CN111337753A - Method for adjusting dielectric constant of high-calcium magnesium titanium concentrate under microwave heating condition - Google Patents
Method for adjusting dielectric constant of high-calcium magnesium titanium concentrate under microwave heating condition Download PDFInfo
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- 239000012141 concentrate Substances 0.000 title claims abstract description 160
- 229910052719 titanium Inorganic materials 0.000 title claims abstract description 152
- 239000010936 titanium Substances 0.000 title claims abstract description 152
- 238000010438 heat treatment Methods 0.000 title claims abstract description 39
- 238000000034 method Methods 0.000 title claims abstract description 34
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 141
- 238000009826 distribution Methods 0.000 claims abstract description 9
- 230000001105 regulatory effect Effects 0.000 claims abstract description 5
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 14
- 230000000694 effects Effects 0.000 claims description 12
- 238000002474 experimental method Methods 0.000 claims description 12
- 238000001704 evaporation Methods 0.000 claims description 9
- 230000008020 evaporation Effects 0.000 claims description 9
- ZBRDCOZOFFMPNX-UHFFFAOYSA-N [Ti].[Mg].[Ca] Chemical compound [Ti].[Mg].[Ca] ZBRDCOZOFFMPNX-UHFFFAOYSA-N 0.000 claims description 8
- 238000001035 drying Methods 0.000 claims description 6
- 238000012417 linear regression Methods 0.000 claims description 6
- 238000005303 weighing Methods 0.000 claims description 6
- 230000005540 biological transmission Effects 0.000 claims description 3
- 238000004364 calculation method Methods 0.000 claims description 3
- 238000003795 desorption Methods 0.000 claims description 3
- 238000009792 diffusion process Methods 0.000 claims description 3
- 239000012153 distilled water Substances 0.000 claims description 3
- 238000001179 sorption measurement Methods 0.000 claims description 3
- 239000002352 surface water Substances 0.000 claims description 3
- 238000009529 body temperature measurement Methods 0.000 abstract description 2
- 239000000523 sample Substances 0.000 description 14
- 230000005855 radiation Effects 0.000 description 9
- 239000013307 optical fiber Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 239000000835 fiber Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 238000009828 non-uniform distribution Methods 0.000 description 1
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
- G01R27/2617—Measuring dielectric properties, e.g. constants
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- G01N1/44—Sample treatment involving radiation, e.g. heat
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3554—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for determining moisture content
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Abstract
The invention relates to a method for adjusting the dielectric constant of high-calcium magnesium titanium concentrate under the microwave heating condition, belonging to the technical field of microwave heating devices. According to the measured local water content and temperature, calculating dielectric coefficient values of different temperature measurement points of the heated high-calcium-magnesium-titanium concentrate, and combining a balanced water content model and an expected dielectric coefficient to further obtain water required by the high-calcium-magnesium-titanium concentrate to reach the expected dielectric coefficient value; the moisture of different parts of the high-calcium magnesium titanium concentrate is regulated, so that the aim of uniformly distributing the dielectric properties of the high-calcium magnesium titanium concentrate in the microwave heating process is fulfilled, and the temperature distribution uniformity is improved; meanwhile, the method can be used for improving the heating efficiency of the high-calcium magnesium titanium concentrate.
Description
Technical Field
The invention relates to a method for adjusting the dielectric constant of high-calcium magnesium titanium concentrate under the microwave heating condition, belonging to the technical field of microwave heating devices.
Background
In the microwave heating process, the temperature control of the heated material is very important, and the essential problem of controlling the temperature change of the material in a microwave field is to control the dielectric coefficient change of the material. Due to the fact that the distribution of the electromagnetic field in the microwave cavity is not uniform, the dielectric property of the material is anisotropic, and the temperature and the water content of the heated material are in a non-uniform distribution state.
Disclosure of Invention
The invention provides a method for adjusting the dielectric constant of high-calcium magnesium titanium concentrate under the microwave heating condition.
