HG/T 3554-1981 Chemical composition analysis method for ammonia synthesis catalyst
Some standard content:
The standard of the Ministry of Chemical Industry of the People's Republic of China for the chemical composition analysis method of ammonia synthesis catalysts is: e3554-1181. This standard is applicable to the analysis and inspection of the chemical composition of ammonia synthesis catalysts A116, A109: A110 and other catalyst products with different chemical compositions. Preparation of samples for analysis Mix the catalyst samples evenly, take about 100 grams by quartering, crush and grind in steel F, and then take about 51 grams by quartering, grind in an agate mortar, make all the samples pass through a 100H sample sieve, put them in a weighing bottle, and store them in a desiccator for analysis. The steel H used for crushing the sample should be dry, clean and free of rust. Before crushing the sample, a small amount of mouse should be used to grind the steel twice to clean the steel door. The process of crushing the sample should be as short as possible to reduce the time the sample is exposed to the air. 2 Preparation of sample solution (A) 2.1 Method summary 2.2 The sample is dissolved in hydrochloric acid, and the acid-insoluble matter is removed by filtration. The filtrate is diluted to a certain volume and set aside. 2.2 Required reagents 2.2.1 Hydrochloric acid. 2.2.2 Hydrochloric acid (2+98). 2.3 Required instruments 2.3 General laboratory instruments.
2.4 Operation steps
Accurately weigh 0.5 g of the sample, place it in a 250 ml beaker, moisten it with water, add 10 ml of hydrochloric acid: cover it with Table III, heat (do not boil) until the sample is completely dissolved, rinse Table III and the wall of the beaker with water, add 60-1010 ml of water, filter with medium-speed German paper, wash the filter paper with (2F98) hydrochloric acid 8 times, wash the filter paper with water until it is neutral, pour the filtrate and washing liquid into a 250 ml container, cool to room temperature, dilute with water to the scale, and shake the spoon.
3 Preparation of sample solution (B)
3.1 Summary of the method
The sample is dissolved in hydrochloric acid and perchloric acid, and dehydrated with fluorinated acid smoke to generate androgenetic colloidal silicic acid in the test. It is separated by filtration and the precipitate is reserved for silica analysis. The filtrate is diluted to a certain volume for other item analysis. 3.2 Required reagents
3.2.1 Hydrochloric acid
3.2.2 Hydrochloric acid (2+98),
3.2.3. Perchloric acid,
3.3 Required instruments
General laboratory instruments:
3.4 Operating steps
Accurately weigh 2.5 g of the sample, place it in a 250 ml beaker, and moisten it with water. Add 20 ml of hydrochloric acid and 20 liters of perchloric acid, cover with table III, heat (do not boil) to completely dissolve the sample: rinse the beaker and the wall of the beaker with a small amount of water, set up the table, and heat on a sand bath. Evaporate until white fumes of perchloric acid appear. Continue evaporating until the volume of the solution in the beaker is less than 10 ml (do not evaporate to dryness), then remove and cool. Add about 1100 liters of hot water, heat until all the soluble salts are dissolved and boil. Remove and filter with medium-speed quantitative filter paper, wash the precipitate with hot (2+98) hydrochloric acid until there is no iron ion, and then wash with warm water until there is no chloride ion. Transfer the filtrate and washing liquid into a 250 ml container, dilute with water to the scale, and dig the hook. The precipitate on the filter paper is used for silica analysis. 4 Determination of total iron content (EDTA volumetric method) 4.1 Method summary
Under pH 1.3~2 and 50~70℃, use sulfosalicylic acid as an indicator and use EDTA complex titration to determine the trivalent iron in the sample solution. The trivalent iron is previously oxidized to trivalent iron with ammonium persulfate and then titrated at the same time. 4,2 Required reagents
4.2.1 Fluoroacetic acid (2M): Weigh 94.5 g of cyanoacetic acid, dissolve in water, and dilute to 500 ml. 4.2.2. Ammonium persulfate (20%). | |tt||4.2.3 Sulfosalicylic acid (20%).
4.2.4 EDTA standard solution (0.02M),
4.3 Required instruments
General laboratory instruments
4.4 Operating steps
Accurately pipette 10 milliliters of the sample drop (4) prepared in Chapter 2 of this standard, place it in a 250-liter beaker, add 100 milliliters of 80-90℃ hot water, 10 milliliters of 2M oxyacetic acid, 0.5 milliliters of 20% sulfosalicylic acid, and 5 drops of 20% ammonium persulfate, and titrate with EDTA standard solution while maintaining the solution at 50-70℃ until the bath solution changes from purple to bright yellow. 4.5 Calculation
Total iron content X, (%) is calculated as follows: X
Where: V-
V × M × 0. 055 85
Amount of EDTA standard solution, ml
Molar concentration of EDTA standard solution;
Amount of sample taken, g;
Amount of iron equivalent to 1 ml of EDTA standard solution, g. 4.6 Precision
The difference between two parallel determination results should not be less than 1.40%. 5 Determination of the ratio of divalent iron to trivalent iron (EDTA method) 5.1 Summary of the method
At pH 1.3～2, Under the condition of 50~70℃, use sulfosalicylic acid as the indicator to complexo-titrate the ferric iron in the sample solution with EDTA. The divalent iron needs to be oxidized to ferric iron with ammonium persulfate, and then complexo-titrated with EDIA under the same conditions. The volume ratio of the EDTA solution consumed by the divalent iron and the divalent iron is the ratio of the divalent iron to the ferric iron in the sample. 5.2 Required Reagents
