A calcination preparation process for high-quality spinel

Abstract

The present application relates to the technical field of spinel preparation, and specifically to a calcination preparation process for high-quality spinel, the process comprising: weighing 40-50% aluminum ash, 10-20% alumina, 40-50% iron-containing raw materials, 0.2-0.3% binder, and 2-3% high-carbon materials as main raw materials, weighing 0.2-0.3% organic fiber and organic microbeads of the total mass of the main raw materials, wherein the sum of the percentages of all main raw materials is one hundred percent; then ball milling, slurry stirring, slurry dehydration predrying, and extrusion molding are performed; the obtained brick preform is dried and calcined, and the temperature data of each data point at each time during the calcination process is collected, and the calcination quality sufficiency coefficient of all data points in each calcination quality monitoring interval is determined, and the temperature of the calcination treatment is adjusted, and insulation and room temperature cooling treatment are performed in sequence to obtain the finished iron-aluminum spinel. The present application improves the quality of iron-aluminum spinel.

Description

Technical Field

[0001] The present application relates to the technical field of spinel preparation, and in particular to a calcination preparation process for high-quality spinel. Background Art

[0002] As a synthetic high-quality fused spinel, ferroaluminum spinel is environmentally friendly and pollution-free, and has excellent thermal shock resistance and alkaline slag corrosion resistance. It is widely used in the field of refractory raw materials for rotary kiln firing zones. At present, the preparation of ferroaluminum spinel is usually sintering and fusion. The preparation of ferroaluminum spinel by sintering is easier to reduce preparation energy consumption and production costs, and is suitable for industrial large-scale production.

[0003] At present, in the process of preparing iron-aluminum spinel by sintering, the sintering quality of the spinel is usually evaluated based on the porosity, density and thermal shock stability of the finished spinel, and the sintering time or temperature in the spinel sintering process is adjusted based on this. However, the sintering time or temperature in the spinel sintering process is not adjusted in real time according to the temperature changes in different areas of the rotary kiln during the spinel preparation process, as well as the temperature changes between adjacent moments, which affects the quality of iron-aluminum spinel preparation. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a calcination preparation process for high-quality spinel to solve the existing problems.

[0005] The calcination preparation process of a high-quality spinel in the present application adopts the following technical scheme:

[0006] An embodiment of the present application provides a calcination preparation process for high-quality spinel, the method comprising the following steps:

[0007] (1) Weigh 40-50% by mass of aluminum ash, 10-20% by mass of alumina, 40-50% by mass of iron-containing raw materials, 0.2-0.3% by mass of a binder, and 2-3% by mass of a high-carbon material as main raw materials, and weigh 0.2-0.3% by mass of organic fibers and organic microbeads;

[0008] (2) All the raw materials in step (1) are fed together with tap water into a continuous ball mill for uniform ball milling to obtain slurry;

[0009] (3) Sending the slurry into the mixing tank for mixing;

[0010] (4) subjecting the slurry stirred evenly in step (3) to filter press dehydration to obtain a filter press mud cake, which is then dried;

[0011] (5) After drying, the mud cake is pressed to obtain a brick preform;

[0012] (6) The preformed brick body is further dried and then sent into a rotary kiln for calcination; the temperature data of each data point at each time during the calcination process are collected, and the calcination temperature difference of each data point at each time is determined based on the degree of disorder of all data points in the local window of each data point at each time, and the difference in temperature between each data point and all data points in its local window at each time; the temperature values ​​of all data points in the local window of each data point at each time are segmented by thresholds, and the data points with temperature values ​​less than or equal to the segmentation threshold are taken as suspected channel data points in the corresponding local window, and the metric distance between all suspected channel data points in the local window of each data point at each time and the central data point of the local window, as well as the difference between the temperature values ​​of any two suspected channel data points in the local window of each data point at each time, are analyzed to determine the channel quality factor of each data point at each time; the calcination quality factor of each data point at each time is determined by combining the calcination temperature difference and the channel quality factor;

[0013] Preset a calcination quality monitoring interval, calculate the difference between the calcination quality factor of each data point at each time and the adjacent time in each calcination quality monitoring interval, record it as the calcination difference, and determine the calcination stability of each data point in each calcination quality monitoring interval based on all the calcination differences of each data point in each calcination quality monitoring interval; for any calcination quality monitoring interval, the calcination quality factors of each data point at all times are combined into a calcination quality sequence of each data point, analyze the correlation between each data point and the calcination quality sequence of other data points in its local window, and determine the calcination quality sufficiency coefficient of all data points in each calcination quality monitoring interval in combination with the calcination stability;

[0014] adjusting the temperature of the calcination treatment according to the calcination quality sufficiency coefficient;

[0015] (7) After the calcination treatment is completed, the product is sequentially subjected to heat preservation and room temperature cooling treatment to obtain the finished product of iron-aluminum spinel.