The technical scheme of the invention is as follows: a method for adjusting the dielectric constant of high-calcium magnesium titanium concentrate under the microwave heating condition comprises the following steps:
determining the initial water content of the high-calcium magnesium titanium concentrate;
calculating the water loss of the high-calcium magnesium titanium concentrate in real time in the microwave heating process;
calculating the dielectric coefficients of the heated high-calcium magnesium titanium concentrate at different temperature measuring points in real time according to the measured current water content and temperature of the high-calcium magnesium titanium concentrate and the relational expression between the dielectric coefficient of the high-calcium magnesium titanium concentrate and the temperature and the water content;
obtaining water required for the high-calcium magnesium titanium concentrate to reach the expected dielectric coefficient according to the balanced water content model and the expected dielectric coefficient of the high-calcium magnesium titanium concentrate;
and regulating the moisture of different parts of the high-calcium magnesium titanium concentrate according to the required moisture, so that the aim of uniformly distributing the dielectric properties of the high-calcium magnesium titanium concentrate in the microwave heating process is fulfilled, the temperature distribution uniformity is improved, and meanwhile, the method can be used for improving the heating efficiency of the high-calcium magnesium titanium concentrate.
Further, the initial water content of the high-calcium-magnesium titanium concentrate is determined by a weighing method, and the method comprises the following steps:
1.1, putting a certain mass of high-calcium magnesium titanium concentrate sample into a container with mass m, and weighing the sample to obtain the total weight mt；
1.2, putting the container containing the sample into a microwave drying device for drying until the weight is constant, and recording the total weight of the container and the sample as m1；
1.3 obtaining the initial water content of the sample
Further, during the microwave heating process, the water loss of the high-calcium magnesium titanium concentrate due to evaporation is as follows:
wherein: d represents the moisture diffusion rate; u. ofaIs the air humidity; u. ofcThe surface water content of the high calcium magnesium titanium concentrate is obtained; h ismThe mass transfer coefficient of the surface of the high-calcium magnesium titanium concentrate is obtained; n represents a unit vector vertical to the surface, u is the current water content of the high-calcium magnesium titanium concentrate, and the current water content u of the high-calcium magnesium titanium concentrate is the initial water content u at the initial stage1。
Further, the surface quality transmission coefficient h of the high-calcium-magnesium titanium concentratemThe calculation formula is related to the evaporation rate of the surface moisture:
hm＝mv/A×VH
wherein: a is the surface area of the high-calcium magnesium titanium concentrate; m isvDenotes the evaporation rate, mv＝104s-1；VHIs the volume of water in the high calcium magnesium titanium concentrate.
Further, the relational expression between the dielectric coefficient of the high-calcium magnesium titanium concentrate, the temperature T and the water content u can be obtained by measuring the dielectric coefficient epsilon '-j epsilon' and the water content u in real time in an experiment of heating the high-calcium magnesium titanium concentrate at constant temperature under different temperatures T through multiple linear regression, and the form is as follows:
ε″＝a1+a2u+a3T+a4u2+a5T2+a6uT
ε′＝b1+b2u+b3T+b4u2+b5T2+b6T
wherein: u and T are the current water content and the temperature of the high-calcium magnesium titanium concentrate respectively, and the current water content u of the high-calcium magnesium titanium concentrate is the initial water content u at the initial stage1；a1…a6And b1…b6For the parameters obtained from the multiple linear regression experiment, j is the imaginary sign.
Further, according to the equilibrium water content model and the expected dielectric coefficient of the high-calcium-magnesium-titanium concentrate, the specific steps of obtaining the water required by the high-calcium-magnesium-titanium concentrate to reach the expected dielectric coefficient are as follows:
4.1, firstly obtaining a balanced moisture content model of the high-calcium-magnesium titanium concentrate, and setting an expected dielectric coefficient;
4.2, deducing the water content of the high-calcium magnesium titanium concentrate under a certain temperature condition when the dielectric coefficient is expected according to a relational expression between the expected dielectric coefficient of the high-calcium magnesium titanium concentrate and the temperature T and the water content u by combining the temperature of the current temperature measuring point and the expected dielectric coefficient;
4.3, obtaining the equilibrium moisture content by utilizing a equilibrium moisture content model according to the temperature, the air humidity and the water activity of the current temperature measuring point;
4.4, measuring the current water content, and comparing the current water content of the measuring point with the water content when the expected dielectric coefficient is reached to obtain a water content value to be added;
if the current water content is smaller than the equilibrium water content, indicating that the high-calcium magnesium titanium concentrate is in an outward adsorption state, adding the required water to a measured point of the high-calcium magnesium titanium concentrate;
and if the current water content is greater than the equilibrium water content, indicating that the high-calcium magnesium titanium concentrate is in an outward desorption state, adding more water than required to be added to a measured point of the high-calcium magnesium titanium concentrate.