5.2.1 Hydrochloric acid.
5 .2.2 Chloroacetic acid (2M): weigh 94.5 g of chloroacetic acid, dissolve it in water, and dilute to 500 liters. 5.2.3 Sulfosalicylic acid.
5.2.4 Ammonium persulfate.
5.2.5 EDTA solution (about 0.05M): weigh 18.7 g of EDTA, heat and melt it with 1000 liters of water, cool it, and shake it. 5.3 Required instruments
Laboratory instruments.
HG [---1430--81
5.4 Operation steps
Take about 0.5 g of the freshly ground sample, place it in a 250 ml chain plate, and add a small amount of water to moisten it. Add 10 ml of hydrochloric acid, add a short-necked funnel to the conical flask, and then heat (do not boil) to completely dissolve the test solution, rinse the funnel and the flask wall with water, quickly cool to room temperature, add about 200 ml of water, and shake.
Take about 10 ml of the above solution, put it in a 250 ml beaker, add about 150 ml of 80-90℃ hot water, 10 liters of 2M fluoroacetic acid, and 0.5 ml of 20% sulfonic acid, and titrate with EDTA solution until the solution changes from purple to bright yellow as the end point. Record the volume of EDTA solution consumed during the first titration. Then add 5 drops of 20% ammonium persulfate to the solution, stir evenly, and titrate with EDTA solution for the second time. The titration end point is the same as the first titration end point. Record the volume of EDTA solution consumed during the second titration. During the whole titration process, the temperature of the titrated solution should be controlled between 50 and 70°C. 5.5 Calculation of the ratio of ferrous iron to ferric iron x is calculated as follows: X2 =
Where: V--the amount of EDTA solution used in the first titration, ml: V--the amount of EDTA solution used in the second titration, ml 5.6 Precision
The difference between the results of two parallel determinations should not be less than 0.0. Determination of potassium oxide content (flame photometry: ·丨 method) 6.1 Method summary
Use nitric acid to oxidize the divalent iron in the sample solution to ferric iron. Under slightly acidic conditions, urea is hydrolyzed and precipitated to remove the interference of coexisting elements such as iron and aluminum, and the flame photometry is used to determine the content, and the standard curve method is used for quantification. The amount of urea added to the standard sample solution should be controlled to eliminate the influence of urea on the determination. 6.2 Required reagents
6.2.1 Nitrogen water (1 + 1)
6.2.2 Nitric acid (1 + 1).
6.2.3 Water system
6.2.4 Weathered calcium standard solution (1 ml contains 1 mg potassium oxide): weigh 1.5829 g potassium oxide (KCl) heated to zero at 500-600℃, transfer to a 1000 ml volumetric flask, dilute to the mark, shake. 6.2.5 Potassium oxide standard solution (1 ml contains 10 μg potassium oxide): accurately pipette 1 ml of 1 mg potassium oxide standard solution into 10 ml, place in a 100 ml volumetric flask, dilute to the mark with water, shake well, and store in a plastic bottle. 6.3 Required instruments
6.3.1 General laboratory instruments.
6.3.2 Flame photometer: With potassium-related filter. 6.4 Operating steps
6.4.1 Plotting standard curve: Accurately pipette 1 ml of 100 μg potassium oxide standard solution at 0, 2.5, 5, 7.5, 10.12.5. 15 ml, respectively, placed in 100 ml equal volume bottles, add 3 g of globulin to each, dilute with water to the mark, shake and hook. Connect the instrument working conditions, use a flame photometer to measure the emission intensity of the standard series potassium line, and draw a standard curve. 6.4.2 Sample analysis: Accurately aspirate 50 ml of the sample solution (A) prepared according to the second paragraph of this standard, place it in a 250 ml beaker, add 30-40 ml of water, 4 ml of (1+1) sodium chloride, and heat to boiling. Remove it, add (1+1) hydrogen water dropwise under constant stirring until the precipitate just appears, add 3 g of urea, cover with blood, heat and boil for 20-25 minutes. During the boiling process, water should be added to keep the solution volume at 70-80 Ⅱ) to make the precipitate condense, remove it and cool it to room temperature, transfer it to a 100 ml volumetric plate, dilute with water to the mark, shake and hook, and dry filter. The filtrate and the standard series are measured under the condition of phase separation to measure the emission intensity of the potassium spectrum line, and the potassium oxide concentration in the tested solution is found from the standard curve. 6. Calculate the potassium oxide content X (%) as follows: X1: HG 1-1430-81 C×v×106 Where: (- the concentration of potassium oxide in the solution to be tested is obtained from the standard curve, μg/ml-- the volume of the final solution to be tested, g: G--- the amount of sample taken, g.