[0016] In one embodiment, the components of the aluminum ash are Al: 10-15%, Al2O3: 45-55%, AlN: 20-30%, MgO: 5-10%, SiO2: 1-1.5%, and the fineness is 150-200 mesh; the aluminum oxide is one or both of γ-Al2O3 and Al(OH)3; the iron-containing raw material is one or more of Fe2O3, Fe3O4, and sponge iron powder;

[0017] The high-carbon material is flake graphite, the binder is one or more of calcium lignin sulfonate, sodium silicate, and polyvinyl alcohol; the organic fiber is polypropylene fiber, with an aspect ratio of 250-500 and a length of 0.05-0.08; the organic microbeads are one or both of polystyrene microbeads and glass microbeads, with a particle size of 0.5-0.6 mm.

[0018] In one embodiment, the ball milling time is 16-21 hours, the ratio of ball material to water is 1.6-1.8:0.8-1:1.2-1.5, and the ball milling speed frequency is 35-45 Hz.

[0019] In one embodiment, the stirring time is 120-180 min; the filtration pressure is 1.8-2.2 Mpa, the moisture content of the filter cake is 18-22%, the drying temperature is 90-110° C., and the moisture content of the dried cake is 6-10%.

[0020] In one embodiment, the molding pressure of the brick preform is 2Mpa; the temperature of the continued drying process is 100-130°C, and the drying moisture is 0.6-0.8%.

[0021] In one embodiment, the calcination quality factor is determined by:

[0022] Calculating the cumulative sum of the differences between the temperature of each data point at each moment and the temperature of all data points in its local window, wherein the calcination temperature difference is the product of the cumulative sum and the degree of disorder;

[0023] Calculate the mean of the metric distance, calculate the cumulative result of the difference between the temperature values ​​of all any two suspected channel data points in the local window of each data point at each time, calculate the sum of the cumulative result and a preset value greater than 0, the channel quality factor is the ratio of the mean to the sum; the calcination quality factor is the ratio of the channel quality factor to the calcination temperature difference.

[0024] In one embodiment, the calcination stability is the reciprocal of the sum of all the calcination differences of each data point in each calcination quality monitoring interval.

[0025] In one embodiment, the process of determining the calcination quality sufficiency coefficient is:

[0026] The addition result of the similarity between any data point and the calcination quality sequence of all data points in its local window is calculated, and the product of the addition result and the calcination stability of any data point is calculated and recorded as the first product. The normalized result of the sum of all the first products in each calcination quality monitoring interval is used as the calcination quality sufficiency coefficient.

[0027] In one embodiment, adjusting the temperature of the calcination process according to the calcination quality sufficiency coefficient includes:

[0028] If the calcination quality sufficiency coefficient of the current calcination quality monitoring interval is greater than or equal to the preset calcination quality sufficiency threshold, the calcination is stopped; otherwise, the calcination temperature is increased by a preset value and the calcination is continued until the condition for stopping the calcination is met.

[0029] In one embodiment, the insulation temperature is 150-550°C, and the insulation time is 1-3h; the room temperature cooling temperature is 15-45°C.

[0030] This application has at least the following beneficial effects:

[0031] The present application collects temperature data of each data point at each moment in the calcination process of a brick preform, and determines the calcination quality factor of each data point at each moment based on the distribution of temperature data of all data points in a local window of each data point at each moment, and the difference in temperature data between each data point and other data points in its local window; the calcination quality factor lays the foundation for real-time evaluation of the calcination quality of the brick preform, comprehensively considers the heating uniformity and pore collapse characteristics of the brick preform, and more accurately quantifies the calcination quality at the position of each data point; a calcination quality monitoring interval is preset, and the calcination stability of each data point in each calcination quality monitoring interval is determined based on the difference between the temperature data of each data point at adjacent moments in the calcination quality monitoring interval. degree; analyzing the time series correlation between the temperature data of each data point and other data points in its local window, and determining the sufficiency coefficient of the sintering quality of all data points in each sintering quality monitoring interval in combination with the sintering stability; the sufficiency coefficient of the sintering quality adds consideration of the similarity of the sintering quality within the neighborhood range on the basis of analyzing the temperature difference and the stability of the pore change during the sintering of the brick preform, and more accurately reflects the sufficiency of the sintering quality of the spinel with the thermal seismic characteristics of the brick preform; adjusting the temperature of the sintering treatment according to the sufficiency coefficient of the sintering quality; improving the accuracy of parameter control during the sintering process, thereby improving the sufficiency of the sintering of the brick preform and the quality of the final ferroaluminum spinel preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1A flow chart of the steps of a calcination preparation process of high-quality spinel provided in this application;

