CN108007959B - Method for detecting assimilation temperature based on iron ore powder temperature-electric signal curve - Google Patents
Method for detecting assimilation temperature based on iron ore powder temperature-electric signal curve Download PDFInfo
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Abstract
The invention discloses a method for detecting assimilation temperature based on an iron ore powder temperature-electric signal curve, and belongs to the field of iron ore powder sintering characteristic detection. Iron ore powder sample powder is covered on a calcium oxide pressure sheet of a detection device, and the iron ore powder sample is connected in series between a first electrode and a second electrode; detecting the change condition of the electric signal of the iron ore powder sample along with time and the change condition of the temperature along with time by a detection unit of the detection device in the temperature rise process, obtaining the corresponding relation between the electric signal and the temperature through a time medium, and drawing a temperature-electric signal curve of the iron ore powder sample; and determining the temperature value of the corresponding coordinate axis according to the electric signal mutation of the electric signal and the temperature curve, and detecting to obtain the assimilation temperature of the iron ore powder. Compared with the method for judging the iron ore powder assimilation temperature through deformation such as a wetting angle, the method improves the accuracy of judgment of the time for judging the iron ore powder assimilation reaction, and improves the detection efficiency.
Description
Technical Field
The invention relates to the field of detection of sintering characteristics of iron ore powder, in particular to a method for detecting assimilation temperature based on an iron ore powder temperature-electric signal curve.
Background
The steel industry is an important industry of pillars for economic and social development and occupies an important position in national economy. The iron ore powder sintering is an essential process in modern large-scale steel and iron combined enterprises, and is a method for sintering powdery materials into blocks by heating the powdery materials at high temperature under the condition of incomplete melting, and the proportion of sintering ores in iron-containing furnace burden of a blast furnace in China is more than 80%.
With the pursuit of iron and steel enterprises for blast furnace product quality and enterprise economic benefits, the iron and steel enterprises need to expand raw material sources to reduce production cost. However, the properties of iron ore powder from different sources are greatly different, and the ore blending and sintering only considering the chemical components can bring great influence to the sintering production, even seriously affect the quality of the sintered ore, so that the blast furnace production is not smooth, and the economic benefit of enterprises is reduced. If the feasibility of the ore blending scheme is verified in advance by adopting the sintering cup, the process parameters are optimized, the most appropriate proportion of the raw materials is found, the risk caused by directly using the raw materials for sintering machine production can be reduced to a certain extent, but the workload is large, the experimental period is long, the experimental result cannot be accurately predicted, and a large amount of manpower and material resources are wasted. The basic performance of the iron ore powder is studied in advance, the low-temperature and high-temperature performance of the iron ore powder is comprehensively known, the superiority is shown by reasonable matching, and a large amount of manpower and material resources can be saved, and the working efficiency is improved.
The assimilation property (expressed by assimilation temperature) of the iron ore powder is one of the basic characteristics of iron ore powder sintering, the assimilation property reflects the reaction capability of the iron ore powder and CaO, and the assimilation property is characterized by the difficulty degree of the iron ore powder in generating a liquid phase in the sintering process. According to the theory of thermodynamics, it is known that if the assimilation temperature of the iron ore powder is lower, it is easier to react to form a liquid phase during sintering, but in the case of a heterogeneous sintered ore, based on the consideration of the consolidation of the sintered ore and the permeability of the sinter bed, it is not desirable that the coarse-grained ore, which is a nuclear ore, be excessively melted in order to avoid the decrease of the nuclear ore, which functions as a consolidated framework, and the deterioration of the permeability of the sinter bed, which affect the quality and yield of the sintered ore. Therefore, in the optimization of ore blending, it is desirable to match the iron ore powder with good assimilation property with the iron ore powder with poor assimilation property, and combine the fuel ratio in the sintering process to make the assimilation property of the mixed ore in a proper range, thereby improving the production quality of the sintered ore. However, no special detection equipment exists for detecting the iron ore powder assimilation temperature, and a device specially applied to detecting the iron ore powder assimilation temperature needs to be developed urgently.
