Some standard content:
GB/T4291-1999
This standard is revised based on the production experience and production technology achievements of the fluoride salt industry over the years. This standard is the fourth revision of the "Cryolite" standard. Compared with GB/T4291-1984, the following changes and additions are made in terms of technical content: 1. The indicators of calcium oxide and ignition loss are added; 2. The particle size of cryolite is relaxed to 10mm.
3. The test method of calcium oxide is equivalent to ISO3391:1976 "Determination of calcium content of natural and artificial cryolite-flame atomic absorption method" and is included as Appendix A of the standard.
Appendix A and Appendix B of this standard are the appendices of the standard. This standard will replace GB/T4291--1984 from the date of implementation. This standard is proposed by the State Bureau of Nonferrous Metals Industry. This standard is under the jurisdiction of the China Nonferrous Metals Industry Standard Metrology and Quality Research Institute. The drafting unit of this standard: Xiangxiang Aluminum Factory.
The main drafters of this standard are Wang Youling, Li Zuxing and Huang Zhongxiao. 255
1 Scope
National Standard of the People's Republic of China
Cryolite
Synthetic cryolite
This standard specifies the requirements, test methods, inspection rules, marking, packaging, transportation and storage of cryolite. GB/T 4291—1999
Replaces GB/T4291---1984
This standard applies to cryolite produced by hydrofluoric acid, which is mainly used in the aluminum smelting industry, as well as in smelting, welding and other industries. 2
Cited Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T 1250--1989
Methods for expressing and determining limit values GB/T6679--1986 General rules for sampling of solid chemical products YS/T273-1994 Chemical analysis methods for natural and artificial cryolite 3 Requirements
3.1 Product classification
Cryolite is divided into three grades according to chemical composition: special grade, first grade and second grade. 3.2 Chemical composition of cryolite
Should comply with the provisions of Table 1.
Table 1 Chemical composition of cryolite
Chemical composition, %
Not less than
The contents of chemical components in the table are calculated on a dry basis after removing the attached water (excluding loss on ignition).
ignition reduction, 550℃30min
2Numerical rounding rules shall be carried out in accordance with Article 5.2 of GB/T1250-1989, and the rounding digits shall be consistent with the limit digits listed in the table. 3The molar ratio of sodium fluoride to aluminum fluoride in the product is generally between 1.8 and 2.9. If the purchaser has other special requirements, it should be indicated in the contract. 4If the purchaser requires the ignition reduction of cryolite to be less than 2.5%, it should be indicated in the contract. 3.3Appearance
The product is divided into powdery and granular cryolite. Note: This standard refers to powdery cryolite with a particle size of less than 0.28mm (60 mesh) greater than 80%; granular cryolite with a particle size of 1~10mm greater than 55%. Approved by the State Administration of Quality and Technical Supervision on March 4, 1999 256
Implemented from September to January, 1999
3.4 Particle size
GB/T4291—1999
The product shall not contain particles or agglomerates with a diameter greater than 10 mm. Particles or agglomerates with a diameter of 4 to 10 mm are allowed in powdered cryolite products, and their weight shall not exceed 5%.
Test method
4.1 The chemical analysis method of the product shall be carried out in accordance with the provisions of YS/T273. 4.2 The analysis method of calcium oxide shall be carried out in accordance with the provisions of Appendix A. 4.3 The determination of ignition loss shall be carried out in accordance with the provisions of Appendix B. 5 Inspection rules
5.1 Inspection and acceptance
5.1.1 The product shall be inspected by the supplier's technical supervision department to ensure that the quality meets the requirements of this standard and fill in the quality certificate. 5.1.2 The buyer shall inspect the received products according to the requirements of this standard. If the inspection results do not match the grade stated in the quality certificate, the buyer shall submit the matter to the supplier within 1 month from the date of receipt of the product, and the supplier and buyer shall negotiate to resolve the issue. If arbitration is required, arbitration sampling shall be conducted jointly by the supplier and buyer.
5.2 Batching
The products shall be submitted for inspection in batches. Each batch shall consist of products of the same grade and weigh no more than 60t. 5.3 Inspection items
Each batch of cryolite shall be inspected for chemical composition. 5.4 Arbitration sampling and sample preparation for chemical composition
5.4.1 Number of sampling bags
Random sampling shall be conducted according to the number of sampling bags specified in Table 2 (when the total number of bags is greater than 500, the number of sampling bags shall be 3×N, where N is the total number of bags).
Table 2 Provisions for the selection of sampling bag numbers
Total number of bags
82~101
102~125
126~151
152~181
5.4.2 Arbitration sampling and sample preparation
Minimum number of bags selected
Total number of bags
182~216
217254
255~296
297~343| |tt||344394
395~450
451~512
Minimum number of bags selected
Randomly select the number of sample bags specified in 5.4.1, use a copper tube probe with an inner diameter of 19~25mm, insert it into the sample bag diagonally to 3/4 of its depth to take equal amounts of samples, the total amount of which shall not be less than 2kg, mix it thoroughly, and use the quartering method to reduce it to not less than 500g and divide it into 3 parts, one for arbitration analysis, and the rest to be kept by both the supplier and the buyer. 5.4.3 Arbitration sampling and sample preparation of granular cryolite Arbitration sampling and sample preparation of granular cryolite shall be carried out in accordance with the provisions of 5.4.1 of this standard and Article 2.3 and Chapter 3 of GB/T6679--1986.
5.5 Arbitration analysis
The arbitration analysis method of chemical composition shall be carried out in accordance with the provisions of YS/T273 and Appendix A and Appendix B. 5.6 Determination rules
GB/T4291-1999
When the arbitration analysis results of chemical composition do not conform to the provisions of this standard, the grade shall be re-determined according to the arbitration analysis results. 6 Marking, packaging, transportation and storage
6.1 Marking
The packaging bag should indicate: supplier name, implementation product standard number, batch number, net weight. 6.2 Packaging
The product is packaged in laminated plastic or plastic woven bags, lined with plastic film bags, with a net weight of 40kg, 50kg or 1000kg per bag. The product packaging shall be in accordance with the requirements of commodity inspection or foreign merchants.
6.3 Transportation
When the product is shipped, it must be packed in a clean and rainproof car box, and products of different grades shall not be mixed. 6.4 Storage
Products must be stored in dry warehouses to avoid damage, contamination and moisture. Products should be stacked in batches. 6.5 Quality Certificate
Each batch of products should be accompanied by a quality certificate, which should indicate: a) Name of supplier;
b) Name of product;
c) Grade,
d) Molecular ratio;
e) Batch number;
1) Weight or number of pieces;
g) Stamp of technical supervision department,
h) Number of this standard;
i) Date of manufacture.
A1 Scope
GB/T4291-1999
Appendix A
(Appendix to the standard)
Determination of calcium content in natural and artificial cryolite Flame atomic absorption method
This standard specifies the determination of calcium content in natural and artificial cryolite by flame atomic absorption method. A2 Reference standards
ISO1619 Natural and artificial cryolite - Preparation and storage of samples A3 Method summary
After the sample is decomposed with concentrated sulfuric acid, it is treated with concentrated hydrochloric acid, and the solution is sprayed into a nitrous oxide-acetylene flame. The absorbance value of the 422.7nm spectrum line emitted by a calcium hollow cathode lamp is measured by spectrophotometry to determine the calcium content. A4 Reagents
Analytical reagents or distilled water or water of equal purity should be used throughout the analysis process. A4.1 Sulfuric acid
p About 1.84 g/mL, concentration about 96% (m/m). A4.2 Hydrochloric acid
0 About 1.19 g/mL, concentration about 38% (m/m). A4.3 Complexing agent
A4.3.1 Lanthanum nitrate solution (310 g/L)
Weigh 31.0 g La(NO.)2·6H,0 (accurate to 0.1 g) and place it in a 100 mL single-scale volumetric flask, dissolve it with water, dilute to the scale and mix it.
