Some standard content:
Record number: 107-1997
Electronic Industry Standard of the People's Republic of China
SJ/T10722-1996
Zircon powder for use in electronic glass
Zircon powder for use in
electronic glass
Published on July 22, 1996
Implemented on November 1, 1996
Published by the Ministry of Electronics Industry of the People's Republic of ChinaTYYKAONKAca
This standard is formulated to meet the needs of zircon powder, a raw material for electronic glass. Since there is no corresponding international standard at present, this standard is based on the data and experience accumulated by major domestic production and use units for many years in terms of technical indicators and test methods, and refers to relevant company information. It has certain advancedness and implementation conditions. In this standard, if there are multiple test methods for a certain element, an arbitration method is specified. This standard is under the jurisdiction of the Standardization Research Institute of the Ministry of Electronics Industry. This standard was drafted by the Standardization Institute of the Ministry of Electronics Industry and Guangdong Shuidong Rare Metals Industry Company. The main drafters of this standard are Lu Jian, Li Guanghui, Pan Tuxing, Liu Chengjun, Liu Yun, and Deng Shiwen. YKAoNrKAas
Electronic Industry Standard of the People's Republic of China
Zircon powder for use in electronic glass
Zircon powder for use in
electronic glass
SJ/T10722-1996
This standard specifies the requirements, inspection rules, test methods, packaging, marking, transportation and storage of zircon powder for use in electronic glass. This standard applies to zircon powder for use in electronic glass. Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards.
GB9000.1
General rules for chemical analysis methods for electronic glass
3 Requirements
3.1 Appearance
Zircon powder for electronic glass should be white, off-white or slightly reddish yellow powder. 3.2 Particle size distribution
The particle size distribution of zircon powder for electronic glass is shown in Table 1Table 1
Note: If there are special requirements, the supply and demand parties shall negotiate. 3.3 Chemical composition
For glass shell
The chemical composition of zircon powder for electronic glass is shown in Table 2. Approved by the Ministry of Electronic Industry of the People's Republic of China on July 22, 1996. Percentage
For low melting point glass powder
Implemented on November 1, 1996
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ZrO (including HfO2)
FO (all iron)
Crn0 (all chromium)
Note: If there are special requirements, the supply and demand parties shall negotiate. 3.4 Adhesion water
SJ/T10722-1996
The adhesion water content of zircon powder for electronic glass shall not exceed 0.3%. 4 Test method
4.1 Appearance
Use visual method to inspect the appearance.
4.2 Determination of particle size distribution
4.2.1 Instruments and samples
a. Standard sieves: 0.106, 0.074, 0.043mm; b. Samples: The samples are dried at 105℃ for 1h, and then 50g is taken for measurement. 4.2.2 Test steps
4.2.2.1 Check the standard sieve, which should be free of any damage and fit tightly. The standard sieve must be cleaned before measurement. 4.2.2.2 When measuring zircon powder for glass shell, weigh two 50g samples and place them in the standard sieves of 0.106 and 0.074mm respectively.
When measuring zircon powder for low melting point glass powder, weigh two 50g samples and place them in the standard sieves of 0.074mm and 0.043mm respectively.
4.2.2.3 Place each sieve with the sample in the prepared clean water and shake it manually until the sample does not leak from the sieve hole to avoid missing the sample during operation. 4.2.2.4 Dry each sieve, take out the sieve material and weigh it. 4.2.3 Explanation of results
4.2.3.1 For zircon powder for glass shell, the sieve material on the standard sieve of 0.106mm should be 0; the sieve material on the standard sieve of 0.074mm should be no more than 5g.
4.2.3.2 For zircon powder for low melting point glass powder, the sieve material on the standard sieve of 0.074mm should be 0; the sieve material on the standard sieve of 0.043mm should be no more than 5g.
4.3 Determination of chemical composition
First, grind the sample in a manao mortar until there is no granular feeling when you touch it with your fingers. Then put the ground stone powder in a weighing bottle, dry it at 105℃ for 2h, and cool it in a desiccator for use. The general principles for the determination of its chemical composition shall be carried out in accordance with the provisions of GB9000.1.
