Some standard content:
HG/T2824—1997
The superior products in this standard adopt the Russian standard OCT2665:1986 "Technical Conditions for Industrial Nickel Sulfate" in a non-equivalent manner. This standard is a revision of the original national standard GB/T6329-1986 and is converted into a chemical industry standard. The differences between this standard and the Russian standard are as follows: 1 The Russian standard is divided into two categories: HC-0 and HC-1. HC-0 is used for the production of chemical reagents, and HC-1 is used for batteries and electroplating. According to the situation in my country, this standard is divided into Class I and Class II. Class I is mainly used for nickel plating and other industries, and Class II is mainly used for batteries. The scope of application is equivalent to Class HC-1 of TOCT2665:1986. 2 Class I indicators have fewer calcium and magnesium indicators than the Russian standard, and one more nitrate; Class II products have two more ammonium precipitation and ammonia content than the Russian standard. The above items are set according to the original national standard and user requirements. In the analytical method, the nickel content is determined by the electrodeposition weight method in IOCT2665:1986, and the cobalt, iron, copper, lead and calcium content are determined by atomic emission light 3
spectroscopy. According to national conditions, the nickel content in this standard is determined by the weight method, the iron by the spectrophotometric method, and the cobalt, copper, lead and calcium by the atomic absorption spectrophotometric method.
Compared with the original national standard, this standard has the following improvements: 1. Class I products are divided into three grades, and Class II products are divided into two grades, one grade more than the original national standard. 2. The requirements for nickel, cobalt, zinc and lead are all improved. 3. In the analytical method, cobalt, copper, lead, zinc, calcium and magnesium are changed from the chemical method of the original national standard to the atomic absorption spectrophotometric method. Appendix A in this standard is a prompt appendix. This standard will be abolished from the date of entry into force of GB/T6329-1986. This standard is proposed by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of Tianjin Chemical Research Institute of the Ministry of Chemical Industry. The drafting units of this standard are: Tianjin Chemical Research Institute of the Ministry of Chemical Industry, Xinxiang Chemical Plant No. 1 of Henan Province, Xiongxian Chemical Plant of Sinochem Hebei Group, and Jiangxi Lithium Plant.
The main drafters of this standard are: Liao Xiaojun, Zeng Xianqin, Yang Hewen, Liu Youruo, and Fan Guoqiang. This standard is entrusted to the technical unit responsible for the standardization of inorganic salt products of the Ministry of Chemical Industry for interpretation. 679
1 Scope
Chemical Industry Standard of the People's Republic of China
Industrial Nickel Sulphate
Nickel Sulphate for Industrial UseHG/T 2824—1997
This standard specifies the requirements, sampling, test methods, as well as marking, packaging, transportation, and storage of industrial nickel sulfate. This standard applies to industrial nickel sulfate. This product is mainly used for nickel plating, battery manufacturing, and other industrial raw materials. Molecular formula: NisO·rH,O
2 Cited standards
r=6~～7
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 will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB 1911990
Pictorial markings for packaging, storage and transportation
GB/T 601—1988
GB/T 602--1988
GB/T 603--1988
GB/T 608—1988
GB/T 1250—1989
GB/T 3049--1986
GB/T 6678--1986
Chemical reagents-Preparation of standard solutions for titration analysis (volumetric analysis)Chemical reagents
Chemical reagents
Chemical reagents
Preparation of standard solutions for determination of impurities (neqISO6353-1:1982)Preparation of preparations and products used in test methods (neq[ISO6353-1:1982)General method for determination of nitrogen
Expression and determination of limit valuesGeneral method for determination of iron content in chemical products-O-phenanthroline spectrophotometric method (neqIS(）6685:1982)wwW.bzxz.Net
General rules for sampling of chemical products
GB/T6682-1992
Specifications and test methods for water used in analytical laboratories (eqvISO3696:1987)GB/T 8946-1988
Plastic woven bags
GB/T 9723—1988
3 General principles of flame atomic absorption spectrometry
3 Classification
This product is divided into two categories: Category I is mainly used for nickel plating and other industrial uses; Category II is mainly used for the production of batteries. 4 Requirements
4.1 Appearance: Emerald green granular crystals. 4.2 Industrial nickel sulfate should meet the requirements of Table 1. Approved by the Ministry of Chemical Industry of the People's Republic of China on February 4, 1997, No. 680
Implementation on October 1, 1997
Nickel (Ni)
Cobalt (Co)
Iron (Fe)
Copper (Cu)
Lead (Pb)
Zinc (Zn)
Calcium (Ca)
Magnesium (Mg)
Nitrate (in N():)
Water insoluble matter
Ammonium precipitate (in AI, excluding Fe) Nitrogen (NH.) content
Chloride (in CI)