Note: LaCl:·7H20 solution (270 g/L) can also be used. A4.3.2 Triethanolamine, diluent
Take 100mL triethanolamine t(CH.OHCH2),N) and dilute to 200mL with water. A4.4 Sodium chloride solution (equivalent to 16.0g/L sodium) Sodium chloride is first dried at about 120℃ for 12h and cooled in a desiccator. Weigh 4.067g sodium chloride, accurate to 0.001g, and place in a 100mL single-scale volumetric flask. Dissolve with water, dilute to scale and mix. A4.5 Aluminum acid solution (equivalent to 6.6g/L aluminum) Weigh 0.66g high-purity aluminum flakes (accurate to 0.001g), put them in a porcelain dish, add 50mL (1+1) hydrochloric acid to dissolve, and then transfer to a 100ml. single-scale volumetric flask, cool and make up to volume and shake well. A4.6 Calcium standard solution (equivalent to 1.00 g/L calcium) Weigh 2.4972 g of calcium carbonate (dried at 110°C for 2 h, cooled in a desiccator) to an accuracy of 0.0001 g, transfer to a 250 mL beaker, carefully add 12 mL of hydrochloric acid solution (4.2) diluted with 12 mL of water in advance to dissolve it. Transfer the solution quantitatively to a 1000 mL single-scale volumetric flask. After cooling, adjust the volume and shake well. Transfer to a storage bottle without calcium materials. This solution contains 1.00 mg of calcium per ml. A4.7 Calcium standard solution (equivalent to 0.10 g/L calcium) Transfer 100.0 mL of calcium standard solution (4.6) to a 1000 mL single-scale volumetric flask, dilute to the mark with water, shake well, and transfer to a storage bottle without calcium materials. This solution contains 0.10 mg of calcium per ml. 259
A5 Equipment
General laboratory instruments and:
A5.1 Platinum III, 30 mm high, 75 mm in diameter. GB/T 4291-- 1999
A5.2 Atomic absorption spectrophotometer, equipped with bottled nitrous oxide and acetylene, the burner is preferably 50~60 mm. A5.3 Calcium hollow cathode lamp.
A6 Analytical procedures
A6.1 Weighing
Weigh 0.500 g (accurate to 0.0001 g) of the sample treated and dried according to ISO1619. A6.2 Blank test
Carry out a blank test at the same time as the sample determination using the same method, reagents, analytical procedures, and add 10.0 ml of aluminum acid solution (A4.5) and 10.0 ml of sodium chloride solution (A4.4) before adding sulfuric acid. A6.3 Drawing of standard curve
A6.3.1 Preparation of standard solution
Add calcium standard solution (A4.7) according to the following table to 6 platinum III (A5.1) Calcium standard solution (A4.7)
1) Reagent blank for standardizing curve.
Equivalent to calcium amount
Equivalent to CaO% content in cryolite
Add 10.0mL of aluminum acid solution (A4.5), 10.0mL of sodium chloride solution (A4.4), and 5.0mL of sulfuric acid solution (A4.1) to each platinum dish. Heat carefully in a sand bath or on a hot plate to evaporate and remove the sulfuric acid. Note: 5.0mL of sulfuric acid solution (A4.1) can be replaced by 10.0mL of perchloric acid solution (p about 1.70g/mL). In this case, use an air-acetylene flame (clear, non-glowing oxidizing flame) for spectrophotometric determination. Add 1.0 mL of hydrochloric acid solution (A4.2) and 30 mL of water to each platinum III, transfer quantitatively into a 100 mL single-scale volumetric flask, then add 10 mL of lanthanum nitrate solution) or lanthanum fluoride solution (A4.3.1), or add 20 mL of triethanolamine solution (A4.3.2), dilute to the scale after cooling and shake. This solution is stored in a flask made of calcium-free material. A6.3.2 Spectrophotometric determination
Install the hollow cathode lamp (A5.3), turn on the instrument (A5.2), and adjust the wavelength to 422.7 nm after sufficient time to stabilize. Adjust the sensitivity and slit according to the characteristics of the instrument, adjust the gas pressure according to the characteristics of the burner to obtain an oxidizing flame, and control the spray rate (such as 2 to 3 mL/min).
Spray the standard solution (A6.3.1) into the flame and measure the absorbance of each solution. Note that the amount of solution sprayed into the flame remains constant throughout the measurement process and time, and the burner should be sprayed with water after each measurement. A6.3.3 Drawing of the standard curve
When drawing the curve, the mass number of calcium in each 100 mL of the standard solution is used as the horizontal axis, and the corresponding absorbance minus the absorbance value of the standard curve reagent blank is used as the vertical axis.
A6.4 Determination
A6.4.1 Preparation of the test solution
Place the sample (A6.1) in platinum blood (A5.1) and add 5.0 mL of sulfuric acid (A4.1) (see A6.3.1). Carefully heat at 260°C on a sand bath or hot plate until the hydrofluoric acid evaporates completely (15 to 20 minutes). Continue to increase the temperature until the sulfuric acid evaporates completely. Add 3.0 mL of hydrochloric acid solution (A4.2) and 30 mL of water to a platinum dish and heat on a water bath until it is completely dissolved. Transfer the solution quantitatively into a 100 ml single-scale volumetric flask and add 10 ml of lanthanum nitrate or lanthanum chloride solution (A4.3.1), or 20 ml of triethanolamine solution (A4.3.2). After cooling, dilute to the mark and mix. This solution is stored in a volumetric flask made of calcium-free material. A6.4.2 Spectrophotometric determination
A6.4.2.1 Preliminary determination
According to the procedure specified in A6.3.2, perform spectrophotometric determination on the standard solution (A6.3.1) and perform preliminary determination on the sample (A6.4.1) and blank solution (A6.2).
A6.4.2.2 Interpolation determination
Take two standard solutions, the calcium content of which differs by 0.10 mg in 100 ml. One of them has a higher concentration and the other has a lower concentration than the test solution. Perform a second determination on the test solution by interpolation determination of the two standard solutions. In preparing these standard solutions, the procedure specified in A6.3.1 should be followed, using an appropriate amount of standard calcium solution (A4.7). At the same time, without interpolation, a second determination is made on the blank solution (A6.2). A7 Result Expression
The concentration of calcium (Ca) in the solution used for spectrophotometric determination is expressed as the mass in 100 mL and calculated according to formula (A1): (A -A) -(A - A))
C= G + (C2 - c) × [
Wherein: A,——spectrophotometric value of reagent blank solution; Ci—--the concentration of the lower concentration interpolation solution used for the test solution, the mass per 100 ml; A—corresponding spectrophotometric value;
C—the concentration of the higher concentration interpolation solution used for the test solution, the mass per 100 mL; A2 corresponding spectrophotometric value;
A:—-—spectrophotometric value of standard blank; A.-—spectrophotometric value of test solution.
Calcium content is expressed as the weight percentage of calcium oxide (CaO) and is calculated according to formula (A2): × 1: 399 × 100 - 0. 139 9 -1000×m
Where: m--sample weight (6.1), g
1.399--coefficient for converting calcium to calcium oxide. Appendix B
(Suggested Appendix)
Determination of ignition loss of cryolite
B1 Method Summary
The sample is burned at 550°C and its loss is determined. B2 Instruments
B2.1-General laboratory instruments.