6.6 Precision
The difference between the results of two determinations should not be less than 0.07%. 7 Determination of potassium oxide content (potassium perchlorate gravimetric method--Ⅱ 7.1 Method Summary
Add perchloric acid to the sample solution and evaporate to dehydrate. Add anhydrous ethanol to make potassium form potassium perchlorate precipitate, while other interfering substances form pernitrogenate without precipitation. Separate by filtration and determine by weight method. 7.2 Required Reagents
7.2.1 Perfluoric acid.
7.2.2 Saturated potassium perchlorate ethanol solution: Add 2 ml perchloric acid to 1000 ml anhydrous ethanol, add 1 ml potassium perchlorate precipitate. Potassium chlorate to saturation, filter before use.
7.3 Required instruments
Experimental case-general instruments.
7.4 Operation steps
Accurately pipette 50 ml of the sample solution (B) prepared in Chapter 3 of this standard, place it in a 100-liter beaker, add 20 ml of perfluoric acid, heat and evaporate on a sand bath until it is concentrated for 30 to 40 minutes, keep the volume of the solution in the beaker at 13 to 15 ml, remove and cool, add 40 ml of saturated potassium perchlorate ethanol solution, stir thoroughly, let stand for 20 to 30 minutes, filter with No. 3 to 4 glass filter crucibles that have been dried at 130 to 140 to constant weight, wash the precipitate 5 to 6 times with saturated potassium perchlorate ethanol solution, and drain. Put the filter glass into the oven and gradually heat it to 130 to 140°C, bake for 40 minutes, take it out and put it in a desiccator to cool to room temperature, then weigh it, and bake it to constant weight, 7.5 Calculate the potassium perchlorate content X. (%) as follows: x. - m × 0.3399, g; - sample volume, g, - coefficient for converting potassium perchlorate to potassium oxide. 7.6 Precision The difference between two parallel determination results should not exceed 10.8 Determination of calcium chloride content (atomic absorption method - 1 method) 8.1 Method summary The atomic absorption method is used with air-acetylene flame and 4227 angstrom analytical line to determine the calcium in the sample solution, and the standard curve method is used for quantification. Coexisting elements such as iron, lead and silicon interfere with the determination, which can be eliminated by adding strontium chloride. The acidity of the standard series and the test solution and the concentration of strontium chloride should be controlled to be consistent. 8.2 Required reagents 8.2.1 8.2.2 Strontium oxide (SrC12-6H20) (15%). 8.2.3 Calcium oxide standard solution (1 ml contains 1 g calcium oxide): weigh 1.7848 g of calcium carbonate (CaCO) dried to constant weight at 105-110°C and place in a beaker, moisten with water, add 20 ml of (1+1) hydrochloric acid, transfer to a 100-ml volumetric flask after complete dissolution, dilute to scale with water, shake well, and store in a material bottle. 8.2.4 Calcium oxide standard solution (1 ml contains 100 μg calcium oxide): accurately pipette 1 ml of 100 μg calcium oxide standard solution containing 1 mg calcium oxide, place in a 100-ml volumetric flask, dilute to scale with water, and shake well. 8.3 Required instruments
8.3.1 Laboratory-general instruments.
8.3.2 Atomic absorption spectrophotometer: with a calcium hollow cathode lamp. 8.4 Operating steps
8.4.1 Plotting the standard curve: Accurately pipette 1 ml of 0, 1, 2, 1, 6, 8, 10 ml of the standard solution containing 100 μg of calcium oxide, respectively, and place them in a 100 ml narrow volumetric bottle, add 2 liters of 15% strontium fluoride and 0.8 ml of (1+1) hydrochloric acid, dilute with water to the scale, and shake well. According to the working conditions of the instrument, use air-acetylene flame and 4227 angstrom analytical line to measure the absorbance of the standard series and plot the standard curve.
8.4.2 Sample analysis: Accurately pipette 10 ml of the sample solution (A) prepared in Chapter 2 of this standard, place it in a 100 liter volumetric bottle, add 2 ml of 15% strontium nitride, dilute with water to the scale, and shake well. Measure the absorbance under the same conditions as the standard series, and find out the calcium oxide concentration in the tested solution from the standard curve. 8.5 Calculation
Calcium oxide content X, (%) is calculated as follows: C ×v x10
Where: C
-Calcium oxide concentration in the tested solution found from the standard curve, μg/ml: - Final volume of the tested solution, ml; Gm--Aliquot sample size, g.