Further, the equilibrium moisture content model of the high-calcium-magnesium titanium concentrate is obtained by experiments and comprises the following steps:
1) dividing a certain amount of high-calcium magnesium titanium concentrate experimental sample into N parts;
2) adding distilled water into the N parts of the high-calcium magnesium titanium concentrate to prepare an experimental sample with the water content gradient of 2%;
3) respectively putting N parts of high-calcium magnesium titanium concentrate into constant-temperature incubators at different temperatures for balancing for a period of time, and recording the air humidity in the incubators;
4) and when the recorded air humidity reaches the balance and does not change any more, measuring the water content of the high-calcium magnesium titanium concentrate at the moment to obtain the balance water content u of the high-calcium magnesium titanium concentratebMeasuring the water activity a by means of a water activity meterwAdopting SAS software to make nonlinear regression to obtain the equilibrium water content u of high-calcium magnesium titanium concentratebWith temperature T, air humidity uaWater activity awThe relationship of three parameters, in the form of
Wherein: c. C1,c2,c3,c4Is a dimensionless parameter obtained by nonlinear regression experiments.
Fig. 1 can be a device for measuring some parameters in a required method, wherein the device comprises an optical fiber radiation thermometer 1, an infrared moisture meter 2, a positive pressure gas flow nozzle 3, a heated medium high calcium magnesium titanium concentrate 4 and a microwave generating device 5; the microwave generating device 5 is provided with a fiber radiation thermodetector 1, an infrared moisture meter 2 and a positive pressure airflow nozzle 3;
the current water content u of the high-calcium magnesium titanium concentrate can be measured by an infrared moisture meter 2 arranged on a microwave generating device 5; the current temperature of the high-calcium magnesium titanium concentrate can be measured by the optical fiber radiation temperature measuring instrument 1, and the water content of different parts of the high-calcium magnesium titanium concentrate can be adjusted by the positive pressure airflow nozzle 3 according to the required water content.
The invention has the beneficial effects that:
the method calculates the water loss of the high-calcium magnesium titanium concentrate in real time in the microwave heating process; calculating the dielectric coefficient values of different temperature measurement points of the heated high-calcium-magnesium titanium concentrate according to the measured local water content and temperature, and further obtaining the water required by the high-calcium-magnesium titanium concentrate to reach the expected dielectric coefficient value by combining a balanced water content model and the expected dielectric coefficient;
the moisture of different parts of the high-calcium magnesium titanium concentrate is regulated, so that the aim of uniformly distributing the dielectric properties of the high-calcium magnesium titanium concentrate in the microwave heating process is fulfilled, and the temperature distribution uniformity is improved; meanwhile, the method can be used for improving the heating efficiency of the high-calcium magnesium titanium concentrate.
Drawings
Fig. 1 is a schematic perspective view of the present invention.
1. The device comprises an optical fiber radiation temperature measuring instrument, 2, an infrared moisture meter, 3, a positive pressure airflow nozzle, 4, high-calcium magnesium titanium concentrate 5 and a microwave generating device.
Detailed Description
Example 1: as shown in fig. 1, a method for adjusting the dielectric constant of high-calcium magnesium titanium concentrate under microwave heating condition includes:
determining the initial water content of the high-calcium magnesium titanium concentrate;
calculating the water loss of the high-calcium magnesium titanium concentrate in real time in the microwave heating process;
calculating the dielectric coefficients of the heated high-calcium magnesium titanium concentrate at different temperature measuring points in real time according to the measured current water content and temperature of the high-calcium magnesium titanium concentrate and the relational expression between the dielectric coefficient of the high-calcium magnesium titanium concentrate and the temperature and the water content;
obtaining water required for the high-calcium magnesium titanium concentrate to reach the expected dielectric coefficient according to the balanced water content model and the expected dielectric coefficient of the high-calcium magnesium titanium concentrate;
and regulating the moisture of different parts of the high-calcium magnesium titanium concentrate according to the required moisture, so that the aim of uniformly distributing the dielectric properties of the high-calcium magnesium titanium concentrate in the microwave heating process is fulfilled, the temperature distribution uniformity is improved, and meanwhile, the method can be used for improving the heating efficiency of the high-calcium magnesium titanium concentrate.
