RU2787808C1 - Manual express analyzer of iron magnetite content in the pulp and a method for determining this content - Google Patents

Abstract

FIELD: measuring technology.

SUBSTANCE: invention relates to analytical control tools and can be used for efficient assessment of the magnetite iron content in the tailings of the enrichment of pulp flows of iron ore factories. The manual express analyzer of magnetite iron content in the pulp contains a pulp receiver, an induction magnetic susceptibility sensor and a control panel. The magnetic susceptibility sensor is fixed in the pulp receiver, communicated with the sedimentation chamber and is made in the form of an induction vector-difference sensor connected to the control panel, equipped with generator windings, two of which are installed with the possibility of in-phase switching, and the third has the possibility of switching in antiphase with them, as well as working and compensation windings.

EFFECT: exclusion of auxiliary actions for sample preparation, coverage of the entire control zone of enrichment tailings and increased efficiency and reliability of the results.

3 cl, 5 dwg

Description

The invention relates to means of analytical control and can be used for the operational assessment of the iron content of magnetite in the tailings of the enrichment of pulp flows of iron ore factories.

From the prior art there are a number of devices for monitoring the content of magnetic iron in the tailing pulp streams of iron ores beneficiation. All of them are stationary, metal-intensive and do not represent the ability to quickly move around the area. In addition, the known devices do not meet the requirements for the efficiency and reliability of assessing the iron content of magnetite in pulp flows, and also differ in the complexity of design and operation.

A device for monitoring the content of magnetic iron (AS USSR No. 512417, IPC G01N27 / 72, publ. 1976) is known, containing a siphon, a magnetic permeability sensor, a computing device, a density meter, at the output of which a storage nozzle is installed, equipped with a locking device in the bottom part connected to the magnetic permeability sensor and kinematically connected to the executive body of the computing device, and a restrictive valve is installed in the upper part of the storage nozzle. The disadvantage of the device is the high threshold of solid controlled pulp, stationary installation of the device, insufficient reliability of the results.

Also known is a system for automatically monitoring the content of magnetite in the pulp (patent RU 2746880C1, IPC G01N1 / 10, publ. 04/21/2021), containing a controlled sampler with an air supply valve, a pulp density sensor in a process tank, a sample receiving device with a pulp level sensor and a valve for supplying water for washing, a hinged support, a movable lever with a counterweight and an electromagnet fixed to it, which is powered through a demagnetization device, a vertical non-magnetic pipe with a load-measuring element installed on it, electrically connected to the weight transducer, a valve for supplying compressed air to the vertical pipe through a filter regulator, a measuring cuvette with a flat rectangular protrusion, a shut-off valve at the outlet of the measuring cuvette with a pneumatic drive, a controller with an operator panel, the controller inputs are connected to the outputs of the pulp density sensor, the pulp level sensor, the weighing transducer, and the outputs connected to the inputs of the valve for supplying air to the controlled sampler, the valve for supplying water for washing, the demagnetization device, the electromagnet, the valve for supplying compressed air to the vertical pipe, and the shut-off valve pneumatic actuator. The disadvantage of the system is a stationary installation, as well as the complexity of the design; At the same time, the use of a ponderomotive device based on the force interaction of a controlled medium with a magnetic field requires maintenance of the moving mechanisms of the system.

The closest to the claimed device is the OKMTs-3.1P ore tester (https://k-variant.com.ua/ru/magnetite-ii-generation/okmts-3-1p) (prototype) containing a control panel, a remote sensor, a glass for samples and charger. The determination of magnetite by a known device is based on filling a special glass with a pre-prepared sample and placing it in an inductive sensor, after which the control panel in static mode calculates the content of the mass fraction of magnetite. The disadvantage of the tester is its stationary installation, as well as the visual control of the solid phase zone when filling the sample glass and the insufficient accuracy of readings. The device allows you to do the analysis only in static mode and without taking into account the size of the sample particles, which does not allow you to show high reliability of the results.

The objective of the invention is to simplify the design of the device, increase mobility, increase efficiency and reliability of monitoring the content of iron magnetite in the pulp.

The problem is solved by using a vector-difference inductive sensor installed in the pulp receiver and connected to the analyzer control panel as a primary converter of the magnetite iron content, as well as by calculating the magnetite iron content in the pulp, taking into account the hydraulic fineness.