5 Sampling
5.1 Each batch of products shall not exceed 20t.
HG/T 2824-1997
Superior products
First-class products
Qualified products
Superior products
5.2 Determine the number of sampling units according to the provisions of 6.6 in GB/T66781986. When sampling, the sampler is placed obliquely from the top of the packaging bag to 3/4 of the depth of the material layer. After mixing the collected samples, they are divided into not less than 500g according to the quartering method, and are divided into two clean and dry wide-mouth bottles with stoppers and sealed. Labels are attached to the bottles, indicating: manufacturer name, product name, batch number, sampling date and name of the sampler. One bottle is used as a laboratory sample, and the other bottle is kept for three months for reference. 5.3 If one of the test results does not meet the requirements of this standard, re-sampling should be carried out from twice the amount of packaging for verification. If the verification results show that only one indicator does not meet the requirements of this standard, the entire batch of products will be unqualified. 6 Test method
The rounded value comparison method specified in 5.2 of GB/T1250-1989 is used to determine whether the test results meet the standard. 6.1
6.2 The reagents and water used in this standard, unless otherwise specified, refer to analytical pure reagents and grade 3 water specified in GB/T6682-1992.
The standard titration solution, impurity standard solution, preparation and product used in the test, unless otherwise specified, are prepared in accordance with the provisions of GB/T601, GJ3/T602 and GB/T603.
6.3 Determination of nickel content
6.3.1 Summary of method
In an ammonia solution, tartaric acid is used as a masking agent to form a soluble complex with impurities such as iron and aluminum to eliminate interference. Dimethylglyoxime is used as a coagulant to react with nickel to form a red dimethylglyoxime nickel precipitate. After filtering, washing and drying to constant weight, the nickel content is calculated. 6.3.2 Reagents and materials
6.3.2.1 Ethanol solution: 1+4;
6.3.2.2 Hydrochloric acid solution: 1+1;
6.3.2.3 Ammonia solution: 1+1;
6.3.2.4 Ammonium chloride solution: 200g/1;
6.3.2.5 Tartaric acid solution: 200g/L;
HG/T 2824—1997
6.3.2.6 Dimethylglyoxal ethanol solution: 10g/L. 6.3.3 Instruments and equipment
Glass sand: filter plate pore size: 5μm～15um. 6.3.4 Analysis steps
Weigh about 2g of sample (accurate to 0.0002g) and place it in a 250ml beaker. Add 1ml hydrochloric acid solution and 50ml water, heat to dissolve, cool to room temperature, transfer to a 100ml volumetric flask, dilute to scale with water, and shake well. Use a pipette to transfer 10ml of the test solution and place it in a 400ml beaker; add 150ml water, 5ml ammonium chloride solution, and 5ml tartaric acid solution, cover with surface III, and heat to boiling. When cooled to 70℃~80℃, slowly add 30ml of dimethylglyoxal ethanol solution under constant stirring, add ammonia solution dropwise to adjust the solution pH to 89 (check with precision pH test paper), and then add 1ml~~2ml in excess. Keep warm at 70℃~80℃ for 30min, filter with a glass sand crucible that has been dried to constant weight at 105℃~110℃, wash with ethanol solution 4~5 times, and dry to constant weight at 105℃~110℃. 6.3.5 Expression of analysis results
Nickel content (Ni)X expressed as mass percentage, calculated according to formula (1): X:=(ml-mo)X0.2031×100
(ml-mo)X203.1
Wherein: m1—mass of precipitate and glass crucible, g; m
—mass of glass crucible, g;
0.2031—coefficient of converting nickel dimethylglyoxal into nickel; mass of sample, g.
6.3.6 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference of the parallel determination results shall not exceed 0.1%. 6.4 Determination of cobalt content
6.4.1 Standard addition method (arbitration method)
6.4.1.1 Summary of method
(1)
Dissolve the sample in water and measure it on an atomic absorption spectrophotometer using the standard addition method at a wavelength of 240.7nm with an air-acetylene flame.