Further, the initial water content of the high-calcium-magnesium titanium concentrate is determined by a weighing method, and the method comprises the following steps:
1.1, putting a certain mass of high-calcium magnesium titanium concentrate sample into a container with mass m, and weighing the total weightmt；
1.2, putting the container containing the sample into a microwave drying device for drying until the weight is constant, and recording the total weight of the container and the sample as m1；
1.3 obtaining the initial water content of the sample
Further, during the microwave heating process, the water loss of the high-calcium magnesium titanium concentrate due to evaporation is as follows:
wherein: d represents the moisture diffusion rate; u. ofaIs the air humidity; u. ofcThe surface water content of the high calcium magnesium titanium concentrate is obtained; h ismThe mass transfer coefficient of the surface of the high-calcium magnesium titanium concentrate is obtained; n represents a unit vector vertical to the surface, u is the current water content of the high-calcium magnesium titanium concentrate, and the current water content u of the high-calcium magnesium titanium concentrate is the initial water content u at the initial stage1。
Further, the surface quality transmission coefficient h of the high-calcium-magnesium titanium concentratemThe calculation formula is related to the evaporation rate of the surface moisture:
hm＝mv/A×VH
wherein: a is the surface area of the high-calcium magnesium titanium concentrate; m isvDenotes the evaporation rate, mv＝104s-1；VHIs the volume of water in the high calcium magnesium titanium concentrate.
Further, the relational expression between the dielectric coefficient of the high-calcium magnesium titanium concentrate, the temperature T and the water content u can be obtained by measuring the dielectric coefficient epsilon '-j epsilon' and the water content u in real time in an experiment of heating the high-calcium magnesium titanium concentrate at constant temperature under different temperatures T through multiple linear regression, and the form is as follows:
ε″＝a1+a2u+a3T+a4u2+a5T2+a6uT
ε′＝b1+b2u+b3T+b4u2+b5T2+b6T
wherein: u and T are the current water content and the temperature of the high-calcium magnesium titanium concentrate respectively, and the current water content u of the high-calcium magnesium titanium concentrate is the initial water content u at the initial stage1；a1…a6And b1…b6For the parameters obtained from the multiple linear regression experiment, j is the imaginary sign.
Further, according to the equilibrium water content model and the expected dielectric coefficient of the high-calcium-magnesium-titanium concentrate, the specific steps of obtaining the water required by the high-calcium-magnesium-titanium concentrate to reach the expected dielectric coefficient are as follows:
4.1, firstly obtaining a balanced moisture content model of the high-calcium-magnesium titanium concentrate, and setting an expected dielectric coefficient;
4.2, deducing the water content of the high-calcium magnesium titanium concentrate under a certain temperature condition when the dielectric coefficient is expected according to a relational expression between the expected dielectric coefficient of the high-calcium magnesium titanium concentrate and the temperature T and the water content u by combining the temperature of the current temperature measuring point and the expected dielectric coefficient;
4.3, obtaining the equilibrium moisture content by utilizing a equilibrium moisture content model according to the temperature, the air humidity and the water activity of the current temperature measuring point;
4.4, measuring the current water content, and comparing the current water content of the measuring point with the water content when the expected dielectric coefficient is reached to obtain a water content value to be added;
if the current water content is smaller than the equilibrium water content, indicating that the high-calcium magnesium titanium concentrate is in an outward adsorption state, adding the required water to a measured point of the high-calcium magnesium titanium concentrate;
and if the current water content is greater than the equilibrium water content, indicating that the high-calcium magnesium titanium concentrate is in an outward desorption state, adding more water than required to be added to a measured point of the high-calcium magnesium titanium concentrate.
Further, the equilibrium moisture content model of the high-calcium-magnesium titanium concentrate is obtained by experiments and comprises the following steps:
1) dividing a certain amount of high-calcium magnesium titanium concentrate experimental sample into N parts;
2) adding distilled water into the N parts of the high-calcium magnesium titanium concentrate to prepare an experimental sample with the water content gradient of 2%;
3) respectively putting N parts of high-calcium magnesium titanium concentrate into constant-temperature incubators at different temperatures for balancing for a period of time, and recording the air humidity in the incubators;
4) and when the recorded air humidity reaches the balance and does not change any more, measuring the water content of the high-calcium magnesium titanium concentrate at the moment to obtain the balance water content u of the high-calcium magnesium titanium concentratebMeasuring the water activity a by means of a water activity meterwAdopting SAS software to make nonlinear regression to obtain the equilibrium water content u of high-calcium magnesium titanium concentratebWith temperature T, air humidity uaWater activity awThe relationship of three parameters, in the form of
Wherein: c. C1,c2,c3,c4Is a dimensionless parameter obtained by nonlinear regression experiments.