B2.2 Platinum crucible: diameter 40mm, height 40mm. B2.3 Muffle furnace, capable of controlling the temperature at 550°C ± 5°C. .Al)
B3 Analysis steps
B3.1 Determination quantity
Measure two samples in parallel and take the average value. GB/T4291—1999
Note: The sample should comply with the provisions of Article 1.2 of YS/T272. B3.2 Sample quantity
Weigh 2.000g sample.
B3.3 Determination
B3.3.7 Place the sample (B3.2) in a platinum crucible that has been pre-burned in a muffle furnace (B2.3) at 550℃ for 30min and cooled in a desiccator, and weigh it (accurate to 0.001g).
B3.3.2 Place the platinum crucible (B3.3.1) containing the sample in a muffle furnace (B2.3) at 550℃±5℃, and immediately close the muffle furnace door. After burning for 30 minutes, take out the platinum crucible and place it in a desiccator. Cool and weigh it (accurate to 0.001g). B4
Calculation of analysis results
Calculate the percentage of loss on ignition according to formula (B1): Loss on ignition -
(ml = mz) × 100%
Where: ml---
Weight of the platinum crucible containing the sample before burning, m2; m2-Weight of the platinum crucible containing the sample after burning, g; m2-sample weight, g.OHCH2), N) is diluted with water to 200mL. A4.4 Sodium chloride solution (equivalent to 16.0g/L sodium) Sodium chloride is first dried at about 120℃ for 12h and cooled in a desiccator. Weigh 4.067g sodium chloride, accurate to 0.001g, and place it in a 100mL single-scale volumetric flask. Dissolve it with water, dilute to the scale and mix well. A4.5 Aluminum acid solution (equivalent to 6.6g/L aluminum) Weigh 0.66g high-purity aluminum flakes (accurate to 0.001g), put them in a porcelain dish, add 50mL (1+1) hydrochloric acid to dissolve, and then transfer them to a 100ml single-scale volumetric flask. After cooling, make up to volume and shake well. A4.6 Calcium standard solution (equivalent to 1.00 g/L calcium) Weigh 2.4972 g of calcium carbonate (dried at 110°C for 2 h, cooled in a desiccator) to an accuracy of 0.0001 g, transfer to a 250 mL beaker, carefully add 12 mL of hydrochloric acid solution (4.2) diluted with 12 mL of water in advance to dissolve it. Transfer the solution quantitatively to a 1000 mL single-scale volumetric flask. After cooling, adjust the volume and shake well. Transfer to a storage bottle without calcium materials. This solution contains 1.00 mg of calcium per ml. A4.7 Calcium standard solution (equivalent to 0.10 g/L calcium) Transfer 100.0 mL of calcium standard solution (4.6) to a 1000 mL single-scale volumetric flask, dilute to the mark with water, shake well, and transfer to a storage bottle without calcium materials. This solution contains 0.10 mg of calcium per ml. 259
A5 Equipment
General laboratory instruments and:
A5.1 Platinum III, 30 mm high, 75 mm in diameter. GB/T 4291-- 1999
A5.2 Atomic absorption spectrophotometer, equipped with bottled nitrous oxide and acetylene, the burner is preferably 50~60 mm. A5.3 Calcium hollow cathode lamp.
A6 Analytical procedures
A6.1 Weighing
Weigh 0.500 g (accurate to 0.0001 g) of the sample treated and dried according to ISO1619. A6.2 Blank test
Carry out a blank test at the same time as the sample determination using the same method, reagents, analytical procedures, and add 10.0 ml of aluminum acid solution (A4.5) and 10.0 ml of sodium chloride solution (A4.4) before adding sulfuric acid. A6.3 Drawing of standard curve
A6.3.1 Preparation of standard solution
Add calcium standard solution (A4.7) according to the following table to 6 platinum III (A5.1) Calcium standard solution (A4.7)
1) Reagent blank for standardizing curve.
Equivalent to calcium amount
Equivalent to CaO% content in cryolite
Add 10.0mL of aluminum acid solution (A4.5), 10.0mL of sodium chloride solution (A4.4), and 5.0mL of sulfuric acid solution (A4.1) to each platinum dish. Heat carefully in a sand bath or on a hot plate to evaporate and remove the sulfuric acid. Note: 5.0mL of sulfuric acid solution (A4.1) can be replaced by 10.0mL of perchloric acid solution (p about 1.70g/mL). In this case, use an air-acetylene flame (clear, non-glowing oxidizing flame) for spectrophotometric determination. Add 1.0 mL of hydrochloric acid solution (A4.2) and 30 mL of water to each platinum III, transfer quantitatively into a 100 mL single-scale volumetric flask, then add 10 mL of lanthanum nitrate solution) or lanthanum fluoride solution (A4.3.1), or add 20 mL of triethanolamine solution (A4.3.2), dilute to the scale after cooling and shake. This solution is stored in a flask made of calcium-free material. A6.3.2 Spectrophotometric determination
Install the hollow cathode lamp (A5.3), turn on the instrument (A5.2), and adjust the wavelength to 422.7 nm after sufficient time to stabilize. Adjust the sensitivity and slit according to the characteristics of the instrument, adjust the gas pressure according to the characteristics of the burner to obtain an oxidizing flame, and control the spray rate (such as 2 to 3 mL/min).
Spray the standard solution (A6.3.1) into the flame and measure the absorbance of each solution. Note that the amount of solution sprayed into the flame remains constant throughout the measurement process and time, and the burner should be sprayed with water after each measurement. A6.3.3 Drawing of the standard curve
When drawing the curve, the mass number of calcium in each 100 mL of the standard solution is used as the horizontal axis, and the corresponding absorbance minus the absorbance value of the standard curve reagent blank is used as the vertical axis.
A6.4 Determination
A6.4.1 Preparation of the test solution
Place the sample (A6.1) in platinum blood (A5.1) and add 5.0 mL of sulfuric acid (A4.1) (see A6.3.1). Carefully heat at 260°C on a sand bath or hot plate until the hydrofluoric acid evaporates completely (15 to 20 minutes). Continue to increase the temperature until the sulfuric acid evaporates completely. Add 3.0 mL of hydrochloric acid solution (A4.2) and 30 mL of water to a platinum dish and heat on a water bath until it is completely dissolved. Transfer the solution quantitatively into a 100 ml single-scale volumetric flask and add 10 ml of lanthanum nitrate or lanthanum chloride solution (A4.3.1), or 20 ml of triethanolamine solution (A4.3.2). After cooling, dilute to the mark and mix. This solution is stored in a volumetric flask made of calcium-free material. A6.4.2 Spectrophotometric determination
A6.4.2.1 Preliminary determination
According to the procedure specified in A6.3.2, perform spectrophotometric determination on the standard solution (A6.3.1) and perform preliminary determination on the sample (A6.4.1) and blank solution (A6.2).
A6.4.2.2 Interpolation determination
Take two standard solutions, the calcium content of which differs by 0.10 mg in 100 ml. One of them has a higher concentration and the other has a lower concentration than the test solution. Perform a second determination on the test solution by interpolation determination of the two standard solutions. In preparing these standard solutions, the procedure specified in A6.3.1 should be followed, using an appropriate amount of standard calcium solution (A4.7). At the same time, without interpolation, a second determination is made on the blank solution (A6.2). A7 Result Expression
The concentration of calcium (Ca) in the solution used for spectrophotometric determination is expressed as the mass in 100 mL and calculated according to formula (A1): (A -A) -(A - A))
C= G + (C2 - c) × [
Wherein: A,——spectrophotometric value of reagent blank solution; Ci—--the concentration of the lower concentration interpolation solution used for the test solution, the mass per 100 ml; A—corresponding spectrophotometric value;
C—the concentration of the higher concentration interpolation solution used for the test solution, the mass per 100 mL; A2 corresponding spectrophotometric value;
A:—-—spectrophotometric value of standard blank; A.-—spectrophotometric value of test solution.
