognition of the type of ore by grindability.

According to mineralogical analysis, this procedure is carried out by an X-ray analyzer on the content of the most viscous and durable material, for example, for apatite-nepheline ores, such mineral is nepheline; as the content increases

nepheline from 32 to 42% ore grindability deteriorates proportionally

II. Evaluation of the size of the finished grinding product, concentrate and tailings, carried out according to the content of the determining class (for example, class + 0.16 mm (-16 + 0 mm). This estimate can be made according to the sieve analysis of the corresponding product or automatic

granulometer, or according to mineralogical analysis (if there are appropriate dependencies). The listed grading options are technical equivalents.

Iii. Finding estimates of the yield of the concentrate and the technological extraction of the valuable component into the concentrate is carried out according to two calculated components: the content of the determining class, for example, -0.16+ 0 mm; the content of a valuable component, for example, R20b.

The following calculation formulas are used.

Have

100 %

 .

but

100 %

where a, / 3 is the content of the calculated component (class-0.16 + 0 mm or R20b), respectively, in the final grinding product, concentrate and tails,%;

the yield of concentrate,%;

Ј - grinding of valuable component in concentrate,%.

Iy. The prediction of the content of the determining class (-0.16 ± 0 mm) in the crushed ore is carried out on the content of nepheline in the final grinding product for a given content of the large class in the crushed ore (Fig. 2).

Y. The prediction of the optimal performance of the grinding unit according to the known content of the determining class in the crushed ore, the final grinding product (determined according to the mineralogical or sieve analysis) and the ore grindability is carried out according to the formula

max

Q 0.16

(Dot) (1 -W)

where / GoI / Sisch is the class-0.16 +0 mm content, respectively, in the final grinding product and crushed ore, the fraction of units;

W - ore moisture, fraction of units

Vpa6. - the volume of the mill, m;

qo, i6max is the maximum specific productivity of the mill (taking into account the ore grindability) at the regular state of the unit (optimum ball filling, etc.), determined by the found grindability (mode I) from the graph of FIG. 3

YI Search mode for optimal settings in the contours of stabilizing the presence of material in the unit and the density of the finished grinding product. This mode functions when

R. tech /. g

- UM / A Israel

2 a be%

where Omtek is the current value of the performance of the grinding unit (the productivity indicator is removed).

Yii. The choice of the dependence of the grain size of the concentrate on the grain size of the finished grinding product D-from (class-t 0.16 mm) is carried out at the found value of technological extraction according to the graphs of fig. four.

YIII. Finding adjustments to the task on the contour of stabilizing the density of the finished product to ensure a given concentrate grain size while observing the limitations on the amount of technological extraction is carried out according to the dependencies found (Zc 16 CD-from 016) and the graphs of FIG. five.

IX.The mode of recognition of malfunctions in the operation of the circuit and the equipment of grinding, technical means of automation is based on the assessment of the magnitude of the discrepancy.

between the performance of the grinding unit, calculated in the computing unit 6, and the predicted optimal performance value.

X. Recognition of inconsistencies in the sampling system, sample delivery

and analysis is based on an estimate of the magnitude of the discrepancy between the calculated concentrate yield values found from the balance equations of the two (different)

calculated components

The dependencies of FIG. 2-5, in the form of matrices or approximating equations, are stored in the memory of the computer of the analyzer 12. For example, the graphs of FIG. 4 may be

approximated as first-order polynomials

y a + bx

where y is the content of class +0.16 mm in concentrate,%;

x - class content - (0.16 mm in the final grinding product%.

Approximation, performed by the method of least squares gives the following analytical dependencies:

y -0.37 + 0.75 x - for schedule 1;

y -2.67 + 0.75 x - for chart 2;

y -4.97 + 0.75 x - for chart 3;

y -7.90 + 0.75 x - for a chart 4.

Similar approximations can be obtained for other dependencies. So, the graphs of FIG. 2 can be approximated by the equations of the form at arr, fig. 3 - hyperbolic dependence of a a + b / x, etc.

The device works as follows

The circuits for stabilizing the productivity of the unit 1-2-3, material reserves 4-5-2, the density of the finished product 9-10-11 implement the optimal settings (tasks) issued by the computing unit 6. With optimal ball and pulp filling for the ore of this type according to - measurability and for these grinding conditions, these contours provide the maximum amount of the finished grinding product of a given size while observing restrictions on the quality of the concentrate (on the content of the valuable component and size).

In the event of a change in the type of ore or the grinding conditions, a search is required for new optimal settings. It is carried out by unit 6 according to the commands of sensors 4 and 7 and analyzer 12. The current monitoring of ore shredability is carried out by analyzer 12 on the basis of data obtained from sampler 13. Mineralogical analysis of crushed ore allows an assessment of the physical properties of the ore; content most resistant to grinding material (eg, nepheline). If the content of nepheline significantly changed in the milled ore, ie. the unit switched to grinding another type of ore, then a command is issued to block 6, which, according to a given algorithm, searches for new optimal settings for the unit performance stabilization and density of the finished product, and the material stock in the unit.

