RU2539127C1 - Thermal control method of grade of ore, and device for its implementation - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: invention refers to measurement equipment and can be used for automatic determination of metal concentration in ore. According to the method before control of grade of ore, ore passes through conveyor without metal impurities. For heating, area thermal source is used, which width does not exceed conveyor width. After time τ_spec when heating is finished, measured is average value of temperature based on heated surface of ore without metal T1_av. Based on these measurements, formed is calibration curve. Then ore containing metal is continuously supplied to conveyor and heated. After time τ_spec average value of temperature T_avi is measured on each i frame. Value T_avi-T_1av is determined based on calibration curve. Using value (T_avi-T_1av), determined is percentage of metal in ore. Besides, a device for implementation of the above method is proposed.

EFFECT: improving reliability of determination of metal concentration in ore.

6 cl, 7 dwg, 1 tbl

Description

Technical field

The invention relates to the field of measuring technology and can be used to automatically determine the concentration of metal in ore based on the control of the distribution of the temperature field of the ore in the process of moving the vessels along the conveyor conveyor for processing.

State of the art

Metallurgical production is playing an increasing role in modern industry, the main task of which is against the backdrop of wear and tear of fixed assets in metal production with maximum productivity and high energy efficiency.

In this regard, methods of increasing the concentration of ore before its processing play an increasingly important role.

A known method for determining the quantitative content of precious metals in rocks and dumps of mining production (RF patent No. 2425363).

The method consists in acid decomposition of the sample, separation, drying and fusion of the insoluble residue with sodium peroxide, leaching of the 2N alloy obtained after alloying. hydrochloric acid, the concentration of gold and elements of the platinum group (EPG) from the combined solution on a complexing sorbent and analysis of the suspension by atomic absorption spectrometry.

This method has sufficient accuracy to determine the composition of the metal, but is applicable only in laboratory conditions for selective analysis of ore.

Closest to the claimed is a method of thermographic lump separation of raw materials (options) and a device for its implementation (options) (RF patent No. 2326738).

This method is as follows.

A piece containing a useful component and waste rock is subjected to irradiation with an electromagnetic field of superhigh frequency (microwave) for a certain time at a certain frequency, a thermal image is fixed using a thermographic system after the exposure is stopped and before or after the attenuation of the heat transfer processes between the components of the controlled piece, which determine the average temperature, by mathematical dependencies determine the mass fraction of the useful component in the piece, the volumetric coefficient of the useful component in the piece, the coefficient of volumetric filling of the useful component, according to the results obtained, the raw materials are divided into flows.

The disadvantages of this method are as follows:

1. Biological hazard for staff in connection with the use of powerful microwave radiation.

2. The ability to control only a small amount of ore due to the limited size of the microwave antenna.

3. Low control performance: the method is applicable to individual pieces of ore.

4. Difficulties in use in the production environment due to the small control performance.

Therefore, today there is a need to create an improved method for controlling the metal content in ore, free from the above disadvantages, which can be applied in practice for various ores using simple and accurate equipment.

Fundamentally, an approach to solving such problems became possible with the development of diagnostic tools based on registration and analysis of the temperature fields of the surface of a controlled object. The most notable results have appeared in the last decade.

It's connected with:

1. The advent of modern technologies based on the use of portable thermal imaging equipment (for example, ON Budadin and others. Thermal non-destructive testing of products. M., Nauka, 2002; Budadin ON, Vavilov VP, Abramova E. B. Thermal control. Safety diagnostics. Under the general editorship of academician of the Russian Academy of Sciences V.V. Klyuev - M .: Publishing house Spektr, 2011, 171 pp .; Salikhov ZG, Budadin ON, Ishmetyev EN Engineering the basics of thermal control. Experience in industrial applications - M .: ID MISiS, 2008, - 476 p .;

2. The creation of a modern mathematical apparatus (in the same place, which makes it possible to solve direct and inverse problems of unsteady heat transfer, which made it possible to switch from flaw detection (defect detection) to defectometry (recognition of internal defects, determination of their characteristics and assessment of the residual life of products).

There are repeated attempts to solve the above problem in various ways. However, this did not lead to the desired results. There are several reasons for this.

1. Most of the known methods are based on chemical reactions, are used in laboratory conditions and are not applicable in real production conditions.