6.4.1.2 Reagents and materials
6.4.1.2.1 Hydrochloric acid solution: 1+1;
6.4.1.2.2 Cobalt standard solution: 1mL of solution contains 0.1mgCo. 6.4.1.3 Instruments and equipment
The atomic absorption spectrophotometer is equipped with a cobalt hollow cathode lamp. 6.4.1.4 Analysis steps
6.4.1.4.1 Preparation of test solution A
Weigh 50g of the sample (accurate to 0.01g) and place it in a 400ml beaker. After dissolving in water, spread 5mL of hydrochloric acid solution and transfer it to a 500ml volumetric flask. Add water to the mark and shake to hook. This solution is test solution A. Keep this solution for the determination of cobalt content, copper content, lead content, magnesium content and calcium content.
6.4.1.4.2 Determination
Pipette 0.20mL of test solution A (6.4.1.4.1) into four clean 100ml volumetric flasks, add 0ml, 0.50ml, 1.00mL, 2.00ml of cobalt standard solution and 2mL of hydrochloric acid solution respectively, dilute with water to the mark and shake to hook. On an atomic absorption spectrophotometer, use air·acetylene flame at a wavelength of 240.7nm to measure the absorbance of the above solution. Take the mass of cobalt in the cobalt standard solution as the abscissa and the corresponding absorbance as the ordinate to draw a curve. Extend the curve in the reverse direction and intersect with the abscissa. The intersection point is the mass of cobalt element in the measured solution. 6.4.1.5 Expression of analysis results
The cobalt (Co) content X2 expressed as mass percentage is calculated according to formula (2): X,=m×10 3
X0.2×100
m×500
ml×250
wherein m,-the mass of cobalt obtained by extrapolation, mg;-the mass of the sample weighed in 6.4.1.4.1, g. 6.4.1.6 Allowable difference
The arithmetic mean of the parallel determination results shall be taken as the determination result. The absolute difference of the parallel determination results shall not exceed 0.01%. 6.4.2 Working curve method
The determination shall be carried out according to the working curve method specified in GB/T9723-1988. 6.5 Determination of iron content
6.5.1 Summary of method
(2)
Under a concentration of about 6N hydrochloric acid, the iron in the test solution is extracted with 4-methylpentanone-(2). After back extraction with water, an iron-containing solution is obtained. The trivalent iron ions in the test solution are reduced to divalent iron ions with ascorbic acid. At pH 2-9, the divalent iron ions react with o-phenanthroline to form an orange-red complex. Its absorbance is measured by a spectrophotometer at the maximum absorption wavelength (510nm). 6.5.2 Reagents and materials
According to Chapter 3 of GB/T3049-1986 and:
6.5.2.1 Hydrochloric acid;
6.5.2.2 4-Methylpentyl ketone-(2);
6.5.2.3 Hydrogen peroxide solution: 30%.
6.5.3 Instruments and equipment
According to Chapter 4 of GB/T3049-1986.
6.5.4 Analysis steps
6.5.4.1 Drawing of working curve
According to 5.3 of GB/T3049--1986, use 3 cm absorption cell and corresponding iron standard solution to draw working curve. 6.5.4.2 Preparation of test solution
Weigh about 10g of sample (accurate to 0.01g), place in a 250mL beaker, add 50mL of water, 1mL~2mL of 1+1 hydrochloric acid solution, 1ml of hydrogen peroxide solution, heat to dissolve, cool and transfer to a 100mL volumetric flask, dilute to scale with water, and shake well. 6.5.4.3 Preparation of blank test solution
Except for not adding sample, the amount of other reagents added is exactly the same as the preparation of test solution, and the same treatment is carried out at the same time as the sample. 6.5.4.4 Determination
Use a pipette to transfer appropriate amount of test solution (superior product: 20ml, first-class product: 10mL, qualified product: 5mL) and corresponding volume of blank test solution, respectively, place in a 125mL separatory funnel, add 30mL of water, 40ml of concentrated hydrochloric acid, and 10mL of 4-methylpentanone-(2), shake for 1min, let stand and separate, and discard the aqueous phase. Add 20ml of water to the separatory funnel, shake for 1min, and let stand to separate. Transfer the aqueous phase to a 100mL volumetric flask, add another 5mL of water to the separatory funnel, shake for 30s, and let stand to separate. Transfer the aqueous phase to the same volumetric flask, add water to about 60mL, and adjust the pH of the solution to 2 with hydrochloric acid solution or ammonia water (check with precision pH test paper). Add 2.5mL of ascorbic acid solution, 10ml of buffer solution, and 5mL of o-phenanthroline solution, respectively, dilute to the scale with water, and shake well. Use a 3cm absorption cell, measure the absorbance according to 5.4 of GB/T3049---1986, and find out the mass of iron in the test solution and blank test solution according to the working curve.