4.3.1 Determination of zirconium dioxide
4.3.1.1 Key points of the method
The sample is melted and decomposed with a mixed flux, leached with hydrochloric acid, and zirconium (including hafnium) is precipitated with a bitter mandelic acid solution in a 20% hydrochloric acid solution. It is calcined at 1000℃ to form zirconium dioxide (including hafnium dioxide) and weighed. 4.3.1.2 Reagents and solutions
a) Mixed flux: borax + sodium carbonate = 2+1: b) Hydrochloric acid;
c) Hydrochloric acid: 1+9;
d) 20% mandelic acid solution: weigh 20g of mandelic acid, dissolve it in 100ml of water, filter and set aside; e) 2% mandelic acid washing solution: weigh 2g of mandelic acid, dissolve it in 100ml2+98) hydrochloric acid. 4.3.1.3 Test steps
First, place 2.0g of mixed flux in a platinum pot, melt it on a gas burner, and make it evenly attached to the bottom of the platinum pot. Accurately weigh 0.20g of the sample and place it on it. Cover it with 3.0g of mixed flux. Gradually heat it on a gas burner to melt it until it is clear. Cool it. Move the platinum pot into a 400ml beaker containing 100ml (1+9) hydrochloric acid. Heat to dissolve the molten material. After it is completely dissolved, wash the platinum pot with (1+9) hydrochloric acid and take it out. Add hydrochloric acid according to the volume of the solution, so that 100ml of the solution contains 20ml of hydrochloric acid, and control the volume within 150ml. Add 25ml of mandelic acid solution, place it in a water bath at 80℃~85℃, keep it warm for 5min while stirring, then continue to keep it warm for 30min and leave it overnight.
Filter with slow quantitative filter paper, wash the precipitate 10 times with mandelic acid detergent, wipe the glass rod and the inner wall of the beaker with a little filter paper, put the filter paper and the precipitate in a constant weight platinum pot, dry and ash, burn in a 1000 high temperature furnace for 30 minutes, take out, cool in a desiccator, and weigh to constant weight.
4.3.1.4 Explanation of results
The percentage of zirconium dioxide (including hafnium dioxide) is calculated according to formula (1): W2-Wl×100%
ZrO2 (including HfO)=
W——empty pot volume, g;
W2—empty pot and precipitate volume, g;
w-sample volume, g.
4.3.2 Determination of silicon dioxide
4.3.2.1 Gravimetric method (parameter method)
4.3.2.1.1 Key points of the method
The sample is melted and decomposed with a mixed flux, dehydrated by leaching with hydrochloric acid, treated with methanol, filtered, dried, ashed and burned to constant weight, and then the amount of silicon dioxide in the sample is weighed.
4.3.2.1.2 Reagents and solutions
a) Mixed flux: borax + sodium carbonate = 2+1; b) Hydrochloric acid;
c) Hydrochloric acid (1+49);
d) Sulfuric acid (1+1);
e) Hydrofluoric acid:
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f) Methanol.
4.3.2.1.3 Test steps
SJ/T10722-1996
First, melt 2.0g of mixed flux in platinum III (or pot) to make it evenly attached to the bottom of the platinum blood, accurately weigh 0.30g of sample into it, flatten it, and cover it with 4.0g of mixed flux. Carefully heat and melt it on a gas burner, and move it into a high-temperature furnace with a constant temperature of 1000℃ after it is clear, keep it for 15 minutes, take it out, and gently rotate platinum III to make the molten material evenly cover the lower part of the bottom of III. After cooling, add 10ml of hydrochloric acid and 30ml of hot water, heat it in a water bath to extract it, and constantly stir and crush the molten block to help dissolve it. When the molten block is soft, add 25ml of hydrochloric acid, heat it on a sand bath, concentrate it to about 20ml, cool it, add 15ml of methanol and 5ml of hydrochloric acid, evaporate it to near dryness on a water bath, and then add 15ml of methanol and 5ml of hydrochloric acid,Evaporate to near dryness on a water bath. Cool, moisten the residue with hydrochloric acid, evaporate to near dryness on a sand bath, crush the salt block with a flat glass rod, and continue evaporating to dryness. After cooling, add hydrochloric acid to moisten the residue, add 60ml of hot water, and dissolve the soluble salts on a water bath. After complete dissolution, filter with slow quantitative filter paper while hot, wash the precipitate with hydrochloric acid (1+49) 3 to 5 times, and then wash with hot water 3 to 5 times. Put the residue filter paper into a platinum pot, add two drops of (1+1) sulfuric acid, dry, and after ashing, burn in a high-temperature furnace at a constant temperature of 1000℃ for 30min, cool in a desiccator, and weigh. Wet the residue with water, add 15ml of hydrofluoric acid and two drops of (1+1) sulfuric acid, heat and evaporate to dryness on a sand bath, then burn at 1000℃ for 5min, cool in a desiccator, and weigh. Add 10ml (1+1) hydrochloric acid to the platinum glass, heat at low temperature to dissolve the residue (melt with 1g~2g potassium pyrosulfate), cool it, and add it to the above filtrate (200ml beaker), which can be used for the determination of zirconium dioxide, aluminum oxide, iron oxide, titanium dioxide, iron oxide, calcium oxide, and magnesium oxide. 4.3.2.1.4 Explanation of results
The percentage of silicon dioxide is calculated according to formula (2): W.-W2,
SiO2=-
X100%....