8.6 Precision
When the calcium oxide content is between 1.00% and 4.0%, the difference between two parallel determination results should not be greater than 0.10%; when the calcium oxide content is below 1.00%, the difference between two parallel determination results should not be greater than 0.07%. Determination of calcium oxide content (EDTA volumetric method -
-method)www.bzxz.net
9.1 Summary of the method
Under near-neutral conditions, hexamethylenetetramine and hydrogen water are used to precipitate and separate the iron, lead, titanium and other light-interfering elements in the sample solution. Under pH 13 conditions, acid chrome blue. K-naphthol green B is used as an indicator, and BDIA is used to titrate the calcium in the solution. The residual interfering ions in the solution are concealed with triethanolamine and copper reagent. For samples containing barium, the interference of vanadium is eliminated by precipitation with sodium sulfate. 9.2 Required reagents
9.2.1 Hexamethylenetetradecanoate (<20%)
9.2.2 Ammonia water (1 + 1).
9.2.3 Ammonium chloride washing solution: Add nitrogen water to 1% ammonium fluoride until pH 29.2.4 Potassium hydroxide (20%)
9.2.5 Copper reagent.
9.2.6 Anhydrous sodium sulfate,
Triethanolamine (1 1)
9.2.8 Acid chrome blue K-naphthol green B mixed indicator: Weigh 1.2 g acid chrome blue K, 0.34 g naphthol green B and 100 g potassium sulfate, mix and grind, and store in a ground-mouth bottle. 9.2.9 EDTA standard solution (0.02 M)
9.3 Required instruments
General laboratory instruments.
9.4 Operation steps
HG 1-1430-81
Accurately pipette 25 ml of the sample solution (B) prepared in Chapter 3 of this standard into a 25 ml beaker, add water to about 100 ml, heat to boiling, add 20% hexamethylenetetramine to a solution pH of 5-6 under constant stirring, and then adjust the pH to 7-8 with (1+1) nitrogen water. Add 0.2 g of anhydrous sodium sulfate (do not add if the sample does not contain sodium sulfate), heat to boil again, filter with medium-speed paper while hot, wash and precipitate with ammonium chloride washing solution for 10-12 times, place the filtrate and washing solution in a 500 ml beaker, and add water to about 250 ml. Add 5 ml (1+1) triethanolamine, about 0.05 g of copper reagent, and 20% potassium oxide to the above solution to make the solution pH about 13. Add about 0.1 g of mixed indicator and titrate with EDTA standard solution until the solution changes from red to blue as the end point. During the operation, pH is tested with standard test paper.
9.5 Calculate the calcium oxide content. (%) is calculated as follows: X6=
V × M × 0.056 08
Where: V·EDTA standard solution, ml M--EDTA standard solution molar concentration:
G—·Test group amount, g.
× 10 yuan
U, 05i U8--1 ml of 1MEDTA standard solution is equivalent to F calcium oxide content, grams 9. Accuracy
When the calcium oxide content is 1.00-4.00%, the difference between two parallel determination results should not be greater than u.10%. When the calcium oxide content is below 1.00%, the difference between two parallel determination results should not be greater than 0.07%. 10 Determination of magnesium oxide content (atomic absorption method-T method) to,1 Method Summary
Use the original absorption method, use air-heated flame, 2852 angstrom analytical line, determine the magnesium in the sample solution, and use the standard curve method to calculate. The coexistence of iron, aluminum, and silicon interferes with the determination, and strontium nitride is added to eliminate it. The acidity and strontium nitride concentration in the standard series and the sample solution should be controlled to be consistent.
10.2 Required reagents
10,2.1 Hydrochloric acid (1+1).
10.2.2 Strontium chloride (SrC12-6H:0) (15%), 10.2.3 Oxidation standard solution (1 ml contains 1 mg of magnesium oxide): Weigh 1.0000 g of magnesium oxide (MgO) calcined at 800℃ to constant weight, put it in a beaker, mix with water, add 20ml of (1+1) hydrochloric acid, and transfer it to a 1000-liter volumetric flask after it is completely dissolved, dilute with water to the scale, shake well, and stick it on a plastic 10.2.4 Magnesium oxide standard solution (1 ml contains 10 μg magnesium oxide): pipette 1 ml of standard solution containing 1 mg magnesium oxide into 10 ml of a 1000 ml container, adjust the scale with water, and shake. 10.3 Required instruments
