RU2567330C2 - Method of automatic control over flotation process - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: invention relates to dressing of mineral resource, particularly, to automatic control over flotation and can be used for optimisation of dressing of ferrous and nonferrous metals. Proposed method comprises the steps that follow. Flotation process is divided into control loops. Ore material constitution, input effects and internal parameters of flotation are measured to evaluate the ore grade of quality. Obtained data is used to compile the info archive that describes the following characteristics: process efficiency for different ore grades, identification of the current data array with available archive data of ore grades similar with the current grade to ensure the preset efficiency criteria, and development of objectives for local control system on the basis of this process. Local criteria of efficiency are fixed for selected ore grade and data archives are formed for every loop at attainment of efficiency criteria for the entire flotation stage. Data archives formed, evaluated is the grade of ore fed to processing to confirm the compliance with preset criteria of efficiency for the entire flotation stage. In case the positive results are obtained, the local regulation systems are left unchanged. In the case of negative result, local control loop efficiency is evaluated. In case inefficient working loops are revealed, data arrays related with said loops are compared with those stored in ore archives for ore grades similar to the current one. Proceeding from this procedure of settings for control system incorporated therewith. Data archives are formed of scalar magnitude obtained at digitisation of vectors describing the analysed situations. Data are written into archives so that after info accumulation in preset time interval said archives are updated by writing the data to the plate of that corresponding to measurement cycles describing the situations with developed at the moments of attainment of preset magnitudes. Additionally, the data describing the mechanical wear of equipment and the magnitude of circulated flows of the flotation local loops are used as the internal parameters.

EFFECT: higher efficiency of control, accuracy and reliability of computation of control effects.

3 cl, 1 dwg

Description

The invention relates to the field of mineral processing, in particular to methods for automatically controlling the flotation process, and can be used to optimize the processing of ores of ferrous and non-ferrous metals.

A known method of monitoring and controlling the flotation process, including measuring the concentration of ions in the liquid phase of the pulp, measuring the contents of a valuable component in the feed and flotation products, calculating the extraction of a valuable component by the balance method, measuring the density and flow rate of the pulp in the feed and enrichment products, as well as measuring pulp temperature and pressure. Based on the calculations and measurements, the flow of reagents is controlled, which, according to the authors, ensures the achievement of optimal flotation parameters (RU, patent No. 2212278, class 03 B 13/00, B03D 1/00, 2002).

The disadvantage of this method is the low efficiency of the process control due to the lack of control of the mineralogical composition of the processed ore.

The closest in technical essence and the achieved result is a method of automatic control and management of the flotation process, including dividing the flotation process into control loops, measuring the parameters of the ore ore composition, measuring input influences and internal parameters of the flotation process, evaluating the grade of ore, forming based on the obtained archive data information characterizing the efficiency of the production process for various grades of ore, identification of the current data array with and available archived data for ore grades similar to the current one and ensuring the achievement of the set efficiency criteria, and the formation on the basis of this procedure of tasks for local regulatory systems (V. Morozov et al. “Development and application of automated control systems for mineral processing”, M. , From “Ore and Metals”, 2013, p. 492-498).

The disadvantage of this method is the low management efficiency due to the following reasons.

1. Flotation is a complex process, especially in the processing of complex ores, and consists of several intermediate operations. The duration of the flotation cycle from the moment of receipt of the food product to obtain the finished concentrate can reach several hours. Failure to achieve the set performance indicators can occur not only due to a change in the grade of ore, but also due to an accident or due to violations of the technological regime committed by operating personnel in any of the initial stages of flotation. In this regard, adjusting the flotation regime according to the final results leads to a delay and untimely change in control actions, which can lead to a deterioration in the quality of the finished product, additional losses of useful components in the tailings and a long restoration of the technological regime.

2. The formation of the information archive is carried out by sequentially memorizing a set of values of input actions and technological parameters characterizing the current state of the controlled process. As a result of a short time, a data array is formed, consisting of a huge number of combinations of values of the monitored parameters, for example, a data array for 10 parameters, the values of which are measured with a resolution of 1 hour for one shift of 8 hours, can theoretically contain more than 10 ⁸ combinations. Therefore, archiving data for several months will lead to the formation of an array with an astronomical number of combinations of variables. The prompt solution of the problem of identifying the current data array to a certain sample from the archive formed according to the proposed principle will require either a reduction in the number of controlled variables or a reduction in the observation period. Obviously, both of these will lead to a decrease in the quality of management.

3. The formation of a data archive for a limited period of observations also reduces the quality of management. The negative influence of this factor is manifested in the fact that the search for optimal values of control actions is carried out on the basis of analysis of data accumulated over a period of time that does not fully cover the slow-flowing processes of changing technological parameters, for example, such as changes in the mineralogical composition of ore as workings move from the core to the periphery of the ore body.