Wherein: W1—the amount of platinum glass and precipitate before hydrofluoric acid treatment, g; W2—the amount of platinum crucible and residue after hydrofluoric acid treatment, g; W-—the amount of sample, g.
4.3.2.2 Potassium Fluorosilicate Volumetric Method
4.3.2.2.1 Key Points of the Method
In nitric acid medium, soluble silicic acid reacts with potassium ions and fluoride ions to generate potassium fluosilicate. The reaction formula is as follows: SiO,+2K*+6F-+6H*=KzSiF+3H20
Potassium fluosilicate can quantitatively release hydrogen fluoride during hydrolysis, which can be used to determine the content of silicon dioxide by titration with sodium hydroxide standard solution.
4.3.2.2.2 Reagents and solutions
a) Potassium hydroxide;
b) Potassium peroxide;
c) Potassium nitride:
d) Potassium chloride solution: 5%;
e) Potassium fluoride solution: 15%;
f) 5% potassium chloride-ethanol solution: 5g potassium chloride is dissolved in 50ml water and 50ml ethanol;g) Hydrochloric acid (1+1);
h) Sodium hydroxide standard solution: 0.1mol/l;4
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SJ/T10722—1996
i) Phenol crisp indicator solution: 1% ethanol solution;j) Nitric acid.
4.3.2.2.3 Test steps
Accurately weigh 0.1g of the sample into nickel, add 1.5g of potassium hydroxide and 0.5g of potassium peroxide, cover the crucible with a lid, leave a little space, melt on a low-temperature electric furnace for about 10min~15min, and then melt on a gas burner until it turns dark red. Be careful to gently shake the crucible, keep it for 4min~5nin, and rotate the crucible so that the molten material adheres evenly to the inner wall of the crucible. After cooling, carefully use hot water to diffuse the molten block several times and transfer it to a 300ml plastic beaker until the molten block is completely transferred to the plastic beaker. Slowly add 15ml of nitric acid to the white plastic beaker to dissolve the molten block, wash the crucible with (1+1) hydrochloric acid 2~3 times, control the liquid volume to about 40ml, and cool it to below 15℃. While stirring, add potassium fluoride to make it supersaturated, add 10ml potassium fluoride solution, and stir with a plastic rod, rinse the inner wall of the cup with a little potassium chloride solution, and keep a little insoluble potassium chloride at the bottom of the cup, let it stand for 3 minutes, quickly use a plastic funnel and filter paper for rapid qualitative filtering, after the precipitate in the cup is transferred to the funnel, rinse the inner wall of the cup and the precipitate with potassium chloride solution (5%) 2 to 3 times, and then wash the filter paper once.
Move the precipitate and filter paper into the original plastic cup, add 10ml potassium chloride-ethanol solution, add 3 to 4 drops of phenolic acid indicator, and neutralize the residual acid with sodium hydroxide standard solution until a slight red color appears and does not fade, and do not count the reading. Add 100ml of neutralized boiling water to hydrolyze the precipitate, and heat it in a boiling water bath while stirring for 3min to 5min. Remove it, add 3 to 4 drops of phenolic acid indicator, and immediately titrate with sodium hydroxide standard solution until the solution turns slightly red and does not fade, which is the end point. 4.3.2.2.4 Explanation of results
The percentage of silicon dioxide is calculated according to formula (3): SiO2 = M×V0.01502x100%..
Wherein: M-concentration of sodium hydroxide standard solution, mol/1; V-volume of sodium hydroxide standard solution consumed in titration after hydrolysis, ml; W-sample volume, g.