As a further illustration of the present invention, fig. 1 may be a device for measuring some parameters in a required method, wherein the device includes an optical fiber radiation thermometer 1, an infrared moisture meter 2, a positive pressure gas flow nozzle 3, a heated medium high calcium magnesium titanium concentrate 4, and a microwave generating device 5; the microwave generating device 5 is provided with a fiber radiation thermodetector 1, an infrared moisture meter 2 and a positive pressure airflow nozzle 3;
the current water content u of the high-calcium magnesium titanium concentrate can be measured by an infrared moisture meter 2 arranged on a microwave generating device 5; the current temperature of the high-calcium magnesium titanium concentrate can be measured by the optical fiber radiation temperature measuring instrument 1, and the water content of different parts of the high-calcium magnesium titanium concentrate can be adjusted by the positive pressure airflow nozzle 3 according to the required water content.
The structure of the device can comprise a microwave oven, wherein 5 optical fiber radiation temperature measuring probes, 5 infrared moisture meters and 5 positive pressure airflow nozzles are respectively arranged in the microwave oven.
In the microwave heating process, the problems of uneven electric field distribution and uneven material temperature distribution caused by anisotropic dielectric properties of the high-calcium magnesium titanium concentrate are solved.
According to the method, the water loss of the high-calcium-magnesium-titanium concentrate is calculated in real time, the dielectric coefficient values of the heated high-calcium-magnesium-titanium concentrate at different temperature measuring points are further calculated according to the local water content measured by the 5 infrared moisture meters and the temperature measured by the optical fiber radiation temperature measuring meter, and the water required by the high-calcium-magnesium-titanium concentrate to reach the expected dielectric coefficient value is obtained by combining the equilibrium water content model and the expected dielectric coefficient. 5 positive pressure airflow nozzles are adopted to adjust the moisture of different parts of the high-calcium magnesium titanium concentrate, so that the aim of uniformly distributing the dielectric coefficients of the high-calcium magnesium titanium concentrate in the microwave heating process is fulfilled, and the uniformity of temperature distribution is improved. Meanwhile, the method can be used for improving the heating efficiency of the high-calcium magnesium titanium concentrate.
While the present invention has been described in detail with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art.
Claims (7)
1. A method for adjusting the dielectric constant of high-calcium magnesium titanium concentrate under the microwave heating condition is characterized by comprising the following steps:
determining the initial water content of the high-calcium magnesium titanium concentrate;
calculating the water loss of the high-calcium magnesium titanium concentrate in real time in the microwave heating process;
calculating the dielectric coefficients of the heated high-calcium magnesium titanium concentrate at different temperature measuring points in real time according to the measured current water content and temperature of the high-calcium magnesium titanium concentrate and the relational expression between the dielectric coefficient of the high-calcium magnesium titanium concentrate and the temperature and the water content;
obtaining water required for the high-calcium magnesium titanium concentrate to reach the expected dielectric coefficient according to the balanced water content model and the expected dielectric coefficient of the high-calcium magnesium titanium concentrate;
and regulating the moisture of different parts of the high-calcium magnesium titanium concentrate according to the required moisture, thereby achieving the purpose that the dielectric properties of the high-calcium magnesium titanium concentrate are uniformly distributed in the microwave heating process and further improving the temperature distribution uniformity.
2. The method for adjusting the dielectric constant of the high-calcium magnesium titanium concentrate under the microwave heating condition according to claim 1, wherein the method comprises the following steps: the initial water content of the high-calcium-magnesium titanium concentrate is determined by a weighing method, and the method comprises the following steps:
1.1, putting a certain mass of high-calcium magnesium titanium concentrate sample into a container with mass m, and weighing the sample to obtain the total weight mt；
1.2, putting the container containing the sample into a microwave drying device for drying until the weight is constant, and recording the total weight of the container and the sample as m1；
1.3 obtaining the initial water content of the sample
3. The method for adjusting the dielectric constant of the high-calcium magnesium titanium concentrate under the microwave heating condition according to claim 1, wherein the method comprises the following steps: in the microwave heating process, the water loss of the high-calcium magnesium titanium concentrate due to evaporation is as follows:
wherein: d represents the moisture diffusion rate; u. ofaIs the air humidity; u. ofcThe surface water content of the high calcium magnesium titanium concentrate is obtained; h ismThe mass transfer coefficient of the surface of the high-calcium magnesium titanium concentrate is obtained; n represents a unit vector vertical to the surface, u is the current water content of the high-calcium magnesium titanium concentrate, and the current water content u of the high-calcium magnesium titanium concentrate is the initial water content u at the initial stage1。
4. The method for adjusting the dielectric constant of the high-calcium magnesium titanium concentrate under the microwave heating condition according to claim 3, wherein the method comprises the following steps: the surface quality transmission coefficient h of the high-calcium magnesium titanium concentratemThe calculation formula is related to the evaporation rate of the surface moisture:
hm＝mv/A×VH
wherein: a is the surface area of the high-calcium magnesium titanium concentrate; m isvDenotes the evaporation rate, mv＝104s-1；VHIs the volume of water in the high calcium magnesium titanium concentrate.