6.5.5 Expression of analysis results
HG/T 2824-1997
Iron (Fe) content X expressed as mass percentage. Calculate according to formula (3): X3
Wherein: ml—-the mass of iron in the test solution, g; m2 --the mass of iron in the blank test solution, g; V--the volume of the test solution, mL;
m—-the mass of the sample, g.
6.5.6 Allowable difference
mi -m2 × 100
m×100
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference of the parallel determination results shall not exceed 0.0004%. 6.6 Determination of copper content
6.6.1 Standard addition method (arbitration method)
6.6.1.1 Summary of the method
Dissolve the sample in water and determine it on an atomic absorption spectrophotometer at a wavelength of 324.8nm using an air-acetylene flame. 6.6.1.2 Reagents and materials
6.6.1.2.1 Hydrochloric acid solution: 1+1;
6.6.1.2.2 Copper standard solution: 1mL solution contains 0.1mgCu. 6.6.1.3 Instruments and equipment
Atomic absorption spectrophotometer is equipped with a copper hollow cathode lamp. 6.6.1.4 Analysis steps
(3)
Take 10mL of test solution A (6.4.1.4.1) and place it in four clean 100mL volumetric flasks. Add 0mL, 0.50ml., 1.00mL, and 2.00mL of copper standard solution respectively, add 2mL of hydrochloric acid solution to each, dilute with water to the scale, and shake well. On the atomic absorption spectrophotometer, use an air-acetylene flame at a wavelength of 324.8nm to measure the absorbance of the above solutions. Take the mass of copper added to the standard solution as the abscissa and the corresponding absorbance as the ordinate to draw a curve. Extend the curve in the opposite direction to intersect with the abscissa. The intersection is the mass of the copper element to be measured. 6.6.1.5 Expression of analysis results
The copper (Cu) content X4 expressed as mass percentage is calculated according to formula (4): X -m X103
m×500
_m × 5
Where: m—the mass of copper obtained by extrapolation, mg; m
m—the mass of the sample weighed in 6.4.1.4.1, g. 6.6.1.6 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference of the parallel determination results shall not exceed 0.0004%. 6.6.2 Working curve method
Determine according to the working curve method specified in GB/T9723-1988. 6.7 Determination of lead content
6.7.1 Summary of the method
HG/T 2824--1997
Dissolve the sample in water, separate and enrich the lead by co-precipitation of lead and lanthanum salt with ammonia water in the presence of ammonium chloride, dissolve the precipitate with dilute hydrochloric acid, and then analyze the precipitate on an atomic absorption spectrophotometer at 283.3nm, measured with air-acetylene flame. 6.7.2 Reagents and materials
6.7.2.1 Ammonia water;
6.7.2.2 Ammonia water solution: 1+6;
6.7.2.3 Hydrochloric acid solution: 1+15;
6.7.2.4 Lanthanum chloride solution: 25g/1; Weigh 25g of lanthanum chloride (LaCl: ·6H2()), dissolve it in water, add 10mL of hydrochloric acid, and dilute it to 1000mL with water.