At present, for the measurement of the lowest assimilation temperature of the iron ore powder, an assimilation detection method is proposed in the literature "experimental research on the assimilation capability of the iron ore powder and CaO" (Wu Sheng, Liu Yu, Dujian Xin, et al., Beijing university of science and technology, 2002, 24 (3): 258) 261): the method for judging the assimilation characteristics of the iron ore powder comprises the steps of pressing a grinded iron ore powder and an analytically pure CaO reagent into cakes, placing a small cake sample of the iron ore powder on the small cake sample of the CaO, placing the small cake sample of the iron ore powder into a miniature sintering device, heating the sample according to a certain temperature rise system, and judging the assimilation characteristics of the iron ore powder. The lowest assimilation temperature can be judged only by trying tests with different temperatures, and the corresponding experimental method is too fast in temperature rise, so that the lowest assimilation temperature of the iron ore powder cannot be accurately judged due to obvious thermal hysteresis, and the phenomenon of over-assimilation is easily caused. The experimental process is time-consuming and labor-consuming, the artificial operation factors have inevitable influence on the experimental result, the lowest assimilation temperature is judged by naked eyes, the accuracy is poor, and the artificial subjectivity in the detection process is strong.
Through the search, patent documents: a method (CN201510829051.X) for measuring the assimilation reaction performance of iron ore powder and CaO, a method (CN201410603085.2) for measuring the assimilation characteristic of iron ore powder, a measuring device (CN201210385867.4) for visualizing the pyrometallurgical performance of iron ore powder and the like, wherein the lowest temperature for assimilating the iron ore powder and the CaO is determined by observing the mutation condition of a sample in an experimental furnace through a camera; however, the subjective nature of the person who determines the assimilation temperature through observation is too large, so that the detection error of the assimilation temperature is large, and the detection process is complex.
Through the analysis, although the lowest assimilation temperature of the iron ore powder can be detected to a certain extent in the prior art, the detection methods need to judge when the assimilation reaction occurs through observation by an experimenter, and the human subjective factors have large influence, so that the iron ore powder assimilation temperature detection result is inaccurate.
Disclosure of Invention
1. Technical problem to be solved by the invention
The invention aims to overcome the defects of large influence of artificial subjective factors and inaccurate detection result of iron ore powder assimilation temperature detection in the prior art, and provides a method for detecting assimilation temperature based on an iron ore powder temperature-electric signal curve.
2. Technical scheme
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
the method for detecting the assimilation temperature based on the iron ore powder temperature-electric signal curve detects the electric signal and the temperature change condition of an iron ore powder sample in the temperature rising process, determines the relation between the electric signal and the temperature, draws the temperature-electric signal curve of the iron ore powder sample, searches for a corresponding temperature value according to the electric signal mutation of the curve, and detects the assimilation temperature of the iron ore powder.
Preferably, the specific method is as follows: covering iron ore powder sample powder on a calcium oxide pressure sheet of a detection device, wherein the iron ore powder sample is connected in series between a first electrode and a second electrode; detecting the change condition of the electric signal of the iron ore powder sample along with time and the change condition of the temperature along with time by a detection unit of the detection device in the temperature rise process, obtaining the corresponding relation between the electric signal and the temperature through a time medium, and drawing a temperature-electric signal curve of the iron ore powder sample; and determining the temperature value of the corresponding coordinate axis according to the electric signal mutation of the electric signal and the temperature curve, and detecting to obtain the assimilation temperature of the iron ore powder.
Preferably, the detection device comprises a heating unit for heating the iron ore powder sample; the detection unit comprises a temperature detection component and an electric signal detection component, and the temperature detection component is used for detecting the temperature of the iron ore powder sample; the electric signal detection component is used for detecting the change condition of the electric signal of the iron ore powder sample in the temperature rising process.
Preferably, the electric signal detection part includes a first electrode, a second electrode, and a detection device; the detection device is electrically connected with the first electrode and the second electrode; and the first electrode and the second electrode are kept in a non-contact state, and at least one of the first electrode or the second electrode is arranged in the calcium oxide wafer.
Preferably, the calcium oxide tablet is provided with at least one electrode hole for accommodating the first electrode or the second electrode.
