GB/T 2679.12-1993 Qualitative analysis of inorganic fillers and inorganic coatings in paper and paperboard - Chemical method
Some standard content:
National Standard of the People's Republic of China
Qualitative analysis of mineral filler and mineral coating in paper and paperboard-Chemical method
Paper and board-Qualitative analysis of mineralfiller and mineral coating-Chemical method1Subject content and scope of application
GB/T 2679.12-93
This standard specifies the chemical qualitative analysis method for the determination of inorganic fillers and inorganic coatings in paper and paperboard. This standard is applicable to the determination of inorganic fillers in paper and paperboard, and also to the determination of inorganic coatings in coated paper. 2 Reference standards
GB450 Paper and paperboard sample collection
GB462 Determination of moisture content in paper and paperboard
GB463 Determination of ash content in paper and paperboard
GB8943.4 Determination of calcium and magnesium content in pulp, paper and paperboardGB12658 Determination of potassium and sodium content in pulp, paper and paperboardGB12910 Determination of titanium dioxide content in paper and paperboard3 Principle
Burning the paper sample at 575 ± 25℃, the ash content and appearance can roughly determine whether the filler and coating contain inorganic matter. If the filler and coating contain inorganic matter, the original paper or the ash burned from the original sample can be used for chemical identification, and the name of the inorganic matter can be inferred based on the chemical reaction phenomenon or the infrared spectrum graph. Then the content of the inorganic matter is determined according to the quantitative test method. 4 Reagents
During the analysis, analytically pure reagents must be used, and water should meet the requirements of Article 4.1. 4.1 Distilled or deionized water.
4.2 Concentrated hydrochloric acid: HCl (p20c=1.19).
4.3 1:1 (V/V) hydrochloric acid.
4.4 Dilute hydrochloric acid: c(HCl)2mol/L.
Dissolve 15mL of concentrated hydrochloric acid in 75mL of water and dilute to 100mL with water. 4.5 Lead acetate test paper
Soak the filter paper in a saturated solution of lead acetate [Pb(C,H,O,)·3H,O], take it out and air dry it for later use. 4.6 Potassium dichromate (K,Cr20,) solution: 4% (m/m). Saturated lime water solution
Dissolve about 0.2g of calcium hydroxide [Ca(OH),] in 100mL of water and filter. 4.8 Iodine solution c(1/2I2)～0.1mol/L. 4.9 Ammonium sulfate (NH.), SO4.
Approved by the State Administration of Technical Supervision on August 7, 1993 314
Implemented on March 1, 1994
4. 10 Concentrated sulfuric acid: H,SO, (p20c1.84). 4.11 Dilute sulfuric acid: 5% (m/m)
GB/T 2679.12—93
Add 3 mL of concentrated sulfuric acid to about 75 mL of water, and then dilute to 100 mL. 4.12 Hydrogen peroxide solution (H,O2): 30% (m/m). 4.13. Barium chloride solution: 10% (m/m). 4.14 Potassium ferrocyanide solution
Take 15 g of potassium ferrocyanide [K,Fe(CN). ·3HzO] and dissolve it in 1000 mL of water. 4.15 Diphenylthiocarbazide (also known as dithizone) solution Dissolve 10g of diphenylthiocarbazide in 100mL of carbon tetrachloride (CCl). 4.16 Magnesium chloride
Dissolve 0.5g of 4-nitrophenylazoresorcinol in 100mL of 1% sodium hydroxide solution.
4.17 Potassium hydroxide solution: c(KOH)～2mol/L Dissolve 11.2g of potassium hydroxide in 75mL of water, cool and dilute to 100mL. 4.18 Sodium hydroxide solution: c(NaOH)～2mol/L Dissolve 8g of sodium hydroxide in 75mL of water, cool and dilute to 100mL. Acetic acid: c(CH:COOH)=2mol/L
4.20 Morin [3,5,7,2\,4'-pentahydroxyflavanone (morin)]: Morin dissolved in a saturated solution of methanol. 4.21
Solid sodium carbonate.
Ammonium hydroxide (NH,OH) solution: 15% (m/m). 4.23
Ammonium carbonate solution: c[(NH,),CO,]~2mol/L. Ammonium oxalate [(NH),C,O] solution: 5% (m/m). 4.241
Sodium hydrogen phosphate [Na2HPO.·12H,O] solution: 20% (m/m). 4.25
Methyl red indicator solution: 1g/L
Weigh 0.1g of methyl red, dissolve it in 95% ethanol, and dilute it to 100mL with ethanol. 4.27 Methyl orange indicator solution: 1g/L
Weigh 0.1g of methyl orange and dissolve it in 100mL of distilled water. 5 Instruments
5.1 General laboratory instruments
5.2 High temperature furnace: The temperature control range is adjustable from room temperature to 1000℃. 5.3 Oven: The temperature can be adjusted to 105±2℃. 5.4 Platinum crucible with lid: 30~50mL.
5.5 Porcelain crucible: 30~50mL.
5.6 A white drip tray.
A black drip tray.
5.8 A platinum wire with a ring.
5.9 Infrared spectrophotometer and its necessary accessories. 5.10 Atomic absorption spectrophotometer and its corresponding hollow cathode lamp for the detected element. 6 Sample collection
Sample collection should be carried out in accordance with the provisions of GB450. 6.1 In order to complete each chemical analysis, a sufficient amount of sample is selected from each test unit so that the ash obtained when burned is not less than 0.2g.
GB/T 2679.12—93
6.2 In order to accurately conduct chemical analysis and verification, it is often necessary to check the original paper sample that has not been ashed. Therefore, a sufficient amount of sample should be selected from each test unit.
6.3 For the identification of inorganic substances in the coating, the coating can be peeled off manually or a sufficient amount of coating can be scraped off from the surface of the paper sample with a blade.