6.7.2.5 Ammonium chloride solution: 200g/L;
6.7.2.6 Lead standard solution: 1mL of solution contains 0.1mgPb. 6.7.3 Instruments and equipment
Atomic absorption spectrophotometer: equipped with a lead hollow cathode lamp. 6.7.4 Analysis steps
6.7.4.1 Drawing of working curve
Take 6 clean 100ml volumetric flasks, transfer 0ml, 2.00ml, 4.00ml, 6.00ml, 8.00ml, 10.00ml of lead standard solution respectively, add 25ml of hydrochloric acid solution respectively, dilute to scale with water, and shake well. On an atomic absorption spectrophotometer, use air-acetylene flame, at a wavelength of 283.3nm, measure the absorbance of the above solutions. Use the mass of lead added to the standard solution as the horizontal axis and the corresponding absorbance as the vertical axis to draw a working curve. 6.7.4.2 Sample analysis
Weigh 5g of sample (accurate to 0.01g), place in a 100ml beaker, dissolve with 40ml hot water, add 2ml lanthanum chloride solution, 10ml ammonium chloride solution, cool to room temperature, add ammonia solution (6.7.2.2) dropwise while shaking until white precipitate appears and 2ml excess, let stand for 20min, filter with medium-speed qualitative filter paper, wash the precipitate and filter paper with ammonia solution (6.7.2.2) 3 to 5 times, add 15ml~20ml hydrochloric acid solution dropwise, dissolve the precipitate in a 25ml colorimetric tube, dilute to scale with hydrochloric acid solution, shake well. Perform a blank test at the same time. Measure the absorbance on the atomic absorption spectrophotometer under the same conditions as the working curve, and find the corresponding lead mass on the working curve. 6.7.5 Expression of analysis results
Lead (Pb) content X expressed as mass percentage; calculated according to formula (5): (m1 -mo) × 10-3
Wherein: m-
The lead mass of the sample found on the working curve, mg; mo——. The lead mass of the blank test found on the working curve, mg; ——-The mass of the sample, g.
6.7.6 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference of the parallel determination results shall not exceed 0.0004%. 6.8 Determination of zinc content
6.8.1 Standard addition method (arbitration method)
6.8.1.1 Summary of the method
The sample is dissolved in water and measured on an atomic absorption spectrophotometer at a wavelength of 213.9nm using an air-acetylene flame. 6.8.1.2 Reagents and materials
Zinc standard solution: 1 mL of solution contains 0.1 mg Zn. 6.8.1.3 Instruments and equipment
Atomic absorption spectrophotometer: equipped with a zinc hollow cathode lamp. - (5)
6.8.1.4 Analysis steps
HG/T 2824-1997
Take 5.0 ml (2.0 ml for qualified products) of test solution A (6.4.1.4.1) respectively, place it in four clean 100 mL volumetric flasks, add 0 ml, 0.10 ml, 0.20 ml, 0.40 ml of zinc standard solution respectively, dilute to the scale with water, and shake well. On the atomic absorption spectrophotometer, use air-acetylene flame at a wavelength of 213.9 nm to measure the absorbance of the above solutions. With the mass of zinc added to the standard solution as the abscissa and the corresponding absorbance as the ordinate, draw a curve, extend the curve in the opposite direction and intersect with the abscissa, the intersection is the mass of the zinc element to be measured. 6.8.1.5 Expression of analysis results
Zinc (Zn) content X expressed as mass percentage. Calculate according to formula (6): X. =mi × 10-3
m×500
Where: ml—mass of zinc obtained by extrapolation, mg; m
mass of the sample weighed in 6.4.1.4.1, g; V-volume of the test solution A (6.4.1.4.1), mL. 6.8.1.6 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference of the parallel determination results shall not exceed 0.0005%. 6.8.2 Working curve method
Determine according to the working curve method specified in GB/T9723-1988. 6.9 Determination of calcium content
6.9.1 Method summary
(6)
Dissolve the sample in water, add lanthanum salt to eliminate the matrix effect, and measure with air-acetylene flame at a wavelength of 422.7nm on an atomic absorption spectrophotometer.
6.9.2 Reagents and materials
6.9.2.1 Nickel sulfate matrix solution: Weigh 4.4g of No. 0 metal nickel, add 30mL (1+1) nitric acid, heat to dissolve, add 4.8mL concentrated sulfuric acid, slowly evaporate to nearly, add appropriate amount of water to dissolve and transfer to a 100mL volumetric flask, dilute to the scale. 6.9.2.2 Hydrochloric acid solution: 1+1;
6.9.2.3 Lanthanum chloride solution: 1mL contains about 10mgLa; weigh 2.5g lanthanum chloride (LaCls·6HzO), dissolve in water, and dilute to 100ml.