Preferably, the calcium oxide tablet is provided with an electrode hole for accommodating the first electrode, and the second electrode is placed on the upper surface of the calcium oxide tablet.
Preferably, the thickness of the electrode hole from the upper surface of the calcium oxide pressing sheet is delta, and delta is 0.2-2 mm.
Preferably, the thickness of the electrode hole from the upper surface of the calcium oxide pressing sheet is delta, and the delta is obtained by the following formula:
delta is the thickness of the diffusion layer, mm; k is the reaction coefficient, kg/m3(ii) a D is the diffusion coefficient, m2S; rho is the density of the diffusion substance, kg/m3(ii) a λ is diffusion time, s.
Preferably, it is characterized in that: the electric signal is a conductivity or voltage signal or a current signal.
3. Advantageous effects
Compared with the prior art, the technical scheme provided by the invention has the following remarkable effects:
(1) the method for detecting the assimilation temperature based on the iron ore powder temperature-electric signal curve comprises the steps of detecting the electric signal and the temperature change condition of an iron ore powder sample in the temperature rising process, determining the relation between the electric signal and the temperature, drawing the temperature-electric signal curve of the iron ore powder sample, searching for a corresponding temperature value according to the electric signal mutation of the curve, and detecting to obtain the assimilation temperature of the iron ore powder; compared with a method for judging the assimilation temperature of the iron ore powder through deformation such as a wetting angle and the like, the method improves the accuracy of judgment of the time for judging the assimilation reaction of the iron ore powder, and further can provide reliable data of the sintering performance of the iron ore powder for sintering production;
(2) according to the method for detecting the assimilation temperature based on the iron ore powder temperature-electric signal curve, the iron ore powder sample is heated in the heating unit, the temperature detection component is used for detecting the temperature of the iron ore powder sample, the electric signal detection component is used for detecting the change condition of the electric signal of the iron ore powder sample in the heating process, the assimilation temperature of the iron ore powder is detected through the change of the electric signal in the heating process, and the accuracy of assimilation temperature detection can be improved;
(3) the method for detecting the assimilation temperature based on the iron ore powder temperature-electric signal curve detects the electric signal change condition of an iron ore powder sample in the temperature rising process by arranging a first electrode and a second electrode, instantly conducts a circuit when the assimilation reaction of the iron ore powder sample and a calcium oxide tablet occurs and a liquid phase is formed, judges the time of the assimilation reaction of the iron ore powder sample, and searches the temperature of the assimilation reaction of the iron ore powder sample through the time of the assimilation reaction of the iron ore powder sample, so that the assimilation temperature of the iron ore powder sample is accurately and objectively detected;
(4) according to the method for detecting the assimilation temperature based on the iron ore powder temperature-electric signal curve, at least one electrode of the first electrode or the second electrode is arranged in the calcium oxide pressing sheet, the time of iron ore powder assimilation reaction can be judged according to the numerical mutation of the resistance value, and the assimilation temperature of the iron ore powder is further judged, so that the detection accuracy is improved.
Drawings
FIG. 1 is a schematic view of the overall structure of the device for detecting the assimilation temperature of iron ore powder according to the present invention;
FIG. 2 is a schematic diagram of the structure of the calcium oxide pellet and the electrode;
FIG. 3 is a schematic diagram of a first electrode according to the present invention incorporated into a calcium oxide pellet;
FIG. 4 is a top view of the calcium oxide pellet of example 2;
FIG. 5 is a graph of temperature versus electrical signal for example 1;
FIG. 6 is a graph of temperature versus electrical signal for comparative example 1;
FIG. 7 is a schematic view of the structure of the detection unit and calcium oxide pellet of example 3;
FIG. 8 is a schematic view of the structure of the detection unit and the calcium oxide pellet of example 4.
The reference numerals in the schematic drawings illustrate:
100. a heating unit; 110. a support table; 120. a heating furnace body; 130. calcium oxide tabletting; 131. an electrode hole; 132. pressing the upper surface of the sheet;
200. a detection unit; 210. a temperature detection part; 211. a temperature measuring end; 220. an electric signal detection section; 221. a first electrode; 222. a second electrode; 223. a detection device;
300. a control processing unit;
400. and (4) iron ore powder samples.