[0034] Figure 2 This is a schematic diagram of the calcination quality factor mapping at time t1;

[0035] Figure 3 This is a schematic diagram of the calcination quality factor mapping at time t2;

[0036] Figure 4 This is a schematic diagram of calcination quality factor mapping at time t3;

[0037] Figure 5 Flow chart for temperature adjustment of calcination treatment. DETAILED DESCRIPTION

[0038] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of the calcination preparation process of a high-quality spinel proposed in the present application, its specific implementation method, structure, characteristics and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0039] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0040] The specific scheme of the calcination preparation process of a high-quality spinel provided in the present application is described in detail below with reference to the accompanying drawings.

[0041] An embodiment of the present application provides a calcination preparation process for high-quality spinel. Specifically, the following calcination preparation process for high-quality spinel is provided. Please refer to Figure 1 , the process comprises the following steps:

[0042] (1) Weighing of raw materials

[0043] In Example 1 of the present application, 40% aluminum ash, 10% alumina, 40% iron-containing raw material, 0.2% binder, and 2% high-carbon material with a mass fraction were weighed as main raw materials, and 0.2% of the total mass of the main raw materials was weighed. The organic fiber and organic microbeads were weighed in a ratio of 1:1;

[0044] The components of aluminum ash are Al: 10%, Al2O3: 45%, AlN: 20%, MgO: 5%, SiO2: 1%, and the fineness is 150 mesh; the alumina is γ-Al2O3; the iron-containing raw material is Fe2O3; the high-carbon material is flake graphite, which can improve the reduction degree of the iron-containing raw material; the binder is calcium lignin sulfonate; the organic fiber is polypropylene fiber; the organic microbeads are polystyrene microbeads, the aspect ratio of the organic fiber is 250, the length is 0.05, and the particle size of the organic microbeads is 0.5mm. The role of the organic fiber and the organic microbeads is that they can be melted to form micropores and microchannels during high-temperature calcination, which is conducive to the passage of water vapor between the micropores and microchannels, releasing the internal pressure of the spinel, and improving the explosion-proof performance of the spinel.

[0045] In Example 2 of the present application, 45% of aluminum ash, 15% of aluminum oxide, 45% of iron-containing raw materials, 0.25% of binder, and 2.5% of high-carbon material were weighed as main raw materials, and 0.25% of the total weight of the main raw materials was weighed. The organic fiber and organic microbeads were weighed in a ratio of 1:1;

[0046] Among them, the components of aluminum ash are Al: 13%, Al2O3: 50%, AlN: 25%, MgO: 8%, SiO2: 1.25%, and the fineness is 175 mesh; the alumina is Al(OH)3; the iron-containing raw materials are Fe2O3 and Fe3O4; the high-carbon material is flake graphite; the binder is calcium lignin sulfonate and sodium silicate; the organic fiber is polypropylene fiber; the organic microbeads are glass microbeads, the aspect ratio of the organic fiber is 375, the length is 0.06, and the particle size of the organic microbeads is 0.55mm.

[0047] In Example 3 of the present application, 50% aluminum ash, 20% aluminum oxide, 50% iron-containing raw material, 0.3% binder, and 3% high-carbon material were weighed as main raw materials, and 0.3% of the total weight of the main raw materials was weighed. The organic fiber and organic microbeads were weighed in a ratio of 1:1;

[0048] Among them, the components of aluminum ash are Al: 15%, Al2O3: 55%, AlN: 30%, MgO: 10%, SiO2: 1.5%, and the fineness is 200 mesh; alumina is γ-Al2O3 and Al(OH)3; the iron-containing raw materials are Fe3O4 and sponge iron powder; the high-carbon material is flake graphite; the binder is polyvinyl alcohol and sodium silicate; the organic fiber is polypropylene fiber; the organic microbeads are polystyrene microbeads and glass microbeads, the aspect ratio of the organic fiber is 500, the length is 0.08, and the particle size of the organic microbeads is 0.6mm.