The technical result consists in the exclusion of auxiliary actions for sample preparation, in covering the entire zone of control of enrichment tailings, starting from the first stage of wet magnetic separation (MMS), as well as in increasing the efficiency and reliability of the result by taking into account the hydraulic fineness by determining the rate of sedimentation of solid particles under the action of gravity in a liquid medium and the use of a vector-difference inductive sensor to compensate for the dispersion of the solid content.

In the analysis of enrichment tailings in slurry flows, representing the liquid and solid phases, the dispersion of the solid content fluctuates over a wide range. Depending on the qualitative-quantitative enrichment scheme, the solids content in the pulp varies: MMC1 (first stage of wet magnetic separation) - 17 ... 25%, MMC2 (second stage) - 5 ... 9%, MMC3 (third stage) - 1 ... 4% and and so on, desliming - 0.1 ... 2%. The mass fraction of iron magnetite is in the range of 0.6 ... 5%. The specified dependence was revealed empirically, on the basis of data known from the qualitative and quantitative schemes of iron ore processing plants. The parameters are regulated by the technological instructions for the production of iron ore concentrate.

The dependence of magnetic susceptibility on the grain size of a ferromagnet is known (Magnetism of rocks / T. Nagata; Translated from English by V.P. Avgustinovich and others; Edited by Dr. G.N. Petrova, Doctor of Physical and Mathematical Sciences. - M.: Mir, 1965). It has been experimentally established that during the normal operation of the enrichment apparatus, solid tailings contain particles of the host rock and intergrowths with a low volume fraction of magnetite. Pure grains of magnetite are present in a very limited composition in a fine size class (revealed as a result of research of technological samples using the method of magnetic fractional analysis).

Induction sensors are widely used to control the magnetic susceptibility of media. Unlike classical inductive sensors, based on the increment of mutual inductance of two winding systems when the magnetic flux in one of them changes, the proposed device uses a vector-difference sensor.

The essence of the proposed invention lies in the fact that in an installation containing a slurry receiver with a sediment chamber fixed on a base (rod), an induction sensor of magnetic susceptibility, and a control panel, an induction sensor of a vector-difference type is used, the winding connection diagram of which is represented by generator windings, of which , the first two windings are in common mode, and the third generator winding is turned on in antiphase. The signal proportional to the magnetic susceptibility of the material is formed by subtracting the signal of the compensation winding from the signal of the working winding. When analyzing the iron content of magnetite in the pulp, the hydraulic size of the sample is taken into account, and the calculation is made according to the formula:

,

,

where:

k - coefficient of proportionality;

D, C are correction factors;

– величина магнитной восприимчивости.

is the magnitude of the magnetic susceptibility.

The essence of the invention is illustrated by graphic materials.

Figure 1 shows a schematic representation of a manual express analyzer of the iron content of magnetite in the pulp (scheme, general view).

Figure 2 shows a diagram of a vector-difference sensor.

On figa and 3b presents a comparative diagram of the magnetic fields of the vector-difference (figa) and conventional (figb) induction sensors.

Figure 4 shows a graph of the comparative integral sensitivity of two types of sensors with uniform packing of layers of a solid sample.

The manual express analyzer of the iron content of magnetite in the pulp contains a base (rod) 1 with a handle on which a pulp receiver 2 is fixed, with a sedimentation chamber 3, an induction sensor of magnetic susceptibility 4, a pulp temperature sensor 5 and a control panel 6 electrically connected to sensors 4 and 5. (Fig.1) The sensor 4 is installed in the slurry receptacle 2, communicated with the sedimentation chamber 3 and is made in the form of a coil with windings placed on it: the first generator winding 7, the second generator winding 8, the third generator winding 9, the working winding 10 and the compensation winding 11. (Fig.2) The variable magnetic field of such a sensor has a non-uniformity specified in the manufacture and a sharp insensitivity limit, i.e. the sensor has focusing in the lower zone of the third generator winding 9. With the help of the third generator winding, which is focusing, the integral sensitivity of the induction sensor 4 is set, in this case it is the dependence of the differential signal on the height of the solid (condensed material) sample (Fig.4). To compensate for the increase in particle packing when the solid content exceeds 2%, the integral sensitivity of the vector-difference sensor with a negative slope above the level of 1-2% solid density due to the turns of the third generator winding is set equal to 50% of the number of turns of the first generator winding. This approach allows the analysis of pulp with a low solids content in the pulp and minimizes the effect of its variations, which leads to an increase in the reliability of the result.