6.9.2.4 Calcium standard solution: 1mL solution contains 0.1mgCa. 6.9.3 Instruments and equipment
Atomic absorption spectrophotometer; equipped with a calcium hollow cathode lamp. 6.9.4 Analysis steps
6.9.4.1 Drawing of working curve
Take 6 clean 100ml volumetric flasks, transfer 0mL, 2.00mL, 4.00mL, 6.00mL, 8.00mL, 10.00mL calcium standard solution respectively, add 10mL nickel sulfate matrix solution, 2mL hydrochloric acid solution, 2mL lanthanum chloride solution to each, dilute to the scale with water, and shake to hook. On an atomic absorption spectrophotometer, use an air-acetylene flame at a wavelength of 422.7nm to measure the absorbance of the above solution. Use the mass of lead added to the standard solution as the horizontal axis and the corresponding absorbance as the vertical axis to draw a working curve. 6.9.4.2 Determination
Pipette 20mL of solution A (6.4.1.4.1), place it in a 100mL volumetric flask, add 2mL of hydrochloric acid solution and 2mL of lanthanum chloride solution, dilute with water to the scale, and shake the hook. Measure the absorbance on the atomic absorption spectrophotometer under the same conditions as the working curve, and find the corresponding calcium mass on the working curve.
6.9.5 Expression of analysis results
HG/T 2824—1997
Calcium (Ca) content X expressed as mass percentage is calculated according to formula (7): X,
(m-ma) X 10 a
_25(ml mo)
Wherein: ml--\-calcium mass of the sample obtained from the working curve, mg; mo.-calcium mass of the blank test obtained from the working curve, mg; -mass of the sample weighed in 6.4.1.4.1, g. mt
6.9.6 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference of the parallel determination results shall not exceed 0.001%. 6.10 Determination of magnesium content
6.10.1 Standard addition method (arbitration method)
6.10.1.1 Summary of the method
Dissolve the sample in water and measure it on an atomic absorption spectrophotometer at a wavelength of 285.2nm using an air-acetylene flame. 6.10.1.2 Reagents and materials
Magnesium standard solution: 1 mL of solution contains 0.1 mgMg. 6.10.1.3 Instruments and equipment
Atomic absorption spectrophotometer: equipped with a magnesium hollow cathode lamp. 6.10.1.4 Analysis steps
Pipette 1.0 mL of test solution A (6.4.1.4.1) respectively and place it in four clean 100 mL volumetric flasks, add 0 mL, 0.10 mL, 0.20 mL, and 0.40 mL of magnesium standard solution respectively, dilute to the mark with water, and shake to check. On an atomic absorption spectrophotometer, use an air-acetylene flame at a wavelength of 285.2nm to measure the absorbance of the above solution. Use the mass of magnesium added to the standard solution as the horizontal axis and the corresponding absorbance as the vertical axis to draw a curve. Extend the curve in the opposite direction and intersect with the horizontal axis. The intersection point is the mass of the magnesium element to be measured. 6.10.1.5 Expression of analysis results
The magnesium (Mg) content Xg expressed as mass percentage is calculated according to formula (8): X. - m X 10-3
m×500
Wherein: ml-
the mass of magnesium obtained by extrapolation, mg;
-the mass of the sample weighed in 6.4.1.4.1, g. 6.10.1.6 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference of the parallel determination results shall not exceed 0.001%. 6.10.2 Working curve method
The determination shall be made according to the working curve method specified in GB/T9723-1988. 6.11 Determination of nitrate content
6.11.1 Method summary
(8)
In 75% sulfuric acid solution at 35°C, nitrate ions react with 2,4-dimethylphenol to form nitro derivatives, which are distilled and absorbed by sodium hydroxide solution. The absorbance is measured by a spectrophotometer at a wavelength of 455nm. 6.11.2 Reagents and materials
6.11.2.1 Mercuric acetate;
6.11.2.2 Sulfuric acid without nitrogen oxides: HG/T 2824—1997
Measure 80ml of concentrated sulfuric acid and slowly add it to 20ml of water. Heat until thick white smoke appears and the volume of sulfuric acid is about 80mL; cool and repeat the operation with 20ml of water. After cooling, store in a covered glass bottle to prevent water absorption. 6.11.2.3 Sodium hydroxide solution: 80g/L: 6.11.2.4 Nitrate standard solution: 1ml. The solution contains 0.01mgN)s: Use a pipette to take 10ml. Nitrate standard solution prepared according to GB/T602, place it in a 100ml volumetric flask, dilute it to the mark with water, and shake it well. Prepare this solution before use. 6.11.2.5 2,4-Dimethylphenol acetic acid solution: 1%. Take 1ml. 2,4-dimethylphenol and dilute it to 100ml with glacial acetic acid. This solution is only used on the same day. 6.11.3 Instruments and equipment
6.11.3.1 Spectrophotometer: with a 3cm absorption cell; 6.11.3.2 Constant temperature water bath: can be controlled at 35℃±1℃; 6.11.3.3 Distillation apparatus: as shown in Figure 1.