[0049] (2) Ball milling

[0050] All the raw materials in step (1) are sent together with tap water to a continuous ball mill for uniform grinding and refining. The purpose of using a continuous ball mill is to enable uninterrupted feeding and discharging of materials, which is suitable for continuous production;

[0051] In Example 1 of the present application, the ball milling time is 16 hours, until the ball milling particle size of 25 μm particles accounts for 94%, the ratio of ball material to water is 1.6:0.8:1.2, and the ball milling speed frequency is 35 Hz; ball milling uniform refinement can obtain ultrafine particle size materials, reduce the subsequent strict requirements on calcination temperature, and reduce preparation energy consumption.

[0052] In Example 2 of the present application, the ball milling time is 18 hours, until the ball milling particles with a particle size of 27 μm account for 95%, the ratio of ball material to water is 1.7:0.9:1.3, and the ball milling speed frequency is 40 Hz.

[0053] In Example 3 of the present application, the ball milling time is 21 hours, until the ball milling particles with a particle size of 30 μm account for 96%, the ratio of ball material to water is 1.8:1:1.5, and the ball milling speed frequency is 45 Hz.

[0054] (3) Slurry stirring

[0055] The slurry uniformly refined by ball milling in step (2) is sent into a stirring tank for stirring;

[0056] In Example 1 of the present application, the stirring time is 120 min.

[0057] In Example 2 of the present application, the stirring time is 150 min.

[0058] In Example 3 of the present application, the stirring time is 180 min.

[0059] (4) Slurry dehydration and pre-drying

[0060] The slurry stirred evenly in step (3) is subjected to filter pressing and dehydration treatment to obtain a filter pressing mud cake, and the filter pressing and dehydration mud cake is sent to a belt dryer for drying treatment;

[0061] In Example 1 of the present application, the filter pressing pressure is 1.8 MPa, and the moisture content of the filter cake is 18%; the pre-drying temperature is 90°C, and the moisture content of the pre-dried mud cake is controlled at 6%. The pre-drying temperature is lower than the melting point of the organic fiber and the organic microbeads, and is only used to remove excess moisture in the mud cake.

[0062] In Example 2 of the present application, the filter pressing pressure is 2 MPa, and the moisture content of the filter pressing mud cake is 20%; the pre-drying temperature is 100° C., and the moisture content of the mud cake after pre-drying is controlled at 8%.

[0063] In Example 3 of the present application, the filter press pressure is 2.2 MPa, and the moisture content of the filter press mud cake is 22%; the pre-drying temperature is 110° C., and the moisture content of the mud cake after pre-drying is controlled at 10%.

[0064] (5) Extrusion molding

[0065] The mud cake that has been pre-dried in step (4) is sent to a brick press for pressing to obtain a brick preform. The molding pressure of the brick preform is 2 MPa.

[0066] (6) Drying and calcining of prefabricated bricks

[0067] In Example 1 of the present application, the brick preform obtained in step (5) is dried in a belt dryer at 100° C., so that the drying moisture content of the brick is controlled at 0.6%.

[0068] In Example 2 of the present application, the brick preform obtained in step (5) is dried in a belt dryer at 120° C., so that the drying moisture content of the brick preform is controlled at 0.7%.

[0069] In Example 3 of the present application, the brick preform obtained in step (5) is dried in a belt dryer at 130° C., so that the drying moisture content of the brick preform is controlled at 0.8%.

[0070] The dried brick preform is sent to a rotary kiln for calcination, which is divided into two steps: early calcination and late calcination.

[0071] In Example 1 of the present application, the temperature of the initial calcination is 330° C. and the calcination time is 30 min, which is used to melt the organic fibers and the organic microbeads to form microchannels and micropores.

[0072] In Example 2 of the present application, the temperature of the initial calcination is 350° C. and the calcination time is 50 min.

[0073] In Example 3 of the present application, the temperature of the initial calcination is 360° C. and the calcination time is 60 min.

[0074] The temperature of the later calcination is between 1350-1550℃. The calcination parameters in the later calcination process are adjusted as follows:

[0075] Step S001, collecting temperature data of each data point at each time of the brick preform in the rotary kiln during the calcination process.

[0076] In order to conduct real-time quantitative evaluation of the pore quality characteristics and thermal shock stability characteristics of the brick preform during the calcination process, and further accurately evaluate the calcination quality, this embodiment acquires the temperature data of the spinel calcination process through the data acquisition module in the SCADA (Supervisory Control And Data Acquisition) system. The specific acquisition method is: a high-temperature resistant infrared probe is placed on the top of the rotary kiln, and the temperature information of the brick preform during the calcination process is collected in real time from a bird's-eye view. In this embodiment, the time interval for temperature information collection is 30s, which can be set by the implementer according to actual conditions. This embodiment does not limit it here. The calcination temperature data at each data point of the brick preform is obtained by an infrared thermal imager, and the temperature data at all data points at each moment are combined into a calcination temperature matrix at each moment.