Manual express analyzer of the iron content of magnetite in the pulp works as follows.

. По приближению к нулю первой производной магнитной восприимчивости по времени определяют время анализа. Учет гидравлической крупности выполняется поправочным коэффициентом «D», зависящим от времени анализа (с увеличением времени коэффициент снижается). Для косвенного учета вязкости среды осаждения вводится поправочный коэффициент «С», использующий показания датчика температуры пульпы 5, (коэффициент повышается с повышением температуры). Расчетное значение массовой доли железа магнетита определяют по эмпирической формуле, выведенной на основании обобщения данных химического анализа и данных описываемого экспресс-анализатора:The operator delivers the express analyzer to a certain place where the pulp is taken to control the magnetite iron, holding it by the handle of the base 1. To bring the device into operation, the operator presses the "Start" button (not shown in the figure) located on the control panel 6. After pressing the button "Start", the operator takes a sample using a pulp receiver 2, in which the solid pulp is thickened in a gravitational field. In the lower part of the sedimentation chamber 3, by means of a vector-difference induction sensor 4, a signal is recorded that is proportional to the magnetic susceptibility of the material. After filling the slurry receptacle, the latter is removed from the pulp flow. The differential signal of the vector-difference inductive sensor 4 is amplified and converted by the control panel into the value of the magnetic susceptibility

. As the first derivative of the magnetic susceptibility with respect to time approaches zero, the analysis time is determined. Accounting for hydraulic fineness is carried out by the correction factor "D", depending on the analysis time (with increasing time, the coefficient decreases). To indirectly take into account the viscosity of the sedimentation medium, a correction factor "C" is introduced, using the readings of the pulp temperature sensor 5 (the coefficient increases with increasing temperature). The calculated value of the mass fraction of iron magnetite is determined by the empirical formula derived from the generalization of chemical analysis data and the data of the described express analyzer:

,

,

- коэффициент пропорциональности;where:

- coefficient of proportionality;

– поправочные коэффициенты;

– correction factors;

– величина магнитной восприимчивости.

is the magnitude of the magnetic susceptibility.

;

;

;

;

t _analysis – analysis time, s;

t – pulp temperature, °C.

For example, upon completion of the analysis, the following data is obtained:

Analysis time t _analysis =15 s.

Pulp temperature t=10°C.

= 7,5%.The magnitude of the magnetic susceptibility

= 7.5%.

;

;

,

;

;

,

those. The identified content of iron magnetite in the pulp is 1.01%.

After completion of the analysis, the operator, holding the device by the handle of the base, turns the slurry receptacle over and rinses under a stream of clean water.

The proposed hand-held express analyzer of the magnetite iron content in the pulp is a compact portable device (approximate weight 2 kg), which allows the operator to move it on the ground and quickly monitor and analyze the magnetite iron content in the pulp at any point in the process stage of the processing plant with high data reliability. .

Thus, the problem of the invention is solved.

Claims (7)

1. A manual express analyzer of the content of magnetite iron in the pulp, containing a slurry receiver, an induction magnetic susceptibility sensor and a control panel, characterized in that the magnetic susceptibility sensor is fixed in the slurry receiver, communicates with the sedimentary chamber and is made in the form of an induction vector-difference instrument connected to the control panel. a sensor equipped with generator windings, two of which are installed with the possibility of common-mode switching, and the third one can be switched on in antiphase with them, as well as the working and compensation windings. 2. Manual express analyzer of the iron content of magnetite in the pulp according to claim 1, characterized in that the number of turns of the third generator winding of the induction vector-difference sensor is 50% of the number of turns of the first generator winding. 3. A method for determining the content of magnetite iron in the pulp using a manual express analyzer according to claim 1, characterized in that the mass fraction of magnetite iron is calculated by the formula:

, where: k - coefficient of proportionality; D, C are correction factors;

is the magnitude of the magnetic susceptibility.

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