1250ml ground-mouth distillation flask; 2-75° ground-mouth distillation elbow; 3-water-cooled condenser (effective length 450mm) Figure 1 Distillation apparatus
6.11.4 Analysis steps
6.11.4.1 Drawing of working curve
In a distillation flask placed in an ice-water bath, add 0ml, 5.0ml, 10.0ml, 15.0ml, 20.0ml, 25.0ml, 30.0ml of nitrate standard solution. Add 0.20g of mercuric acetate respectively, shake and place in an ice-water bath for several minutes. Slowly add 20ml of sulfuric acid without nitrogen oxides while shaking. During the operation, the temperature of the test solution should be kept below 35℃ (measured by a thermometer). Take out the distillation flask, add 1ml of 2,4-dimethylphenol solution, and shake well. Place the distillation flask in a constant temperature water bath at 35℃±1℃ for 30min, add appropriate amount of water, the volume is about 120mL, and shake well. Assemble the distillation apparatus according to Figure 1, slowly heat to boiling, and collect the distillate in a 100mL volumetric flask containing 10mL sodium hydroxide solution. Collect 70ml.~80ml, dilute with water to the scale, and shake well. Use a spectrophotometer to measure its absorbance at a wavelength of 455nm, using a 3cm absorption cell and water as a reference. Draw a working curve with nitrate content as the horizontal axis and the corresponding absorbance as the vertical axis. 6.11.4.2 Preparation of test solution
Weigh about 1g of sample (accurate to 0.02g), place it in a distillation flask, and add 10ml of water to dissolve it. 6.11.4.3 Preparation of blank test solution
Except for not adding sample, the amount of other reagents added is exactly the same as the preparation of the test solution, and the same treatment is carried out at the same time as the sample. 6.11.4.4 Determination
Place the distillation flask containing the test solution and the blank test solution in an ice-water bath, and perform the following operations according to 6.11.4.1 from "add 0.20 g of mercuric acetic acid to each solution" to "measure the absorbance thereof.". Find out the mass of nitrate in the test solution and the blank test solution according to the working curve. 6.11.5 Expression of analysis results
The nitrate (NO.) content X expressed as mass percentage is calculated according to formula (9): m×1000×100
mi - m2
Wu: mi -
mass of nitrate in the test solution, g;
mass of nitrate in the blank test solution, g; mass of the sample, g.
6.11.6 Allowable difference
The arithmetic mean of the parallel determination results shall be taken as the determination result. The absolute difference of the parallel determination results shall not exceed 0.005%. 6.12 Determination of water-insoluble matter content
6.12.1 Reagents and materials
Barium chloride solution: 100g/L.
6.12.2 Instruments and equipment
Glass sand crucible: filter plate pore size 5μm15μm. 6.12.3 Analysis steps
(9)
Weigh about 25g of sample (accurate to 0.01g), place it in a 400mL beaker, and add 100mL of water to dissolve it. Filter it with a glass sand crucible that has been dried to constant weight at 105℃~110℃, wash it with hot water until there is no sulfate (check with barium chloride solution), and dry it at 105℃~110℃ to constant weight. The filtrate and washing solution are retained as solution B for the determination of the content of ammonium precipitate. 6.12.4 Expression of analytical results
The water-insoluble matter X1 expressed as a mass percentage is calculated according to formula (10): ml = m2 × 100
Where: mi—…-mass of the glass crucible and water-insoluble matter, g; m2 -
-mass of the glass crucible, g;
mass of the sample, g.