7 Qualitative chemical analysis method
7.1 The operation of qualitative chemical analysis is as follows.
Part I
Treat with 2mol/LHCl
Produce gas
Test for odor
Test with lime water
Precipitate as CO, (H, S and SOF does not exist) add Pb(C,H,O,)2
add K,Cr;O, turns green
turns into smoke color
(HaS does not exist)
Part 2
0.05g paper ash (575℃)
treat with (NH),SO. and hot concentrated H,SO. and separate the insoluble matter
aluminum, calcium or magnesium silicates
aluminum hydroxide, sodium aluminosilicate or diatomaceous earth
dilute with equal volume of H2O
precipitate as BaSOi|| tt||Pour out another part, dilute to 100mL, filter+
Flame test
Green is Ba, orange is Ca
Add 1mL30%H,02
Yellow-orange is Ti
Yellow is Na
Clear solution
Flame test
Green is Ba, orange is Ca
Yellow is Na
Divide into 6 parts
Take about 1/5, add BaClz
Precipitate is SO#
GB/T 2679.12—93
Part 3
0.1g paper sample ash
Treat with HCI and filter:
Take about 1/10, add K, Cr, 0
The green color is SO2
Insoluble matter
(see Part 4)
Take about 1/5, add K, Fe(CN)s
The precipitate is Zn?
Take about 1/10, add magnesium sulfate and filter
Add one drop of filtrate
Take about 2/5, add NH,OH and NH,Cl
dithiol, the purple-red color is Zn
and filter
the precipitate is acid-soluble A!
Add (NH),CO3
precipitate is Ba or Ca
Add acetic acid and K,Cr,O,
the filtrate yellow precipitate is Ba
Add (NH,),C,0
the white precipitate is Ca
calibrate with flame test
add KOH to neutralize,Acidify with acetic acid
Add mulberry pigment
Green fluorescence is Al
Sky blue precipitate is Mg
Insoluble matter
GB/T2679.12—93
Part 4
HCI insoluble matter
Use Na:CO, melt, dissolve in HCI and filter the filtrate
Add HCI as hot, if it is insoluble, add H,SO,(NH),SO, heat to remove SO
Pour into water
White precipitate is BaSO,
The sediment can be SiO,
Filtrate
Add 30%H,02
Yellow-orange is Ti
Dry, dissolve in HCI and filter
Insoluble matter is SiOz
Take 3/4, add NH,OH Take 1/4, add BaCl2+
precipitate as SO
precipitate as Al, Ti
precipitate as Ti The filtrate is acidified with
HCI
add NH, OH
precipitate as Al
add H, SO., boil and filter
precipitate as Ba
add NH, OH and (NH), C, O
and filter
add phosphate to the filtrate
precipitate as Mg
precipitate as Ca
GB/T 2679.12—93
7.2 Identification of sulfites, sulfides and carbonates (unburned paint or paper sample) 7.2.1 Place part of the unburned paint or paper sample in a small beaker or in a test tube, add 2 mol/L hydrochloric acid (4.4), and observe whether bubbles or odorous gases are released. If sulfur dioxide (SO2) or hydrogen sulfide (H2S) is released, it indicates the presence of sulfites or sulfides. Heat the beaker or test tube and test the vapor with wet lead acetate test paper (4.5). If a metallic silver-gray or black color appears, it confirms the presence of sulfides. If no sulfides are present, you can continue to add a few grains of crystalline potassium dichromate or a few drops of 4% potassium dichromate solution (4.6) to the above beaker or test tube. If a green color is produced, it indicates the presence of a reducing agent. In this case, it is most likely sulfites. In paper for filling or coating, it is not common to use a mixture of sulfites and sulfides. 7.2.2 If neither sulfites nor sulfides are present, then the presence of some carbonate is best evidenced by the presence of escaping bubbles. To test the carbon dioxide released by the decomposition of carbonates, a glass rod can be dipped into a drop of saturated lime water (4.7) just above the heated beaker or test tube containing the sample dissolved in hydrochloric acid. If the drop appears turbid (milky), it indicates the presence of carbon dioxide (CO,), which will later dissolve. When sulfites are present, the sulfites can be oxidized to sulfates. That is, iodine solution (4.8) is added drop by drop to the test beaker or test tube until the test solution turns yellow, then a glass rod is dipped into lime water (4.7) and tested as described earlier in this paragraph to verify whether carbon dioxide escapes. 7.3 Ash burning and observation Ash identification
Take a sufficient amount of sample in a crucible, carbonize at low temperature, and then move it into a high-temperature furnace and burn it at 575±25℃ (such a low temperature is used to protect the components of various fillers and coatings, or to minimize their changes. If the ash is burned according to GB463 method, the temperature is 925±25℃, then calcium carbonate will not exist), and determine its ash content and observe its ash appearance to determine whether it contains inorganic matter. If the ash content is less than 1% or slightly greater than 1%, it is light and fluffy, and inorganic fillers may not be added; if the ash content is greater than 1%, it is compact and solid, and it seems that fillers are added; if the ash content is 1%, it may also be mixed with waste paper, and other methods should be used for verification, such as microscopic determination.
During the process of sample carbonization and burning, some inorganic fillers or coatings will undergo chemical changes, such as carbonates, sulfides and sulfites. Therefore, the inspection of the above components should use unburned original paper samples. 7.4 Aluminum hydroxide, sodium aluminosilicate, aluminum, calcium or magnesium silicate, calcium or barium sulfate, titanium dioxide. 7.4.1 To about 0.05 g of ash (7.3), add 10 g of ammonium sulfate and 20 mL of concentrated sulfuric acid in a 250 mL beaker, cover with a glass watch glass, and boil for at least 3 minutes. The white smoke that appears is sulfur trioxide produced by the decomposition of sulfuric acid. 7.4.2 Under the action of such a strong acid, the insoluble matter in the ash in the beaker may be: calcium, aluminum or magnesium silicate, aluminum hydroxide or diatomaceous earth. If the hot solution is clear, it means that the above inorganic substances do not exist, and calcium and/or barium sulfate can also be dissolved in hot concentrated sulfuric acid. If the ash taken is more than 0.05 g, it may not be completely dissolved. Titanium dioxide can be dissolved in that solvent. 7.4.3 Pour some of the supernatant into a small beaker, cool it, and carefully dilute it with some cold water (dilute to 5 times the original volume). If a white precipitate is formed during dilution, it indicates the presence of barium sulfate. This is because barium sulfate is relatively soluble in hot concentrated sulfuric acid, but not in dilute sulfuric acid.