0.01502-millimoles of silicon dioxide
4.3.3 Determination of aluminum oxide (chrome-guanidine S spectrophotometry) 4.3.3.1 Summary of the method
.. (3)
The sample is decomposed with sodium hydroxide, leached with water in a polytetrafluoroethylene beaker, and filtered to remove interfering elements such as zirconium, titanium, iron, halogen and rare earth. In a nitric acid solution of pH 5.8 ± 0.4, using hexamethylenetetramine as a buffer, aluminum and chrome azuro blue S form a red chrome complex, and its absorbance is measured at a wavelength of 550nm on a spectrophotometer. 4.3.3.2 Reagents and instruments
a) Sodium hydroxide;
b) Nitric acid: (1+1), (1+19);
c) Hydrochloric acid: (1+1);
d) Ammonia water: (1+19);
e) Ascorbic acid solution: 10g/l (prepared when used); r) Hexamethylenetetramine solution: 250g/l; g) 2.4-dinitrophenol solution: 1g/l [prepared with ethanol (1+1)]; h) Chrome azuro blue S solution: 1g/l [prepared with ethanol (1+ 1) Preparation] i) Aluminum standard solution:
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SJ/T10722-1996
Weigh 0.1000g pure aluminum (99.9% or more) and place it in a 200ml plastic beaker, add 10ml 10% sodium hydroxide solution (superior grade) to dissolve the aluminum, then neutralize with hydrochloric acid (1+1) until a precipitate is precipitated, then add hydrochloric acid dropwise until the precipitate is dissolved, and add 20ml excess, cool, transfer to a 1000ml volumetric flask, dilute to the mark with water, and mix. This solution contains 10μg aluminum in 1ml. Transfer 10.00ml aluminum standard solution and place it in a 100ml volumetric flask, add 1ml hydrochloric acid (1+1), dilute to the mark with water, and mix. This solution contains 10μg aluminum in 1ml. j) Spectrophotometer.
4.3.3.3 Test steps
4.3.3.3.1 Weigh 0.1000g of the sample and place it in a silver pot. Add 4g of sodium hydroxide. Heat on an electric furnace to remove moisture. Place it in a muffle furnace that has been heated to 700C. Keep warm for 45 minutes. Shake it four times in the middle. Take it out and cool it. Place it in a 250ml polytetrafluoroethylene beaker. Add 50ml boiling water to soak it. Wash the pot with water. Add a few drops of ethanol. Boil it on a low-temperature electric furnace until large bubbles appear. Continue for 2min to 3min to drive out all the hydrogen peroxide. Cool it, transfer it to a 100ml volumetric flask, dilute it to the mark with water, and mix it. Pour it into a dry 100ml plastic beaker. After it is clarified by standing still (preferably overnight), dry filter it with quantitative dense filter paper. Collect the filtrate in a dry plastic beaker and discard the first 10ml filtrate. 4.3.3.3.2 Weigh 2.0ml5.0ml of the filtrate into a 50ml colorimetric tube pre-filled with about 10ml of water (if less than 5.0ml of the test solution, use the accompanying sample blank solution to make up), add two drops of 2,4-dinitrophenol solution, neutralize with nitric acid (1+1) until the yellow color disappears, then neutralize with ammonia water until the yellow color just appears, then add nitric acid (1+19) until the yellow color disappears, and add 2ml of nitric acid (1+19) in excess, add 5ml of ascorbic acid solution, 2.0ml of chrome azuro blue S solution, 3ml of hexamethylenetetramine solution, dilute with water to the scale, and mix. 4.3.3.3.3 After standing for 15 minutes, transfer part of the solution into a 0.5cm colorimetric dish, use the accompanying sample blank as a reference, and measure its absorbance at a wavelength of 550nm on a spectrophotometer. Find the corresponding aluminum content from the working curve. 4.3.3.3.4 Drawing of standard working curve: a) Weigh 0.000.50, 1.00, 1.50, 2.00 ml aluminum standard solution, place in a series of 50 ml colorimetric tubes, add about 10 ml water, two drops of 2,4-dinitrophenol solution, neutralize with ammonia water until yellow just appears, then add nitric acid (1+19) until the yellow disappears, and add 2 ml of nitric acid (1+19) in excess, and then develop the color according to 4.3.3.3. b) After standing for 15 minutes, transfer part of the solution into a 0.5 cm colorimetric III, use the reagent blank solution as a reference, measure its absorbance at a wavelength of 550 nm on a spectrophotometer, and draw a working curve with the aluminum content as the horizontal axis and the absorbance as the vertical axis. 4.3.3.4 Explanation of results