Calcium content is expressed as the weight percentage of calcium oxide (CaO) and is calculated according to formula (A2): × 1: 399 × 100 - 0. 139 9 -1000×m
Where: m--sample weight (6.1), g
1.399--coefficient for converting calcium to calcium oxide. Appendix B
(Suggested Appendix)
Determination of ignition loss of cryolite
B1 Method Summary
The sample is burned at 550°C and its loss is determined. B2 Instruments
B2.1-General laboratory instruments.
B2.2 Platinum crucible: diameter 40mm, height 40mm. B2.3 Muffle furnace, capable of controlling the temperature at 550°C ± 5°C. .Al)
B3 Analysis steps
B3.1 Determination quantity
Measure two samples in parallel and take the average value. GB/T4291—1999
Note: The sample should comply with the provisions of Article 1.2 of YS/T272. B3.2 Sample quantity
Weigh 2.000g sample.
B3.3 Determination
B3.3.7 Place the sample (B3.2) in a platinum crucible that has been pre-burned in a muffle furnace (B2.3) at 550℃ for 30min and cooled in a desiccator, and weigh it (accurate to 0.001g).
B3.3.2 Place the platinum crucible (B3.3.1) containing the sample in a muffle furnace (B2.3) at 550℃±5℃, and immediately close the muffle furnace door. After burning for 30 minutes, take out the platinum crucible and place it in a desiccator. Cool and weigh it (accurate to 0.001g). B4
Calculation of analysis results
Calculate the percentage of loss on ignition according to formula (B1): Loss on ignition -
(ml = mz) × 100%
Where: ml---
Weight of the platinum crucible containing the sample before burning, m2; m2-Weight of the platinum crucible containing the sample after burning, g; m2-sample weight, g.OHCH2), N) is diluted with water to 200mL. A4.4 Sodium chloride solution (equivalent to 16.0g/L sodium) Sodium chloride is first dried at about 120℃ for 12h and cooled in a desiccator. Weigh 4.067g sodium chloride, accurate to 0.001g, and place it in a 100mL single-scale volumetric flask. Dissolve it with water, dilute to the scale and mix well. A4.5 Aluminum acid solution (equivalent to 6.6g/L aluminum) Weigh 0.66g high-purity aluminum flakes (accurate to 0.001g), put them in a porcelain dish, add 50mL (1+1) hydrochloric acid to dissolve, and then transfer them to a 100ml single-scale volumetric flask. After cooling, make up to volume and shake well. A4.6 Calcium standard solution (equivalent to 1.00 g/L calcium) Weigh 2.4972 g of calcium carbonate (dried at 110°C for 2 h, cooled in a desiccator) to an accuracy of 0.0001 g, transfer to a 250 mL beaker, carefully add 12 mL of hydrochloric acid solution (4.2) diluted with 12 mL of water in advance to dissolve it. Transfer the solution quantitatively to a 1000 mL single-scale volumetric flask. After cooling, adjust the volume and shake well. Transfer to a storage bottle without calcium materials. This solution contains 1.00 mg of calcium per ml. A4.7 Calcium standard solution (equivalent to 0.10 g/L calcium) Transfer 100.0 mL of calcium standard solution (4.6) to a 1000 mL single-scale volumetric flask, dilute to the mark with water, shake well, and transfer to a storage bottle without calcium materials. This solution contains 0.10 mg of calcium per ml. 259
A5 Equipment
General laboratory instruments and:
A5.1 Platinum III, 30 mm high, 75 mm in diameter. GB/T 4291-- 1999
A5.2 Atomic absorption spectrophotometer, equipped with bottled nitrous oxide and acetylene, the burner is preferably 50~60 mm. A5.3 Calcium hollow cathode lamp.
A6 Analytical procedures
A6.1 Weighing
Weigh 0.500 g (accurate to 0.0001 g) of the sample treated and dried according to ISO1619. A6.2 Blank test
Carry out a blank test at the same time as the sample determination using the same method, reagents, analytical procedures, and add 10.0 ml of aluminum acid solution (A4.5) and 10.0 ml of sodium chloride solution (A4.4) before adding sulfuric acid. A6.3 Drawing of standard curve
A6.3.1 Preparation of standard solution
Add calcium standard solution (A4.7) according to the following table to 6 platinum III (A5.1) Calcium standard solution (A4.7)
1) Reagent blank for standardizing curve.
Equivalent to calcium amount
Equivalent to CaO% content in cryolite
Add 10.0mL of aluminum acid solution (A4.5), 10.0mL of sodium chloride solution (A4.4), and 5.0mL of sulfuric acid solution (A4.1) to each platinum dish. Heat carefully in a sand bath or on a hot plate to evaporate and remove the sulfuric acid. Note: 5.0mL of sulfuric acid solution (A4.1) can be replaced by 10.0mL of perchloric acid solution (p about 1.70g/mL). In this case, use an air-acetylene flame (clear, non-glowing oxidizing flame) for spectrophotometric determination. Add 1.0 mL of hydrochloric acid solution (A4.2) and 30 mL of water to each platinum III, transfer quantitatively into a 100 mL single-scale volumetric flask, then add 10 mL of lanthanum nitrate solution) or lanthanum fluoride solution (A4.3.1), or add 20 mL of triethanolamine solution (A4.3.2), dilute to the scale after cooling and shake. This solution is stored in a flask made of calcium-free material. A6.3.2 Spectrophotometric determination
Install the hollow cathode lamp (A5.3), turn on the instrument (A5.2), and adjust the wavelength to 422.7 nm after sufficient time to stabilize. Adjust the sensitivity and slit according to the characteristics of the instrument, adjust the gas pressure according to the characteristics of the burner to obtain an oxidizing flame, and control the spray rate (such as 2 to 3 mL/min).
Spray the standard solution (A6.3.1) into the flame and measure the absorbance of each solution. Note that the amount of solution sprayed into the flame remains constant throughout the measurement process and time, and the burner should be sprayed with water after each measurement. A6.3.3 Drawing of the standard curve
When drawing the curve, the mass number of calcium in each 100 mL of the standard solution is used as the horizontal axis, and the corresponding absorbance minus the absorbance value of the standard curve reagent blank is used as the vertical axis.
A6.4 Determination
A6.4.1 Preparation of the test solution
Place the sample (A6.1) in platinum blood (A5.1) and add 5.0 mL of sulfuric acid (A4.1) (see A6.3.1). Carefully heat at 260°C on a sand bath or hot plate until the hydrofluoric acid evaporates completely (15 to 20 minutes). Continue to increase the temperature until the sulfuric acid evaporates completely. Add 3.0 mL of hydrochloric acid solution (A4.2) and 30 mL of water to a platinum dish and heat on a water bath until it is completely dissolved. Transfer the solution quantitatively into a 100 ml single-scale volumetric flask and add 10 ml of lanthanum nitrate or lanthanum chloride solution (A4.3.1), or 20 ml of triethanolamine solution (A4.3.2). After cooling, dilute to the mark and mix. This solution is stored in a volumetric flask made of calcium-free material. A6.4.2 Spectrophotometric determination
A6.4.2.1 Preliminary determination
According to the procedure specified in A6.3.2, perform spectrophotometric determination on the standard solution (A6.3.1) and perform preliminary determination on the sample (A6.4.1) and blank solution (A6.2).
