Discussion on the detection method and distributio

2022-08-23
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Discussion on the iridescence detection method and distribution of flat glass

in the production of flat glass, a temporary plant quarantine decree aimed at China was signed on this basis. The amount of tin penetration is the key index to judge the sealing effect of tin bath and whether the process system is reasonable. When the amount of tin permeating on the surface of glass reaches a certain degree, the iridescence phenomenon that affects the use of glass will appear after thermal processing

jc/t ultra white float glass and the newly revised national standard of flat glass have made requirements for glass iridescence, but jc/t has relatively simple steps and methods for iridescence detection, and the actual operation is greatly affected by external factors. Through the iridescence detection of 30 batches of samples provided by 29 flat glass enterprises in China, combined with the determination of tin penetration, the relationship between tin penetration and iridescence of flat glass and the more suitable observation method of flat glass iridescence were found

in order to verify the applicability and reliability of the flat glass iridescence detection method, combined with the detection of tin penetration, the method adopts Phenylfluorone cetyltrimethylammonium bromide spectrophotometry. Its principle is to erode the surface of the glass sample with hydrofluoric acid nitric acid mixed acid solution, so that all tin penetration is transferred into the mixed acid solution. All divalent tin is oxidized to tetravalent tin with potassium permanganate. In sulfuric acid medium, tin (Ⅳ) - Phenylfluorone - cetyltrimethylammonium bromide forms a red ternary complex. The absorbance was measured at the wavelength of 510nm. Within a certain concentration range, the absorbance is directly proportional to the concentration of tin. Therefore, the research results show that the amount of tin permeating on the unit surface area of the glass sample (pg/cm2)

after heat treatment, the divalent tin ions permeating into the surface layer of the glass are oxidized to tetravalent tin ions, and the surface volume expands due to the introduction of oxygen atoms. The molecular unit cell volume of stannous oxide is 0 Nm, the molecular unit cell volume of tin dioxide is 0 Nm3, as a result of volume expansion, molecules squeeze each other on the surface, resulting in micro wrinkles on the surface. The size of these folds is close to the size of the wavelength of visible light, so they will significantly interfere with visible light, and the interference result of light is iridescence. Before the test, first use the tin surface tester to determine the tin stained surface. After heating the heat treatment furnace to 730 ℃ and stabilizing, put the sample with the tin stained surface upward and horizontally into the heat treatment furnace. The heat treatment time refers to jc/t. After reaching the heat treatment time, take out the sample, put it into the annealing cooling box for natural slow cooling, and put the cooled sample into the rainbow observation box. The size of the observation box Results and light position aluminum alloy material tensile machine is widely used in building materials, aerospace, machinery manufacturing, wire and cable, rubber and plastic, shock absorber, textile, household appliances and other industries, and the material inspection and analysis device and light intensity are specified in detail. Observe the sample with a polarizing lens at the place 600mm in front of the sample and at the depression angle of 45 ° -60 °, and turn the polarizing lens to record the iridescence when it is the clearest. This method determines the light source and illumination intensity, observation distance and observation angle. By using a polarizer to convert the observation light into polarized light, the influence of the rainbow can be observed very clearly, which is repeatable. At the same time, through the image processing of the interference fringe by the computer, the computer can realize automatic interpretation

the reliability of this detection method is also directly verified by the determination of tin penetration. Through comparative analysis, it is found that the higher the amount of tin infiltration on the glass surface, the heavier the rainbow, but there is no strict linear relationship between the glass rainbow and the amount of tin infiltration. Table 1 shows the relationship between left, middle and right tin penetration and iridescence in sequence

data analysis

through the analysis of test data and the investigation of the enterprises submitting for inspection, the following conclusions are drawn:

1) there are great differences in tin penetration and iridescence of flat glass produced by different enterprises with the same thickness, which is mainly related to the installation level of the enterprise and the sealing of the kiln. The technology is advanced, the kiln is well sealed, the tin penetration is low, and the iridescence is slight

2) the longer the contact time between the glass ribbon and the tin solution, the higher the tin penetration, that is, the thicker the glass plate, the greater the tin penetration, and the greater the iridescence

3) in the thickness direction of the glass plate, from the outside to the inside, and the tearing expansion speed is directly related to the tensile speed of the gripper, the amount of tin penetration gradually decreases

4) tin penetration is high on both sides along the plate width direction, and the lowest in the middle. The tin penetration on the upper surface of the glass plate is low, and the tin penetration on the lower surface is high

5) the four corners of the glass rainbow are the most obvious in the test, which may be related to the rapid cooling of the corners

during the test, the operation and observation vision of different personnel will deviate from the test data, but it is generally controllable

tin penetration and rainbow detection are of great significance to the control of furnace thermal parameters in flat glass enterprises. The results can directly reflect the kiln process conditions, and provide a theoretical basis for enterprises to adjust and improve process parameters. The improvement of thermal engineering of flat glass furnace can not only improve product quality and reduce energy consumption, especially tin consumption, but also greatly reduce harmful gas emissions and environmental pollution

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