The percentage of aluminum oxide is calculated according to formula (4). W,xVx1.8894
×100%…
Al2O,=
Wherein: W,——the amount of aluminum found from the standard working curve, g; V the total volume of the test solution, ml:
V—the volume of the test solution, ml;
W the amount of the sample, g;
1.8894—the coefficient for converting aluminum to aluminum oxide. 4.3.4 Atomic absorption spectrophotometric determination of calcium oxide, magnesium oxide, ferric hydride and aluminum oxide 4.3.4.1 Key points of the method
After the sample is decomposed by the mixed flux, it is diffused and dissolved in a hydrochloric acid solution, and the atomic absorbance of calcium, magnesium, iron and aluminum is analyzed and determined, and the percentage of each oxide is determined respectively. 4.3.4.2 Reagents and solutions
a) Hydrochloric acid (1+1);
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b) Mixed solvent: boric acid + lithium carbonate = 2+1; c) Lanthanum chloride solution: La3+20mg/ml: weigh 26.7gl of chloride (LaCls·7H20) in a 200ml beaker, add 40ml (1+1) hydrochloric acid to dissolve, transfer to a 500ml volumetric flask, and dilute to the scale with water; d) Calcium oxide standard solution: 0.1mg/ml; e) Magnesium oxide standard solution: 0.1mg/ml; f) Ferrous oxide standard solution: 0.1mg/ml; g) Aluminum oxide standard solution: 1.0mg/ml. 4.3.4.3 Instruments and test conditions
a) Atomic absorption spectrophotometer;
b) Hollow cathode lamp;
c) Test conditions: see Table 3.
Analysis line
4.3.4.4 Test steps
Burner length
Burner height
Flame type
AIR-CH2
AIR-CH2
AIR-CH
N,O-CH
Combustion-assisting gas
4.3.4.4.1 First, melt 2.0g of mixed flux in platinum blood and make it evenly adhere to the bottom of the dish. Accurately weigh 0.5g of sample into the platinum dish, shake it evenly and spread it flat. Cover it with 4.0g of mixed flux and carefully heat it on a gas burner to melt it. After it becomes clear, move it into a high-temperature furnace and keep it at 1000℃ for 15min. Take it out and gently rotate the platinum dish to make the melt evenly cover the bottom of the blood in a thin layer. After cooling, add 40ml of hydrochloric acid and 30ml of hot water to dissolve. After clarifying, transfer to a 100ml volumetric flask, add 5ml of lanthanum nitride solution, and dilute to scale with water. Prepare a reagent blank at the same time. Note: The filtrate after the silicon determination in 4.3.2 (gravimetric method) can also be evaporated and concentrated to 80ml, transferred to a 100ml volumetric flask after cooling, and 5ml of lanthanum chloride solution is added, and diluted to scale with water.
4.3.4.3 Measure the atomic absorbance of the sample blank at the same time as the test conditions listed in Table 3. 4.3.4.4.2 Drawing of standard working curvewwW.bzxz.Net
Prepare the mixed standard solution according to Table 4 and place it in 100ml volumetric flasks respectively. According to the test conditions given in Table 3, measure the atomic absorbance of each element to be measured in the mixed standard series solution and draw a standard working curve. 4.3.4.4.3 Preparation of mixed standard solution series For the preparation of mixed standard solution series, see Table 4YYKAONrKAca
Add the most
Calcium oxide standard solution
Magnesium oxide standard solution
Ferric oxide standard solution
Aluminum oxide standard solution
Copper chloride solution
Hydrochloric acid (1+1)
4.3.4.5 Explanation of results
SJ/T10722-—1996
Standard solution serial number
According to the absorbance of each element in the solution, find the concentration of the corresponding oxide from the standard working curve. The percentage of each oxide is calculated according to formula (5).
