Some standard content:
Record number: 2778-1999
HG/T 2969-1999
This standard is a revision of the chemical industry standard HG/T2969-1989 (1997) "Industrial Strontium Carbonate". This standard is divided into two types according to product use: Type I is used for color TV glass shells; Type II is used for magnetic materials and others. The main technical differences between this standard and HG/T2969-1989 (1997) are: it is divided into two types according to product use, replacing the three grades in the original industry standard; the control of chromium content indicators is added;
the phosphorus content, hydrochloric acid insoluble content and bulk density indicators are cancelled; the particle size index parameters are different due to different user requirements, and are stipulated to be negotiated with users. From the date of entry into force of this standard, it will replace HG/T2969-1989 (1997). This standard was proposed by the Technical Supervision Department of the former Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Inorganic Chemical Branch of the National Chemical Standardization Technical Committee. The drafting units of this standard are: Tianjin Chemical Research and Design Institute of the Ministry of Chemical Industry, Jiangsu Lishui County Chemical Plant, and Henan Xinxiang Chemical Plant No. 1. The main drafters of this standard are: Yao Jinjuan, Liao Xiaojun, Wu Weidong, Guo Fengxin, and Zhang Qinglin. This standard was first issued as the national standard GB10660-1989 "Industrial Strontium Carbonate" in 1989, adjusted to the chemical industry standard in 1992, and renumbered as HG/T2969-1989 (1997) in 1998. This standard is entrusted to the Inorganic Chemical Branch of the National Technical Committee for Chemical Standardization for interpretation. 938
Chemical Industry Standard of the People's Republic of China
Industrial Strontium Carbonate
Strontium carbonate for industrial useHG/T 2969—1999
Replaces HG/T 2969---1989(1997)
This standard specifies the requirements, test methods, inspection rules, marking, labeling, packaging, transportation and storage of industrial strontium carbonate. This standard applies to industrial strontium carbonate. This product is mainly used as a raw material for color picture tube glass shells, magnetic materials, glass, ceramics, fireworks, metallurgy and other strontium salts.
Molecular formula: SrCO3
Relative molecular mass: 147.63 (according to the 1995 international relative atomic mass) 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard was published, the versions shown were all valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest version of the following standards. GB191—1990 Pictorial markings for packaging, storage and transportation
Preparation of standard solutions for titration analysis (volume analysis) of chemical reagents GB/T 601—19881
GB/T 602—19881
Preparation of standard solutions for determination of impurities in chemical reagents (negISO6353-1:1982) GB/T 603--- 1988
Preparation of preparations and products used in test methods for chemical reagents (neqISO6353-1:1982) GB/T 1250--1989
GB/T 3049-
GB/T 6003-1985
GB/T 6678—1986
GB/T 6682--1992
3 Requirements
Methods for expressing and determining limit values General method for determining iron content in chemical products O-phenanthroline spectrophotometry (neqISO6685:1982) Test sieve
General rules for sampling of chemical products
Specifications and test methods for water used in analytical laboratories (eqvISO3696:1987) 3.1 Appearance: white powder or granules.
3.2 Industrial strontium carbonate is divided into two types:
Type I: used for color picture tube glass shell;
Type II: used for magnetic materials and others.
3.3 Industrial strontium carbonate should meet the requirements of Table 1. Approved by the State Administration of Petroleum and Chemical Industry on April 20, 1999 and implemented on April 1, 2000
Combined content of strontium and barium (SrCO3+BaCO3)
Content of strontium carbonate (SrCO3)
Content of calcium carbonate (CaC2O3)
Content of barium carbonate (BaC2O3)
Content of sodium (calculated as Na2O3)
Content of iron (calculated as Fe2O3)
Content of chlorine (CI3)
Content of total sulfur (calculated as SO2O3)
Content of chromium oxide (Cr2O3)
4 Test method
HG/T 2969--1999
Requirements in Table 1
The reagents and water used in this standard, unless otherwise specified, refer to analytically pure reagents and grade 3 water specified in GB/T6682-92.
