GB/T 15057.2-1994 Determination of calcium oxide and magnesium oxide content in limestone for chemical industry
Some standard content:
National Standard of the People's Republic of China
Determination of calcium oxide and magnesium oxide content in limestone for chemical industry Limestone for chemical industry---Determination of calcium oxide and magnesium oxide content Part I Determination of calcium oxide and magnesium oxide content EDTA titration method bZxz.net
1 Subject content and scope of application
This standard specifies the determination of calcium oxide and magnesium oxide content by EDTA titration method. GB/T 15057.2—94
This standard is applicable to the determination of calcium oxide and magnesium oxide content in limestone products for chemical industry, and the determination range is calcium oxide greater than 49% and magnesium oxide 1% to 4%.
2 Reference standards
GB6682 Specifications and test methods for water used in analytical laboratories GB601 Preparation of standard solutions for titration analysis (volume analysis) of chemical reagents GB/T15057.4 Determination of trioxide content in limestone for chemical industry by gravimetric method 3 Method summary
The sample is decomposed by hydrochloric acid, hydrofluoric acid and peracid, and interfering elements such as iron and aluminum are masked with triethanolamine. In a solution with a pH greater than 12.5, calcium carboxylic acid is used as an indicator and calcium is titrated with EDTA standard titration solution. At pH 10, acid chrome blue K-naphthol green B is used as a mixed indicator, and the total amount of calcium and magnesium is titrated with EDTA standard titration solution, and the content of magnesium oxide is obtained by subtraction. 4 Reagents and solutions
The water used in this standard should meet the specifications of grade 3 water in GB6682. The listed reagents, unless otherwise specified, refer to analytical pure reagents. 4.1 Hydrochloric acid (GB622): 1+1 solution.
4.2 Hydrofluoric acid (GB 620).
4.3 Perfluoric acid (GB623).
4.4 Triethanolamine: 1+1 solution.
4.5 Potassium hydroxide (GB2306): 200g/L solution. 4.6 Dextrin: 40g/L solution. Weigh 4g dextrin, mix into a paste with water, add 100mL boiling water (prepare before use). 4.7 Ammonium chloride-ammonia buffer solution (pH~10): Weigh 67.5g ammonium chloride (GB658) and dissolve in 300mL water, add 570mL ammonia (GB631), transfer to a 1000mL volumetric flask, dilute to the mark with water, and shake well. 4.8 Hydroxylamine hydrochloride (GB6685) 50g/L solution. 4.9 Disodium ethylenediaminetetraacetate (EDTA) (GB1401) c (EDTA) is about 0.02mol/L standard titration solution, and its preparation and calibration are in accordance with GB601 approved by the State Administration of Technical Supervision on May 5, 1994.
1995-02-01 implementation
GB/T15057.2--94
4.10 Calcium carboxylic acid indicator [2-hydroxy-1-(2-carboxyl-4-sulfonic acid-1-naphthylazo)-3-naphthoic acid]: weigh 1g calcium carboxylic acid and 100g sodium chloride (GB1266) dried at 105℃, grind, mix and store in a ground-mouth bottle. 4.11 Acid chrome blue K indicator: 5g/L solution. Weigh 0.5g acid chrome blue K and dissolve it in 100mL water (use period is one week). 4.12 Naphthol Green B Indicator: 5g/L solution. Weigh 0.5g of Naphthol Green B and dissolve it in 100mL of water (useable period is --- week). 4.13 Eriochrome Black T Indicator: 5g/L solution. Weigh 0.5g of Eriochrome Black T and dissolve it in 100mL of triethanolamine (4.4) solution (useable period is half a month).
5 Sample
The laboratory sample passes through a 125μm test sieve (GB6003), is dried at 105110℃ for more than 2h, and is placed in a desiccator to cool to room temperature.