[0077] The calcination temperature matrix at each moment during the spinel calcination process is transmitted to the data statistical analysis module of the SCADA system for subsequent quantitative evaluation of the pore quality and thermal shock stability. The SCADA system is a known technology and will not be described in detail in this embodiment.

[0078] Step S002, determining the calcination quality factor of each data point at each moment based on the distribution of temperature data of all data points in the local window of each data point at each moment and the difference in temperature data between each data point and other data points in its local window.

[0079] During the calcination process of the brick preform after drying, the better the calcination quality of the spinel, the more uniform the material is heated, and the more uniform its thermal stress distribution will be. Specifically, in the calcination temperature matrix, it is manifested as: the degree of heating within the neighborhood of the data point is uniform, and the temperature difference between the edge and the center is small.

[0080] Based on the above analysis, the calcination temperature matrix at any moment is taken as an example for subsequent analysis, and a local window is constructed with each data point in the calcination temperature matrix as the center. In this embodiment, the local window size is 7×7, and the implementer can set it according to the actual situation. This embodiment is not limited here. For the calcination temperature difference of the central data point in any local window, the degree of confusion of all data points in the local window of each data point at each moment is calculated, and the cumulative sum of the differences between the temperatures of each data point at each moment and all data points in its local window is calculated, and the product of the cumulative sum and the degree of confusion is used as the calcination temperature difference of each data point at each moment.

[0081] It should be noted that the degree of disorder can be calculated by information entropy, standard deviation, etc., and this embodiment uses information entropy as the calculation method for the degree of disorder; the temperature difference can be calculated by the absolute value of the difference, the ratio, the square of the difference, etc., and this embodiment uses the absolute value of the difference as the calculation method for the difference.

[0082] In this embodiment, the specific calculation method of the calcination temperature difference of each data point at each time is:

[0083] ;in, is the calcination temperature difference of the i-th data point at any time; is the information entropy of the temperature values ​​of all data points in the local window of the i-th data point at any time; is the cumulative sum of the absolute values ​​of the temperature differences between the ith data point at any moment and all the data points in its local window;

[0084] When the calcination quality of the brick preform is better during the calcination process, the material is heated more evenly, the temperature difference between the edge and the center is smaller, the calcination temperature difference is smaller, the information entropy of all data points in the local window is smaller, and the temperature difference between the central data point corresponding to the local window and all other data points is smaller.

[0085] Since organic fibers and organic microbeads melt during the calcination process to form micropores and microchannels, and since the thermal conductivity of gas is lower than that of solid materials, the temperature of the micropore and microchannel area is lower than that of the spinel material area. The presence of micropores and microchannels can reduce the overall thermal conductivity of the spinel material, and at the same time facilitate the passage of water vapor between the micropores and microchannels, releasing the internal pressure of the spinel. When the calcination quality of the brick preform is better, the distribution of micropores and microchannels in the spinel material is more uniform, and the collapse of the channels caused by uneven heating during the calcination process is less obvious, that is, the temperature difference between the channels is smaller.

[0086] Therefore, it is necessary to divide the suspected channel area in the local window, that is, the temperature cold spot area, and analyze its temperature difference characteristics, take the temperature values ​​of all data points in each local window at each moment as input, and use the OTSU method to obtain the segmentation threshold of the temperature values ​​of all data points in each local window, and record all data points in each local window whose temperature values ​​are less than or equal to the segmentation threshold, that is, the temperature cold spot, as the suspected channel data points in each local window. Among them, the OTSU method is an existing well-known technology, and the implementer can select other existing threshold segmentation algorithms according to actual conditions, and this embodiment does not limit it here.

[0087] Calculate the pore quality factor of each data point at each time. The specific calculation method is:

[0088] ;in, is the pore quality factor of the i-th data point at any time; is the average value of the Euclidean distances between all suspected pore data points and the i-th data point in the local window of the i-th data point at any time, is the cumulative result of the absolute value of the difference between the temperature values ​​of all any two suspected pore data points in the local window of the i-th data point at any time; is a preset value greater than 0. The value is 0.1 to prevent the denominator from being 0. The implementer can set it according to the actual situation, and this embodiment does not limit it here;

[0089] When the sintering quality of the brick preform is better, the pore quality factor inside the spinel material is larger, and the temperature difference between the pores is smaller, that is, the distribution of the suspected pore data points in the local window is more discrete, and the average Euclidean distance between all the suspected pore data points and the central data point in the local window is larger; and the pore collapse phenomenon caused by uneven heating in the local window is less obvious, that is, the temperature difference between all the suspected pore data points is smaller.