The standard titration solutions, impurity standard solutions, preparations and products used in the test, unless otherwise specified, are prepared in accordance with the provisions of GB/T601, GB/T602 and GB/T603.
Safety Tips: The strong acids and alkalis used in this standard are corrosive. Users should be careful when handling them to avoid splashing on the skin! 4.1 Determination of the total amount of strontium and barium (SrCO: + BaCO) 4.1.1 Summary of the method
After the sample is dissolved in acid, it is titrated with ethylenediaminetetraacetic acid disodium standard titration solution at pH=10 using chrome black T as an indicator to determine the contents of calcium, strontium and barium. The contents of calcium and barium are subtracted to obtain the content of strontium carbonate, and then the content of barium carbonate is added. 4.1.2 Reagents and materials
4.1.2.1 Hydrochloric acid solution: 1+1.
Ammonia solution: 1+1.
Ammonia-ammonium chloride buffer solution A: pH~10. 4.1.2.4 Disodium ethylenediaminetetraacetic acid-magnesium chloride solution: c(EDTA-MgCl2) is about 0.05 mol/L. Preparation: Take equal volumes of disodium ethylenediaminetetraacetic acid solution [c (EDTA) is about 0.1 mol/L solution] and magnesium chloride solution [c (MgCl.) is about 0.1 mol/solution] and mix them evenly, then adjust to the end point with disodium ethylenediaminetetraacetic acid solution or magnesium chloride solution. End point test method: Take 25 ml of the mixed solution, add 10 mL of ammonia-ammonium chloride buffer solution A and an appropriate amount of chrome black T indicator, and titrate with disodium ethylenediaminetetraacetic acid solution or magnesium chloride solution until it turns pure blue or purple, which is the end point. The consumption should be less than 0.05 mL. 4.1.2.5 Standard titration solution of disodium ethylenediaminetetraacetic acid: c (EDTA) is about 0.02 mol/L. 4.1.2.6 Methyl red indicator solution: 1 g/L.
4.1.2.7 Chrome black T indicator.
4.1.3 Analysis steps
Weigh about 1g of sample (accurate to 0.0002g), place in a 250mL beaker, and add a small amount of water to moisten. Cover with a watch glass, and add 3mL of hydrochloric acid solution to dissolve it. Heat to boil, cool, add 1 drop of methyl red indicator solution, and neutralize with ammonia solution until the solution just turns yellow. Transfer all to a 500mL volumetric flask, dilute to the scale with water, and shake well. Dry filter with medium-speed qualitative filter paper. Discard about 50mL of pre-filtrate, collect the filtrate at 940
,
HG/T2969-—1999
Use a pipette to transfer 50ml of filtrate, place it in a 250mL conical flask, add 10ml of ammonia-ammonium chloride buffer solution A, 5ml of disodium ethylenediaminetetraacetic acid-magnesium chloride solution and an appropriate amount of chrome black T indicator, and titrate with disodium ethylenediaminetetraacetic acid standard titration solution until the solution turns pure blue as the end point.
At the same time, do a blank test: add a small amount of water, 3mL of hydrochloric acid solution, and 1 drop of methyl red indicator solution to a 250ml beaker. The following is the same as above, starting from "…neutralization with ammonia solution". 4.1.4 Expression of analysis results
The strontium carbonate content (SrCO:) (X,) expressed as mass percentage is calculated according to formula (1): X: (V-Ve) × 0:1476 × 100 -(1.475 Xg + 0.7480X,)%
147.6 × c (V - V.)
2-(1.475X: +0.7480X)
The total strontium content (SrCO: + BaCO:) (X,) expressed as mass percentage is calculated according to formula (2): X2 = Xi + X4
wherein: c-
actual concentration of disodium ethylenediaminetetraacetic acid standard titration solution, mol/L; V—volume of disodium ethylenediaminetetraacetic acid standard titration solution consumed by titration test solution, mL; V
volume of disodium ethylenediaminetetraacetic acid standard titration solution consumed by titration blank test solution, mL; m
mass of sample, g;
·（1）
·（2）
and 1.00mL standard titration solution of disodium ethylenediaminetetraacetic acid Ec(EDTA)=1.000mol/L] is equivalent to the mass of strontium carbonate expressed in grams;
Calcium carbonate is converted into strontium carbonate coefficient;
0.7480---Barium carbonate is converted into strontium carbonate coefficient; X
Calcium carbonate content measured by 4.2;
Barium carbonate content measured by 4.3.