6 Analysis Steps
6.1 Preparation of Sample Solution
Weigh about 0.2g of sample, accurate to 0.0001g, and place it in a 100mL polytetrafluoroethylene plastic beaker. Perform a blank test at the same time. Wet the sample with a little water, cover with a watch glass, drip hydrochloric acid solution (4.1) along the mouth of the beaker, wait for the violent reaction to stop, add 1 mL excess, rinse the surface blood and beaker wall. Add 4 mL hydrofluoric acid (4.2) and 2 mL perfluoric acid (4.3), place on a hot plate and heat at low temperature until almost dry. Remove the beaker, cool it slightly, rinse the cup wall with a little water, continue to heat until the white smoke is gone and dry. Cool it slightly, add 3 mL hydrochloric acid (4.1), heat and dissolve until clear, cool to room temperature, transfer to a 250 ml volumetric flask, dilute with water to the scale, and spread evenly. This prepared solution is also used for the determination of magnesium oxide by atomic absorption spectrometry. 6.2 Determination of calcium oxide
Put 50.00 mL of the solution prepared in 6.1 into a 250 mL beaker. Add 100mL water, 10mL dextrin solution (4.6), 5mL triethanolamine solution (4.4), 15mL potassium hydroxide solution (4.5) to make the solution pH greater than 12.5, add a little calcium carboxylate indicator (4.10), and stir well. Titrate with EDTA standard titration solution (4.9) until the solution changes from wine red to pure blue as the end point. Note: ① For ore samples that can be completely decomposed by hydrochloric acid, 20.00mL of the filtrate retained in Article 5.1 of GB/T15057.4 can also be taken for the determination of calcium oxide, and triethanolamine solution is not added during the determination. ② For samples with magnesium oxide content less than 3%, dextrin solution is not added. 6.3 Determination of magnesium oxide
Put 50.00mL of the solution prepared in Article 6.1 into a 250ml beaker. Add 100mL water, 5mL hydroxylamine hydrochloride solution (4.8), 5mL triethanolamine solution (4.4), stir well, add 10mL ammonia buffer solution (4.7), 2-3 drops of acid chrome blue K indicator solution (4.11) and 6-7 drops of naphthol green B indicator solution (4.12), stir well, and titrate with EDTA standard titration solution (4.9) until the solution changes from dark red to bright green. Note: For ore samples that can be completely decomposed by hydrochloric acid, 20.00mL of the filtrate retained in Article 5.1 of GB/T15057.4 can also be used to determine magnesium oxide. Hydroxylamine hydrochloride solution and triethanolamine solution are not added during the determination, and chrome black T can also be used as an indicator. 7 Expression of analytical results
7.1 The calcium oxide (CaO) content (ri) expressed as mass percentage is calculated according to formula (1), and the calcium carbonate (CaCO) content (α2) is calculated according to formula (2): c(VV)X0.056 08 ×1
c(Vz-V)x0.100 1
Wherein: c—actual concentration of EDTA standard titration solution, mol/LV2—volume of EDTA standard titration solution titrated with calcium oxide, nLV, volume of EDTA standard titration solution titrated with calcium oxide blank test solution, mL, (1)
（2）
GB/T 1 5057. 2-94
V——total volume of sample solution, mL,
VA——volume of sample solution absorbed, mL; mass of sample, g
0.05608The mass of calcium oxide expressed in grams, which is equivalent to 1.00mLEDTA standard titration solution Lc(EDTA)=1.000mol/LJ:
The mass of calcium carbonate expressed in grams, which is equivalent to 1.00mLEDTA standard titration solution Lc(EDTA)-1.000mol/L.
The content of magnesium oxide (MgO) (xa) expressed in mass percentage is calculated according to formula (3), and the content of magnesium carbonate (MgCO.) (ar4) is calculated according to formula (4)7.2
In the formula:
cL(V.-V.)-(V,-V)IX0. 040 30
cL(V,-V.)-(Vz-V)1×0. 084 31m
-The actual concentration of EDTA standard titration solution, mol /L;—volume of EDTA standard titration solution for titration of calcium and magnesium, mL, V.-
8 allowable difference
volume of blank test solution of EDTA standard titration solution for titration of calcium and magnesium, mL,-volume of calcium oxide of EDTA standard titration solution, mL-volume of blank test solution of calcium oxide of EDTA standard titration solution, mL, total volume of sample solution, mL,
volume of sample solution absorbed, mL,
mass of sample, g,
mass of magnesium oxide equivalent to 1.00mL EDTA standard titration solution [c(EDTA)=1.000mol/L], expressed in grams,
mass of magnesium carbonate equivalent to 1.00mL EDTA standard titration solution [c(EDTA)-1.000mol/L], expressed in grams.