[0090] The calcination quality factor of each data point at each moment can be determined by the calcination temperature difference and the pore quality factor. Specifically, in this real-time example, the calcination quality factor of each data point at each moment is the ratio of the pore quality factor of each data point at each moment to the calcination temperature difference. When the calcination temperature difference is 0, the pore quality factor is used as the calcination quality factor at the corresponding moment.

[0091] When the calcination quality of the brick preform is better, the spinel material is heated more evenly and the temperature difference between the edge and the center is smaller; the pore distribution formed by the melting of organic fibers and organic microbeads is more uniform and the temperature difference between the pores is smaller, that is, the smaller the calcination temperature difference is, the larger the pore quality factor is.

[0092] Step S003, presetting a calcination quality monitoring interval, determining the calcination stability of each data point in each calcination quality monitoring interval based on the difference between the temperature data of each data point at adjacent moments in the calcination quality monitoring interval; analyzing the time series correlation between the temperature data of each data point and other data points in its local window, and determining the calcination quality sufficiency coefficient of all data points in each calcination quality monitoring interval in combination with the calcination stability.

[0093] When the calcination quality of the brick preform is better, the thermal conductivity of the spinel material is lower, the thermal shock stability is stronger, and when it is used as a refractory material for the rotary kiln firing zone, it is more conducive to reducing heat loss, improving the thermal efficiency of the rotary kiln, and reducing the thermal stress inside the spinel material. Specifically, in the calcination temperature matrix, it is manifested as: within a certain time range, the temperature difference change in the neighborhood range of each position of the brick preform and the change of the channel quality are slower.

[0094] Figure 2 This is a schematic diagram of the mapping of calcination quality factors of some data points in the calcination temperature matrix at time t1 during the calcination process of the brick preform. The specific mapping process is: mapping the calcination quality factors of all data points in the calcination temperature matrix at time t1 within the range of [0,1] to obtain a schematic diagram of the mapping of calcination quality factors.

[0095] Figure 3 is the calcination temperature matrix at time t2 during the calcination of the brick preform Figure 2 Schematic diagram of calcination quality factor mapping for data points at the same position, Figure 3 and Figure 2 In comparison, the temperature difference changes slowly and steadily, and the pore quality changes slowly and steadily; Figure 4 is the calcination temperature matrix at time t3 during the calcination of the brick preform Figure 2 Schematic diagram of calcination quality factor mapping for data points at the same position, Figure 4 and Figure 2 In comparison, the temperature difference changes rapidly, and the pore quality changes rapidly, indicating that the calcination quality of the brick preform is improved at time t3 compared to time t1, but the temperature difference and the pore quality change rapidly, and sufficient calcination treatment is still required to stabilize the calcination of the brick preform, thereby improving the thermal shock stability of the spinel. In this embodiment, t1=100, t2=120, and t3=110.

[0096] Based on the above analysis, this embodiment sets every 1 hour as a calcination quality monitoring interval, and the implementer can set it according to the actual situation, and this embodiment does not limit it here. For each data point in any calcination quality monitoring interval, the calcination stability can be calculated as follows:

[0097] ;in, is the calcination stability of the i-th data point in any calcination quality monitoring interval; is the total number of moments in any calcination quality monitoring interval; , are the calcination quality factors of the i-th data point at the t-th and t-1-th moments in any calcination quality monitoring interval, respectively;

[0098] The better the calcination quality of the brick preform, the stronger the thermal shock stability of the spinel material, the slower the temperature difference change and the pore quality change at adjacent moments within a certain time range, that is, the smaller the cumulative absolute value of the difference between the calcination quality factor at each moment and the previous moment within the calcination quality monitoring interval, the greater the calcination stability.

[0099] The sequence of calcination quality factors of each data point in any calcination quality monitoring interval in a time series order is used as the calcination quality sequence of each data point in any calcination quality monitoring interval. The calcination quality sufficiency coefficient of each data point in any calcination quality monitoring interval can be calculated as follows:

[0100] ; Wherein, D is the calcination quality sufficiency coefficient of any calcination quality monitoring interval; is the total number of data points in the calcination temperature matrix; is the cumulative result of the cosine similarity between the ith data point in any calcination quality monitoring interval and the calcination quality sequence of all data points in its local window; Norm[] is a normalization function that makes the value range of the calcination quality sufficiency coefficient D within the range of [0,1].

