A method for testing the touch quantity of titanium dioxide filter cake

Abstract

The invention discloses a method for testing the thixotropic amount of a titanium dioxide filter cake. The invention quantitatively determines the thixotropic performance of the filter cake by monitoring the difference in electrical properties of the filter cake before and after thixotropy, thereby obtaining high-precision thixotropic data and replacing the traditional visual determination of the thixotropic degree. The invention also implements quantitative measurement of the thixotropic performance by inserting electrodes into the filter cake to measure the electrical properties.

Description

Technical Field

[0001] The invention relates to the technical field of chemical production, and in particular to a method for testing the contact amount of titanium dioxide filter cake. Background Art

[0002] Titanium dioxide is the strongest tinting power among white pigments. It has high whiteness, good hiding power, strong tinting power and good dispersibility. It is a very important raw material in industrial production and is widely used in coatings, plastics, papermaking, printing inks, chemical fibers, rubber, cosmetics, ceramics, enamel, electronics, food, medicine and other industries.

[0003] At present, in the post-processing process of titanium dioxide production, inorganic coating is required to achieve better pigment performance. Generally, after coating, it is necessary to wash with water to remove water-soluble salts first, and then filter cake is obtained after filter pressing, and then the filter cake is dried and crushed to obtain the finished titanium dioxide. Whether the filter cake after coating is thixotropic directly affects whether the production can proceed normally. This is because the drying process of titanium dioxide mostly adopts flash drying. If the filter cake is thixotropic, in the subsequent belt transportation process, due to mechanical vibration, the filter cake will become sticky or even become watery. In mild cases, it will adhere to the belt or flash spiral stirring, affecting production efficiency. In severe cases, it will cause the flash to stall, causing the post-processing production of titanium dioxide to stop.

[0004] The thixotropy of filter cakes in the production process is mostly determined by visual observation, and there is no quantitative test method for the thixotropy of filter cakes. Therefore, it is necessary to quantitatively grade the thixotropy of filter cakes to guide new product development and process improvement. Summary of the invention

[0005] The invention provides a method for testing the touch quantity of titanium dioxide filter cake.

[0006] The scheme of the present invention is:

[0007] A method for testing the touch quantity of titanium dioxide filter cake comprises the following steps:

[0008] 1) The titanium dioxide filter cake to be tested is placed in a container, and then a positive electrode and a negative electrode are inserted into the top of the titanium dioxide filter cake;

[0009] 2) placing the container on an oscillator, and measuring the resistance value of the titanium dioxide filter cake when the oscillator is not turned on. The resistance value of the titanium dioxide filter cake in the container is R0;

[0010] 3) Turn on the oscillator, and calculate the thixotropic grade by measuring the resistance values ​​under different oscillation intensities and different oscillation times. The resistance value of the filter cake after oscillation for a period of time is R1. The thixotropic index calculation formula is:

[0011]

[0012] The thixotropic grade of the titanium dioxide filter cake is determined according to the range of the thixotropic index T. If it meets the thixotropic range, the titanium dioxide powder from the same batch as the titanium dioxide filter cake can be subsequently transported and flash dried.

[0013] As a preferred technical means, the distance between the positive electrode and the negative electrode is 1 cm to 50 cm.

[0014] As a preferred technical means, the oscillation mode of the oscillator is one of longitudinal oscillation, transverse oscillation or mixed oscillation.

[0015] As a preferred technical means, the oscillation frequency of the oscillator is 0.01 Hz to 1 MHz, the oscillation amplitude is 1 mm to 100 mm, and the oscillation time is 1 s to 100 s.

[0016] As a preferred technical means, the solid content of the titanium dioxide filter cake is 50% to 90%, and the size of the titanium dioxide filter cake matches the internal space of the containing container.

[0017] As a preferred technical means, the thixotropic index T≤50, which meets the thixotropic range.