2. Some methods are dangerous from the point of view of safety measures (they use quite powerful microwave radiation), for the operator - a flaw detector.

SUMMARY OF THE INVENTION

The problem to which the invention is directed, is to develop a method and device for determining the concentration of ore in a metal in the process of real metallurgical production.

The technical result consists in providing a reliable determination of the content (concentration) of metal in the ore under production conditions (in the process of moving ore on the conveyor conveyor).

An additional technical result is the automatic control of the ore concentration to ensure maximum efficiency of the smelting process.

The technical result is achieved due to the fact that in the method for determining the metal content in the ore, consisting in the fact that the ore is irradiated, the temperature field is recorded after the irradiation is stopped and after the attenuation of the heat exchange processes between the ore components is stopped, the average temperature is determined and then the metal content is determined in ore

before monitoring the metal content in the ore, the conveyor passes ore without metal impurities (0% metal content),

in the process of moving ore, it is continuously heated with a power of "P" as an areal source of thermal (infrared) radiation, while:

- the width of the source exceeds the width of the conveyor along which the ore moves,

- the power of the radiation source "P", the conveyor speed "V" and the heating time "t _n " are related by the ratio of ensuring the optimal average temperature "T0 _cf " of ore heating over the recorded area with coordinates (x, y):

T0 _cf = f (P, V, τ _ass , t _n ),

where the functional dependence f (P, V, τ _ass , t _n ) is determined based on the solution of the unsteady heat equation. In the book of O.N. Budadin et al. Thermal non-destructive testing of products. M., Nauka, 2002, on pages 39-47, the solution of this equation is described in detail and a brief description of the corresponding computer program is given. Simultaneously with the functional dependence itself, in the calculation process, the numerical values of the parameters were determined: P, V, τ _ass , t _n .

In the described theoretical justification of the method, the calculation program mentioned above was used.

Thus, the optimality of “T0 _sr ” by the parameters of thermal excitation (P, V, τ _back , t _n ) should correspond to the dynamic temperature range of the thermal imaging system when it is adjusted before monitoring and the maximum temperature of ore heating on the conveyor.

After a time (τ _backside) after heating was measured the average temperature of the heated surface of the metal content of the ore without - (T1 _avg).

The time τ _{ass is} determined using the above literature from the condition of ensuring the heating of ore over the entire thickness of the layer with an error of no more (δ). The determination of this value was carried out in accordance with the book of O.N. Budadin et al. Thermal non-destructive testing of products. M., Science, 2002, on pages 39-47.

Based on the measurements, a calibration curve is formed

Δ = f ₁ (T _sr -T1 _sr ), where

Δ -% metal content in ore,

T _cf - the average temperature of the surface of the ore containing metal - (Δ ·%).

_Cf. quantity T is determined before the control or experimentally on the basis of calibration mixtures control according to claims 2, 3 (calibration mixture - a mixture with known metal content), or theoretically based solutions unsteady heat conduction equation. In the book of O.N. Budadin et al. Thermal non-destructive testing of products. M., Nauka, 2002, on pages 39-47, the solution of this equation is described in detail and a brief description of the corresponding computer program is given. In the theoretical and experimental substantiation of the proposed method described below, the calculation program indicated above was used.

Further, ore containing metal is continuously fed to the conveyor.

After a time (τ _backside) is measured on each frame (i), the formed thermal imaging apparatus, the average temperature T _cpi.

Measure the value (T _cpi -T1 _sr ).

Based on the calibration curve, using the value (T _cpi -T1 _sr ), determine the percentage of metal in the ore.

The technical result is enhanced due to the fact that the registration of the temperature field of ore with metal is carried out non-contact using a thermal imaging system.

The spatial period of registration of the temperature field is determined by solving a system of equations:

$$\Delta a\le \{\begin{array}{l}(0,2...0,3)x\Delta x_{dmin}\text{,}e\mathrm{from}l\mathrm{and}\Delta x_{dmin}\le \Delta y_{dmin}\\ (0,2...0,3)x\Delta y_{dmin},e\mathrm{from}l\mathrm{and}\Delta y_{dmin}\le \Delta x_{dmin}\end{array}$$

where Δx _dmin , Δy _dmin - geometric dimensions of the temperature response from the minimum piece of ore.