10.3.1 General laboratory instruments.
10.3.2 Atomic absorption spectrophotometer: with a magnesium hollow cathode lamp. 10.4 Operation steps ||tt t||10.4.1 Drawing of standard curve: Accurately pipette 0.1 ml of 10 μg magnesium cyanide standard solution 0, -1, 2, 4, 6, 8 ml, respectively, and place them in 100 ml volumetric flasks, add 2 ml of 15% strontium fluoride and 0.8 ml of (1+1) hydrochloric acid, dilute with water to the scale, and shake. According to the working conditions of the instrument, use air acetylene flame and 2852 angstrom analytical line to measure the absorbance of the standard series, and draw the standard curve. 10.4.2 Sample analysis: Accurately pipette 10 liters of the sample solution (A) prepared according to Chapter 2 of this standard, place it in a 100 ml volumetric flask, add 2 ml of 15% strontium fluoride, dilute with water to the scale, and shake. Determine the absorbance with the standard series under the condition of phase separation, and find the magnesium oxide concentration in the tested solution from the standard curve. 33
10.5 Calculation
The magnesium oxide content (%) is calculated as follows;
HG 1-1430-81
C ××10
Wherein: C is the concentration of magnesium oxide in the test solution obtained from the standard curve, μg/ml; V is the final volume of the test solution, mK; G
The amount of sample taken, g.
10.6 Accuracy
The difference between the results of two parallel determinations should not exceed 0.05%. 11 Determination of magnesium oxide content (from DTA egg method) 11.1 Summary of the method
Use the solution after adding calcium with EDTA, adjust it to pH 10, and then continue to titrate magnesium with EDTA. Various interferences in the solution have been eliminated before titrating calcium.
11.2 Required reagents
11.2.1 Hydrochloric acid (1 +1).
11.2.2 Ammonia-ammonium chloride buffer solution (pH 10): Weigh 27 g ammonium chloride, dissolve in 100 ml boiling water, add 175 ml nitrogen water, dilute to 500 ml with water.
11.2.3 EDTA standard solution (0.02M). Quantity 1.3 Required receiver
General laboratory instruments,
11.4 Operation steps
Use the solution after titrating calcium with EDTA in the determination of oxygen content in calcium oxide in Chapter 9 of this standard to determine the content of magnesium oxide.
Add (1+1) hydrochloric acid to the above solution to neutralize it, so that the color of the solution changes from mountain blue to purple red, blue, and finally red (pH 5). Add 30 liters of pH 10 ammonia buffer solution and titrate with EDTA standard solution until the bath solution turns from red to blue, which is the end point. 11.5 Calculate the magnesium oxide content X (%) as follows: Xy=
V × M × 0.040 31
Wherein: VEDTA standard solution dosage, milliliter: M——EDTA standard solution concentration, gram volume of test sample, volume:
0.040 31--1L 1M EDTA standard solution is equivalent to the amount of magnesium oxide, gram 11.6 Accuracy
The difference between two parallel determination results should not be greater than 0.U5%. 12 Determination of aluminum oxide content (EDTA volumetric method) 12.1 Summary of the method
In the acidic sample solution, add excess sodium hydroxide to precipitate and separate coexisting elements such as iron and titanium to eliminate interference: aluminum is completely dissolved in the solution in the form of aluminate
In the slightly acidic solution, add excess EDTA to complex and chelate other metal ions, and the excess EDTA is back-titrated with zinc standard solution, and sodium hydroxide is used to replace the BDTA complexed with aluminum: the released EDTA is titrated again with zinc standard solution. The interference of residual iron in the solution on the titration is eliminated with ascorbic acid. 33
Required reagents
Sodium hydroxide (30%).
Sodium hydroxide (1%).
Glacial acetic acid (i+1)
HG 1-143081
Phenolic acid indicator: weigh 1 g of phenolic acid, dissolve in ethanol, and dilute to 100 ml with ethanol. 12.2.4
Ascorbic acid.
Acetic acid-sodium acetate buffer solution (pH 5.7): weigh 100 g of sodium acetate (CH,COONa·3H2O), add 13 ml of 6N acetic acid to water, and dilute to 500 ml with water. 12.2.7
Xylenol orange indicator (0.2%).
12.2.8: Sodium fluoride.
EDTA standard solution (0.02M).
12.2.10 Zinc standard solution (0.02M). ;12.3 Required instruments
Laboratory-·General instruments.
12.4 Operation steps
Add 10 ml of 30% sodium hydroxide to a 250 ml beaker, add about 40 ml of water, and heat to boil. Accurately pipette 10 g of the sample solution (B) prepared according to Chapter 3 of this standard, add it dropwise to the above sodium hydroxide solution under constant stirring, and boil it slightly for 2 to 3 minutes. Filter it with medium-speed filter paper while hot, wash the precipitate with hot 1% sodium hydroxide 7-8 times, and collect the filtrate and washing liquid in a 250 ml beaker.
Add 1 drop of phenolic acid indicator to the above solution, neutralize it with (1+1) acetic acid until the red color disappears, and add an excess of 2 ml, add about 15 ml of EDTA standard solution, fan it and boil it for 3 minutes, remove it and cool it quickly. Add 10 ml of acetic acid-sodium acetate buffer solution, about 0:2 g of ascorbic acid, and 5 drops of xylenol orange indicator, and titrate with zinc standard solution until the solution turns orange-red as the end point. Then add about 1 gram of sodium fluoride, boil for 2 minutes, remove and cool quickly. Titrate again with zinc standard solution, and the titration end point is the same as the end point of the first titration. Record the volume of zinc standard solution used in the second titration.