A6.4.2.2 Interpolation determination
Take two standard solutions, the calcium content of which differs by 0.10 mg in 100 ml. One of them has a higher concentration and the other has a lower concentration than the test solution. Perform a second determination on the test solution by interpolation determination of the two standard solutions. In preparing these standard solutions, the procedure specified in A6.3.1 should be followed, using an appropriate amount of standard calcium solution (A4.7). At the same time, without interpolation, a second determination is made on the blank solution (A6.2). A7 Result Expression
The concentration of calcium (Ca) in the solution used for spectrophotometric determination is expressed as the mass in 100 mL and calculated according to formula (A1): (A -A) -(A - A))
C= G + (C2 - c) × [
Wherein: A,——spectrophotometric value of reagent blank solution; Ci—--the concentration of the lower concentration interpolation solution used for the test solution, the mass per 100 ml; A—corresponding spectrophotometric value;
C—the concentration of the higher concentration interpolation solution used for the test solution, the mass per 100 mL; A2 corresponding spectrophotometric value;
A:—-—spectrophotometric value of standard blank; A.-—spectrophotometric value of test solution.
Calcium content is expressed as the weight percentage of calcium oxide (CaO) and is calculated according to formula (A2): × 1: 399 × 100 - 0. 139 9 -1000×m
Where: m--sample weight (6.1), g
1.399--coefficient for converting calcium to calcium oxide. Appendix B
(Suggested Appendix)
Determination of ignition loss of cryolite
B1 Method Summary
The sample is burned at 550°C and its loss is determined. B2 Instruments
B2.1-General laboratory instruments.
B2.2 Platinum crucible: diameter 40mm, height 40mm. B2.3 Muffle furnace, capable of controlling the temperature at 550°C ± 5°C. .Al)www.bzxz.net
B3 Analysis steps
B3.1 Determination quantity
Measure two samples in parallel and take the average value. GB/T4291—1999
Note: The sample should comply with the provisions of Article 1.2 of YS/T272. B3.2 Sample quantity
Weigh 2.000g sample.
B3.3 Determination
B3.3.7 Place the sample (B3.2) in a platinum crucible that has been pre-burned in a muffle furnace (B2.3) at 550℃ for 30min and cooled in a desiccator, and weigh it (accurate to 0.001g).
B3.3.2 Place the platinum crucible (B3.3.1) containing the sample in a muffle furnace (B2.3) at 550℃±5℃, and immediately close the muffle furnace door. After burning for 30 minutes, take out the platinum crucible and place it in a desiccator. Cool and weigh it (accurate to 0.001g). B4
Calculation of analysis results
Calculate the percentage of loss on ignition according to formula (B1): Loss on ignition -
(ml = mz) × 100%
Where: ml---
Weight of the platinum crucible containing the sample before burning, m2; m2-Weight of the platinum crucible containing the sample after burning, g; m2-sample weight, g.0g/L sodium) Sodium chloride is first dried at about 120℃ for 12h and cooled in a desiccator. Weigh 4.067g sodium chloride, accurate to 0.001g, and place in a 100mL single-scale volumetric flask. Dissolve with water, dilute to scale and mix. A4.5 Aluminum acid solution (equivalent to 6.6g/L aluminum) Weigh 0.66g high-purity aluminum flakes (accurate to 0.001g), put them in a porcelain dish, add 50mL (1+1) hydrochloric acid to dissolve, and then transfer to a 100ml. single-scale volumetric flask, cool and shake to volume. A4.6 Calcium standard solution (equivalent to 1.00g/L calcium) Weigh 2.4972g calcium carbonate (dried at 110℃ for 2h, cooled in a desiccator) accurate to 0.0001g, transfer to a 250mL beaker, and carefully add 12mL hydrochloric acid solution (4.2) diluted with 12mL water in advance to dissolve it. Transfer the solution quantitatively into a 1000ml single-scale volumetric flask. After cooling, adjust the volume and shake well. Transfer to a storage bottle without calcium materials. This solution contains 1.00mg calcium per ml. A4.7 Calcium standard solution (equivalent to 0.10g/L calcium) Transfer 100.0mL of calcium standard solution (4.6) into a 1000mL single-scale volumetric flask, dilute with water to the scale, shake well, and transfer to a storage bottle without calcium materials. This solution contains 0.10mg calcium per ml. 259
A5 Equipment
Ordinary laboratory instruments and:
A5.1 Platinum III, 30mm high, 75mm in diameter. GB/T 4291-- 1999
A5.2 Atomic absorption spectrophotometer, equipped with bottled nitrous oxide and acetylene, the burner should be 50~60mm. A5.3 Calcium hollow cathode lamp.
A6 Analysis steps
A6.1 Weighing samples
Weigh 0.500 g (accurate to 0.0001 g) of the sample treated and dried according to ISO1619. A6.2 Blank test
Use the same method, reagents, and analysis steps to perform a blank test at the same time as the sample determination, and add 10.0 ml of aluminum acid solution (A4.5) and 10.0 ml of sodium chloride solution (A4.4) before adding sulfuric acid. A6.3 Drawing of standard curve
A6.3.1 Preparation of standard solution
In 6 platinum III (A5.1), add calcium standard solution (A4.7) according to the table below. Calcium standard solution (A4.7)
1) Reagent blank for standardizing the curve.
Equivalent to calcium content
Equivalent to CaO% content in cryolite
Add 10.0mL aluminum acid solution (A4.5), 10.0mL sodium chloride solution (A4.4), and 5.0mL sulfuric acid solution (A4.1) to each platinum dish. Carefully heat on a sand bath or hot plate to evaporate and remove the sulfuric acid. Note: 5.0mL sulfuric acid solution (A4.1) can be replaced by 10.0mL perchloric acid solution (p about 1.70g/mL), and then use air-acetylene flame (clear, non-glowing oxidizing flame) for spectrophotometric determination. Add 1.0mL hydrochloric acid solution (A4.2) and 30mL water to each platinum III, quantitatively transfer to a 100mL single-scale volumetric flask, then add 10mL lanthanum nitrate solution) or lanthanum fluoride solution (A4.3.1), or add 20mL triethanolamine solution (A4.3.2), cool and dilute to the scale and shake. This solution is stored in a flask made of calcium-free material. A6.3.2 Spectrophotometric determination
Install the hollow cathode lamp (A5.3), turn on the instrument (A5.2), and after sufficient time to stabilize, adjust the wavelength to 422.7nm. Adjust the sensitivity and slit according to the characteristics of the instrument, and adjust the gas pressure according to the characteristics of the burner to obtain an oxidizing flame, while controlling the spray rate (such as 2-3 mL/min).
Spray the standard solution (A6.3.1) into the flame, and measure the absorbance of each solution. Note that the amount of solution sprayed into the flame remains constant throughout the entire measurement process and time, and the burner should be sprayed with water after each measurement. A6.3.3 Drawing of the standard curve
When drawing the curve, the mass number of calcium contained in each 100mL of the standard solution is used as the horizontal axis, and the corresponding absorbance minus the absorbance value of the standard curve reagent blank is used as the vertical axis.
A6.4 Determination
A6.4.1 Preparation of test solution
Place the sample (A6.1) in platinum blood (A5.1) and add 5.0ml sulfuric acid (A4.1) (see A6.3.1). Carefully heat at 260°C on a sand bath or hot plate until the hydrofluoric acid evaporates completely (15-20min). Continue to raise the temperature until the sulfuric acid evaporates completely. Add 3.0ml hydrochloric acid solution (A4.2) and 30ml water to a platinum dish and heat on a water bath until completely dissolved. Quantitatively transfer the solution into a 100ml single-scale volumetric flask and add 10ml lanthanum nitrate or lanthanum chloride solution (A4.3.1), or 20ml triethanolamine solution (A4.3.2). After cooling, dilute to the scale and mix well. This solution is stored in a volumetric flask made of calcium-free material. A6.4.2 Spectrophotometric determination
A6.4.2.1 Preliminary determination
According to the procedure specified in A6.3.2, while the standard solution (A6.3.1) is being spectrophotometrically determined, a preliminary determination is made on the test sample (A6.4.1) and the blank solution (A6.2).