Detailed Description
The following detailed description of exemplary embodiments of the invention refers to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration exemplary embodiments in which the invention may be practiced. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that various changes to the invention may be made without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the invention is not intended to limit the scope of the invention, as claimed, but is presented for purposes of illustration only and not limitation to describe the features and characteristics of the invention, to set forth the best mode of carrying out the invention, and to sufficiently enable one skilled in the art to practice the invention. Accordingly, the scope of the invention is to be limited only by the following claims.
The detailed description and exemplary embodiments of the invention will be better understood when read in conjunction with the appended drawings, where the elements and features of the invention are identified by reference numerals.
Example 1
In the method for detecting the assimilation temperature based on the iron ore powder temperature-electric signal curve, the electric signal and the temperature change condition of the iron ore powder sample 400 are detected in the temperature rising process, the relation between the electric signal and the temperature is determined, the temperature-electric signal curve of the iron ore powder sample 400 is drawn, a corresponding temperature value is searched according to the electric signal mutation of the curve, the assimilation temperature of the iron ore powder is obtained through detection, and particularly, the method for judging the assimilation temperature of the iron ore powder sample 400 by using the temperature-electric signal curve is creatively provided, so that the detection efficiency and the detection accuracy are greatly improved. The method comprises the following specific steps:
step one, equipment assembly
A. 2g CaO powder with a purity of 98.0% is weighed by balance and pressed into a piece in a convex bar die under a pressure of 20MPa
A grooved calcium oxide pellet 130.
B. The first electrode 221 with the diameter of 0.8mm is placed in a groove of the calcium oxide pressing sheet 130, calcium oxide powder is uniformly added into the groove, the first electrode 221 completely covers the lower portion of the calcium oxide powder, the calcium oxide powder is lightly pressed and smoothed to form an electrode hole 131, so that the first electrode 221 is installed in the electrode hole 131, the second electrode 222 is placed on the calcium oxide pressing sheet 130, in the embodiment, the first electrode 221 and the second electrode 222 are observed to be on the same line from a top view angle, it is ensured that the two electrodes are in an open circuit state, the first electrode 221 and the second electrode 222 are connected with a detection device 223, and the detection device 223 is used for detecting and collecting an electric signal of the iron ore powder sample 400.
Step two, sample preparation
A. The iron ore powder of the embodiment is MAC powder, the iron ore powder to be measured is ground into fine powder with the particle size of less than 0.147 mu m, wherein the passing rate of 200 meshes is 80%, and the iron ore powder is dried for 4 hours at 105 ℃ for standby; it should be noted that the iron ore powder does not need to be pressurized to prepare a sample, and only the iron ore powder is coated on the surface of the calcium oxide tablet 130, so that the iron ore powder sample 400 can better simulate the actual production process in the detection process; in the prior art, in order to observe the wetting angle between the iron ore powder sample 400 and the calcium oxide tabletting 130 by naked eyes or an image analysis system, the sample with a regular shape is prepared by pressurization, and the iron ore powder is not subjected to pressurization and sample preparation in the sintering process, so that the actual production process is difficult to effectively simulate by the conventional method, the technical bias of the prior art is broken through, and the accuracy of assimilation temperature detection is improved.