12.5 Calculate
The content of aluminum oxide X, (%) is calculated as follows: Xg =
Wu Zhong:
V × M × 0.050 98
The amount of zinc standard solution used in the second titration, milliliters; the molar concentration of zinc standard solution;
The amount of sample taken in one aliquot, grams;
1 milliliter of 1M zinc standard solution is equivalent to the amount of aluminum oxide, grams. 0.050 98-
12.6 Accuracy
The difference between the results of two parallel determinations should not be greater than 0.10%. 13* Determination of silicon difluoride content (perchloric acid dehydration and volumetric method) 13.1 Method summary
(9)
The silicon in the sample solution is dehydrated with perchloric acid to form a difficult-to-chromate colloidal acid, which is separated from other soluble interfering substances by filtration. After burning, hydrofluoric acid is added and heated to make the silicon tetrafluoride. The difference in amount is the amount of silicon dioxide. 13.2 Required reagents
13,2,1 Sulfuric acid (1 1).
Hydrofluoric acid.
13.3 Required instruments
General laboratory instruments.
13.3.2 Platinum glass: 25~30 ml.
HG 1-1430-81
13.4 Operation steps
Put the precipitate separated by filtration in Chapter 3 of this standard together with the filter paper into a platinum crucible, first dry and completely dissolve the filter paper, then burn in a 900℃ high-temperature furnace for 1 hour, take it out, cool it to room temperature in a desiccator, weigh it, and burn it to constant weight. Add 3 to 4 drops of (1+1) sulfuric acid and about 5 ml of fluoric acid along the wall of the platinum crucible; heat it in a sand bath in a fume hood and then burn it in a 900℃ high-temperature furnace for half an hour, take it out, cool it to room temperature in a desiccator, weigh it, and burn it to constant weight. 13.5 Calculation
Silicon dioxide content X10 (%) is calculated as follows: Xio-
Wherein, mi
m—mz
Precipitate and crucible weight before hydrofluoric acid treatment, g:Precipitate and crucible weight after hydrofluoric acid treatment, g:Weighed sample amount, g.
13.6 Accuracy
The difference between the results of two parallel determinations should not exceed 0.04%. Determination of titanium dioxide content (chromotropic acid spectrophotometry) 14
14.1 Summary of the method
In an acidic solution with pH 1 to 3, titanium and chromotropic acid form a brown-red complex, which is measured by spectrophotometry. The maximum absorption wavelength of the complex is 470 nanometers, and the titanium content in the colorimetric solution conforms to Beer's law within the range of 10 to 150 micrograms/50 ml. Trivalent iron interferes with the determination, and ascorbic acid should be used to reduce it in advance to eliminate the interference. 14.2 Required reagents
14.2,1 Chromotropic acid (3%): weigh 3 g chromotropic acid and 3 g anhydrous sodium sulfite, dissolve in water and dilute to 100% liter. Prepare when needed.
Ascorbic acid (5%), prepare when needed.
14,2.3 2,4-Dinitrophenol indicator (0.1%). 14.2.4
Ammonium hydroxide (1+1).
14.2.5 Hydrochloric acid (1+1).
14.2,6: Titanium dioxide standard solution (1 ml contains 100 μg titanium dioxide): Accurately weigh 0.1 g titanium dioxide (TiO2) burned to constant weight at 1000℃, place in platinum, add 10 g potassium pyrosulfate, melt at 600℃, cool and diffuse with 100 ml (1+1) sulfuric acid, transfer to a 1000-liter volumetric flask, dilute with water to the mark, and shake to hook. 14.2.7 Cobalt dioxide standard solution (1 ml contains 20 μg titanium dioxide): Accurately pipette 20 ml of 1 ml xenon standard solution containing 100 μg of titanium dioxide, place in a 100-liter volumetric flask, dilute with water to the mark, and shake to hook. 14,3 Required instruments
14.3,1 Laboratory instruments.
14.3.2 Spectrophotometer.
14.4 Operation steps
14.4.1 Drawing of standard curve: Accurately pipette 0, 1, 2, 3, 4, 5 ml of 1 mM titanium dixenide standard solution containing 20 μg, and place them in 50 ml volumetric flasks respectively. Add 5 ml of 5% ascorbic acid to each, dilute with water to about 40 ml, and add 2 drops of 0.1% 2.4 dinitrophenol indicator: neutralize with (.1+1) ammonia water until yellow. Then adjust with (11) hydrochloric acid until the yellow color just disappears, and add 3 drops in excess. Add 5 ml of 3% chromotropic acid, dilute with water to the scale, and shake well. Let it stand for 10 minutes, use the reagent blank as a reference, use a 1 cm colorimetric, measure the absorbance of the standard series at a wavelength of 750 nm, and draw the standard curve. 14.4.2 Sample analysis: Accurately absorb 5 ml of the sample solution (A) prepared in Chapter 2 of this standard, place it in a 50 ml volumetric flask, add 5 ml of 5% ascorbic acid, dilute with water to about 40 ml, adjust the acidity and color development in the same way as the standard series, and compare with the standard series under the condition of phase separation, measure the absorbance, and find out the amount of titanium dioxide in the measured solution from the standard curve. 14.5 Calculate the titanium monoxide content X (%) according to the following formula: Xua
$ × 10-6
Where: S---the amount of titanium dioxide in the measured solution found from the standard curve, micrograms; G--the amount of sample taken, grams.