7.4.4 After cooling the strong acid-treated product in 7.4.2, dilute it with water to 5 times the original volume, mix it with the test solution in 7.4.3 and filter it. The residue is reserved for the test in 7.4.5. Add 1 mL of 30% hydrogen peroxide solution (4.12) to the filtrate obtained. If the solution appears yellow or orange at this time, it indicates that titanium is present. The depth of its color is proportional to the titanium content. If only a slightly yellow color is produced, it may be caused by titanium in kaolin or titanium dissolved in the production water of the industrial plant. 7.4.5 The residue obtained in 7.4.4 can be determined by the following flame color test to determine whether it contains calcium and barium. Take a platinum wire loop and dip it in the wet residue left on the filter paper, and bring it to the flame of an alcohol burner to observe the color of the flame: green flame: indicates a barium compound; red flame: indicates a calcium compound; yellow flame: indicates aluminum and/or magnesium silicate, aluminum hydroxide.
7.4.6 The flame color test can be used to detect the soluble calcium and sodium in the clear solution obtained in 7.4.3. The method is to carefully dilute a small part of the solution with an equal volume of water, dip the platinum wire in this solution, and bring it to the flame of an alcohol burner to observe the color of the flame: green flame: indicates a barium compound red flame: indicates a calcium compound; strong yellow flame: indicates a sodium compound. 7.5 Sulfide: Identification of sulfites and carbonates (using the ash from the sample burned at 575 ± 25℃) 319
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7.5.1 Take about 0.1g of ash (7.3) in a small beaker, moisten it with a small amount of water, add 10mL of 1:1 hydrochloric acid (4.3), and observe it in the same way as in 7.2.1. If bubbles are precipitated, it indicates the presence of a carbonate. Take out 1-2mL of the solution and add 2 drops of 4% potassium dichromate solution (4.6). The green color produced indicates the presence of sulfites. 7.5.2 Heat the contents of the above small beaker to boiling, and test the flue gas with wet lead acetate test paper. If metallic gray or black appears, it indicates the presence of sulfides.
These tests of 7.5.1 and 7.5.2 should be checked with the original paper for comparison test, because carbonates may be lost during ignition, carbonates may be reduced to sulfites or sulfides, or sulfites and sulfides may be oxidized to sulfates. All this depends on the temperature and oxidation conditions during ignition.
, ..7.5.3 If the contents of the small beaker of 7.5.1 are not completely dissolved, boil them for 5 minutes, then add 35 mL of water and heat to boil again. If this solution is still not clear, filter it through quantitative tight filter paper, wash it with twice the amount of water in the solution, and use the filtrate for analysis of the acid soluble part (7.6). Wash the insoluble residue thoroughly until there is no acid reaction [check with methyl orange indicator solution (4.27)], discard the washing solution, and retain the acid insoluble matter on the filter paper for the test of 7.7. 7.6 Sulfates of zinc, magnesium, aluminum, barium, and calcium 7.6.1 Take about 1/5 of the volume of the acid-soluble filtrate obtained in 7.5.3 and add 1 mL of barium chloride solution (4.13). If a precipitate appears, or if a precipitate appears after heating for 10 min, it indicates the presence of sulfate. Take about 1/5 of the volume of the filtrate and add a few mL of potassium ferrocyanide solution (4.14). A thick white precipitate appears, indicating the presence of zinc. The presence of zinc can be confirmed by reducing it to red in the disulfide test in the next section.
7.6.2 Take a drop of the acid-soluble filtrate obtained in 7.5.3 and place it on a glass surface. Add 1 drop of 2 mol/L sodium hydroxide solution (4.18) and a few drops of disulfide solution (4.15). When stirred with a glass rod, the carbon tetrachloride evaporates and the solution appears purple-red, confirming the presence of zinc. Other colors of the precipitate can be ignored. 7.6.3 Take the retained filtrate (7.5.3) Add 1-2 drops of tryptone (4.16) to 3/5 volume of the sample and alkalize with sodium hydroxide solution (4.18). A sky-blue precipitate is produced, indicating the presence of magnesium, whereas other inorganic substances used in ordinary paper give a purple (different from sky-blue) solution. Be careful not to add excess reagent, because even if magnesium is present, the excess may mask the blue precipitate. If in doubt, filter the solution and check whether there is a blue precipitate on the filter paper. 7.6.4 Take 1 mL of the acid-soluble filtrate (7.5.3), add 2 mol/L potassium hydroxide solution (4.17) to neutralize and make it excessive. Take 1 drop of this solution, acidify it with 2 mol/L acetic acid (4.19) on a black drip tray, and then add 1 drop of morin solution (4.20). If aluminum is present, this mixture will show a green fluorescence when examined at night or under ultraviolet light. : 7.6.5 Add ammonium hydroxide solution (4.22) drop by drop to the remaining acid-soluble filtrate (7.5.3) to neutralize until ammonia smell appears. If aluminum exists in the form of acid dissolution, a white flocculent precipitate will be produced. Filter and discard the precipitate, add ammonium carbonate solution (4.23) to the filtrate, if a white precipitate appears, it indicates the presence of calcium and barium, do not filter, acidify the solution with acetic acid (4.19) (acetic acid will dissolve the precipitate), add potassium dichromate solution (4.6), if barium exists in the form of acid dissolution, a yellow precipitate will be produced, filter and discard the yellow precipitate, add excess ammonium carbonate solution (4.23), a white precipitate will appear, indicating that it is calcium (barium has been removed during the operation). For the inspection of calcium, you can also check the precipitate according to the flame color test in 7.4.5. 7.7 Silicates of magnesium and aluminum (talc, kaolin), aluminum hydroxide, and sulfates 7.7.1 Place the filter paper of the acid-insoluble matter retained in 7.5.3 into a platinum crucible, dry, carbonize, and burn to remove organic matter, cool, and add 1-2 g of anhydrous sodium carbonate to mix, place in a high-temperature furnace at 925-1000°C to melt for half an hour, remove and cool, add a small amount of water to the crucible, gently rotate the frit left and right with a glass rod to make the frit fall off, place it with the lid in a 250 mL beaker containing 20 mL of water, cover the surface with blood, and slowly add 20 mL of 1:1 hydrochloric acid solution (4.3) to dissolve the frit. After the action stops, wash the crucible and lid, remove, heat to boiling, stir and filter. Save the residue for analysis in 7.8. 7.7.2 Evaporate the filtrate obtained in 7.7.1 to dryness on a water bath, add 5 mL of concentrated hydrochloric acid (4.2) and 40 mL of water, and heat. If a bright insoluble flocculent appears in the solution, this may be due to the precipitation of silicon in the silicate after dehydration. It is best to observe with the help of a smoked background. Let it stand for a while and then filter.