[0101] When the calcination quality of the brick preform is higher, the thermal shock stability of the spinel material is stronger, the calcination stability is greater, the temperature difference change at adjacent moments within a certain time range and the channel quality change are slower, and the temperature difference change and the channel quality change within the neighborhood range of the spinel material are more similar, the calcination quality sufficiency coefficient is larger, that is, the thermal shock stability is stronger, and the cumulative result of the cosine similarity is larger.

[0102] Step S004, adjusting the temperature of the brick preform calcination treatment according to the calcination quality sufficiency coefficient of all data points in each calcination quality monitoring interval.

[0103] The sufficient sintering quality threshold of the early warning management module in the SCADA system is set to W, and the sufficient sintering quality coefficient of each sintering quality monitoring interval is transmitted to the early warning management module in the SCADA system. If the sufficient sintering quality coefficient of the current sintering quality monitoring interval is greater than or equal to the sufficient sintering quality threshold W, it is determined that the sintering quality of the brick preform has reached a sufficient state at this time, and the state information is sent to the control instruction issuing module in the SCADA system to stop the sintering treatment of the brick preform; if the sufficient sintering quality coefficient of the current sintering quality monitoring interval is less than the sufficient sintering quality threshold W, it is determined that the sintering treatment of the brick preform is insufficient at this time, and the brick preform still needs to continue sintering to further improve the sintering quality to obtain high-quality spinel, and the insufficient sintering treatment information is sent to the control instruction issuing module in the SCADA system, so that the rotary kiln increases the sintering temperature by H℃ until the sufficient sintering quality coefficient obtained in real time by the SCADA system is greater than or equal to the sufficient sintering quality threshold, and then the sintering is stopped. In this embodiment, the calcination quality sufficient threshold W is 0.6, H=50, and the implementer can set it according to the actual situation. This embodiment does not limit it. It should be noted that if the calcination quality sufficient coefficient obtained in real time is still less than the calcination quality sufficient threshold when the calcination temperature reaches 1550℃, the calcination time of one calcination quality monitoring interval will be extended. The calcination treatment temperature adjustment flow chart is as follows Figure 5 shown.

[0104] (7) Insulation and cooling

[0105] After the brick preform is calcined, it is sequentially subjected to heat preservation and room temperature cooling treatments to obtain the iron-aluminum spinel finished product.

[0106] In Example 1 of the present application, the insulation temperature is 150°C, and the insulation time is 1h; the room temperature cooling temperature is 15°C.

[0107] In Example 2 of the present application, the insulation temperature is 350°C, and the insulation time is 2h; the room temperature cooling temperature is 30°C.

[0108] In Example 3 of the present application, the insulation temperature is 550°C, and the insulation time is 3 hours; the room temperature cooling temperature is 45°C.

[0109] Comparative Example 1

[0110] The temperature of the late calcination in step (6) was kept constant at 1450°C, and the other preparation parameters and steps were the same as those in Example 1 of the present application to obtain spinel.

[0111] The spinels prepared in the examples and comparative examples were subjected to performance tests, and the test results are shown in Table 1.

[0112] Table 1 Performance test results

[0113]

[0114] It can be seen from Table 1 that the spinel prepared in this embodiment has higher compressive strength, lower thermal conductivity and higher thermal shock stability.