The arithmetic mean of the parallel analysis results is taken as the final analysis result. The absolute difference between the parallel analysis results of calcium oxide should not be greater than 0.30%, the absolute difference of parallel analysis results of calcium carbonate should not be greater than 0.60%; the absolute difference of parallel analysis results of magnesium oxide and magnesium carbonate should not be greater than the allowable differences listed in Table 1 and Table 2 respectively. Magnesium oxide (MgO) content
1.00~2.50
>2.50～4.00
Magnesium carbonate (MgCO,) content
2.00~5.00
>5.00 ~8.00
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External Standard Buddha
Allowance difference
Allowance difference
9 Subject content and scope of application
GB/T 1 5057.2—94
Part II Determination of magnesium oxide content Flame atomic absorption spectrometry (arbitration method)
This standard specifies the determination of magnesium oxide content by flame atomic absorption spectrometry. This standard is applicable to the determination of magnesium oxide content in limestone products for chemical use, and the determination range is less than 4%. 10 Reference standards
GB6682 Specifications and test methods for water used in analytical laboratories GB/T9723 General rules for flame atomic absorption spectrometry of chemical reagents 11 Method shortcuts
The sample is decomposed by hydrochloric acid, hydrofluoric acid and perchloric acid, and strontium fluoride is added to eliminate the interference of coexisting ions. The absorbance of magnesium oxide is measured by flame atomic absorption spectrometer with acetylene-air flame in a dilute hydrochloric acid medium containing a calcium matrix solution. 12 Reagents and solutions
The water used in this standard should meet the specifications of grade 3 water in GB6682; the listed reagents, unless otherwise specified, refer to analytically pure reagents. 12.1 Hydrochloric acid (GB622): 1+1 solution.
12.2 Hydrofluoric acid (GB620).
12.3 Perchloric acid (GB623).
12.4 Strontium chloride: 100g/L solution. Weigh 168g of strontium chlorofluoride (SrCl2·6H,0), add 300mL of water to dissolve it at warm temperature, cool it, and dilute it with water to 1000mL (filter it if necessary).
12.5 Calcium carbonate matrix solution: 2mg/mL. Weigh 2.0g of calcium carbonate (GB12596) standard reagent that has been dried at 110-120℃ in advance and place it in a 250mL beaker, cover it with a watch glass, add 25mL of water, and slowly add 25mL of hydrochloric acid (12.1). Heat to dissolve, boil to remove carbon dioxide, cool it, transfer it to a 1000mL volumetric flask, dilute it with water to the scale, and shake it well. This solution contains about 2mg of calcium carbonate per milliliter. 12.6 Magnesium oxide standard solution: 1mg/mL. Accurately weigh 1.0000g of magnesium oxide (high purity reagent) that has been pre-burned at 900℃ for 1h and cooled to room temperature in a desiccator, and place it in a 250mL beaker. Moisten with a little water, add 20mL of hydrochloric acid solution (12.1), and heat until completely dissolved. Cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, and shake well. This solution contains 1mg magnesium oxide per liter. 12.7 Magnesium oxide standard solution: 50μg/mL. Pipette 50.00mL of magnesium oxide standard solution (12.6) and place it in another 1000mL volumetric flask, dilute to scale with water, and shake well. This solution contains 50μg magnesium oxide per liter. 13 Instruments
13.1 Flame atomic absorption spectrometer: It should comply with the provisions of GB/T9723. 14 Analysis steps
14.1 Pipette the solution prepared in 6.1 of the EDTA titration method of this standard according to Table 3 and place it in a 100mL volumetric flask. Perform a blank test at the same time. Add the matrix solution (12.5) according to the amount specified in Table 3. 187
Subtract
Magnesium oxide content, %
>1.5~4. 0
GB/T 1 5057. 2 --94
Volume flask for dilution
Volume, mL
Absorb test solution
Volume, ml
Add matrix solution
Liquid volume.mL
14.2Add 5.0mL strontium chloride solution (12.4), add 2.0mL hydrochloric acid solution (4.1) and dilute to scale with water, shake well. 14.3 Adjust the working parameters of the flame atomic absorption spectrometer to the best, use acetylene-air flame, magnesium hollow cathode lamp, at a wavelength of 285.2nm, adjust to zero with water, and splash the absorbance of the sample solution. Subtract the absorbance of the blank test solution from the measured absorbance to find the corresponding magnesium oxide concentration on the working curve.