B. Covering the calcium oxide tabletting 130 with iron ore powder sample 400 powder, and fully contacting the calcium oxide tabletting 130 to ensure that the iron ore powder sample 400 is connected in series between the first electrode 221 and the second electrode 222;
step three, detecting the temperature of assimilation reaction
The heating unit 100 of the present embodiment heats up according to the set temperature rise curve and at N2The simulation experiment under the atmosphere comprises the following specific steps:
the room temperature is between 600 ℃, and the heating rate is 2.5 ℃/s;
the temperature is 600-1000 ℃, and the temperature rising speed is 3.3 ℃/s;
the temperature is 1000-1150 ℃, and the heating rate is 1.7 ℃/s;
1150-1280 ℃, and the heating rate is 1.1 ℃/s;
when the temperature detecting part 210 detects that the temperature rises to 1200 ℃, the time-dependent change of the electric signal and the time-dependent change of the temperature are recorded from 1200 ℃, the corresponding relation between the electric signal and the temperature is obtained through the time medium, and a temperature-electric signal curve of the iron ore powder sample 400 is drawn, as shown in fig. 5. Determining the temperature value of the corresponding coordinate axis according to the electric signal mutation of the electric signal and the temperature curve, determining the corresponding assimilation temperature as T-1226 ℃, and detecting to obtain the assimilation temperature of the iron ore powder. The sudden change of the electric signal and the temperature curve means that the electric signal is remarkably changed along with the change of the temperature, and a remarkable inflection point is formed on an image, so that the method is more visual and accurate. The sudden change of the resistance value refers to the change of the resistance value in the order of magnitude within 1-5 s, namely the change of the order of magnitude refers to the following steps: phi-n/￠m>100, wherein-nIs the resistance value at the temperature of n ℃ and has the unit of omega; phi-mMeans the resistance value at m ℃ in omega and m-n>1℃。
In this example, n ═ 1225 ℃, phin53000 Ω; m is 1226 deg.C and phi-n＝159Ω；￠n/￠m>100, this time, the time when the assimilation temperature occurred.
And the assimilation temperature detected by the method is 1230 ℃ by adopting Wu Shengli which is a test research on the assimilation capability of iron ore powder and CaO. Compared with the conventional detection method, the method improves the accuracy of assimilation temperature detection.
Referring to fig. 1, 2 and 3, the device for detecting the assimilation temperature of iron ore powder by using electric signals according to the present invention includes a heating unit 100 and a detecting unit 200, wherein the heating unit 100 is used for heating an iron ore powder sample 400, the heating unit 100 includes a heating furnace body 120, and the heating furnace body 120 may be an electric heating furnace, a microwave heating furnace or other heating furnaces, or may be a fuel heating furnace. The heating furnace body 120 is provided with a support table 110 therein, and the support table 110 is used for carrying the calcium oxide tablets 130. A calcium oxide tablet 130 is arranged in the heating unit 100, and the calcium oxide tablet 130 is used for bearing the iron ore powder sample 400. The support table 110 is located at the center of the heating furnace body 120. The heating unit 100 and the detection unit 200 are electrically connected with the control processing unit 300, the control processing unit 300 is used for controlling the temperature rise system of the heating unit 100, the control processing unit 300 can acquire the electric signal and the temperature signal detected by the detection unit 200, and the temperature-electric signal curve drawn by the control processing unit 300 can realize the online detection of the assimilation temperature, so that the detection efficiency and the detection accuracy are improved.
The detection unit 200 of the embodiment includes a temperature detection unit 210 and an electrical signal detection unit 220, the temperature detection unit 210 is used for detecting the temperature of the iron ore powder sample 400, and the temperature detection unit 210 may be a thermocouple or an infrared temperature measurement device, or other devices or instruments with temperature measurement function. In this embodiment, the temperature measuring end 211 of the temperature detecting component 210 is disposed right below the calcium oxide tablet 130, and the temperature measuring end 211 can effectively and rapidly detect the temperature of the iron ore powder sample 400 during assimilation reaction, so as to improve the detection accuracy.
The electric signal detection unit 220 is used for detecting the change of the electric signal of the iron ore powder sample 400 during the temperature rise. The resistance signal of the iron ore powder sample 400 detected in this embodiment may also be referred to as the resistance value of the iron ore powder sample 400. The electrical signal of the present embodiment may be a conductivity signal, a voltage signal, or a current signal.
The electric signal detection part 220 includes a first electrode 221, a second electrode 222, and a detection device 223; the detection device 223 is electrically connected to the first electrode 221 and the second electrode 222; and the first electrode 221 and the second electrode 222 are kept in a non-contact state, that is, the iron ore powder sample 400 is connected in series between the first electrode 221 and the second electrode 222 during the detection. The first electrode 221 and the second electrode 222 are made of high temperature resistant and inert platinum-rhodium wires, so that the wires do not melt at high temperature and do not react with gas.