4. When creating a data archive, factors that are associated with a deterioration in the performance of mechanical elements of technological equipment due to its wear or aging are not taken into account, and circulation loads that have a significant impact on the final performance are not taken into account.

The technical result, the achievement of which the present technical solution is aimed, is to increase the efficiency of automatic control and management of the flotation process by improving the accuracy and reliability of calculating the optimal values of the control actions.

The specified technical result is achieved by the fact that in the method of automatic control and management of the flotation process, including dividing the flotation process into control loops, measuring the parameters of the ore material composition, measuring the input effects and internal parameters of the flotation process, evaluating the grade of the ore, forming an information archive based on the obtained data , characterizing the efficiency of the production process for various grades of ore, the identification of the current data array with existing archival data for ore grades similar to the current one and ensuring the achievement of the set efficiency criteria, and the formation of tasks on the basis of this procedure for local control systems, according to the invention, for each control loop, when the performance criteria are achieved in general, for the redistribution of flotation for the selected ore grade, local efficiency criteria are fixed, separate data archives are formed for each circuit; after completion of the data archiving process, the ore grade arriving at work, establish the fact that the specified performance criteria have been achieved in general for the redistribution of flotation, in case of achieving positive results, the tasks to the local control systems are left unchanged, and if the result is negative, the efficiency of the local control loops is evaluated and, in case of detected inefficiently working loops, the data arrays associated with them are identified with available in the archives for ore grades similar to the current one and form, on the basis of this procedure, tasks included in their becoming regulatory systems.

In addition, the indicated technical result is achieved in that the information archives are formed from scalar values obtained by digitally encoding the parameters of vectors characterizing the observed situations, and the data are recorded in archives in such a way that after the accumulation of information for a specified period of time, the archives are updated by recording in place of information corresponding to the first measurement cycles in time, the results of recent measurements describing situations that have developed at moments d the achievement of the specified values of the performance criteria, and as internal parameters additionally use information characterizing the mechanical wear of the process equipment and the magnitude of the circulation flows of the local flotation circuits.

The drawing shows a diagram of a system for implementing a method of automatically controlling the flotation process.

To illustrate the operation of the system as an object of control, for example, the classical scheme of the flotation process is selected, consisting of 3 operations (control circuits) - main flotation (circuit “A”), clean flotation (circuit “B”) and control flotation (circuit “ AT").

исходного питания, датчики 2 внутренних параметров $$\overrightarrow{X}2$$

флотации и локальные системы 3 регулирования контура «А»; датчики 4 вещественного состава $$\overrightarrow{X}3$$

концентрата, датчики 5 внутренних параметров $$\overrightarrow{X}4$$

флотации, датчики 6 внутренних параметров $$\overrightarrow{X}5$$

циркуляционной нагрузки и локальные системы 7 контура «Б»; датчики 8 вещественного состава $$\overrightarrow{X}6$$

питания (хвостов основной флотации), датчики 9 вещественного состава $$\overrightarrow{X}7$$

хвостов, датчики 10 внутренних параметров $$\overrightarrow{X}8$$

флотации, датчики 11 внутренних параметров $$\overrightarrow{X}9$$

циркуляционной нагрузки и локальные системы 12 контура «В»; конвертор 13 векторов контролируемых параметров $$\overrightarrow{X}1÷\overrightarrow{X}9$$

в соответствующие скалярные величины; контроллер 14; обратный конвертор 15 числовых значений оптимальных управляющих воздействий в задания $$\overrightarrow{Y}1$$

, $$\overrightarrow{Y}2$$

, $$\overrightarrow{Y}3$$

локальным системам 3, 6, 10 регулирования.The system includes sensors 1 material composition $$\overrightarrow{X}\mathrm{one}$$

power supply, sensors 2 internal parameters $$\overrightarrow{X}2$$

flotation and local systems 3 control circuit "A"; sensors 4 material composition $$\overrightarrow{X}3$$

concentrate, sensors 5 internal parameters $$\overrightarrow{X}\mathrm{four}$$

flotation sensors 6 internal parameters $$\overrightarrow{X}5$$

circulation load and local systems 7 of the circuit "B"; sensors 8 material composition $$\overrightarrow{X}6$$

power supply (tailings of the main flotation), sensors 9 of material composition $$\overrightarrow{X}7$$

tails, sensors 10 internal parameters $$\overrightarrow{X}8$$

flotation sensors 11 internal parameters $$\overrightarrow{X}9$$

circulation load and local systems 12 of the circuit "B"; converter 13 vectors of controlled parameters $$\overrightarrow{X}\mathrm{one}÷\overrightarrow{X}9$$

into the corresponding scalar quantities; controller 14; inverse converter 15 numerical values of optimal control actions in tasks $$\overrightarrow{Y}\mathrm{one}$$

, $$\overrightarrow{Y}2$$

, $$\overrightarrow{Y}3$$

local systems 3, 6, 10 regulation.