The optimal interval for sequential registration and analysis of the temperature field T (x, y) _i (τ) is determined by solving the equation

, где $$P=\frac{\mathrm{one}}{\tau }{\displaystyle \underset{To-\frac{\mathrm{<figure-callout\; id="2"\; label="\tau "\; filenames="00000012.png,00000015.png"\; state="\{\{state\}\}">\tau </figure-callout>}}{2}}{\overset{\frac{\tau }{2}}{\int }}d\eta {\displaystyle \underset{\eta -\frac{\mathrm{<figure-callout\; id="2"\; label="\tau "\; filenames="00000012.png,00000015.png"\; state="\{\{state\}\}">\tau </figure-callout>}}{2}}{\overset{\eta +\frac{\tau }{2}}{\int }}f(T)dT}}$$

where

f (T) - density distribution of the duration in time of the information signal,

τ - time interval of measurement,

P is the probability of missing an information signal,

T ₀ is the temporal resolution of the measuring sensors.

An additional technical result is achieved due to the fact that the range of sizes of pieces of ore, starting from the minimum size (Δ _{x dmin} , Δy _dmin ), is determined by solving the system of equations:

$$\{\begin{array}{l}{\displaystyle \underset{0}{\overset{\Delta X_{min}}{\int }}p}(\Delta \text{A.}Xi)d(\Delta X)=\mathrm{one}-\delta \\ {\displaystyle \underset{0}{\overset{\Delta Y_{min}}{\int }}p}(\Delta \text{A.}Yi)d(\Delta Y)=\mathrm{one}-\delta \end{array}$$

Where

δ is the probability that (Δx _di , Δy _di ) ≥ (Δx _dmin , Δy _dmin )

p (ΔX _i ) is the distribution function of the quantities Δx _di , Δy _di .

The technical result in terms of the device is ensured by the fact that in the device for determining the metal content in the ore containing the ore supply device, an ore irradiation unit, recording means and a computing device, the ore supply means is made in the form of a conveyor, the ore irradiation unit is made in the form of heat radiation source, while additionally introduced:

conveyor speed sensor,

a distance sensor between the end point of heating by an area source of thermal radiation and the point of registration of the temperature field by the thermal imaging system,

size sensor of the area source of thermal radiation,

temperature field registration unit,

unit for setting operating modes,

electronic unit for determining T1 _avg ,

microprocessor unit for constructing a calibration curve, electronic unit for determining T _cpi ,

an electronic unit for determining the percentage of metal in ore, a thermal imaging system, a distance sensor between the end point of heating by an area source of thermal radiation and a temperature field registration point by a thermal imaging system, a size sensor of an area source of thermal radiation, a conveyor speed sensor and a thermal radiation source are installed near the conveyor with the possibility obtaining relevant information and heating the ore, respectively,

the outputs of the distance sensor between the end point of heating by an area source of thermal radiation and the registration point of the temperature field by the thermal imaging system, the size sensor of the area source of thermal radiation, the conveyor speed sensor and the source of thermal radiation are connected respectively to the first or fourth inputs of the microprocessor unit for constructing the calibration curve,

the output of the thermal imaging system is connected to the input of the temperature field registration unit,

the output of the temperature field registration unit is connected to the input of the operation mode setting unit,

the first output of the unit for setting the operating modes is connected through the electronic unit for determining T1 _cf - to the fifth input of the microprocessor unit for constructing the calibration curve,

the second output of the unit for setting operating modes is connected to the input of the electronic unit for determining T _cpi ,

the output of the electronic unit for determining T _{cpi is} connected to the input of the electronic unit for determining the percentage of metal in ore, to the second input of which the output of the microprocessor unit for constructing the calibration curve is connected.

The invention and the possibility of achieving a technical result will be more clear from the following description with reference to the position of the drawings, where:

figure 1 shows the structural diagram of the device,

Fig 2 shows graphs of the results of theoretical studies,

figure 3 shows the calibration curves

figure 4 shows a thermogram of the surface of the heated ore,

figure 5 shows the calibration curve obtained by the results of experimental studies,

6 is a graph of the error in determining the metal content in ore from the value of the metal content,

Fig.7 shows photographs of a device for thermal control of the concentration of metal ore.