15 Drawing of the working curve
According to the magnesium oxide content in the sample, measure 0.00, 1.00, 2.00, 3.00, 4.00, 5.00, 6.00mL of magnesium oxide standard solution (12.7) and place them in another set of 100mL volumetric flasks. Add 15.0mL of matrix solution (12.5), and proceed as follows in 6.2 and 6.3. Measure the absorbance of the standard series solution under the same conditions as the sample determination, subtract the reagent blank absorbance, and draw the working curve with the magnesium oxide concentration as the horizontal axis and the corresponding absorbance as the vertical axis. 16 Expression of analysis results
The content of magnesium oxide (MgO) (z) expressed as mass percentage is calculated according to formula (5), and the content of magnesium carbonate (MgCO,) (r2) is calculated according to formula (6):
In the formula: c-
×100×2.5
cX100×10-
c×2.092×100×10-
The concentration of magnesium oxide found from the working curve, μg/mL, V-the volume of the sample solution absorbed, mL,
mThe mass of the sample, 83
2.092-The factor for converting magnesium oxide into magnesium carbonate. 17 Allowable difference
The arithmetic mean of the parallel analysis results is taken as the final analysis result. The absolute difference between the parallel analysis results of magnesium oxide and magnesium carbonate should not be greater than the allowable difference listed in Tables 4 and 5.
Oxide (MgO) content
0.50~1.50
>1. 50～~4. 00
Standard authorization network table
Standard industry data fee lower level
Allowance difference
Additional instructions:
Magnesium carbonate (MgCO,) content
1.00-3.00
>3. 00~8. 00
GB/T15057.2—94
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Chemical Industry and Mining Design and Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Chemical Industry and Mining Design and Research Institute of the Ministry of Chemical Industry. The main drafters of this standard are Xu Xiulan and Li Donghao. Allowance difference
This standard refers to the Japanese Industrial Standard JISM8850-1982 "Limestone Analysis Method". Standards search network AT
All standard industry data are free to download10g of calcium carbonate (GB12596) standard reagent that has been dried at 110-120℃ in advance is placed in a 250mL beaker, covered with a watch glass, added with 25mL of water, and slowly added with 25mL of hydrochloric acid (12.1). Heat to dissolve, boil to remove carbon dioxide, cool, transfer to a 1000mL volumetric flask, dilute to scale with water, and shake well. This solution contains about 2mg of calcium carbonate per milliliter. 12.6 Magnesium oxide standard solution: 1mg/mL. Accurately weigh 1.0000g of magnesium oxide (high-purity reagent) that has been pre-burned at 900℃ for 1h and cooled to room temperature in a desiccator, and place it in a 250mL beaker. Moisten with a little water, add 20mL of hydrochloric acid solution (12.1), and heat until completely dissolved. Cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, and shake well. This solution contains 1mg of magnesium oxide per liter. 12.7 Magnesium oxide standard solution: 50μg/mL. Pipette 50.00mL of magnesium oxide standard solution (12.6) into another 1000mL volumetric flask, dilute to scale with water, and shake well. This solution contains 50μg magnesium oxide per liter. 13 Instruments
13.1 Flame atomic absorption spectrometer: It should comply with the provisions of GB/T9723. 14 Analysis steps
14.1 Pipette the solution prepared in 6.1 of the EDTA titration method of this standard according to Table 3 and place it in a 100mL volumetric flask. Perform a blank test at the same time. Add the matrix solution (12.5) according to the amount specified in Table 3. 187
Subtract
Magnesium oxide content, %
>1.5~4. 0
GB/T 1 5057. 2 --94
Volume flask for dilution
Volume, mL
Absorb test solution
Volume, ml
Add matrix solution
Liquid volume.mL
14.2Add 5.0mL strontium chloride solution (12.4), add 2.0mL hydrochloric acid solution (4.1) and dilute to scale with water, shake well. 14.3 Adjust the working parameters of the flame atomic absorption spectrometer to the best, use acetylene-air flame, magnesium hollow cathode lamp, at a wavelength of 285.2nm, adjust to zero with water, and splash the absorbance of the sample solution. Subtract the absorbance of the blank test solution from the measured absorbance to find the corresponding magnesium oxide concentration on the working curve.