[0115] It should be noted that the above sequence of the embodiments of the present application is for description only and does not represent the advantages and disadvantages of the embodiments. The above is a description of a specific embodiment of this specification. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0116] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0117] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Modifications to the technical solutions recorded in the aforementioned embodiments, or equivalent replacement of some of the technical features therein, do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A calcination preparation process for high-quality spinel, characterized in that: The process includes the following steps: (1) Weigh 40-50% by mass of aluminum ash, 10-20% by mass of aluminum oxide, 40-50% by mass of iron-containing raw materials, 0.2-0.3% by mass of a binder, and 2-3% by mass of a high-carbon material as main raw materials, and weigh 0.2-0.3% by mass of organic fibers and organic microbeads, wherein the total percentage of all main raw materials is 100%; (2) All the raw materials in step (1) are fed together with tap water into a continuous ball mill for uniform ball milling to obtain slurry; (3) Sending the slurry into the mixing tank for mixing; (4) subjecting the slurry stirred evenly in step (3) to filter press dehydration to obtain a filter press mud cake, which is then dried; (5) After drying, the mud cake is pressed to obtain a brick preform; (6) The preformed brick body is further dried and then sent into a rotary kiln for calcination; the temperature data of each data point at each time during the calcination process are collected, and the calcination temperature difference of each data point at each time is determined based on the degree of disorder of all data points in the local window of each data point at each time, and the difference in temperature between each data point and all data points in its local window at each time; the temperature values ​​of all data points in the local window of each data point at each time are segmented by thresholds, and the data points with temperature values ​​less than or equal to the segmentation threshold are taken as suspected channel data points in the corresponding local window, and the metric distance between all suspected channel data points in the local window of each data point at each time and the central data point of the local window, as well as the difference between the temperature values ​​of any two suspected channel data points in the local window of each data point at each time, are analyzed to determine the channel quality factor of each data point at each time; the calcination quality factor of each data point at each time is determined by combining the calcination temperature difference and the channel quality factor; Preset a calcination quality monitoring interval, calculate the difference between the calcination quality factor of each data point at each time and the adjacent time in each calcination quality monitoring interval, record it as the calcination difference, and determine the calcination stability of each data point in each calcination quality monitoring interval based on all the calcination differences of each data point in each calcination quality monitoring interval; for any calcination quality monitoring interval, the calcination quality factors of each data point at all times are combined into a calcination quality sequence of each data point, analyze the correlation between each data point and the calcination quality sequence of other data points in its local window, and determine the calcination quality sufficiency coefficient of all data points in each calcination quality monitoring interval in combination with the calcination stability; adjusting the temperature of the calcination treatment according to the calcination quality sufficiency coefficient; (7) After the calcination treatment is completed, the product is sequentially subjected to heat preservation and room temperature cooling treatment to obtain the finished product of iron-aluminum spinel; The determination process of the calcination quality factor is: Calculating the cumulative sum of the differences between the temperature of each data point at each moment and the temperature of all data points in its local window, wherein the calcination temperature difference is the product of the cumulative sum and the degree of disorder; Calculate the mean of the metric distance, calculate the cumulative result of the difference between the temperature values ​​of all any two suspected channel data points in the local window of each data point at each time, calculate the sum of the cumulative result and a preset value greater than 0, and the channel quality factor is the ratio of the mean to the sum; The calcination quality factor is the ratio of the pore quality factor to the calcination temperature difference; The calcination stability is the reciprocal of the sum of all the calcination differences of each data point in each calcination quality monitoring interval; The determination process of the calcination quality sufficient coefficient is: Calculate the sum of similarities between any data point and the calcination quality sequences of all data points in its local window, calculate the product of the sum and the calcination stability of any data point, record it as a first product, and normalize the sum of all the first products in each calcination quality monitoring interval as the calcination quality sufficiency coefficient; The step of adjusting the temperature of the calcination process according to the calcination quality sufficient coefficient comprises: If the calcination quality sufficiency coefficient of the current calcination quality monitoring interval is greater than or equal to the preset calcination quality sufficiency threshold, the calcination is stopped; otherwise, the calcination temperature is increased by a preset value and the calcination is continued until the condition for stopping the calcination is met.

2. The calcination preparation process of a high-quality spinel according to claim 1, characterized in that: The components of the aluminum ash are Al: 10-15%, Al2O3: 45-55%, AlN: 20-30%, MgO: 5-10%, SiO2: 1-1.5%, and the fineness is 150-200 mesh; the aluminum oxide is one or both of γ-Al2O3 and Al(OH)3; the iron-containing raw material is one or more of Fe2O3, Fe3O4, and sponge iron powder; The high-carbon material is flake graphite, the binder is one or more of calcium lignin sulfonate, sodium silicate, and polyvinyl alcohol; the organic fiber is polypropylene fiber, with an aspect ratio of 250-500 and a length of 0.05-0.08; the organic microbeads are one or both of polystyrene microbeads and glass microbeads, with a particle size of 0.5-0.6 mm.

3. The calcination preparation process of a high-quality spinel according to claim 1, characterized in that: The ball milling time is 16-21 hours, the ratio of ball material to water is 1.6-1.8:0.8-1:1.2-1.5, and the ball milling speed frequency is 35-45 Hz.

4. The calcination preparation process of a high-quality spinel according to claim 1, characterized in that: The stirring time is 120-180 minutes; the filtration pressure is 1.8-2.2Mpa, the moisture content of the filter cake is 18-22%, the drying temperature is 90-110°C, and the moisture content of the dried cake is 6-10%.

5. The calcination preparation process of a high-quality spinel according to claim 1, characterized in that: The molding pressure of the brick preform is 2Mpa; the temperature of the continued drying treatment is 100-130°C, and the drying moisture is 0.6-0.8%.

6. The calcination preparation process of a high-quality spinel according to claim 1, characterized in that: The temperature of the insulation is 150-550°C, and the insulation time is 1-3h; the temperature of the room temperature cooling is 15-45°C.

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