In the above figures, the following notation:

1 - conveyor with ore,

2 - thermal imaging system,

3 - areal source of thermal radiation,

4 - sensor speed carpet,

5 - distance sensor,

6 - sensor size of the heated area by an area source of thermal (infrared) radiation,

7 - registration unit,

8 - electronic unit for setting operating modes (switch),

9 - electronic unit for determining T1 _avg (adder No. 1),

10 - microprocessor unit for constructing a calibration curve,

11 is an electronic unit for determining T _cpi (adder No. 2),

12 - electronic comparison unit - determining the percentage of metal in ore,

13 - a device for thermal control of the concentration of metal ore, including blocks: 4-12.

P is the heating power,

V is the speed of movement of the conveyor with ore,

L _ass - the distance between the end of heating and registration of the temperature field,

T _ass - the time of movement of the conveyor between the end of heating and registration of the temperature field,

L _n - the size of the heated ore section,

τ _n - the time of movement of the conveyor in the region of the heated area.

Preferred Embodiment

All used electronic components are built on the basis of standard microprocessor circuits and microprocessor assemblies with reprogrammable memory devices, and the control system (on / off) of the loading system is built on standard relay systems (see, for example, Ugryumov EP Digital circuitry: a training manual for universities - 3rd ed. revised and supplemented - St. Petersburg: - BHV-Petersburg, 2010). As a thermal imaging device (2), thermal imagers from FLIR, IRTIS-2000 or similar in technical characteristics are used. The method is as follows.

Impurities of metal in ore increase the integral thermal conductivity of a mixture of ore and metal (by integral thermal conductivity is meant the average thermal conductivity over the thickness of the mixture). Therefore, the heating temperature of the mixture will depend on the concentration of the metal. Thus, by measuring the surface temperature and knowing the calibration curve (temperature dependence on the concentration of metal in ore), the value of the metal concentration can be determined from the temperature value.

The method is as follows

1. Before monitoring the metal content in the ore, ore without metal impurities is passed through a conveyor (0% metal content).

2. In the process of moving the ore, it is continuously heated with a power of "P" as an area source of thermal (infrared) radiation, while:

- the width of the source exceeds the width of the conveyor along which the ore moves,

- the power of the radiation source "P", the conveyor speed "V" and the heating time "t _n " are related by the ratio of ensuring the optimal average temperature "T0 _cf " of ore heating over the recorded area with coordinates (x, y):

T0 _cp = f (P, V, τ _ass , t _n ),

where the functional dependence f (P, V, t _n ) is determined based on the solution of the unsteady heat equation. In the book of O.N. Budadin et al. Thermal non-destructive testing of products. M., Nauka, 2002, on pages 39-47, the solution of this equation is described in detail and a brief description of the corresponding computer program is given. In the theoretical and experimental substantiation of the method described below, the calculation program indicated above was used.

Thus, the optimality of “T0 _sr ” by the parameters of thermal excitation (P, V, τ _back , t _n ) should correspond to the dynamic temperature range of the thermal imaging system when it is adjusted before monitoring and the maximum temperature of ore heating on the conveyor, see book O. N. Budadin et al. Thermal non-destructive testing of products. M., Nauka, 2002, where on pages 68-87 describes in detail the methodological aspects of choosing the optimal relationship between the temperature of the controlled surface (in this case, "T0 _sr ") and the parameters of the technical means: the characteristics of the thermal imaging equipment, the power of the heating source. This value is necessary for the correct selection of the temperature range of thermal imaging equipment.

3. After time (τ _back ) after the end of heating, measure the average temperature over the heated surface of the ore without metal content - (T1 _sr ).

τ _ass - the time interval between the end of heating and the time of registration of the temperature field.

This time interval is determined based on the solution of the non-stationary heat equation. In the book of O.N. Budadin et al. Thermal non-destructive testing of products. M., Nauka, 2002, on pages 39-47, the solution of this equation is described in detail and a brief description of the corresponding computer program is given.

4. Based on the measurements, a calibration curve is formed:

Δ = f ₁ (T _sr -T1 _sr ), where

Δ -% metal content in ore,

T _cf - the average temperature of the surface of the ore containing metal - (Δ%).