7.7.3 Take 1/4 volume of the filtrate obtained in 7.7.2 and add 5 mL of barium chloride solution (4.13). If a precipitate appears, it indicates the presence of sulfate. Slowly add ammonium hydroxide solution (4.22) to the remaining 3/4 volume of the filtrate. If a white gelatinous precipitate appears, it indicates the presence of aluminum. Heat and filter the precipitate, combine it with 7.7.1 and save it for analysis in 7.8. Add 5 mL of 5% sulfuric acid (4.11) to the filtrate. At this time, barium precipitates in the form of barium sulfate. Then boil and filter. Alkalinize the filtrate with ammonia until it smells ammonia. Add ammonium oxalate solution (4.24) to ensure that calcium precipitation is complete. If calcium precipitates, filter out the precipitate. Then add 5 mL of ammonium hydroxide solution (4.22) and excess (about 5 mL) of disodium hydrogen phosphate solution (4.25) or ammonium hydrogen phosphate solution. Stir evenly. Precipitation within 15 minutes indicates the presence of magnesium compounds. Of course, the identification of magnesium can also be tested with magnesium alkaloid according to the method in 7.6.3. 7.8 Silicon dioxide, barium sulfate and titanium dioxide. Wash the residue stored in 7.7.1 and the precipitate of aluminum hydroxide tested in 7.7.3 with a thin stream of water and return the precipitate to the original beaker. Add 5 mL of concentrated hydrochloric acid (4.2). If it is not completely dissolved, add 10 mL of concentrated sulfuric acid (4.10) and heat in a fume hood until sulfur trioxide smoke appears. After cooling, pour into 35 mL of water. If white precipitate appears, it is sulfuric acid, because barium sulfate will not be melted and decomposed by sodium carbonate and can be dissolved in hot concentrated sulfuric acid. Filter out the precipitate, add 2 drops of methyl red indicator (4.26), neutralize with 2 mol/L sodium hydroxide solution (4.18), and add sodium hydroxide of the same volume as the solution required for neutralization. Heat to boiling and cool. If the precipitate appears, it is titanium hydroxide (for the identification of titanium, you can also treat the above residue with ammonium sulfate and sulfuric acid according to the method of 7.4, and add hydrogen peroxide solution to the treated solution for testing). Filter out the titanium hydroxide precipitate. The filtrate is neutralized with 1:1 hydrochloric acid (4.3), heated to boiling, and then neutralized with ammonium hydroxide solution (4.22) until an ammonia smell is detected (add 2 to 3 drops after the methyl red in the solution changes color). If a precipitate is generated, it is aluminum hydroxide [AI(OH)].
7.9 Observation and interpretation of phenomena in qualitative chemical tests 7.9.1 The inorganic components contained in fillers and coatings in paper can be judged according to the following specified chapters Experiment Calcium carbonate: Ca (7.6.5), CO2 (7.2.2) Calcium carbonate with magnesium hydroxide or other carbonates: Ca (7.6.5).Mg (7.6.3), CO2 (7.2.2) Calcium sulfite: Ca (7.6.5), SO, (7.2.1) Calcium sulfate: Ca (7.6.5), SO ( 7.6.1) Barium carbonate: Ba (7.6.5), CO, (7.2.2) Sulfuric acid: Ba (7.4.3, 7.8), SO (7.7.3) Lithopone (lithopone, sulfide): sulfide (7.2.1), Zn (7.6.1, 7.6.2), Ba (7.4.3, 7.8), SO (7.7.3)
Zinc oxide: Zn (7.6.1, 7.6.2)
Zinc sulfide: Zn (7.6 .1,7.6.2), sulfide (7.2.1) Titanium dioxide-barium sulfate: Ti (7.4.4,7.8), Ba (7.4.3,7.8), SO (7.7.3) Titanium dioxide-calcium sulfate: Ti (7.4.4,7.8), Ca7.6.5), SO (7.6.1) Satin white (paint): Al (7.6.4,7.6.5), Ca (7.6.5), SO (7.6.1) Sodium aluminosilicate: Na (7.4.6), Al (7.6 .4,7.6.5,7.7.3),SiO2(7.7.2)Aluminum hydroxide: A1(7.6.4,7.6.5,7.7.3)Kaolin: Al(7.7.3,7.8)
Diatomaceous earth: SiO2(7.7.2)
Talc: Mg(7.6.3),SiO2(7.7.2)7.9.2Sulfide is used as filler or coating in papermaking industry, which is limited to zinc sulfide alone or combined with sulfate (zinc barium white). In the absence of sulfide, zinc is detected, indicating that zinc oxide is used. Sulfite is detected, and calcium sulfite is generally used. 7.9.3 Most commercial fillers contain impurities, such as satin white may contain calcium carbonate, kaolin (such as American kaolin) may contain a small amount of titanium, and may also contain calcium and magnesium; titanium dioxide may contain a small amount of aluminum and sulfate; calcium fillers may contain magnesium; sulfide and sulfite fillers usually contain sulfate, so be careful when making judgments. 7.9.4 Aluminum is used in the ordinary papermaking process, so even when no filler is added, it will also lead to the presence of considerable amounts of aluminum compounds. In paper without fillers, small amounts or traces of calcium sulfate and magnesium sulfate, etc., may also be detected, which come from the pulp and the hard water used in the mill. 321
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7.9.5 Carbonates usually exist with many acid-soluble calcium salts, such as chalk or satin white. If it can be dissolved with hydrochloric acid, it may contain magnesium, showing a mixture of calcium carbonate and magnesium carbonate. A mixture of barium and carbonate may exist in the form of spar. In this form, when the ash is treated with hydrochloric acid, barium can be dissolved and detected because barium sulfate is insoluble in dilute hydrochloric acid. 7.9.6 The test proves that the inorganic substance is an acid-soluble sulfate, and calcium is detected, indicating that the high-quality filler calcium sulfate, gypsum, satin white, etc. is used. If there is a considerable amount of hydrochloric acid-soluble aluminum in the paint, then the inorganic substance used may be satin white or aluminum hydroxide. If carbonates and sulfides are used in combination, there is no sulfate, but sulfate may be detected during the test. 7.9.7 The test confirms the presence of calcium and sulfite, indicating that industrial calcium sulfate is used. 7.9.8 The presence of considerable amounts of magnesium and silicates indicates that talc, fibrous talc or micro-asbestos is used. The detection of only silicon dioxide indicates that silica is used, and the diatomaceous earth shape can be identified by microscopic examination. 7.9.9 The partial residue obtained by treating the ash with concentrated sulfuric acid may be kaolin, talc, sodium aluminosilicate, calcium silicate, diatomaceous earth, aluminum hydroxide or a mixture of these substances. If the presence of aluminum is confirmed in the test, it indicates that kaolin, sodium aluminosilicate or aluminum hydroxide is used.