5. The method for adjusting the dielectric constant of the high-calcium magnesium titanium concentrate under the microwave heating condition according to claim 1, wherein the method comprises the following steps: the relational expression between the dielectric coefficient of the high-calcium magnesium titanium concentrate, the temperature T and the water content u can be obtained by measuring the dielectric coefficient epsilon ∈' -j ∈ ″ and the water content u in real time in a constant-temperature heating experiment of the high-calcium magnesium titanium concentrate at different temperatures T through multiple linear regression, and the form is as follows:
ε″＝a1+a2u+a3T+a4u2+a5T2+a6uT
ε′＝b1+b2u+b3T+b4u2+b5T2+b6T
wherein: u and T are the current water content and the temperature of the high-calcium magnesium titanium concentrate respectively, and the current water content u of the high-calcium magnesium titanium concentrate is the initial water content u at the initial stage1；a1…a6And b1…b6For the parameters obtained from the multiple linear regression experiment, j is the imaginary sign.
6. The method for adjusting the dielectric constant of the high-calcium magnesium titanium concentrate under the microwave heating condition according to claim 1, wherein the method comprises the following steps: the specific steps of obtaining the water required for the high-calcium-magnesium titanium concentrate to reach the expected dielectric coefficient according to the equilibrium water content model and the expected dielectric coefficient of the high-calcium-magnesium titanium concentrate are as follows:
4.1, firstly obtaining a balanced moisture content model of the high-calcium-magnesium titanium concentrate, and setting an expected dielectric coefficient;
4.2, deducing the water content of the high-calcium magnesium titanium concentrate under a certain temperature condition when the dielectric coefficient is expected according to a relational expression between the expected dielectric coefficient of the high-calcium magnesium titanium concentrate and the temperature T and the water content u by combining the temperature of the current temperature measuring point and the expected dielectric coefficient;
4.3, obtaining the equilibrium moisture content by utilizing a equilibrium moisture content model according to the temperature, the air humidity and the water activity of the current temperature measuring point;
4.4, measuring the current water content, and comparing the current water content of the measuring point with the water content when the expected dielectric coefficient is reached to obtain a water content value to be added;
if the current water content is smaller than the equilibrium water content, indicating that the high-calcium magnesium titanium concentrate is in an outward adsorption state, adding the required water to a measured point of the high-calcium magnesium titanium concentrate;
and if the current water content is greater than the equilibrium water content, indicating that the high-calcium magnesium titanium concentrate is in an outward desorption state, adding more water than required to be added to a measured point of the high-calcium magnesium titanium concentrate.
7. The method for adjusting the dielectric constant of the high-calcium magnesium titanium concentrate under the microwave heating condition according to claim 1 or 6, wherein: the equilibrium moisture content model of the high-calcium magnesium titanium concentrate is obtained by experiments and comprises the following steps:
1) dividing a certain amount of high-calcium magnesium titanium concentrate experimental sample into N parts;
2) adding distilled water into the N parts of the high-calcium magnesium titanium concentrate to prepare an experimental sample with the water content gradient of 2%;
3) respectively putting N parts of high-calcium magnesium titanium concentrate into constant-temperature incubators at different temperatures for balancing for a period of time, and recording the air humidity in the incubators;
4) and when the recorded air humidity reaches the balance and does not change any more, measuring the water content of the high-calcium magnesium titanium concentrate at the moment to obtain the balance water content u of the high-calcium magnesium titanium concentratebMeasuring the water activity a by means of a water activity meterwAdopting SAS software to make nonlinear regression to obtain the equilibrium water content u of high-calcium magnesium titanium concentratebWith temperature T, air humidity uaWater activity awThe relationship of three parameters, in the form of
Wherein: c. C1,c2,c3,c4Is a dimensionless parameter obtained by nonlinear regression experiments.
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