The system operates in the following sequence.

, $$\overrightarrow{Y}2$$

, $$\overrightarrow{Y}3$$

локальным системам 3, 7, 12 регулирования и вводят полученную информацию в конвертор 13.At the initial stage (“training” mode), a cyclic survey of automatic sensors 1, 4, 8, 9 of the material composition of enrichment products, sensors 2, 5, 10 internal parameters and 6, 11 circulation loads of control circuits, tasks is performed $$\overrightarrow{Y}\mathrm{one}$$

, $$\overrightarrow{Y}2$$

, $$\overrightarrow{Y}3$$

local systems 3, 7, 12 regulation and enter the received information into the converter 13.

Additionally, the internal parameters characterizing the process include information characterizing the change in the efficiency of the mechanical elements of the technological equipment due to its wear or aging and the magnitude of the circulation flows.

The mechanical wear of the elements of technological equipment significantly affects the change in its technical characteristics. Information on the amount of wear allows you to increase the efficiency of the equipment due to timely repair or complete replacement of worn parts of mechanisms.

Accounting for wear can be carried out using the function obtained as a result of statistical analysis of the relationship, connecting, for example, a change in the geometric parameters of the impeller blades with the operating time of the aeration unit of the flotation machine. The source of information about the operating time can be the contacts of the starting equipment.

Another important parameter that influences the choice of the optimal control mode is the circulation flows, which are intermediate products returned to the head of the operation. A change in the ratio of the original power to the flotation operation and the values of the circulating flows significantly affect the efficiency of the process.

The estimation of the circulation flow value can be carried out, for example, by constructing some statistical function F, which describes the dependence of the circulation value Q on the deviation of the pulp level ΔL from the overflow threshold and the opening area of the outlet, determined by the stroke ΔН of the gate actuator rod:

Next, in the converter 13 carry out digital encoding of information.

The need for coding, as mentioned above, is due to the fact that the formation of archives containing a huge amount of raw information leads to increased energy consumption and wasteful use of computer resources, complicates and lengthens the computational process in time, which ultimately leads to a decrease the effectiveness of the search for optimal solutions.

The proposed information coding system is as follows.

Let the ith situation on the object be described by a vector

where Xmi are the controlled process parameters,

i = 1, 2, 3 ... - the serial number of the situation,

m = 1, 2, 3 ... n - serial number of the controlled parameter.

If we divide the full range of variation of each parameter into a given number of intervals of discreteness and number the resulting subranges of each parameter in the direction from the lower to the upper bounds, then the specific value of any parameter can be represented by the number of the subband into which it falls.

In this case, equality (2) can be represented as

where jmi is the number of the subband into which the value of the parameter Xm falls. If for the convenience of calculations we take the number of intervals, or subranges, equal to 10, then the situation vector can be represented as a number obtained from the expression

Example.

потоке пульпы характеризуется объемным расходом пульпы "V" и плотностью пульпы "Y"Let solid consumption $$\overrightarrow{Q}$$

pulp flow is characterized by pulp volumetric flow rate "V" and pulp density "Y"

For arbitrary values of V = 155 m ³ / h and Y = 1550 kg / m ³ we get

Suppose that the volumetric flow rate of the pulp varies in the range from 100 m ³ / hour (lower limit) to 200 m ³ / hour (upper limit), and the pulp density in the range from 1100 kg / m ³ (lower limit) to 1800 kg / m ³ (upper limit).

Dividing the variation range of each parameter by 10, we obtain the discreteness of measuring the volumetric flow rate of 10 m ³ / h, and the density - 70 kg / m ³ .

For the selected conditions, the value V = 155 m ³ / h falls into the 6th subrange from the lower boundary (j ₁ = 6), and Y = 1550 kg / m ³ into the 7th subrange (j ₂ = 7).

As a result of coding by the formula (4) of the selected situation, we obtain

Thus, we have a correspondence

The given example clearly illustrates the advantage of the proposed coding principle due to a significant reduction in the archive dimension due to the "compression" of information.

After completing the encoding procedure, the information from the output of the converter 13 is fed to the input of the controller 14. At the stage of "training", the controller 14 implements the following functions:

;- determines the grades of processed ores by the ratio of the components of the material composition of the feed $${\overrightarrow{X}}_{\mathrm{one}}$$

;

- calculates the efficiency of the flotation process;

- calculates and fixes the achieved values of local performance criteria;

- information archives are formed in accordance with the structure described below.

In the event that the efficiency of the process does not meet the selected criterion, the incoming information is erased and the polling cycle of the sensors is repeated.