15 Drawing of the working curve
According to the magnesium oxide content in the sample, measure 0.00, 1.00, 2.00, 3.00, 4.00, 5.00, 6.00mL of magnesium oxide standard solution (12.7) and place them in another set of 100mL volumetric flasks. Add 15.0mL of matrix solution (12.5), and proceed as follows in 6.2 and 6.3. Measure the absorbance of the standard series solution under the same conditions as the sample determination, subtract the reagent blank absorbance, and draw the working curve with the magnesium oxide concentration as the horizontal axis and the corresponding absorbance as the vertical axis. 16 Expression of analysis results
The content of magnesium oxide (MgO) (z) expressed as mass percentage is calculated according to formula (5), and the content of magnesium carbonate (MgCO,) (r2) is calculated according to formula (6):
In the formula: c-
×100×2.5
cX100×10-
c×2.092×100×10-
The concentration of magnesium oxide found from the working curve, μg/mL, V-the volume of the sample solution absorbed, mL,
mThe mass of the sample, 83
2.092-The factor for converting magnesium oxide into magnesium carbonate. 17 Allowable difference
The arithmetic mean of the parallel analysis results is taken as the final analysis result. The absolute difference between the parallel analysis results of magnesium oxide and magnesium carbonate should not be greater than the allowable difference listed in Tables 4 and 5.
Oxide (MgO) content
0.50~1.50
>1. 50～~4. 00
Standard authorization network table
Standard industry data fee lower level
Allowance difference
Additional instructions:
Magnesium carbonate (MgCO,) content
1.00-3.00
>3. 00~8. 00
GB/T15057.2—94
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Chemical Industry and Mining Design and Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Chemical Industry and Mining Design and Research Institute of the Ministry of Chemical Industry. The main drafters of this standard are Xu Xiulan and Li Donghao. Allowance difference
This standard refers to the Japanese Industrial Standard JISM8850-1982 "Limestone Analysis Method". Standards search network AT
All standard industry data are free to download10g of calcium carbonate (GB12596) standard reagent that has been dried at 110-120℃ in advance is placed in a 250mL beaker, covered with a watch glass, added with 25mL of water, and slowly added with 25mL of hydrochloric acid (12.1). Heat to dissolve, boil to remove carbon dioxide, cool, transfer to a 1000mL volumetric flask, dilute to scale with water, and shake well. This solution contains about 2mg of calcium carbonate per milliliter. 12.6 Magnesium oxide standard solution: 1mg/mL. Accurately weigh 1.0000g of magnesium oxide (high-purity reagent) that has been pre-burned at 900℃ for 1h and cooled to room temperature in a desiccator, and place it in a 250mL beaker. Moisten with a little water, add 20mL of hydrochloric acid solution (12.1), and heat until completely dissolved. Cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, and shake well. This solution contains 1mg of magnesium oxide per liter. 12.7 Magnesium oxide standard solution: 50μg/mL. Pipette 50.00mL of magnesium oxide standard solution (12.6) into another 1000mL volumetric flask, dilute to scale with water, and shake well. This solution contains 50μg magnesium oxide per liter. 13 Instruments
13.1 Flame atomic absorption spectrometer: It should comply with the provisions of GB/T9723. 14 Analysis steps
14.1 Pipette the solution prepared in 6.1 of the EDTA titration method of this standard according to Table 3 and place it in a 100mL volumetric flask. Perform a blank test at the same time. Add the matrix solution (12.5) according to the amount specified in Table 3. 187
Subtract
Magnesium oxide content, %
>1.5~4. 0
GB/T 1 5057. 2 --94
Volume flask for dilution
Volume, mL