The value of T _{cf is} determined before control is carried out either experimentally based on the control of calibration mixtures in accordance with paragraphs 2, 3 (calibration mixtures are mixtures with a known metal content), or theoretically, based on the solution of the unsteady heat equation. In the book of O.N. Budadin et al. Thermal non-destructive testing of products. M, Nauka, 2002, pp. 39-47 describe in detail the solution of this equation and provides a brief description of the corresponding computer program. In the theoretical and experimental substantiation of the proposed method described below, the calculation program indicated above was used.

5. Further, ore containing metal is continuously fed to the conveyor.

6. Through time (τ _back ), the average temperature T _{cpi is} measured on each frame (i).

7. Determine the value (T _sr- T1 _sr ).

8. On the basis of the calibration curve, using the value (T _sr- T1 _sr ), determine the percentage of metal in the ore.

9. The registration of the temperature field of the structure is carried out non-contact using a thermal imaging system.

10. The spatial period of registration of the temperature field is determined by solving a system of equations:

$$\Delta a\le \{\begin{array}{l}(0,2...0,3)x\Delta x_{dmin},e\mathrm{from}l\mathrm{and}\Delta x_{dmin}\le \Delta y_{dmin}\\ (0,2...0,3)x\Delta y_{dmin},e\mathrm{from}l\mathrm{and}\Delta y_{dmin}\le \Delta x_{dmin}\end{array}$$

where Δx _dmin , Δy _dmin - geometric dimensions of the temperature response from the minimum piece of ore.

11. The optimal interval for sequential registration and analysis of the temperature field T (x, y) _i (τ) is determined by solving the equation

$$P=\frac{\mathrm{one}}{\tau }{\displaystyle \underset{To-\frac{\mathrm{<figure-callout\; id="2"\; label="\tau "\; filenames="00000012.png,00000015.png"\; state="\{\{state\}\}">\tau </figure-callout>}}{2}}{\overset{\frac{\tau }{2}}{\int }}d\eta {\displaystyle \underset{\eta -\frac{\mathrm{<figure-callout\; id="2"\; label="\tau "\; filenames="00000012.png,00000015.png"\; state="\{\{state\}\}">\tau </figure-callout>}}{2}}{\overset{\eta +\frac{\tau }{2}}{\int }}f(T)dT}}$$

f (T) - density distribution of the duration in time of the information signal,

τ is the measurement time interval,

P is the probability of missing an information signal,

T ₀ is the temporal resolution of the measuring sensors.

11. The range of sizes of pieces of ore starting from the minimum size (Δ _{x dmin} , Δy _dmin ), determine by solving the system of equations:

$$\{\begin{array}{l}{\displaystyle \underset{0}{\overset{\Delta X_{min}}{\int }}p}(\Delta \text{A.}Xi)d(\Delta X)=\mathrm{one}-\delta \\ {\displaystyle \underset{0}{\overset{\Delta Y_{min}}{\int }}p}(\Delta \text{A.}Yi)d(\Delta Y)=\mathrm{one}-\delta \end{array}$$

Where

δ is the probability that (Δx _di , Δy _di ) ≥ (Δx _dmin , Δy _dmin ),

p (ΔX _i ) is the distribution function of the quantities Δx _di , Δy _di .

The technical result in terms of the device is ensured by the fact that the device for thermographic lump separation of raw materials (patent No. 2326738) is additionally equipped with:

- areal source of thermal (infrared) radiation with a power of "P" 3,

- sensor 4 speed V movement of the conveyor 1,

- distance sensor - L _back = Vxτ _back - 5 between the end of heating by an area source of thermal (infrared) radiation with a power of "" 3 and registration of the temperature field T (x, y) with the thermal imaging system 2,

- a sensor 6 of the size of the areal source of thermal (infrared) radiation:

L _n = Vxτ _n ,

- registration unit 7 of the temperature field T (x, y),

- block 8 job modes,

- an electronic unit 9 for determining T1 _avg ,

- microprocessor unit 10 for constructing a calibration curve,

- an electronic unit 11 for determining T _cpi ,

- electronic comparison unit 12 - determine the percentage of metal in ore.