In case of achievement of the specified criterion during the next polling cycle, information archives are formed separately for each control loop. Archive structures include, for each successful observation cycle (situation i), several independent arrays containing information about the grade of the ore being processed, internal parameters Xi, the magnitude of the control actions Yi, and the magnitude of the local performance criteria.

The volume of archives at the training stage is limited by a certain limit number of "N" observed situations. The number "N" for each object is set individually, taking into account the drift velocity of the material composition of the processed ores.

Upon completion of the archive formation stage, after each subsequent survey cycle, the information contained in it is partially reset by recording the newly received information packet and erasing the equivalent array of outdated information. This principle of archiving allows for a “time-based” updating of the data array as new information arrives and thus tracks the influence on the efficiency of the flotation process of slowly developing factors, the duration of which exceeds the period corresponding to the length of time the archive was formed.

Next, the system is transferred to the "Work" mode.

Similarly to the “training” stage, the operation of the system in this mode begins with the collection of information, its conversion and input into the controller 14, which implements the following functions:

;- determination of the grade of processed ores by the ratio of the components of the material composition of the feed $${\overrightarrow{X}}_{\mathrm{one}}$$

;

- calculation of the efficiency of the flotation process; 2 outcomes are possible depending on the calculation results:

a) in case of achievement of positive results of the task, the local regulatory systems remain unchanged;

b) if the result is negative, the efficiency of the local control loops is evaluated and, in the case of detected inefficient loops, it identifies current information for them with archive data for ore grades similar to the current one and ensuring the achievement of local performance criteria, and generates, based on this procedure, the numerical values Yi of the optimal control impacts.

, $${\overrightarrow{Y}}_2$$

, $${\overrightarrow{Y}}_3$$

локальным системам 3, 7, 12 регулирования.From the output of the controller 14, the numerical values of Yi are fed to the input of the inverse converter 15, in which the numerical values of Yi are converted in the optimal control actions to the physical signals of the tasks $${\overrightarrow{Y}}_{\mathrm{one}}$$

, $${\overrightarrow{Y}}_2$$

, $${\overrightarrow{Y}}_3$$

local regulatory systems 3, 7, 12.

As follows from the algorithm of the system, an additional advantage of the proposed method is to reduce the time of adjustment of the technological process of flotation in case of deviation from the established regulations. This is achieved by the fact that, with negative work results, instead of completely adjusting the operating mode of the redistribution of flotations, they eliminate violations only in individual local control loops, the transient time in each of which is significantly lower than in the redistribution as a whole.

Thus, dividing the flotation process into separate circuits and operative control of their effectiveness depending on the efficiency of the flotation process as a whole, the formation of an information archive based on scalar values obtained by digitally encoding the parameters of vectors characterizing the observed situations, continuous updating of the archive by writing in place of outdated information of new data arrays, as well as accounting for changes in the efficiency of the mechanical elements of the technological equipment Hovhan due to wear or aging of the internal parameters and control of circulating loads can improve the accuracy and reliability of calculating the optimal value of exposure control and, consequently, greatly increase the effectiveness of automatic control of the flotation process.

Claims (3)

1. A method of automatic control and management of the flotation process, including dividing the flotation process into control loops, measuring the parameters of the ore material composition, measuring input influences and internal parameters of the flotation process, evaluating the grade of ore, forming, on the basis of the obtained data, an archive of information characterizing the efficiency of the production process for different grades of ore, identification of the current data array with available archival data for ore grades similar to the current one and providing which achieve the specified performance criteria, and the formation of tasks on the basis of this procedure for local control systems, characterized in that for each control circuit, when the performance criteria as a whole are achieved for the flotation redistribution for the selected ore grade, local performance criteria are fixed, and separate data archives for each contour, after completion of the process of forming data archives, evaluate the grade of ore coming for processing, establish the fact of achieving the specified crit As a whole, for the redistribution of flotation efficiency, in the case of achieving positive results, the tasks to local control systems are left unchanged, and if the result is negative, the effectiveness of the local control loops is evaluated and, in the case of detected ineffectively working loops, the corresponding data arrays with archives for varieties are identified ore, similar to the current one, and form, on the basis of this procedure, the task of the control systems included in their composition. 2. The method of automatic monitoring and control of the flotation process according to claim 1, characterized in that the information archives are formed from scalar values obtained by digitally encoding the parameters of vectors characterizing the observed situations, and the data are written to archives in such a way that after the accumulation of information for a specified period of time, the archives are updated by recording in place the information corresponding to the first measurement cycles in time, the results of the latest measurements that describe the screens ation on the moment of achieving the setpoint performance criteria. 3. The method of automatic monitoring and control of the flotation process according to claim 1, characterized in that it additionally uses information characterizing the mechanical wear of the process equipment and the magnitude of the circulation flows of the local flotation circuits as internal parameters.

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