A6.4.2.2 Interpolation determination
Take two standard solutions, each with a calcium content of 0.10 mg different in 100 ml, one with a higher concentration and the other with a lower concentration than the test solution, and make a second determination of the test solution by interpolation of the two standard solutions. In preparing these standard solutions, follow the procedure specified in A6.3.1 and use an appropriate amount of standard calcium solution (A4.7). At the same time, without interpolation, make a second determination on the blank test solution (A6.2). A7 Result Expression
The concentration of calcium (Ca) in the solution used for spectrophotometric determination is expressed as the mass in 100 mL and calculated according to formula (A1): (A -A) -(A - A))
C= G + (C2 - c) × [
Wherein: A,——spectrophotometric value of reagent blank solution; Ci—--the concentration of the lower concentration interpolation solution used for the test solution, the mass per 100 ml; A—corresponding spectrophotometric value;
C—the concentration of the higher concentration interpolation solution used for the test solution, the mass per 100 mL; A2 corresponding spectrophotometric value;
A:—-—spectrophotometric value of standard blank; A.-—spectrophotometric value of test solution.
Calcium content is expressed as the weight percentage of calcium oxide (CaO) and is calculated according to formula (A2): × 1: 399 × 100 - 0. 139 9 -1000×m
Where: m--sample weight (6.1), g
1.399--coefficient for converting calcium to calcium oxide. Appendix B
(Suggested Appendix)
Determination of ignition loss of cryolite
B1 Method Summary
The sample is burned at 550°C and its loss is determined. B2 Instruments
B2.1-General laboratory instruments.
B2.2 Platinum crucible: diameter 40mm, height 40mm. B2.3 Muffle furnace, capable of controlling the temperature at 550°C ± 5°C. .Al)
B3 Analysis steps
B3.1 Determination quantity
Measure two samples in parallel and take the average value. GB/T4291—1999
Note: The sample should comply with the provisions of Article 1.2 of YS/T272. B3.2 Sample quantity
Weigh 2.000g sample.
B3.3 Determination
B3.3.7 Place the sample (B3.2) in a platinum crucible that has been pre-burned in a muffle furnace (B2.3) at 550℃ for 30min and cooled in a desiccator, and weigh it (accurate to 0.001g).
B3.3.2 Place the platinum crucible (B3.3.1) containing the sample in a muffle furnace (B2.3) at 550℃±5℃, and immediately close the muffle furnace door. After burning for 30 minutes, take out the platinum crucible and place it in a desiccator. Cool and weigh it (accurate to 0.001g). B4
Calculation of analysis results
Calculate the percentage of loss on ignition according to formula (B1): Loss on ignition -
(ml = mz) × 100%
Where: ml---
Weight of the platinum crucible containing the sample before burning, m2; m2-Weight of the platinum crucible containing the sample after burning, g; m2-sample weight, g.0g/L sodium) Sodium chloride is first dried at about 120℃ for 12h and cooled in a desiccator. Weigh 4.067g sodium chloride, accurate to 0.001g, and place in a 100mL single-scale volumetric flask. Dissolve with water, dilute to scale and mix. A4.5 Aluminum acid solution (equivalent to 6.6g/L aluminum) Weigh 0.66g high-purity aluminum flakes (accurate to 0.001g), put them in a porcelain dish, add 50mL (1+1) hydrochloric acid to dissolve, and then transfer to a 100ml. single-scale volumetric flask, cool and shake to volume. A4.6 Calcium standard solution (equivalent to 1.00g/L calcium) Weigh 2.4972g calcium carbonate (dried at 110℃ for 2h, cooled in a desiccator) accurate to 0.0001g, transfer to a 250mL beaker, and carefully add 12mL hydrochloric acid solution (4.2) diluted with 12mL water in advance to dissolve it. Transfer the solution quantitatively into a 1000ml single-scale volumetric flask. After cooling, adjust the volume and shake well. Transfer to a storage bottle without calcium materials. This solution contains 1.00mg calcium per ml. A4.7 Calcium standard solution (equivalent to 0.10g/L calcium) Transfer 100.0mL of calcium standard solution (4.6) into a 1000mL single-scale volumetric flask, dilute with water to the scale, shake well, and transfer to a storage bottle without calcium materials. This solution contains 0.10mg calcium per ml. 259
A5 Equipment
Ordinary laboratory instruments and:
A5.1 Platinum III, 30mm high, 75mm in diameter. GB/T 4291-- 1999
A5.2 Atomic absorption spectrophotometer, equipped with bottled nitrous oxide and acetylene, the burner should be 50~60mm. A5.3 Calcium hollow cathode lamp.
A6 Analysis steps
A6.1 Weighing samples
Weigh 0.500 g (accurate to 0.0001 g) of the sample treated and dried according to ISO1619. A6.2 Blank test
Use the same method, reagents, and analysis steps to perform a blank test at the same time as the sample determination, and add 10.0 ml of aluminum acid solution (A4.5) and 10.0 ml of sodium chloride solution (A4.4) before adding sulfuric acid. A6.3 Drawing of standard curve
A6.3.1 Preparation of standard solution
In 6 platinum III (A5.1), add calcium standard solution (A4.7) according to the table below. Calcium standard solution (A4.7)
1) Reagent blank for standardizing the curve.
Equivalent to calcium content
Equivalent to CaO% content in cryolite
Add 10.0mL aluminum acid solution (A4.5), 10.0mL sodium chloride solution (A4.4), and 5.0mL sulfuric acid solution (A4.1) to each platinum dish. Carefully heat on a sand bath or hot plate to evaporate and remove the sulfuric acid. Note: 5.0mL sulfuric acid solution (A4.1) can be replaced by 10.0mL perchloric acid solution (p about 1.70g/mL), and then use air-acetylene flame (clear, non-glowing oxidizing flame) for spectrophotometric determination. Add 1.0mL hydrochloric acid solution (A4.2) and 30mL water to each platinum III, quantitatively transfer to a 100mL single-scale volumetric flask, then add 10mL lanthanum nitrate solution) or lanthanum fluoride solution (A4.3.1), or add 20mL triethanolamine solution (A4.3.2), cool and dilute to the scale and shake. This solution is stored in a flask made of calcium-free material. A6.3.2 Spectrophotometric determination
Install the hollow cathode lamp (A5.3), turn on the instrument (A5.2), and after sufficient time to stabilize, adjust the wavelength to 422.7nm. Adjust the sensitivity and slit according to the characteristics of the instrument, and adjust the gas pressure according to the characteristics of the burner to obtain an oxidizing flame, while controlling the spray rate (such as 2-3 mL/min).
Spray the standard solution (A6.3.1) into the flame, and measure the absorbance of each solution. Note that the amount of solution sprayed into the flame remains constant throughout the entire measurement process and time, and the burner should be sprayed with water after each measurement. A6.3.3 Drawing of the standard curve
When drawing the curve, the mass number of calcium contained in each 100mL of the standard solution is used as the horizontal axis, and the corresponding absorbance minus the absorbance value of the standard curve reagent blank is used as the vertical axis.
A6.4 Determination
A6.4.1 Preparation of test solution
Place the sample (A6.1) in platinum blood (A5.1) and add 5.0ml sulfuric acid (A4.1) (see A6.3.1). Carefully heat at 260°C on a sand bath or hot plate until the hydrofluoric acid evaporates completely (15-20min). Continue to raise the temperature until the sulfuric acid evaporates completely. Add 3.0ml hydrochloric acid solution (A4.2) and 30ml water to a platinum dish and heat on a water bath until completely dissolved. Quantitatively transfer the solution into a 100ml single-scale volumetric flask and add 10ml lanthanum nitrate or lanthanum chloride solution (A4.3.1), or 20ml triethanolamine solution (A4.3.2). After cooling, dilute to the scale and mix well. This solution is stored in a volumetric flask made of calcium-free material. A6.4.2 Spectrophotometric determination
A6.4.2.1 Preliminary determination
According to the procedure specified in A6.3.2, while the standard solution (A6.3.1) is being spectrophotometrically determined, a preliminary determination is made on the test sample (A6.4.1) and the blank solution (A6.2).