Barium sulfate (baryte or barium sulfate powder) is shown to be soluble in hot concentrated sulfuric acid when tested, but forms a precipitate in dilute sulfuric acid. This can be confirmed by flame color test of the residue. 7.9.11 Titanium generally exists in the form of titanium dioxide. Titanium barium pigment (BaSO4-TiO2) and titanium calcium pigment (CaSO4-TiO2) are usually used in papermaking.
8 Infrared spectroscopy analysis
The chemical qualitative analysis method in Chapter 7 detects inorganic ions. During the test, not only the inorganic ions that make up the filler and coating can be detected, but sometimes the inorganic ions of impurities can also be detected. This makes identification difficult, as it is difficult to distinguish whether it is filled or coated or impurities, and the chemical qualitative analysis uses many chemicals and the steps are complicated.
If infrared spectroscopy can be combined with chemical qualitative analysis, the identification work can usually be simplified. Because infrared not only detects the groups in the molecule, but also after the substance is slightly purified, its scanning spectrum represents the characteristic spectrum of the entire inorganic substance. When the impurity is less than 5%, it cannot be detected. Based on the characteristic spectrum, the name of the inorganic substance in the filler and coating can be inferred, so that the identification can be fast and accurate. 8.1 Carbonize an appropriate amount of paper sample according to the method in 7.2, burn it into ash, take a small amount of ash and press it into a tablet with potassium bromide, then scan it with an infrared spectrophotometer, and compare the infrared spectrum obtained by scanning with the standard spectrum. If the inorganic filler and coating in the sample are single-component, the spectrum obtained by scanning is the same as the standard spectrum of the inorganic substance of the component, so it is easy to get the name of the inorganic substance (the infrared spectra of various single-component inorganic substances are attached for reference).
If the inorganic filler and coating are a mixture of two to three inorganic substances, then the inorganic substances of various components will have peaks on the infrared spectrum, so the name of the inorganic substance can be inferred in a targeted manner based on the peak shape and peak position of the infrared spectrum (Figure 16 is an overlapping infrared spectrum of calcium carbonate and kaolin, and Figure 12 is an overlapping infrared spectrum of sodium sulfate and titanium dioxide). 8.2 Mixture of carbonate and titanium dioxide
Infrared scanning diagram If calcium carbonate and titanium dioxide are mixed, then take about 0.1g of the ash obtained in 7.2 and add 10mL of 2mol/L hydrochloric acid solution (4.4) to dissolve it. If a large number of bubbles appear, it proves that it is carbonate, and heat it to dissolve the carbonate. Filter and wash with hot water until it is no longer acidic [check with methyl orange indicator (4.27)]. Perform the calcium confirmation test on the filtrate by chemical method according to the method in 7.6.5. The acid insoluble matter on the filter paper is dried and carbonized in a crucible and burned to ash at 925℃. The ash is pressed into a potassium bromide tablet for infrared spectrum scanning. The spectrum obtained should be the disappearance of the carbonate peak, and the spectrum should be the same as the titanium dioxide spectrum to be confirmed. 8.3 Silicate (kaolin or talc) and titanium dioxide If the scanning spectrum of the ash is silicate and titanium dioxide, two methods can be used to confirm it: 8.3.1 Take 0.1g of paper ash, add 10g of ammonium sulfate and 20mL of concentrated sulfuric acid, cover with a watch glass and boil for at least 3min to dissolve the titanium dioxide. After cooling, carefully pour it into 200mL of distilled water, cool and filter, and add 5mL of 30% hydrogen peroxide (4.12) to the filtrate. If yellow color appears, it means the presence of titanium dioxide. The residue on the filter paper is thoroughly washed, dried again, and burned into ash. The ash is subjected to infrared scanning. At this time, the peak of titanium dioxide should disappear, leaving only the peak of silicate. Compare it with the standard chart to identify whether it is kaolin or talc. 322
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8.3.2 Take 0.1g of ash and melt it with sodium carbonate according to the method of 7.7.1, dissolve it with 1:1 hydrochloric acid, and make the confirmation test of magnesium or aluminum ion according to 7.6.3 and 7.6.4 respectively. The precipitate must be a mixture of silicon dioxide and titanium dioxide. 8.4 Titanium calcium pigment (CaSO-TiO,)
If titanium calcium pigment is observed from the infrared spectrum of the sample ash, take 0.1g of the paper ash treated in 7.2, add 20mL of 1:1 hydrochloric acid solution (4.3), heat to boil, dilute with 20mL of water, and filter. First wash with dilute hydrochloric acid (4.4), then wash with hot water until there is no acidic reaction [use methyl orange indicator (4.27) for inspection test, the filtrate is tested for calcium sulfate according to the methods of 7.6.5 and 7.6.1 respectively, the residue is dried and burned, and the infrared spectrum of titanium dioxide is tested according to the above method. 8.5 Titanium barium pigment (BaSO4-TiO,)
If it is observed from the spectrum of the sample ash that it is titanium barium pigment, this can only be further confirmed by the following method: The method is to take 0.1g of the ash in 7.2, heat and dissolve the ash with ammonium sulfate-concentrated sulfuric acid according to the method of 7.4.1, and after cooling, pour it into 200mL of water. If a white precipitate appears, it is barium sulfate. Add 5mL of 30% hydrogen peroxide to the supernatant and it should turn yellow, the depth of which is proportional to the content of titanium dioxide. If the precipitated barium sulfate is filtered, washed, dried, and burned, and its ash is scanned by infrared again, the spectrum of barium sulfate will appear. 8.6 Zinc barium white (ZnS-BaSO4)bzxZ.net
After scanning the ash of the sample, if the spectrum of zinc barium white appears, you can take another 0.1g of the ash in 7.2, add 1:1 hydrochloric acid to dissolve, filter, and perform the zinc confirmation test for the filtrate according to the method in 7.6.1, and the confirmation test for sulfide according to the method in 7.2. The residue is burned again to make an infrared spectrum and compared with the barium sulfate spectrum. In short, infrared spectroscopy is to perform infrared scanning on the ash of the original sample, and then preliminarily judge the most likely inorganic components based on the peak shape of the spectrum, and then use chemical methods to perform targeted separation, dissolve one of the components, and identify it by qualitative method, while the other component is still a solid precipitate, and is scanned again for identification after drying. 4000
Figure 1 Infrared spectrum of talc (unburned)
Figure 2 Infrared spectrum of talc (burned below 600℃) 200(cm-\)
200 Counts(cm-)
GB/T 2679.12—93
200 Counts(cm-\）
Figure 3 Infrared spectrum of talc in double-sided offset printing paper (burned at 900℃) 200 Counts(cm~\)
Figure 4 Infrared spectrum of magnesium oxide
200 Counts(cm\）