In this case, the inputs of the thermal imaging system 1, the distance sensor - L _back = Vxτ _back - 5, the sensor 6 size of the areal source of thermal (infrared) radiation, the sensor 4 speed V of the conveyor and the source of thermal (infrared) radiation 3 are connected to the conveyor, the outputs of the distance sensors - L _ass = Vxτ _ass - 5 sizes of the area source of thermal (infrared) radiation 6, the speed V of the conveyor 4 and the source of thermal (infrared) radiation 3 are connected, respectively, to the 1, 2, 3, 4 inputs of block 10, the output of the thermal imaging system 2 p it is connected to the input of the registration unit 7 of the temperature field T (x, y), the output of the registration unit 7 of the temperature field T (x, y) is connected to the input of unit 8 for setting operating modes, the 1st output of unit 8 for setting operating modes is connected to the input of unit 9 , The 2nd output of block 8 is connected to the input of block 11 for determining T _cpi , the output of block 9 is connected to the 5th input of microprocessor block 10, the output of block 11 for determining T _{cpi is} connected to the input of electronic block 12 for determining the percentage of metal in ore, to the second input of which the output of the unit is microprocessor-connected a unit 10 for constructing a calibration curve.

The device operates as follows.

At the first stage, ore is passed through conveyor 1 without metal impurities. The conveyor moves at a speed of "V". Ore is heated by source 3 for a time “τ _n ” or at a distance of “L _n ”. After a time “τ _back ” or a distance “L _back ”, the heated ore section enters the field of view of thermal imaging system 2. Thermal imaging system 2 registers the temperature field T (x, y) within the field of view, which enters through the set mode unit 8 (switch) in the electronic unit 9 - the adder, where the value T1 _cf is determined - the average temperature of the ore surface without metal impurities in the field of view of the thermal imaging system according to the formula

T1 _cp = (1 / N) ΣT (x, y) _j ,

where N is the number of temperature measurement points in the field of view,

j is the number of the temperature measurement point in the field of view,

Σ is the sign of the sum.

The value of T1 _cf from block 9 is transmitted to the microprocessor unit 10. At the same time, block 10 receives signals from the blocks: 4 - about the value of the conveyor speed, 5 - about the distance - L _back = Vxτ _back , 6 - size of the area source of thermal (infrared) radiation, 3 - heating power by a source of thermal (infrared) radiation. In block 10 on the basis of the available reference point «T1 _compare" on the basis of mathematical models set out in the above-mentioned sources, is determined by the calibration curve, ie, dependence

Δ = f ₁ (T _av- T1 _av ).

Here, the value of T _{cf is} adjusted with respect to T1 _cf (i.e., when Δ = 0) and then, based on mathematical models, it is calculated for various values of Δ. Below in the “research” section, a view of this dependence will be given.

After its determination, the calibration curve from block 10 is transmitted to the electronic comparison unit 12.

After determining the calibration curve, block 8 switches to control mode. The value of T (x, y) from block 7 goes to block 11 - the adder, where the value of T _cpi with a given period is determined by the formula

T _cpi = (1 / N) ΣZT (x, y) _ji .

The optimal interval for sequential registration and analysis of the temperature field T (x, y) _i (τ) is determined by solving the equation

, $$P=\frac{\mathrm{one}}{\tau }{\displaystyle \underset{To-\frac{\mathrm{<figure-callout\; id="2"\; label="\tau "\; filenames="00000012.png,00000015.png"\; state="\{\{state\}\}">\tau </figure-callout>}}{2}}{\overset{\frac{\tau }{2}}{\int }}d\eta {\displaystyle \underset{\eta -\frac{\mathrm{<figure-callout\; id="2"\; label="\tau "\; filenames="00000012.png,00000015.png"\; state="\{\{state\}\}">\tau </figure-callout>}}{2}}{\overset{\eta +\frac{\tau }{2}}{\int }}f(T)dT}}$$

,

f (T) - density distribution of the duration in time of the information signal,

τ is the measurement time interval,

P - probability of skipping the information signal

T ₀ is the temporal resolution of the measuring sensors.

The value of T _cpi from block 11 enters block 12, where the value is calculated (T _{cpi -T1 sr} ) and its comparison with the calibration curve. As a result, Δ is determined - the metal content in the ore, i.e. the problem posed in this patent is solved - the determination of the metal content in ore in production conditions.