[0018] The present invention also discloses a device for testing the contact variable of titanium dioxide filter cake, comprising an oscillator, a containing container is placed on the top oscillating platform of the oscillator, the containing container is used to place the titanium dioxide filter cake, two electrodes are inserted into the top of the titanium dioxide filter cake, and an ohmmeter is provided on one side of the oscillator.

[0019] The two test leads of the ohmmeter are fixedly connected to the two electrodes respectively.

[0020] Due to the adoption of the above technical solution, a method for testing the contact amount of titanium dioxide filter cake includes the following steps:

[0021] 1) The titanium dioxide filter cake to be tested is placed in a container, and then a positive electrode and a negative electrode are inserted into the top of the titanium dioxide filter cake; 2) The container is placed on an oscillator, and when the oscillator is not turned on, the resistance value of the titanium dioxide filter cake is measured. The resistance value of the titanium dioxide filter cake in the container is R0; 3) The oscillator is turned on, and the thixotropic grade is calculated by measuring the resistance values ​​under different oscillation intensities and different oscillation times. After oscillating for a period of time, the resistance value of the filter cake is R1. The thixotropic index calculation formula is,

[0022]

[0023] The thixotropic grade of the titanium dioxide filter cake is determined according to the range of the thixotropic index T. If it meets the thixotropic range, the titanium dioxide powder from the same batch as the titanium dioxide filter cake can be subsequently transported and flash dried.

[0024] The advantages of the present invention are as follows: since thixotropy is caused by the external force on the filter cake, which causes the internal chemical bond structure of the filter cake to break, resulting in a decrease in the mechanical properties of the filter cake while improving its electrical properties, the present invention quantitatively monitors the thixotropy degree of the filter cake through the difference in the resistance value of the filter cake before and after thixotropy, instead of visually judging the thixotropy degree based on experience, and provides a more precise numerical basis for laboratory research on the thixotropy performance of the filter cake;

[0025] The conventional method of quantitatively determining the degree of thixotropy is to measure the viscosity change caused by shear force. However, the initial state of the filter cake is a water-containing solid phase, and the viscosity cannot be measured. Therefore, the thixotropic performance cannot be quantitatively determined by the viscosity change. The present invention quantitatively monitors the degree of thixotropy of the filter cake through the difference in resistance value of the filter cake before and after thixotropy, which is independent of the phase state of the measured object. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the process of measuring the thixotropy of titanium dioxide filter cake according to an embodiment of the present invention;

[0027] 1- container, 2- titanium dioxide filter cake, 3- oscillation platform, 4- oscillator, 5- electrode, 6- ohmmeter. DETAILED DESCRIPTION

[0028] In order to make up for the above shortcomings, the present invention provides a method for testing the touch quantity of titanium dioxide filter cake to solve the problems in the above background technology.

[0029] A method for testing the touch quantity of titanium dioxide filter cake comprises the following steps:

[0030] 1) The titanium dioxide filter cake to be tested is placed in a container, and then a positive electrode and a negative electrode are inserted into the top of the titanium dioxide filter cake;

[0031] 2) Place the container on an oscillator. When the oscillator is not turned on, measure the resistance value of the titanium dioxide filter cake. The resistance value of the titanium dioxide filter cake in the container is R 0； ;

[0032] 3) Turn on the oscillator, and calculate the thixotropic grade by measuring the resistance values ​​under different oscillation intensities and different oscillation times. The resistance value of the filter cake after oscillation for a period of time is R1. The thixotropic index calculation formula is:

[0033]

[0034] The thixotropic grade of the titanium dioxide filter cake is determined according to the range of the thixotropic index T. If it meets the thixotropic range, the titanium dioxide powder from the same batch as the titanium dioxide filter cake can be subsequently transported and flash dried.

[0035] The distance between the positive electrode and the negative electrode is 1 cm to 50 cm.

[0036] The oscillation mode of the oscillator is one of longitudinal oscillation, transverse oscillation or mixed oscillation.

[0037] The oscillation frequency of the oscillator is 0.01 Hz to 1 MHz, the oscillation amplitude is 1 mm to 100 mm, and the oscillation time is 1 s to 100 s.