14.6 Precision
The difference between the results of two determinations should not be greater than 0.04%. 15 Determination of phosphorus content (phosphomolybdic heteropoly blue spectrophotometry) 15.1 Summary of the method
After phosphorus in the sample solution is converted into orthophosphoric acid by perfluoric acid, 5-ammonium molybdate generates phosphomolybdic heteropoly acid, which is reduced to magnetic heteropoly sulphate by ascorbic acid in n.N to 1.N sulfuric acid and spectrophotometrically determined directly in aqueous solution. Its maximum absorption wavelength is 650-700 nanometers, and the phosphorus content in the colorimetric solution is 550 micrograms/50 liters, which conforms to Beer's law. The test solution after silicon separation is used to eliminate the interference of silicon. The interference of free valent iron is eliminated by reduction with sodium sulfite in advance. In order to make the color stable, the color reaction of the standard series and the sample is heated at the same time under the same conditions. 15.2 Required reagents
15.2.1 Ammonium aluminate (2%): Weigh 20 g of ammonium aluminate (superior purity), dissolve in about 200 ml of warm water, add 20 ml of (1+1) sulfuric acid, and dilute to 1000 ml after cooling. 15.2.2 Ascorbic acid (5%), prepare when needed. 15.2.3 Sulfuric acid (1+1)
15,2.4 Anhydrous sodium sulfite (10%).
15.2.5 Phosphorus standard solution (1 ml contains 100 μg of phosphorus): Weigh 0.4394 g of dihydrogen phosphate (KH2FO4) dried at 100°C to constant weight, dissolve in water, add 5 drops of nitric acid, transfer to a 100 ml volumetric flask, dilute to scale with water, and shake well. 15.2.6 Phosphorus standard solution (1 ml contains 5 μg phosphorus): Accurately pipette 1 ml of 100 μg phosphorus standard solution into a 100 ml volumetric flask, dilute to the mark with water, and shake. 15.3 Required instruments
15.3.1 General instruments for the experiment.
15.3.2 Spectrophotometer.
15.4 Operation steps
15.4.1 Plotting the standard curve: Accurately pipette 1 ml of 5 μg magnetic standard solution 0.1, 2, 3, 4, 5 ml, and place them in 50 ml colorimetric tubes respectively: add 0.5 ml of (1+1) sulfuric acid, 5 ml of 10% sodium sulfite, 1 ml of 5% ascorbic acid, add water to about 4 ml, 5 ml of 2% ammonium calcium, and dilute to 50 ml with water accurately, according to the sentence. Place in a 70~80℃ water bath for 5 minutes, cool to room temperature with running water, place for 20 minutes, use the reagent vacuum as a reference, use a 2 cm colorimetric tube, measure the absorbance of the standard series at a wavelength of 680 nm, and draw a standard curve. 15.4.2 Sample analysis: Accurately pipette 1 liter of the sample rolling solution (B) prepared according to the third rate of this standard, cover it in a 50 ml colorimetric tube, add (1+1) sulfuric acid (5 liters, 10% sodium sulfite 5 ml, put it in a boiling water bath and cook until the color of trivalent iron disappears, take out the running water and cool to room temperature. Add 1 ml of 5 external ascorbic acid, add water to about 40 liters, add the color developer in the same way as the standard series, and color and measure the absorbance at the same time under the same conditions. Find the phosphorus content in the solution to be tested from the standard curve. 15.5 Calculation
Contains X (treatment) Calculate according to the following formula:
S ×106
HG 1-1430—-81
Where: S.… The phosphorus content in the solution to be tested is obtained from the standard curve, micrograms; G
The sample volume is taken, grams.
15.6 Accuracy
The difference between the results of two parallel determinations should not be less than 0.004%. If the phosphorus content analysis results of the product inspection are only required to be not greater than a certain specified value, it can be prepared! A color scale with the corresponding content is used for color development at the same time as the sample solution. , determined by convexometry colorimetry. 16 Determination of barium content (barium sulfate gravimetric method) 16.1 Summary of the method
The sample is dissolved in hydrochloric acid, and the acid-insoluble matter is removed by filtration. The filtrate is precipitated with sulfuric acid to form barium sulfate, which is filtered and separated from other acid-soluble substances, and the barium is determined by gravimetry.