It should be noted that at least one of the first electrode 221 and the second electrode 222 is disposed in the calcium oxide pellet 130, in this embodiment, the first electrode 221 is disposed in the calcium oxide pellet 130, and the second electrode 222 is disposed in the iron ore powder sample 400. That is, at least one of the first electrode 221 and the second electrode 222 is not directly contacted with the iron ore powder sample 400, so that the accuracy of experimental detection is improved.
The calcium oxide pellet 130 of this embodiment has at least one electrode hole 131, and the electrode hole 131 is used for accommodating the first electrode 221 or the second electrode 222. The calcium oxide tablet 130 of this embodiment is provided with an electrode hole 131, the electrode hole 131 is used for accommodating the first electrode 221, the second electrode 222 is placed on the upper surface 132 of the calcium oxide tablet 130, and the upper part of the second electrode 222 is covered with the iron ore powder sample 400. The method for judging the assimilation temperature of the iron ore powder through morphological observation is omitted, so that the step of preparing a sample by pressing the iron ore powder is omitted, and the accuracy of detecting the assimilation temperature of the iron ore powder is further improved.
As shown in fig. 3, the thickness of the top of the electrode hole 131 from the upper surface of the calcium oxide pellet 130 is δ, which can be calculated by the following formula:
delta is the thickness of the diffusion layer, mm; k is the reaction coefficient, kg/m3(ii) a D is the diffusion coefficient, m2S; rho is the density of the diffusion substance, kg/m3(ii) a λ is diffusion time, s.
k is generally 1.0-1.8, this value is 1.0;
d is 3.0 × 10-7-5.0×10-6In between, this example takes the value 5 × 10-7；
Rho, the density of the iron ore powder, is usually 4.5-4.9X 103kg/m3The density of the iron ore powder in this example is 4.61X 103kg/m3；
Regarding lambda, the temperature of solid phase reaction between iron ore powder and CaO is about 600 ℃, considering that diffusion is slow at low temperature, in this example, timing is started after 600 ℃, the actual effective diffusion time is usually between 300-360s according to different assimilation temperatures of iron ore powder, and 305s is taken in this example.
Comparative example 1
The basic content of this embodiment is the same as that of embodiment 1, except that the first electrode 221 and the second electrode 222 are both disposed in the iron ore powder sample 400, the electric signal and the temperature change of the iron ore powder sample 400 are detected during the temperature rising process, the relationship between the electric signal and the temperature is determined, and the temperature-electric signal curve of the iron ore powder sample 400 is plotted, as shown in fig. 6.
As shown in fig. 6, the resistance of the iron ore powder sample 400 detected during the temperature rise is continuously decreased, and before and after the iron ore powder and calcium oxide are subjected to assimilation reaction to form a calcium ferrite liquid phase, the resistance value does not change suddenly, and after the liquid phase appears, the resistance value is almost unchanged and fluctuates slightly; it is difficult to determine the timing of the assimilation of the iron ore powder by detecting the resistance mutation of the iron ore powder sample 400, and thus the assimilation temperature of the iron ore powder. The reasons for this may be: as the temperature increases to intensify molecular motion, the iron ore powder begins to develop a conductivity signal. When the temperature is increased to over 1200 ℃, the resistance value is gradually reduced to about 200 ohms when the position of the first electrode 221 or the second electrode 222 is not changed; with the further increase of the temperature, the resistance value of the detected iron ore powder sample 400 is continuously reduced, the whole reduction process is relatively uniform, resistance changes before and after a liquid phase is formed by measuring the assimilation reaction of the contact surface of the iron ore powder sample 400 and the calcium oxide tabletting 130 are only relied on, the time of the assimilation reaction of the iron ore powder is difficult to judge, and the assimilation temperature of the iron ore powder is also difficult to judge.