Infrared spectrum of kaolin
200 Counts(cm-\）
Figure 6 Infrared spectrum of kaolin in paper (burned below 600℃) 4000
GB/T 2679. 12-93
Infrared spectra of calcium sulfate with two crystal watersFigure 7
Figure 8 Infrared spectra of calcium sulfate in paper (burned below 600℃)Figure 9 Infrared spectra of zinc oxide
Figure 10 Infrared spectra of titanium dioxide in decorative paper200 um (cm-)
200 um (cm-\
200 um (cm-\)
200 um (cm-t)According to the method of item 2, carbonize an appropriate amount of paper sample and burn it into ash. Take a small amount of ash and press it into a tablet with potassium bromide, then scan it with an infrared spectrophotometer, and compare the infrared spectrum obtained by scanning with the standard spectrum. If the inorganic filler and coating in the sample are single components, the spectrum obtained by scanning is the same as the standard spectrum of the inorganic substance of the component, so it is easy to get the name of the inorganic substance (the infrared spectra of various single-component inorganic substances are attached for reference).
If the inorganic filler and coating are a mixture of two to three inorganic substances, then the inorganic substances of various components will have peaks on the infrared spectrum, so the name of the inorganic substance can be inferred in a targeted manner based on the peak shape and peak position of the infrared spectrum (Figure 16 is an overlapping infrared spectrum of calcium carbonate and kaolin, and Figure 12 is an overlapping infrared spectrum of sodium sulfate and titanium dioxide). 8.2 Mixing of carbonate and titanium dioxide
Infrared scanning graph If calcium carbonate and titanium dioxide are mixed, take about 0.1g of the ash obtained in 7.2 and add 10mL of 2mol/L hydrochloric acid solution (4.4) to dissolve it. If a large number of bubbles appear, it proves that it is carbonate. Heat to dissolve the carbonate. Filter and wash with hot water until it is no longer acidic [check with methyl orange indicator solution (4.27)]. The filtrate is chemically tested for calcium according to the method in 7.6.5. The acid-insoluble matter on the filter paper is placed in a crucible for drying and carbonization, and burned at 925℃ to ash. The ash is then pressed with potassium bromide tablets for infrared spectroscopy scanning. The resulting spectrum should be the disappearance of the carbonate peak, and the spectrum should be the same as the titanium dioxide spectrum to be confirmed. 8.3 Silicate (kaolin or talc) and titanium dioxide If the scanning spectrum of the ash is silicate and titanium dioxide, two methods can be used to confirm it: 8.3.1 Take 0.1g of paper ash, add 10g of ammonium sulfate and 20mL of concentrated sulfuric acid, cover with a watch glass and boil for at least 3min to dissolve the titanium dioxide. After cooling, carefully pour it into 200mL of distilled water, cool and filter, and add 5mL of 30% hydrogen peroxide (4.12) to the filtrate. If yellow color appears, it means the presence of titanium dioxide. The residue on the filter paper is thoroughly washed, dried again, and burned into ash. The ash is subjected to infrared scanning. At this time, the peak of titanium dioxide should disappear, leaving only the peak of silicate. Compare it with the standard chart to identify whether it is kaolin or talc. 322
GB/T 2679. 12-~93
8.3.2 Take 0.1g of ash and melt it with sodium carbonate according to the method of 7.7.1, dissolve it with 1:1 hydrochloric acid, and make the confirmation test of magnesium or aluminum ion according to 7.6.3 and 7.6.4 respectively. The precipitate must be a mixture of silicon dioxide and titanium dioxide. 8.4 Titanium calcium pigment (CaSO-TiO,)
If titanium calcium pigment is observed from the infrared spectrum of the sample ash, take 0.1g of the paper ash treated in 7.2, add 20mL of 1:1 hydrochloric acid solution (4.3), heat to boil, dilute with 20mL of water, and filter. First wash with dilute hydrochloric acid (4.4), then wash with hot water until there is no acidic reaction [use methyl orange indicator (4.27) for inspection test, the filtrate is tested for calcium sulfate according to the methods of 7.6.5 and 7.6.1 respectively, the residue is dried and burned, and the infrared spectrum of titanium dioxide is tested according to the above method. 8.5 Titanium barium pigment (BaSO4-TiO,)
If it is observed from the spectrum of the sample ash that it is titanium barium pigment, this can only be further confirmed by the following method: The method is to take 0.1g of the ash in 7.2, heat and dissolve the ash with ammonium sulfate-concentrated sulfuric acid according to the method of 7.4.1, and after cooling, pour it into 200mL of water. If a white precipitate appears, it is barium sulfate. Add 5mL of 30% hydrogen peroxide to the supernatant and it should turn yellow, the depth of which is proportional to the content of titanium dioxide. If the precipitated barium sulfate is filtered, washed, dried, and burned, and its ash is scanned by infrared again, the spectrum of barium sulfate will appear. 8.6 Zinc barium white (ZnS-BaSO4)
After scanning the ash of the sample, if the spectrum of zinc barium white appears, you can take another 0.1g of the ash in 7.2, add 1:1 hydrochloric acid to dissolve, filter, and perform the zinc confirmation test for the filtrate according to the method in 7.6.1, and the confirmation test for sulfide according to the method in 7.2. The residue is burned again to make an infrared spectrum and compared with the barium sulfate spectrum. In short, infrared spectroscopy is to perform infrared scanning on the ash of the original sample, and then preliminarily judge the most likely inorganic components based on the peak shape of the spectrum, and then use chemical methods to perform targeted separation, dissolve one of the components, and identify it by qualitative method, while the other component is still a solid precipitate, and is scanned again for identification after drying. 4000
Figure 1 Infrared spectrum of talc (unburned)
Figure 2 Infrared spectrum of talc (burned below 600℃) 200(cm-\)
200 Counts(cm-)
GB/T 2679.12—93
200 Counts(cm-\）
Figure 3 Infrared spectrum of talc in double-sided offset printing paper (burned at 900℃) 200 Counts(cm~\)
Figure 4 Infrared spectrum of magnesium oxide
200 Counts(cm\）
Infrared spectrum of kaolin
200 Counts(cm-\）
Figure 6 Infrared spectrum of kaolin in paper (burned below 600℃) 4000
GB/T 2679. 12-93
Infrared spectra of calcium sulfate with two crystal watersFigure 7
Figure 8 Infrared spectra of calcium sulfate in paper (burned below 600℃)Figure 9 Infrared spectra of zinc oxide
Figure 10 Infrared spectra of titanium dioxide in decorative paper200 um (cm-)
200 um (cm-\
200 um (cm-\)
200 um (cm-t)According to the method of item 2, carbonize an appropriate amount of paper sample and burn it into ash. Take a small amount of ash and press it into a tablet with potassium bromide, then scan it with an infrared spectrophotometer, and compare the infrared spectrum obtained by scanning with the standard spectrum. If the inorganic filler and coating in the sample are single components, the spectrum obtained by scanning is the same as the standard spectrum of the inorganic substance of the component, so it is easy to get the name of the inorganic substance (the infrared spectra of various single-component inorganic substances are attached for reference).