The justification of the proposed method was carried out theoretically and experimentally.

Consider the theoretical study of the method.

Based on the methods of mathematical modeling described in the literature

1. O.N. Budadin et al. Thermal non-destructive testing of products. M., Science, 2002.

2. Budadin O.N., Vavilov V.P., Abramova E.V. Thermal control. Safety diagnostics. Under the general editorship of academician of the RAS V.V. Klyuev - M .: Publishing house Spektr, 2011, 171 p.

3. Salikhov Z. G., Budadin O. N., Ishmetyev E. N. Engineering basics of thermal control. Experience in industrial application - M .: ID MISiS, 2008, - 476 p.

A mathematical model of the thermal control process used in the present invention is constructed.

Based on the mathematical model, the thermal conditions of ore control are determined.

Figure 2, as an example, shows some graphs of the results of theoretical studies.

Figure 3, as an example, shows some calibration curves, constructed according to the results of theoretical studies.

If we assume that the resolving temperature ability of thermal imaging equipment under production conditions is, on average, 0.5 degrees, then from the obtained results it can be seen that the method allows determining the concentration of metal in ore with an error of not more than 0.8%, which is quite enough for practical use .

Experimental studies were carried out in accordance with the above description. To simplify the experiment without reducing the error of the obtained results, the experimental studies were carried out on a fixed conveyor.

The order of the experimental work was as follows.

Metal-free ore was poured onto the surface. Next, the ore was heated for 15 ° C with infrared radiation with a power of P = 50 kW / m ² . After 10-12 ° C, the temperature field was recorded. Figure 4 shows a thermogram of ore without metal content. Average surface temperature T1 _avg = 81 ° C.

Further, based on this average temperature, a calibration curve was determined (FIG. 5).

Then metal was mixed into the ore (from 1% to 10%) and the surface temperature field was recorded and the metal content in the ore was determined on the basis of the calibration curve and this determined value was compared with the actual content. Based on the comparison results, the relative error of the method (μ) was determined.

µ = | Δ-Δ ₀ | × 100% / Δ ₀ , here

Δ ₀ - the actual metal content in the ore,

Δ is the metal content in the ore, determined in accordance with the proposed method.

Figure 6 shows a graph of the error in determining the metal content in ore from the value of the metal content.

From Fig.6 it is seen that the maximum error in determining the metal content in the ore does not exceed 0.73%, which is fully confirmed by theoretical studies.

The research results and a comparison of the results of experimental studies with the control method adopted as the closest analogue are shown in table 1.

pp Parameter Numerical and qualitative parameter values Invention Prototype method 2 3 four The ability to control objects in real operating conditions is available limited The need for special equipment The equipment is serial, there are no special requirements The equipment is expensive, stationary, with biological hazard Error Not more than 0.80% No more than 10% Field of view Really up to 2 × 2 m (limited by the geometric resolution of the equipment) Limited by the area of the radiating antenna, actually no more than 0.3 × 0.3 m Performance control Not less than 3 m ² / s Not determined

The method has the following advantages:

- provides control in real operating conditions,

- allows you to increase the reliability of the control results, tentatively, from 3 to 10 times,

- improves the reliability of the control system,

- improves the efficiency of metallurgical processes.

Claims (6)

1. The method of determining the metal content in the ore, which consists in the fact that the ore is irradiated, the temperature field is recorded after the irradiation is stopped and after the cessation of heat transfer processes between the ore components, the average temperature is determined and then the metal content in the ore is determined, characterized in that
before monitoring the metal content in the ore, ore is passed through the conveyor without metal impurities,
in the process of moving the ore, it is continuously heated with power P by an areal source of thermal radiation, the width of which exceeds the width of the conveyor,
after time τ _ass after the end of heating measure the average temperature on the heated surface of the ore without metal content - (T1 _sr ),
based on the measurements form a calibration curve:
Δ = f ₁ (T _cp -T1 _cp ),
where Δ -% metal content in the ore, _cf. T - average surface temperature of an ore containing the metal - (Δ%),
then ore containing metal is continuously fed to the conveyor, heated by power P,
after time τ, the _{backside is} measured on each frame i of the video image of the temperature field, the average temperature T _cpi ,
determine the value of T _cpi -T1 _cf ,
on the basis of the calibration curve, using the value (T _cpi -T1 _sr ) determine the percentage of metal in the ore. 2. The method according to claim 1, characterized in that the registration of the temperature field of ore with metal is carried out contactlessly using a thermal imaging system. 3. The method according to claim 1, characterized in that the spatial period of registration of the temperature field is determined by solving a system of equations:
$$\Delta a\le \{\begin{array}{l}(0,2...0,3)x\Delta x_{d\min },e\mathrm{from}l\mathrm{and}\Delta x_{d\min }\le \Delta y_{d\min }\\ (0,2...0,3)x\Delta y_{d\min },e\mathrm{from}l\mathrm{and}\Delta y_{d\min }<\Delta x_{d\min }\end{array}$$