According to the invention, the first electrode 221 and the second electrode 222 are arranged, the electric signal change condition of the iron ore powder sample 400 is detected in the temperature rising process, the circuit is instantly conducted when the iron ore powder sample 400 and the calcium oxide tabletting 130 are subjected to the assimilation reaction and form a liquid phase, the time of the assimilation reaction of the iron ore powder sample 400 is judged, the temperature of the assimilation reaction of the iron ore powder sample 400 is searched through the time of the assimilation reaction of the iron ore powder sample 400, and the assimilation temperature of the iron ore powder sample 400 is accurately and objectively detected.
Particularly, the assimilation temperature of the iron ore powder is obtained by drawing a temperature-electric signal curve of the iron ore powder sample 400, searching a corresponding temperature value according to electric signal mutation of the curve, and detecting the assimilation temperature of the iron ore powder, so that the assimilation temperature of the iron ore powder is judged by observing deformation such as a wetting angle between the iron ore powder sample 400 and the calcium oxide tabletting 130 through naked eyes or an image analysis system, the assimilation temperature detection accuracy and the assimilation temperature detection efficiency are improved, and reliable data of the sintering performance of the iron ore powder are provided for sintering production; therefore, the defects caused by subjective observation are avoided, the time of iron ore powder assimilation reaction and the assimilation temperature of the iron ore powder are detected on line and visually, and the accuracy of iron ore powder assimilation temperature detection is improved.
Example 2
As shown in fig. 4, the basic content of this embodiment is different from that of embodiment 1 in that: the first electrode 221 and the second electrode 222 are arranged in parallel, the horizontal distance between the first electrode 221 and the second electrode 222 is d, d is less than or equal to R/2, in this embodiment, d is R/2, and R is the diameter of the accumulation surface of the iron ore powder sample 400 on the calcium oxide tablet 130. The first electrode 221 and the second electrode 222 penetrate through the calcium oxide tablet 130, so that the detection accuracy is improved, the change of an electric signal can be detected timely by assimilating the iron ore powder at one position, and the detection accuracy is improved. In this example, the thickness δ of the top of the electrode hole 131 from the upper surface of the calcium oxide pellet 130 was 0.2 to 2mm, and δ was 0.5mm in this example.
Example 3
As shown in fig. 7, the basic contents of this embodiment are different from those of embodiment 1 in that: in this embodiment, the first electrode 221 is disposed in the calcium oxide pellet 130, and the second electrode 222 is disposed in the iron ore powder sample 400. The detection unit 200 is located on the upper portion of the iron ore powder sample 400, the detection unit 200 is located right above the first electrode 221, and the temperature measurement end 211 of the detection unit 200 is close to the iron ore powder sample 400, so that the temperature measurement end 211 can timely and rapidly detect the temperature of the iron ore powder during assimilation reaction, and the detection accuracy is improved.
Example 4
As shown in fig. 8, the basic contents of this embodiment are different from those of embodiment 1 in that: the calcium oxide tablet 130 of this embodiment is provided with 2 electrode holes 131, the first electrode 221 is disposed in the electrode hole 131 of the calcium oxide tablet 130, the second electrode 222 is also disposed in the electrode hole 131 of the calcium oxide tablet 130, and the first electrode 221 and the second electrode 222 are disposed in parallel.
The detection unit 200 is located above the iron ore powder sample 400, the detection unit 200 is located right above the symmetry axis of the first electrode 221 and the second electrode 222, and the temperature measurement end 211 of the detection unit 200 is close to the iron ore powder sample 400, so that the temperature measurement end 211 can timely and rapidly detect the temperature of the iron ore powder during assimilation reaction, and the detection accuracy is improved.
The invention has been described in detail hereinabove with reference to specific exemplary embodiments thereof. It will, however, be understood that various modifications and changes may be made without departing from the scope of the invention as defined in the appended claims. The detailed description and drawings are to be regarded as illustrative rather than restrictive, and any such modifications and variations are intended to be included within the scope of the present invention as described herein. Furthermore, the background is intended to be illustrative of the state of the art as developed and the meaning of the present technology and is not intended to limit the scope of the invention or the application and field of application of the invention.