If the inorganic filler and coating are a mixture of two to three inorganic substances, then the inorganic substances of various components will have peaks on the infrared spectrum, so the name of the inorganic substance can be inferred in a targeted manner based on the peak shape and peak position of the infrared spectrum (Figure 16 is an overlapping infrared spectrum of calcium carbonate and kaolin, and Figure 12 is an overlapping infrared spectrum of sodium sulfate and titanium dioxide). 8.2 Mixing of carbonate and titanium dioxide
Infrared scanning graph If calcium carbonate and titanium dioxide are mixed, take about 0.1g of the ash obtained in 7.2 and add 10mL of 2mol/L hydrochloric acid solution (4.4) to dissolve it. If a large number of bubbles appear, it proves that it is carbonate. Heat to dissolve the carbonate. Filter and wash with hot water until it is no longer acidic [check with methyl orange indicator solution (4.27)]. The filtrate is chemically tested for calcium according to the method in 7.6.5. The acid-insoluble matter on the filter paper is placed in a crucible for drying and carbonization, and burned at 925℃ to ash. The ash is then pressed with potassium bromide tablets for infrared spectroscopy scanning. The resulting spectrum should be the disappearance of the carbonate peak, and the spectrum should be the same as the titanium dioxide spectrum to be confirmed. 8.3 Silicate (kaolin or talc) and titanium dioxide If the scanning spectrum of the ash is silicate and titanium dioxide, two methods can be used to confirm it: 8.3.1 Take 0.1g of paper ash, add 10g of ammonium sulfate and 20mL of concentrated sulfuric acid, cover with a watch glass and boil for at least 3min to dissolve the titanium dioxide. After cooling, carefully pour it into 200mL of distilled water, cool and filter, and add 5mL of 30% hydrogen peroxide (4.12) to the filtrate. If yellow color appears, it means the presence of titanium dioxide. The residue on the filter paper is thoroughly washed, dried again, and burned into ash. The ash is subjected to infrared scanning. At this time, the peak of titanium dioxide should disappear, leaving only the peak of silicate. Compare it with the standard chart to identify whether it is kaolin or talc. 322
GB/T 2679. 12-~93
8.3.2 Take 0.1g of ash and melt it with sodium carbonate according to the method of 7.7.1, dissolve it with 1:1 hydrochloric acid, and make the confirmation test of magnesium or aluminum ion according to 7.6.3 and 7.6.4 respectively. The precipitate must be a mixture of silicon dioxide and titanium dioxide. 8.4 Titanium calcium pigment (CaSO-TiO,)
If titanium calcium pigment is observed from the infrared spectrum of the sample ash, take 0.1g of the paper ash treated in 7.2, add 20mL of 1:1 hydrochloric acid solution (4.3), heat to boil, dilute with 20mL of water, and filter. First wash with dilute hydrochloric acid (4.4), then wash with hot water until there is no acidic reaction [use methyl orange indicator (4.27) for inspection test, the filtrate is tested for calcium sulfate according to the methods of 7.6.5 and 7.6.1 respectively, the residue is dried and burned, and the infrared spectrum of titanium dioxide is tested according to the above method. 8.5 Titanium barium pigment (BaSO4-TiO,)
If it is observed from the spectrum of the sample ash that it is titanium barium pigment, this can only be further confirmed by the following method: The method is to take 0.1g of the ash in 7.2, heat and dissolve the ash with ammonium sulfate-concentrated sulfuric acid according to the method of 7.4.1, and after cooling, pour it into 200mL of water. If a white precipitate appears, it is barium sulfate. Add 5mL of 30% hydrogen peroxide to the supernatant and it should turn yellow, the depth of which is proportional to the content of titanium dioxide. If the precipitated barium sulfate is filtered, washed, dried, and burned, and its ash is scanned by infrared again, the spectrum of barium sulfate will appear. 8.6 Zinc barium white (ZnS-BaSO4)
After scanning the ash of the sample, if the spectrum of zinc barium white appears, you can take another 0.1g of the ash in 7.2, add 1:1 hydrochloric acid to dissolve, filter, and perform the zinc confirmation test for the filtrate according to the method in 7.6.1, and the confirmation test for sulfide according to the method in 7.2. The residue is burned again to make an infrared spectrum and compared with the barium sulfate spectrum. In short, infrared spectroscopy is to perform infrared scanning on the ash of the original sample, and then preliminarily judge the most likely inorganic components based on the peak shape of the spectrum, and then use chemical methods to perform targeted separation, dissolve one of the components, and identify it by qualitative method, while the other component is still a solid precipitate, and is scanned again for identification after drying. 4000
Figure 1 Infrared spectrum of talc (unburned)
Figure 2 Infrared spectrum of talc (burned below 600℃) 200(cm-\)
200 Counts(cm-)
GB/T 2679.12—93
200 Counts(cm-\）
Figure 3 Infrared spectrum of talc in double-sided offset printing paper (burned at 900℃) 200 Counts(cm~\)
Figure 4 Infrared spectrum of magnesium oxide
200 Counts(cm\）
Infrared spectrum of kaolin
200 Counts(cm-\）
Figure 6 Infrared spectrum of kaolin in paper (burned below 600℃) 4000
GB/T 2679. 12-93
Infrared spectra of calcium sulfate with two crystal watersFigure 7