where Δx _dmin , Δy _dmin - geometric dimensions of the temperature response from the minimum piece of ore. 4. The method according to claim 1, characterized in that the optimal interval for sequential registration and analysis of the temperature field T (x, y) _i (τ) is determined by solving the equation
$$P=\frac{\mathrm{one}}{\tau }{\displaystyle \underset{To-\frac{\tau }{2}}{\overset{\frac{\tau }{2}}{\int }}d\eta {\displaystyle \underset{\eta -\frac{\tau }{2}}{\overset{\eta +\frac{\tau }{2}}{\int }}f(T)dT}}$$

,
where f (T) is the distribution density of the duration in time of the information signal,
τ - time interval of measurement,
P is the probability of missing an information signal,
T ₀ is the temporal resolution of the measuring sensors. 5. The method according to claim 1, characterized in that the size range of the ore pieces, starting with the minimum size (Δx _dmin , Δy _dmin ), is determined by solving the system of equations:
$$\{\begin{array}{l}{\displaystyle \underset{0}{\overset{\Delta X_{\min }}{\int }}p}(\Delta Xi)d(\Delta X)=\mathrm{one}-\delta \\ {\displaystyle \underset{0}{\overset{\Delta Y_{\min }}{\int }}p}(\Delta Yi)d(\Delta Y)=\mathrm{one}-\delta \end{array}$$

where δ is the probability that (Δx _di , Δy _di ) ≥ (Δx _dmin , Δy _dmin ),
p (ΔX _i ) is the distribution function of the quantities Δx _di , Δy _di . 6. A device for determining the metal content in ore, containing an ore supply device, an ore irradiation unit, recording means and a computing device, characterized in that the ore supply means is made in the form of a conveyor, the ore irradiation unit is made in the form of an areal source of thermal radiation, additionally introduced:
conveyor speed sensor,
a distance sensor between the end point of heating by an area source of thermal radiation and the point of registration of the temperature field by the thermal imaging system,
size sensor of the area source of thermal radiation,
temperature field registration unit,
unit for setting operating modes,
electronic unit for determining T1 _avg ,
microprocessor unit for constructing a calibration curve,
electronic unit for determining T _cpi ,
electronic unit for determining the percentage of metal in ore,
a thermal imaging system, a distance sensor between the end point of heating by an area source of heat radiation and a temperature field registration point by a thermal imaging system, a size sensor of an area source of heat radiation, a conveyor speed sensor and a source of heat radiation are installed near the conveyor with the possibility of obtaining relevant information and ore heating, respectively
the outputs of the distance sensor between the end point of heating by an area source of thermal radiation and the registration point of the temperature field by the thermal imaging system, the size sensor of the area source of thermal radiation, the conveyor speed sensor and the source of thermal radiation are connected respectively to the first or fourth inputs of the microprocessor unit for constructing the calibration curve
the output of the thermal imaging system is connected to the input of the temperature field registration unit,
the output of the temperature field registration unit is connected to the input of the operation mode setting unit,
the first output of the unit for setting the operating modes is connected through the electronic unit for determining T1 _cf - to the fifth input of the microprocessor unit for constructing the calibration curve,
the second output of the unit for setting operating modes is connected to the input of the electronic unit for determining T _cpi ,
the output of the electronic unit for determining T _{cpi is} connected to the input of the electronic unit for determining the percentage of metal in ore, to the second input of which the output of the microprocessor unit for constructing the calibration curve is connected.

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