Absorb test solution
Volume, ml
Add matrix solution
Liquid volume.mL
14.2Add 5.0mL strontium chloride solution (12.4), add 2.0mL hydrochloric acid solution (4.1) and dilute to scale with water, shake well. 14.3 Adjust the working parameters of the flame atomic absorption spectrometer to the best, use acetylene-air flame, magnesium hollow cathode lamp, at a wavelength of 285.2nm, adjust to zero with water, and splash the absorbance of the sample solution. Subtract the absorbance of the blank test solution from the measured absorbance to find the corresponding magnesium oxide concentration on the working curve.
15 Drawing of the working curve
According to the magnesium oxide content in the sample, measure 0.00, 1.00, 2.00, 3.00, 4.00, 5.00, 6.00mL of magnesium oxide standard solution (12.7) and place them in another set of 100mL volumetric flasks. Add 15.0mL of matrix solution (12.5), and proceed as follows in 6.2 and 6.3. Measure the absorbance of the standard series solution under the same conditions as the sample determination, subtract the reagent blank absorbance, and draw the working curve with the magnesium oxide concentration as the horizontal axis and the corresponding absorbance as the vertical axis. 16 Expression of analysis results
The content of magnesium oxide (MgO) (z) expressed as mass percentage is calculated according to formula (5), and the content of magnesium carbonate (MgCO,) (r2) is calculated according to formula (6):
In the formula: c-
×100×2.5
cX100×10-
c×2.092×100×10-
The concentration of magnesium oxide found from the working curve, μg/mL, V-the volume of the sample solution absorbed, mL,
mThe mass of the sample, 83
2.092-The factor for converting magnesium oxide into magnesium carbonate. 17 Allowable difference
The arithmetic mean of the parallel analysis results is taken as the final analysis result. The absolute difference between the parallel analysis results of magnesium oxide and magnesium carbonate should not be greater than the allowable difference listed in Tables 4 and 5.
Oxide (MgO) content
0.50~1.50
>1. 50～~4. 00
Standard authorization network table
Standard industry data fee lower level
Allowance difference
Additional instructions:
Magnesium carbonate (MgCO,) content
1.00-3.00
>3. 00~8. 00
GB/T15057.2—94
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Chemical Industry and Mining Design and Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Chemical Industry and Mining Design and Research Institute of the Ministry of Chemical Industry. The main drafters of this standard are Xu Xiulan and Li Donghao. Allowance difference
This standard refers to the Japanese Industrial Standard JISM8850-1982 "Limestone Analysis Method". Standards search network AT
All standard industry data are free to download2—94
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Chemical Industry Mine Design and Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Chemical Industry Mine Design and Research Institute of the Ministry of Chemical Industry. The main drafters of this standard are Xu Xiulan and Li Donghao. Allowable difference
This standard refers to the Japanese Industrial Standard JISM8850-1982 "Limestone Analysis Method". Standards authorized search network AT
All standard industry data are free to download2—94
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Chemical Industry Mine Design and Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Chemical Industry Mine Design and Research Institute of the Ministry of Chemical Industry. The main drafters of this standard are Xu Xiulan and Li Donghao. Allowable difference
This standard refers to the Japanese Industrial Standard JISM8850-1982 "Limestone Analysis Method". Standards authorized search network AT
All standard industry data are free to download
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