The search is considered complete when the rates of change of the signals of the sensors of the presence of material 4 and the active power of the mill 7 in the phase of reduction are two or more times different. In this case, unit 6 provides the corresponding corrections to the settings of controller 5 and 10, respectively, of the material stock and the density of the finished product. The optimal performance value found is compared with the predicted one, which is calculated by the calculating unit 12 of the analyzer on the basis of data obtained from sensor 8

and samplers 13–15. The forecast of the maximum possible productivity for a given (by grindability and grain composition) ore type is carried out according to the algorithm and

formulas.

If the actual and predicted performance values are the same or slightly different, the system continues to function in the found

0 optimal mode without any adjustments. In case of large deviations of the mentioned performance values, the analyzer 12 gives the operator a message about the possible reason for the discrepancy. If a

5 the actual performance value is higher than the maximum possible for these conditions, this usually indicates a malfunction of the weighing sensor (the balance is overestimated. The divergence of the opposite sign may be due to one of the following events: malfunction of one of the sensors 1,4, 7; non-regulatory grind - telnogo aggregate (non-optimal in granular composition or volume of grinding

5 load, malfunction of the mill grille, etc.).

The motive for the inclusion of block 6 in the work may be the current change in ore type or the presence of a significant discrepancy between the actual and predicted productivity of the mill.

The automatic grinding control system operates with

5 considering the quality of the final product (concentrate). If the grain size deviates from the target, then a correction may be introduced into the setpoint of the density stabilization system of the finished product from 0 grinding, increasing the setpoint if the concentrate size needs to be increased, and vice versa. The system monitors that the extraction and content of the valuable component (for example, PaOs ) in the concentrate did not go beyond the established limits. This corrective action is generated by the computing unit of the analyzer 12 and through block 6 a pulse is output for a corresponding change in the setpoint-controller 10 for stabilizing the density of the finished product.

The control system also includes a number of diagnostic algorithms for the healthy state of measurement channels. In addition to the monitoring of (operation) of the sensors of productivity and material stock already mentioned, control of the reliability of information obtained through the sampling and sample delivery system is provided. Such control can be carried out, for example, by

calculating several estimates of the same parameter on the balance of several calculated components at once. The calculation of the concentrate yield can be carried out according to the balance of the determining size class (+ 0.16 mm) and the valuable component (content; .0s). This allows, in the event of a significant discrepancy between the obtained estimates, to draw a conclusion (and take appropriate measures) about the malfunction of the channels for obtaining information (in this particular case, the system of sampling and sample delivery). With a small discrepancy between the estimates, it is concluded that the information received is reliable. Thus, the reliability of the channels for receiving and processing information from the analyzer 12 from samplers 13-15 is monitored.

In the automatic control system of this method, the issuance of corrections to the fine crushing process control system can also be provided in the event that the target is exceeded by the size of the crushed product. This correction is issued either to the crusher's capacity control circuit, or to the control slot of the discharge gap or as advice to the operator.

This method will allow at least a two-fold increase in control accuracy due to the more rapid introduction of corrective actions.

Claims (1)

The invention The method of automatic control of a closed-cycle wet grinding unit, including measuring the performance of an aggregate, the stock of material in an aggregate, the density of the finished grinding product. Power / motor consumed by the mill, the large class content in crushed ore and stabilization at a given unit productivity , the stock of material in the unit and the density of the finished product, the search for the optimal value of the unit productivity by a step-wise change is set s stock material values in the unit and density of the final product in varying moments ore type with a locking unit start overload torque to achieve at least 0 double excess of the rate of change of power compared with the rate of change of the noise of the grinding zone, is also distinguished by the fact that, in order to improve the control accuracy, the mineralogical 5, the composition and content of the valuable component in the final grinding product, concentrate and tailings, determine the yield of the concentrate and the extraction of the recovered component in the concentrate, determine the content of the determining grain size in the crushed ore and calculate the optimum performance corresponding to the grain size of the crushed ore according to the large class, the size of the finished grinding product according to the determining class and the grindability of the ore, and compare the obtained value of the optimal performance with the current value of itelnosti mill, fix the beginning of the search 0 optimal performance value, calculate the required grinding size depending on the content of a large class in crushed ore, and adjust the target density value, 5 with which the search for the optimal performance value is started when the optimum performance value and the current performance value diverge, and the target value correction density is carried out depending on the calculated required grinding size. Enrichment process Concentrate Tails ZE Correction Fm f 6 Gtt + OtfV,% ti v I h I / 7 L IS / J // 7 L X one N h. I I I J 57 JЈ 4/7 2 2 FIG. f J7 J 4 / 4J r .J N No% KJUXЈQ t5qM Ј5% / (Jiacca 25w 3 7% mas 25 25m &% $ .to) 16 16 K 12 10 6 6 & Got o / o, / b / o