6.12.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference of the parallel determination results shall not exceed 0.005%. 6.13 Determination of ammonium precipitate
6.13.1 Summary of the method
* (10)
In the hot ammonium chloride-ammonia water medium, aluminum, tin, chromium, vanadium, etc. in the test solution are precipitated in the form of hydroxides, filtered and burned at 800°C.
Reagents and materials
6. 13. 2. 1
Ammonia water;
6. 13. 2. 3
6. 13. 2. 4
Ammonium chloride solution: 250 g/L;
Hydrochloric acid solution: 1+1;
Ammonia solution: 7+3;
Ammonia solution: 5+95;
Ammonium nitrate solution: 250 g/L;
Dimethylglyoxal solution: 10 g/L.
Analysis steps
HG/T 2824—1997
Add 20ml of ammonium chloride solution and 50ml of ammonia water (6.13.2.1) to solution B (6.12.3) after the determination of water-insoluble matter, stir evenly, keep warm at 50℃±3℃ for 1h, filter with qualitative filter paper, wash with ammonia water (6.13.2.4) 2~3 times, then wash with hot water 3~4 times, collect the residue and dissolve it with 5ml~8ml of hydrochloric acid solution, wash the funnel and filter paper 3~4 times with hot water, collect the filtrate and washing liquid in a clean beaker, adjust to weak alkalinity with ammonia water (6.13.2.1), let stand for 1h, filter with quantitative filter paper, wash with hot ammonia solution (6.13.2.5) 4~5 times, and wash with ammonium nitrate solution until there is no nickel ion (check with dimethyldiacetaldehyde solution). The residue and filter paper are transferred to a crucible that has been burned to constant weight at 800℃ and burned to constant weight.
6.13.4 Expression of analysis results
The ammonium precipitate (in terms of Al) X expressed as a mass percentage is calculated according to formula (11): (mlmX,X1.43) × 0.53,
_ (m mX; ×1.43) × 53
where: m—mass of residue, g;
m—mass of the sample in 6.12.3; X,—percentage of iron measured in 6.5; 1.43—coefficient of iron converted to ferric oxide; 0.53—coefficient of aluminum oxide converted to aluminum. 6.13.5 Allowable difference
The arithmetic mean of the results of parallel determinations is taken as the determination result. The absolute difference between the parallel determination results shall not exceed 0.0005%. 6..14 Determination of ammonia content
6.14.1 Method Summary
Add sodium hydroxide to the ammonium salt solution, evaporate the ammonia, absorb it with sulfuric acid, and titrate the excess sulfuric acid with sodium hydroxide. 6.14.2 Reagents and Materials
6.14.2.1 Sodium hydroxide solution: 300g/L; 6.14.2.2 Standard sodium hydroxide titration solution: c(NaOH) about 0.1mol/L; 6.14.2.3 Standard sulfuric acid solution: c(-
H2SO,) about 0.01 mol/L;
6.14.2.4 Methyl red-bromocresol green indicator solution. 6.14.3 Instruments and Equipment
GB/T608 Nitrogen Determination Method (Instrument in Figure 2). 6.14.4 Analysis steps
.(11)
Weigh 10g of sample (accurate to 0.01g), dissolve it in 150mL of water, transfer all of it into a 500mL nitrogen determination bottle, add 25mL of sodium hydroxide solution, and install the distillation device according to the diagram. Heat and distill until the residual in the bottle is about 60ml, and absorb the distillate with absorption liquid. Preparation of absorption liquid: Accurately transfer 30mL of sulfuric acid standard solution, place it in a 250mL conical flask, and add 10 drops of methyl red-bromocresol green indicator solution (during the distillation process, if the absorption liquid turns yellow, it should be re-sampled and distilled, and the amount of sulfuric acid standard solution should be appropriately increased). Titrate the obtained absorption liquid with sodium hydroxide standard titration solution until the test solution changes from red to green. 6.14.4 Expression of analysis results
The ammonia (NH) content X12 expressed as mass percentage is calculated according to formula (12): (niVi - NV2) X 0.017
Xi2 —
Wherein: N, the concentration of sulfuric acid standard solution, mol/L; V,.-the volume of sulfuric acid standard solution, mL;
N. - the actual concentration of sodium hydroxide standard titration solution, mol/I; V.…-the volume of sodium hydroxide standard titration solution consumed in titration, mL; 690
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