The sulfate of trivalent iron is easy to co-precipitate with barium sulfate, and should be reduced to divalent iron in advance with ascorbic acid and retained in the solution. 16.2 Required reagents
16.2.1 Hydrochloric acid
Hydrochloric acid (1 +99)
Ascorbic acid.
16.2.4 Sulfuric acid (14.1)
16.2.5 Sulfuric acid (1 +200),
16.3 Required instruments
General instruments for the laboratory.
16.4 Operation steps
Accurately weigh 3 grams of the sample, place it in a 250 ml beaker, and add a small amount of water to moisten it. Add 20 liters of concentrated hydrochloric acid, heat to completely dissolve the sample, and evaporate it to a wet salt state, add 100 ml of water, heat and stir to dissolve the salts, filter with medium-speed filter paper, and wash the filter paper 78 times with (1+99) hydrochloric acid. Dilute the filtrate and washings to about 300 ml with water in a 400 ml beaker. ml: Heat to initial boiling, add ascorbic acid slowly in small amounts and several times under constant stirring until the liquid turns light green, add 3 liters of (1+1) sulfuric acid dropwise, place at room temperature for half an hour, remove and let stand overnight, filter with dense fixed filter paper, and wash the precipitate with (1+200) sulfuric acid until there is no iron ion, then wash with hot water until there is no sulfate ion, put the precipitate and filter paper into a porcelain jar that has been heated, first dry and make the filter paper completely coke, then burn in a high-temperature furnace at 800°C for half an hour, put it into a desiccator and cool it to room temperature, then weigh it and burn it to constant weight. 16.5 Calculate the
oxide content X13 (%).Calculate as follows: Xi3
Wu Zhong, m
Amount of barium sulfate after burning, g,
Amount of sample, g.
mt ×0,6570
Coefficient of converting barium sulfate to barium oxide.
16,6Precision
The difference between two parallel determination results should not be greater than 0.05%13
A10.02M disodium ethylenediaminetetraacetic acid standard solutionA1.1 Required reagents
HG1-1430-81
Appendix A
Preparation of standard solution
(Supplement)
A1.1.1 Ammonia water (1 + 1).
A1.1.2 Chrome black T indicator (0.5%): weigh 0.5g Chrome black T and 2g hydroxylamine hydrochloride and dissolve in ethanol, dilute to 100ml with ethanol
A1.1.3 Ammonia-ammonium chloride buffer solution (pH10): weigh 27g ammonium chloride, dissolve in 100ml water, add 175ml ammonia water, dilute to 500L with water.
A1.1.4 Disodium ethylenediaminetetraacetic acid
A1.1.5 Zinc standard solution (0.02M): weigh 1.6276g zinc oxide (ZnO) burned to constant weight at 800℃, put it in a 300ml beaker, mix with water, add 20ml (1+1) hydrochloric acid, slowly heat to dissolve, cool to room temperature after complete dissolution, transfer to a 100ml volumetric jar, mark the scale of the water dilution chamber, and shake the hook. A1,2 Preparation steps
A1.2.1 Solution preparation: Weigh 7.8 g of disodium zinc diaminetetraacetate (ClOH4Nr0gNa22H20), dissolve in 1000 liters of water, shake and wait for calibration.
A1.2.2 Calibration method: Accurately pipette 20 ml of 0.02M zinc standard solution, place in 250 ml of flask, add water to about 100 ml, add (1+1) ammonia water until precipitation appears, add 10 liters of ammonia-ammonium chloride buffer solution and 5 drops of chrome black T indicator, and titrate with the EDTA solution to be calibrated: the end point is when the solution changes from purple to pure blue. A1.3 Formula: M EDTA standard solution molar concentration: -EDTA standard solution dosage, ml: Zinc standard solution molar concentration: Zinc standard solution dosage, ml 0.02M zinc standard solution A2.1 Reagents A2.1 Ammonia-ammonium nitride buffer solution (pH 10): weigh 27 g ammonium fluoride, dissolve in 100 ml water, add 175 ml ammonia water, dilute with water to 500 ml A2.1.2 Eriochrome black T indicator (U.5%): weigh 0.5 g riochrome black T and 2 g hydroxylamine hydrochloride, dissolve in ethanol, dilute with ethanol to 100 ml. A2.1.3 EDTA standard bath solution (0.02M). ：A2.2 Preparation steps
：A2.2.1 Solution preparation: Weigh 2.8g zinc chloride (ZnCl2), dissolve in appropriate amount of water, add 0.5ml hydrochloric acid: transfer to a 1000 liter volumetric flask, dilute to scale with water, add hook, and wait for calibration. A2.2.2. Calibration method: Accurately pipette 20ml of the zinc standard solution to be calibrated, place it in a 250ml beaker, add water to about 100ml, 10ml nitrogen·chloride buffer solution, 5 drops of black T indicator, and titrate with 0.02MEDTA standard solution. The end point is when the solution changes from purple to pure blue.
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