A6.4.2.2 Interpolation determination
Take two standard solutions, each with a calcium content of 0.10 mg different in 100 ml, one with a higher concentration and the other with a lower concentration than the test solution, and make a second determination of the test solution by interpolation of the two standard solutions. In preparing these standard solutions, follow the procedure specified in A6.3.1 and use an appropriate amount of standard calcium solution (A4.7). At the same time, without interpolation, make a second determination on the blank test solution (A6.2). A7 Result Expression
The concentration of calcium (Ca) in the solution used for spectrophotometric determination is expressed as the mass in 100 mL and calculated according to formula (A1): (A -A) -(A - A))
C= G + (C2 - c) × [
Wherein: A,——spectrophotometric value of reagent blank solution; Ci—--the concentration of the lower concentration interpolation solution used for the test solution, the mass per 100 ml; A—corresponding spectrophotometric value;
C—the concentration of the higher concentration interpolation solution used for the test solution, the mass per 100 mL; A2 corresponding spectrophotometric value;
A:—-—spectrophotometric value of standard blank; A.-—spectrophotometric value of test solution.
Calcium content is expressed as the weight percentage of calcium oxide (CaO) and is calculated according to formula (A2): × 1: 399 × 100 - 0. 139 9 -1000×m
Where: m--sample weight (6.1), g
1.399--coefficient for converting calcium to calcium oxide. Appendix B
(Suggested Appendix)
Determination of ignition loss of cryolite
B1 Method Summary
The sample is burned at 550°C and its loss is determined. B2 Instruments
B2.1-General laboratory instruments.
B2.2 Platinum crucible: diameter 40mm, height 40mm. B2.3 Muffle furnace, capable of controlling the temperature at 550°C ± 5°C. .Al)
B3 Analysis steps
B3.1 Determination quantity
Measure two samples in parallel and take the average value. GB/T4291—1999
Note: The sample should comply with the provisions of Article 1.2 of YS/T272. B3.2 Sample quantity
Weigh 2.000g sample.
B3.3 Determination
B3.3.7 Place the sample (B3.2) in a platinum crucible that has been pre-burned in a muffle furnace (B2.3) at 550℃ for 30min and cooled in a desiccator, and weigh it (accurate to 0.001g).
B3.3.2 Place the platinum crucible (B3.3.1) containing the sample in a muffle furnace (B2.3) at 550℃±5℃, and immediately close the muffle furnace door. After burning for 30 minutes, take out the platinum crucible and place it in a desiccator. Cool and weigh it (accurate to 0.001g). B4
Calculation of analysis results
Calculate the percentage of loss on ignition according to formula (B1): Loss on ignition -
(ml = mz) × 100%
Where: ml---
Weight of the platinum crucible containing the sample before burning, m2; m2-Weight of the platinum crucible containing the sample after burning, g; m2-sample weight, g.66g high-purity aluminum flakes (accurate to 0.001g) are placed in a porcelain dish and 50mL (1+1) hydrochloric acid is added to dissolve the flakes. Then the flakes are transferred to a 100ml single-scale volumetric flask. After cooling, the flakes are adjusted to volume and shaken well. A4.6 calcium standard solution (equivalent to 1.00g/L calcium) Weigh 2.4972g calcium carbonate (dried at 110℃ for 2h and cooled in a desiccator) to an accuracy of 0.0001g, transfer to a 250mL beaker, and carefully add 12mL hydrochloric acid solution (4.2) diluted with 12mL water in advance to dissolve the flakes. Quantitatively transfer the solution to a 1000ml single-scale volumetric flask. After cooling, the flakes are adjusted to volume and shaken well. Transfer to a storage bottle without calcium materials. This solution contains 1.00mg calcium per ml. A4.7 Calcium standard solution (equivalent to 0.10 g/L calcium) Pipette 100.0 mL of calcium standard solution (4.6) into a 1000 mL single-scale volumetric flask, dilute with water to the scale, shake well, and transfer to a storage bottle without calcium material. This solution contains 0.10 mg calcium per mL. 259
A5 Equipment
General laboratory instruments and:
A5.1 Platinum III, 30 mm high, 75 mm in diameter. GB/T 4291-- 1999
A5.2 Atomic absorption spectrophotometer, equipped with bottled nitrous oxide and acetylene, the burner is preferably 50~60 mm. A5.3 Calcium hollow cathode lamp
A6 Analysis steps
A6.1 Weighing samples
Weigh 0.500 g (accurate to 0.0001 g) of the sample treated and dried according to ISO1619. A6.2 Blank test
Use the same method, reagents, and analysis steps to perform a blank test at the same time as the sample determination, and add 10.0 ml of aluminum acid solution (A4.5) and 10.0 ml of sodium chloride solution (A4.4) before adding sulfuric acid. A6.3 Drawing of standard curve
A6.3.1 Preparation of standard solution
In 6 platinum III (A5.1), add calcium standard solution (A4.7) according to the table below. Calcium standard solution (A4.7)
1) Reagent blank for standardizing the curve.
Equivalent to calcium content
Equivalent to CaO% content in cryolite
Add 10.0mL aluminum acid solution (A4.5), 10.0mL sodium chloride solution (A4.4), and 5.0mL sulfuric acid solution (A4.1) to each platinum dish. Carefully heat on a sand bath or hot plate to evaporate and remove the sulfuric acid. Note: 5.0mL sulfuric acid solution (A4.1) can be replaced by 10.0mL perchloric acid solution (p about 1.70g/mL), and then use air-acetylene flame (clear, non-glowing oxidizing flame) for spectrophotometric determination. Add 1.0mL hydrochloric acid solution (A4.2) and 30mL water to each platinum III, quantitatively transfer to a 100mL single-scale volumetric flask, then add 10mL lanthanum nitrate solution) or lanthanum fluoride solution (A4.3.1), or add 20mL triethanolamine solution (A4.3.2), cool and dilute to the scale and shake. This solution is stored in a flask made of calcium-free material. A6.3.2 Spectrophotometric determination
Install the hollow cathode lamp (A5.3), turn on the instrument (A5.2), and after sufficient time to stabilize, adjust the wavelength to 422.7nm. Adjust the sensitivity and slit according to the characteristics of the instrument, and adjust the gas pressure according to the characteristics of the burner to obtain an oxidizing flame, while controlling the spray rate (such as 2-3 mL/min).
Spray the standard solution (A6.3.1) into the flame, and measure the absorbance of each solution. Note that the amount of solution sprayed into the flame remains constant throughout the entire measurement process and time, and the burner should be sprayed with water after each measurement. A6.3.3 Drawing of the standard curve
When drawing the curve, the mass number of calcium contained in each 100mL of the standard solution is used as the horizontal axis, and the corresponding absorbance minus the absorbance value of the standard curve reagent blank is used as the vertical axis.