Wherein: ei - the concentration of each oxide found from the standard working curve, mg/ml; - the sample volume, g:
RO - represents calcium oxide, magnesium oxide, ferric oxide and aluminum oxide. 4.3.5 Analysis of titanium dioxide
4.3.5.1 Key points of the method
The sample is decomposed by a mixed solvent, dissolved in hydrochloric acid, and then titanium is determined by diantipyrine methane spectrophotometry. 4.3.5.2 Reagents and solutions
a) Hydrochloric acid (1+1);
b) Mixed solvent: borax + sodium carbonate + potassium carbonate = 2+1+1; c) EDTA solution: 0.04 mol;
d) Ascorbic acid solution: 5% (prepare when needed); e) Titanium dioxide standard stock solution: 0.2 mg/ml; (5)
Weigh 0.2000 g of standard titanium dioxide into a platinum pot, add 4 g of potassium pyrosulfate, heat to melt and clear, cool, place in a 200 ml beaker, add (1+1 0) 100ml of sulfuric acid, heat at low temperature to dissolve, take out the crucible, wash it, transfer the solution into a 1000ml volumetric flask, dilute it to the mark with (1+1) sulfuric acid, and shake it well; f) Titanium dioxide standard solution: 10μg/ml; accurately pipette 10ml of titanium dioxide standard stock solution into a 200ml volumetric flask, and dilute it to the mark with water; g) Diantipyrine methane solution: 1%;
Weigh 1.0g of diantipyrine methane [C23H24N.02J and dissolve it in 25ml (1+4) hydrochloric acid, and dilute it to 100ml with water. 4.3.5.3 Test steps
4.3.5.3.1 First, melt 2.0g of the mixture in a platinum crucible so that it is evenly attached to the bottom. Accurately weigh 0.300g of the sample and place it in the platinum pot. Cover it with 4.0g of the mixed flux and heat it over a gas burner at gradually increased temperature until it is melted, about 10 minutes. Move it into a high-temperature furnace and keep it at 1000℃ for 10 minutes. Take it out and cool it. Soak it with 30ml of hydrochloric acid and 40ml of hot water. When it is dissolved clearly, move it into a 100ml volumetric flask and dilute it to the scale with water. Pipette 5ml of the above solution into a 50ml volumetric flask, add 10ml of (1+1) hydrochloric acid, 5ml of ascorbic acid solution, 8ml of EDTA solution, shake well, cover for 5min, add 15ml of diantipyrine methane solution, dilute to scale with water, shake well, and measure its absorbance within 15min after color development.
At the same time, pipette 5ml of test solution into a 50ml volumetric flask, operate with the sample, but do not add diantipyrine methane solution as the sample blank, use the sample blank as the control, and measure the absorbance at a wavelength of 390nm using 2cm dual color III. 4.3.5.3.2 Drawing of standard working curve: Pipette 0, 2, 46, 8, 10 ml of titanium dioxide standard solution into 50 ml volumetric flasks respectively, add 10 ml of (1+1) hydrochloric acid, 5 ml of ascorbic acid, and 5 ml of EDTA solution, shake well, let stand for 5 minutes, add 18 ml of diantipyrine methane solution, dilute to scale with water, shake well, and measure its absorbance within 15 minutes after color development. Using No. 0 colorimetric as reference, use a 2 cm colorimetric dish to measure the absorbance of the standard series of solutions at a wavelength of 390 nm and draw a standard working curve.
4.3.5.4 Interpretation of results
According to the measured absorbance of the sample solution, find out the corresponding amount of titanium dioxide from the standard working curve. The percentage of titanium dioxide is calculated according to formula (6).
Ti0,=w××1000
W,—the amount of titanium dioxide in the sample solution obtained from the standard working curve, mg; V—the volume of the sample solution, ml;
W-—the amount of sample.
4.3.6 Analysis of ferric oxide
4.3.6.1 Key points of the method
..··(6)
Take aliquots of the sample solution used to determine titanium dioxide in 4.3.5.3 and determine iron in a weakly acidic medium using the o-phenanthroline spectrophotometric method.
4.3.6.2 Reagents and solutions
a) Ammonium acetate solution: 20%;
b) EDTA solution: 0.1mol;
c) Ascorbic acid solution: 5% (prepare when needed); d) Phenanthroline solution: 0.1% (prepare with 20% ethanol solution); e) Ferrous oxide standard solution: 10μg/ml: Accurately weigh 0.600g of ammonium ferric sulfate in a 200ml beaker, dissolve it with 50ml of sulfuric acid (5+95), transfer it to a 1000ml volumetric flask, and dilute it to the mark with water. This is the standard stock solution. Accurately pipette 10ml of the standard stock solution into a 100ml volumetric flask and dilute it to the mark with water.