More specifically, although exemplary embodiments of the invention have been described herein, the invention is not limited to these embodiments, but includes any and all embodiments modified, omitted, combined, e.g., between various embodiments, adapted and/or substituted, as would be recognized by those skilled in the art from the foregoing detailed description. The limitations in the claims are to be interpreted broadly based the language employed in the claims and not limited to examples described in the foregoing detailed description or during the prosecution of the application, which examples are to be construed as non-exclusive. For example, in the present invention, the term "preferably" is not exclusive, and it means "preferably, but not limited to" herein. Any steps recited in any method or process claims may be executed in any order and are not limited to the order presented in the claims. The scope of the invention should, therefore, be determined only by the appended claims and their legal equivalents, rather than by the descriptions and examples given above.
Claims (8)
1. A method for detecting assimilation temperature based on iron ore powder temperature-electric signal curve is characterized in that: covering iron ore powder sample (400) powder on a calcium oxide tabletting (130) of a detection device, wherein the iron ore powder sample (400) is connected in series between a first electrode (221) and a second electrode (222); in the process of temperature rise, a detection unit (200) of the detection device detects the change situation of an electric signal of the iron ore powder sample (400) along with time and the change situation of temperature along with time, obtains the corresponding relation between the electric signal and the temperature through a time medium, and draws a temperature-electric signal curve of the iron ore powder sample (400); and searching for a corresponding temperature value according to the electric signal mutation of the curve, wherein the electric signal mutation refers to the magnitude order change of the electric signal within 1-5 s, and detecting to obtain the assimilation temperature of the iron ore powder.
2. The method for detecting assimilation temperature based on iron ore powder temperature-electric signal curve as claimed in claim 1, wherein the method comprises the following steps: the detection device comprises
A heating unit (100), wherein the heating unit (100) is used for heating the iron ore powder sample (400); and
the detection unit (200), the detection unit (200) includes the temperature detection part (210) and the electric signal detection part (220), the temperature detection part (210) is used for detecting the temperature of the iron ore powder sample (400); the electric signal detection component (220) is used for detecting the change condition of the electric signal of the iron ore powder sample (400) in the temperature rising process.
3. The method for detecting assimilation temperature based on iron ore powder temperature-electric signal curve as claimed in claim 2, wherein the method comprises the following steps: the electric signal detection part (220) comprises a first electrode (221), a second electrode (222) and a detection device (223); the detection device (223) is electrically connected with the first electrode (221) and the second electrode (222); and the first electrode (221) and the second electrode (222) are kept in a non-contact state, and at least one of the first electrode (221) and the second electrode (222) is arranged in the calcium oxide tabletting (130).
4. The method for detecting assimilation temperature based on iron ore powder temperature-electric signal curve as claimed in claim 3, wherein the method comprises the following steps: at least one electrode hole (131) is formed in the calcium oxide pressing sheet (130), and the electrode hole (131) is used for containing a first electrode (221) or a second electrode (222).
5. The method for detecting assimilation temperature based on iron ore powder temperature-electric signal curve as claimed in claim 4, wherein the method comprises the following steps: an electrode hole (131) is formed in the calcium oxide pressing sheet (130), the electrode hole (131) is used for containing a first electrode (221), and the second electrode is placed on the upper surface (132) of the calcium oxide pressing sheet (130).
6. The method for detecting assimilation temperature based on iron ore powder temperature-electric signal curve as claimed in claim 4 or 5, wherein the method comprises the following steps: the thickness of the electrode hole (131) from the upper surface of the calcium oxide tablet (130) is delta, and delta is 0.2-2 mm.
7. The method for detecting assimilation temperature based on iron ore powder temperature-electric signal curve as claimed in claim 4 or 5, wherein the method comprises the following steps: the thickness of the electrode hole (131) from the upper surface of the calcium oxide pellet (130) is delta, which is obtained by the following formula:
delta is the thickness of the diffusion layer, mm; k is the reaction coefficient, kg/m3(ii) a D is the diffusion coefficient, m2S; rho is the density of the diffusion substance, kg/m3(ii) a λ is diffusion time, s.
8. The method for detecting assimilation temperature based on iron ore powder temperature-electric signal curve as claimed in claim 4 or 5, wherein the method comprises the following steps: the electric signal is a conductivity or voltage signal or a current signal.
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