Figure 8 Infrared spectra of calcium sulfate in paper (burned below 600℃)Figure 9 Infrared spectra of zinc oxide
Figure 10 Infrared spectra of titanium dioxide in decorative paper200 um (cm-)
200 um (cm-\
200 um (cm-\)
200 um (cm-t)1. Perform the confirmation test of calcium sulfate respectively, dry and burn the residue, and perform the confirmation test of titanium dioxide infrared spectrum according to the above method. 8.5 Titanium barium pigment (BaSO4-TiO,)
If it is observed from the spectrum of the sample ash that it is titanium barium pigment, this can only be further confirmed by the following method: The method is to take 0.1g of the ash in 7.2, heat and dissolve the ash with ammonium sulfate-concentrated sulfuric acid according to the method of 7.4.1, and after cooling, pour it into 200mL of water. If a white precipitate appears, it is barium sulfate. Add 5mL30% hydrogen peroxide to the supernatant and it should turn yellow. The depth is proportional to the content of titanium dioxide. If the precipitated barium sulfate is filtered, washed, dried, and burned, and the ash is scanned by infrared again, the spectrum of barium sulfate will appear. 8.6 Zinc barium white (ZnS-BaSO4)
After scanning the ash of the sample, if the spectrum of zinc barium white appears, you can take another 0.1g of the ash in 7.2, add 1:1 hydrochloric acid to dissolve, filter, and perform the zinc confirmation test according to the method in 7.6.1 for the filtrate, and perform the confirmation test for sulfide according to the method in 7.2. The residue is burned again to make an infrared spectrum and compare it with the barium sulfate spectrum. In short, infrared spectroscopy is to perform infrared scanning through the ash of the original sample, and then preliminarily judge the most likely inorganic components based on the peak shape of the spectrum, and then use chemical methods to perform targeted separation, dissolve one of the components, and identify it by qualitative method, while the other component is still a solid precipitate, which is scanned again after drying for identification. 4000
Figure 1 Infrared spectrum of talc (unburned)
Figure 2 Infrared spectrum of talc (burned below 600℃) 200(cm-\)
200 Counts(cm-)
GB/T 2679.12—93
200 Counts(cm-\）
Figure 3 Infrared spectrum of talc in double-sided offset printing paper (burned at 900℃) 200 Counts(cm~\)
Figure 4 Infrared spectrum of magnesium oxide
200 Counts(cm\）
Infrared spectrum of kaolin
200 Counts(cm-\）
Figure 6 Infrared spectrum of kaolin in paper (burned below 600℃) 4000
GB/T 2679. 12-93
Infrared spectra of calcium sulfate with two crystal watersFigure 7
Figure 8 Infrared spectra of calcium sulfate in paper (burned below 600℃)Figure 9 Infrared spectra of zinc oxide
Figure 10 Infrared spectra of titanium dioxide in decorative paper200 um (cm-)
200 um (cm-\
200 um (cm-\)
200 um (cm-t)1. Perform the confirmation test of calcium sulfate respectively, dry and burn the residue, and perform the confirmation test of titanium dioxide infrared spectrum according to the above method. 8.5 Titanium barium pigment (BaSO4-TiO,)
If it is observed from the spectrum of the sample ash that it is titanium barium pigment, this can only be further confirmed by the following method: The method is to take 0.1g of the ash in 7.2, heat and dissolve the ash with ammonium sulfate-concentrated sulfuric acid according to the method of 7.4.1, and after cooling, pour it into 200mL of water. If a white precipitate appears, it is barium sulfate. Add 5mL30% hydrogen peroxide to the supernatant and it should turn yellow. The depth is proportional to the content of titanium dioxide. If the precipitated barium sulfate is filtered, washed, dried, and burned, and the ash is scanned by infrared again, the spectrum of barium sulfate will appear. 8.6 Zinc barium white (ZnS-BaSO4)
After scanning the ash of the sample, if the spectrum of zinc barium white appears, you can take another 0.1g of the ash in 7.2, add 1:1 hydrochloric acid to dissolve, filter, and perform the zinc confirmation test according to the method in 7.6.1 for the filtrate, and perform the confirmation test for sulfide according to the method in 7.2. The residue is burned again to make an infrared spectrum and compare it with the barium sulfate spectrum. In short, infrared spectroscopy is to perform infrared scanning through the ash of the original sample, and then preliminarily judge the most likely inorganic components based on the peak shape of the spectrum, and then use chemical methods to perform targeted separation, dissolve one of the components, and identify it by qualitative method, while the other component is still a solid precipitate, which is scanned again after drying for identification. 4000
Figure 1 Infrared spectrum of talc (unburned)
Figure 2 Infrared spectrum of talc (burned below 600℃) 200(cm-\)
200 Counts(cm-)
GB/T 2679.12—93
200 Counts(cm-\）
Figure 3 Infrared spectrum of talc in double-sided offset printing paper (burned at 900℃) 200 Counts(cm~\)
Figure 4 Infrared spectrum of magnesium oxide
200 Counts(cm\）
Infrared spectrum of kaolin
200 Counts(cm-\）
Figure 6 Infrared spectrum of kaolin in paper (burned below 600℃) 4000
GB/T 2679. 12-93
Infrared spectra of calcium sulfate with two crystal watersFigure 7
Figure 8 Infrared spectra of calcium sulfate in paper (burned below 600℃)Figure 9 Infrared spectra of zinc oxide
Figure 10 Infrared spectra of titanium dioxide in decorative paper200 um (cm-)
200 um (cm-\
200 um (cm-\)
200 um (cm-t)
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