A6.4 Determination
A6.4.1 Preparation of test solution
Place the sample (A6.1) in platinum blood (A5.1) and add 5.0ml sulfuric acid (A4.1) (see A6.3.1). Carefully heat at 260°C on a sand bath or hot plate until the hydrofluoric acid evaporates completely (15-20min). Continue to raise the temperature until the sulfuric acid evaporates completely. Add 3.0ml hydrochloric acid solution (A4.2) and 30ml water to a platinum dish and heat on a water bath until completely dissolved. Quantitatively transfer the solution into a 100ml single-scale volumetric flask and add 10ml lanthanum nitrate or lanthanum chloride solution (A4.3.1), or 20ml triethanolamine solution (A4.3.2). After cooling, dilute to the scale and mix well. This solution is stored in a volumetric flask made of calcium-free material. A6.4.2 Spectrophotometric determination
A6.4.2.1 Preliminary determination
According to the procedure specified in A6.3.2, while the standard solution (A6.3.1) is being spectrophotometrically determined, a preliminary determination is made on the test sample (A6.4.1) and the blank solution (A6.2).
A6.4.2.2 Interpolation determination
Take two standard solutions, each with a calcium content of 0.10 mg different in 100 ml, one with a higher concentration and the other with a lower concentration than the test solution, and make a second determination of the test solution by interpolation of the two standard solutions. In preparing these standard solutions, follow the procedure specified in A6.3.1 and use an appropriate amount of standard calcium solution (A4.7). At the same time, without interpolation, make a second determination on the blank test solution (A6.2). A7 Result Expression
The concentration of calcium (Ca) in the solution used for spectrophotometric determination is expressed as the mass in 100 mL and calculated according to formula (A1): (A -A) -(A - A))
C= G + (C2 - c) × [
Wherein: A,——spectrophotometric value of reagent blank solution; Ci—--the concentration of the lower concentration interpolation solution used for the test solution, the mass per 100 ml; A—corresponding spectrophotometric value;
C—the concentration of the higher concentration interpolation solution used for the test solution, the mass per 100 mL; A2 corresponding spectrophotometric value;
A:—-—spectrophotometric value of standard blank; A.-—spectrophotometric value of test solution.
Calcium content is expressed as the weight percentage of calcium oxide (CaO) and is calculated according to formula (A2): × 1: 399 × 100 - 0. 139 9 -1000×m
Where: m--sample weight (6.1), g
1.399--coefficient for converting calcium to calcium oxide. Appendix B
(Suggested Appendix)
Determination of ignition loss of cryolite
B1 Method Summary
The sample is burned at 550°C and its loss is determined. B2 Instruments
B2.1-General laboratory instruments.
B2.2 Platinum crucible: diameter 40mm, height 40mm. B2.3 Muffle furnace, capable of controlling the temperature at 550°C ± 5°C. .Al)
B3 Analysis steps
B3.1 Determination quantity
Measure two samples in parallel and take the average value. GB/T4291—1999
Note: The sample should comply with the provisions of Article 1.2 of YS/T272. B3.2 Sample quantity
Weigh 2.000g sample.
B3.3 Determination
B3.3.7 Place the sample (B3.2) in a platinum crucible that has been pre-burned in a muffle furnace (B2.3) at 550℃ for 30min and cooled in a desiccator, and weigh it (accurate to 0.001g).
B3.3.2 Place the platinum crucible (B3.3.1) containing the sample in a muffle furnace (B2.3) at 550℃±5℃, and immediately close the muffle furnace door. After burning for 30 minutes, take out the platinum crucible and place it in a desiccator. Cool and weigh it (accurate to 0.001g). B4
Calculation of analysis results
Calculate the percentage of loss on ignition according to formula (B1): Loss on ignition -
(ml = mz) × 100%
Where: ml---
Weight of the platinum crucible containing the sample before burning, m2; m2-Weight of the platinum crucible containing the sample after burning, g; m2-sample weight, g.66g high-purity aluminum flakes (accurate to 0.001g) are placed in a porcelain dish and 50mL (1+1) hydrochloric acid is added to dissolve the flakes. Then the flakes are transferred to a 100ml single-scale volumetric flask. After cooling, the flakes are adjusted to volume and shaken well. A4.6 calcium standard solution (equivalent to 1.00g/L calcium) Weigh 2.4972g calcium carbonate (dried at 110℃ for 2h and cooled in a desiccator) to an accuracy of 0.0001g, transfer to a 250mL beaker, and carefully add 12mL hydrochloric acid solution (4.2) diluted with 12mL water in advance to dissolve the flakes. Quantitatively transfer the solution to a 1000ml single-scale volumetric flask. After cooling, the flakes are adjusted to volume and shaken well. Transfer to a storage bottle without calcium materials. This solution contains 1.00mg calcium per ml. A4.7 Calcium standard solution (equivalent to 0.10 g/L calcium) Pipette 100.0 mL of calcium standard solution (4.6) into a 1000 mL single-scale volumetric flask, dilute with water to the scale, shake well, and transfer to a storage bottle without calcium material. This solution contains 0.10 mg calcium per mL. 259
A5 Equipment
General laboratory instruments and:
A5.1 Platinum III, 30 mm high, 75 mm in diameter. GB/T 4291-- 1999
A5.2 Atomic absorption spectrophotometer, equipped with bottled nitrous oxide and acetylene, the burner is preferably 50~60 mm. A5.3 Calcium hollow cathode lamp
A6 Analysis steps
A6.1 Weighing samples
Weigh 0.500 g (accurate to 0.0001 g) of the sample treated and dried according to ISO1619. A6.2 Blank test
Use the same method, reagents, and analysis steps to perform a blank test at the same time as the sample determination, and add 10.0 ml of aluminum acid solution (A4.5) and 10.0 ml of sodium chloride solution (A4.4) before adding sulfuric acid. A6.3 Drawing of standard curve
A6.3.1 Preparation of standard solution
In 6 platinum III (A5.1), add calcium standard solution (A4.7) according to the table below. Calcium standard solution (A4.7)
1) Reagent blank for standardizing the curve.
Equivalent to calcium content
Equivalent to CaO% content in cryolite
Add 10.0mL aluminum acid solution (A4.5), 10.0mL sodium chloride solution (A4.4), and 5.0mL sulfuric acid solution (A4.1) to each platinum dish. Carefully heat on a sand bath or hot plate to evaporate and remove the sulfuric acid. Note: 5.0mL sulfuric acid solution (A4.1) can be replaced by 10.0mL perchloric acid solution (p about 1.70g/mL), and then use air-acetylene flame (clear, non-glowing oxidizing flame) for spectrophotometric determination. Add 1.0mL hydrochloric acid solution (A4.2) and 30mL water to each platinum III, quantitatively transfer to a 100mL single-scale volumetric flask, then add 10mL lanthanum nitrate solution) or lanthanum fluoride solution (A4.3.1), or add 20mL triethanolamine solution (A4.3.2), cool and dilute to the scale and shake. This solution is stored in a flask made of calcium-free material. A6.3.2 Spectrophotometric determination
Install the hollow cathode lamp (A5.3), turn on the instrument (A5.2), and after sufficient time to stabilize, adjust the wavelength to 422.7nm. Adjust the sensitivity and slit according to the characteristics of the instrument, and adjust the gas pressure according to the characteristics of the burner to obtain an oxidizing flame, while controlling the spray rate (such as 2-3 mL/min).
Spray the standard solution (A6.3.1) into the flame, and measure the absorbance of each solution. Note that the amount of solution sprayed into the flame remains constant throughout the entire measurement process and time, and the burner should be sprayed with water after each measurement. A6.3.3 Drawing of the standard curve
When drawing the curve, the mass number of calcium contained in each 100mL of the standard solution is used as the horizontal axis, and the corresponding absorbance minus the absorbance value of the standard curve reagent blank is used as the vertical axis.
A6.4 Determination
A6.4.1 Preparation of test solution
Place the sample (A6.1) in platinum blood (A5.1) and add 5.0ml sulfuric acid (A4.1) (see A6.3.1). Carefu
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