4.3.6.3 Test steps
4.3.6.3.1 Place 4.3.2 (Gravimetric method) Determine the silica filtrate, evaporate and concentrate to about 80ml, cool and transfer to a 100ml volumetric flask, dilute to scale with water. Pipette 20ml~40ml of it into a 100ml volumetric flask (Note 1), add 5ml of EDTA solution, and shake well. Add 2ml of ascorbic acid solution, 10ml of o-phenanthroline solution, and 20ml of ammonium acetate solution, dilute to scale with water and shake the spoon, and leave for 30min
Pipette part of the solution, and measure the absorbance at a wavelength of 510nm on a spectrophotometer in 1cm colorimetric blood with the sample blank (see Note 2) as a reference.
Note: 1 You can also take 30ml~40ml of the remaining solution used for the determination of titanium dioxide in 4.3.5.3.1. In a 100ml volumetric flask, follow the same steps as above.
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2 Take the same amount of test solution, operate in the same steps as the test sample, and add o-ferroline solution. As the sample blank. 4.3.6.3.2 Drawing of standard working curve
Take 0, 5, 10, 15.20, 25, 30ml of ferric oxide standard solution into 100ml volumetric flasks respectively, and proceed as in 4.3.6.3.1. Take No. 0 colorimetric solution as reference and measure the absorbance of the standard series of solutions. According to the measured absorbance of the standard series of solutions, draw the relationship line between the ferric oxide content and the corresponding absorbance as the standard working curve.
4.3.6.4 Explanation of results
According to the measured absorbance of ferric oxide, find the corresponding amount of ferric oxide from the standard working curve. The percentage of ferric oxide is calculated according to formula (7). W.x100
Fe20,=W×V×1000
W,——the amount of ferric oxide in the sampled test solution from the standard working curve, mg; V-the volume of the sampled test solution, ml;
W, the sample volume, g.
4.3.7 Analysis of chromium trioxide (total chromium) (diphenylcarbazide spectrophotometry) 4.3.7.1. Key points of the method
The sample is alkali-melted and decomposed with sodium peroxide, leached with water, and filtered to remove interfering elements such as zirconium hafnium and iron. In sulfuric acid medium, chromium (VI) reacts with diphenylcarbazide to form a soluble red-purple complex, and its absorbance is measured at a wavelength of 545nm on a spectrophotometer.
4.3.7.2 Reagents and instruments
a) Sodium peroxide:
b) Sulfuric acid: (1+1);
c) Methyl orange solution: 0.2%:
d) Permanganate solution: 3% (stored in a brown bottle);
0 Urea solution: 10% (prepared when used);
0 Urea solution: 10% (prepared when used);
g) Diphenylcarbonyl disulfide solution: 0.25% (prepared with acetone when used);
Weigh 0.2829g potassium dichromate (standard reagent, dried at 150℃ for 1h) in a 150ml beaker, dissolve it with water, transfer it to a 1000ml volumetric flask, dilute it with water to the mark, and mix it. This solution contains 100ug chromium in 1ml. Pipette 10ml of the above solution into a 100ml volumetric flask, dilute it with water to the mark, and mix it. This solution contains 10μg chromium per ml; i) Spectrophotometer
4.3.7.3 Test steps
4.3.7.3.1 Weigh 0.2000g~0.5000g of sample and place it in high alumina, add 4g~6g of sodium peroxide, mix well, bake on an electric furnace until yellow, put it in a 600℃ muffle furnace, keep warm for 45min, and shake it 3~4 times in the middle. Take it out and cool it, put it in a 200ml beaker, add 50ml boiling water to soak it, wash the crucible with water, add a few drops of anhydrous ethanol, boil it on a low-temperature electric furnace until big bubbles appear, and continue for 2min~3min to destroy hydrogen peroxide. Take it out, cool it to room temperature with running water, transfer it to a 100ml volumetric flask, dilute it to the scale with water, and mix well. Transfer it to a 100ml dry beaker, let it stand and clarify, and dry filter it with quantitative dense filter paper. 4.3.7.3.2 Take 50.00ml of the filtrate (containing chromium below 4μg) and put it into a 100ml beaker, add two drops of methyl orange solution, neutralize with sulfuric acid until it turns red, then add 1.0ml of sulfuric acid. Add three drops of potassium permanganate and boil it on a low-temperature electric stove for 5 minutes. If the boiling process is too high,
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