[0038] The solid content of the titanium dioxide filter cake is 50% to 90%, and the size of the titanium dioxide filter cake matches the internal space of the containing container.

[0039] The thixotropic index T≤50, which meets the thixotropic range.

[0040] The present invention also discloses a device for testing the contact variable of titanium dioxide filter cake, comprising an oscillator, a containing container is placed on the top oscillating platform of the oscillator, the containing container is used to place the titanium dioxide filter cake, two electrodes are inserted into the top of the titanium dioxide filter cake, and an ohmmeter is provided on one side of the oscillator.

[0041] The two test leads of the ohmmeter are fixedly connected to the two electrodes respectively.

[0042] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments.

[0043] Example

[0044] As shown in Fig. 1, a titanium dioxide filter cake thixotropy measurement method according to an exemplary embodiment of the present invention is used to achieve quantitative measurement of the thixotropy degree of titanium dioxide filter cake. It includes an oscillator 4, a container 1 is placed on an oscillating platform 3 at the top of the oscillator 4, the container 1 is used to place a titanium dioxide filter cake 2, two electrodes 5 are inserted into the top of the titanium dioxide filter cake 2, and an ohmmeter 6 is provided on one side of the oscillator 4.

[0045] When using the device for measuring the thixotropy of the titanium dioxide filter cake 2, the following operating steps are included: a titanium dioxide filter cake 4 having a cross-sectional area similar to and slightly smaller than the internal volume of the container 1 is placed in the container 1, the solid content of the titanium dioxide filter cake 2 is 70%, and an electrode 5 is inserted into the filter cake, the distance between the two electrodes 5 is 10 cm, the electrode 5 is fixed on the container 1, and the initial resistance R0 = 5000 ohms is measured, the oscillation frequency is set to 60 Hz, the oscillation amplitude is set to 1 cm, the oscillation time is 1 min, the oscillation mode is mixed oscillation, and the resistance after the oscillation test is R1 = 100 ohms. The thixotropy index of the titanium dioxide filter cake is calculated to be 50, which means there is a slight thixotropy, but it does not affect production, and flash crushing can continue.

[0046] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for testing the thixotropic amount of titanium dioxide filter cake, characterized in that: The following steps are involved: 1) The titanium dioxide filter cake to be tested is placed in a container, and then a positive electrode and a negative electrode are inserted into the top of the titanium dioxide filter cake; 2) placing the container on an oscillator, and measuring the resistance value of the titanium dioxide filter cake when the oscillator is not turned on. The resistance value of the titanium dioxide filter cake in the container is R0; 3) Turn on the oscillator and calculate the thixotropic grade by measuring the resistance values ​​under different oscillation intensities and different oscillation times. The resistance value of the filter cake after oscillation for a period of time is R1. The thixotropic index calculation formula is: , According to the range of thixotropic index T, the thixotropic grade of titanium dioxide filter cake is determined. If it meets the thixotropic range, the titanium dioxide powder from the same batch as the titanium dioxide filter cake is subsequently transported and flash dried. The thixotropic index T≤50, which meets the thixotropic range.

2. A method for testing the thixotropic amount of titanium dioxide filter cake as claimed in claim 1, characterized in that: The distance between the positive electrode and the negative electrode is 1 cm to 50 cm.

3. A method for testing the thixotropic amount of titanium dioxide filter cake as claimed in claim 1, characterized in that: The oscillation mode of the oscillator is one of longitudinal oscillation, transverse oscillation or mixed oscillation.

4. A method for testing the thiocyanate content of a titanium dioxide filter cake as claimed in claim 1, characterized in that: The oscillation frequency of the oscillator is 0.01 Hz to 1 MHz, the oscillation amplitude is 1 mm to 100 mm, and the oscillation time is 1 s to 100 s.

5. A method for testing the thixotropic amount of titanium dioxide filter cake as claimed in claim 1, characterized in that: The solid content of the titanium dioxide filter cake is 50% to 90%, and the size of the titanium dioxide filter cake matches the internal space of the containing container.

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