4.1.5 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 0.3%. 4.2 Determination of calcium carbonate content
4.2.1 Summary of method
The sample is dissolved in hydrochloric acid, and the calcium content in the sample is determined by the standard addition method at 422.7nm on an atomic absorption spectrophotometer. 4.2.2 Reagents and materials
4.2.2.1 Hydrochloric acid solution: 1+1;
4.2.2.2 Calcium standard solution: 1mL solution contains 0.1mgCa. 4.2.3 Instruments and equipment
Atomic absorption spectrophotometer: equipped with a calcium hollow cathode lamp. 4.2.4 Analysis steps
Weigh about 4g of sample (accurate to 0.0lg), place in a 250mL beaker, add 50mL water. Cover the surface with blood, add 10ml of hydrochloric acid solution to dissolve. Heat and boil for 2min, cool, transfer all to a 500mL volumetric flask, dilute to the mark with water, shake well. Filter to obtain test solution A. Keep this solution for the determination of sodium content. In a series of 100mL volumetric flasks, use a pipette to transfer 10mL (5mL for type I) of test solution A, add 2ml of hydrochloric acid solution, and then add 0.00mL, 1.00mL, 2.00mL, 3.00mL, and 4.00mL of calcium standard solution, dilute to the scale with water, and shake well. In an atomic absorption spectrophotometer, at a wavelength of 422.7nm, use an air-acetylene flame and adjust to zero with water to measure the absorbance of each solution. Draw a working curve with the calcium content as the horizontal axis and the corresponding absorbance as the vertical axis. The intersection of the curve with the horizontal axis when the curve is extended in the reverse direction is the calcium content in the test solution.
4.2.5 Expression of analysis results
HG/T 2969---1999
Calcium carbonate (CaCO) content (X:) expressed as mass percentage is calculated according to formula (3): Xx = m × 10 × 2.497 × 100
Wherein: m is the calcium content in the test solution found from the working curve, mg; - the mass of the sample contained in the test solution A, g; m-
2.497-——the coefficient for converting calcium into calcium carbonate. 4.2.6 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 0.08%. 4.3 Determination of barium carbonate content
4.3.1 Summary of the method
Under the condition of pH=5.9, barium ions react with potassium dichromate to form barium chromate precipitate. The precipitate is filtered, washed, dissolved with hydrochloric acid, and titrated with sodium thiosulfate standard titration solution. The content of barium carbonate is calculated from the volume of the consumed standard titration solution. 4.3.2 Reagents and materials
4.3.2.1 Hydrochloric acid solution: 1+1.
4.3.2.2 Hydrochloric acid solution: 1+4.
4.3.2.3 Ammonia solution: 1+1.
Ammonium acetate solution: 10g/L.
4. 3. 2. 5
Disodium ethylenediaminetetraacetic acid solution: 50g/L. 4.3.2.6 Potassium dichromate solution: 50g/L. Potassium iodide solution: 200g/L.
Silver nitrate solution: 20g/1.
4.3.2.9 Acetic acid-sodium acetate buffer solution (pH about 5.9). Weigh 164g of anhydrous sodium acetate, dissolve it in water, add 7.5mL of glacial acetic acid, dilute with water to 1000mL, and shake the spoon. 4.3.2.10 Sodium thiosulfate standard titration solution: c(Na2SO)=0.01mol/L. Accurately dilute the 0.1mol/L sodium thiosulfate standard titration solution prepared and calibrated according to GB/T601 by 10 times. 4.3.2.11 Methyl red indicator solution: 1g/L. 4.3.2.12 Starch indicator solution: 10g/L.
4.3.3 Instruments and equipment
Porous constant temperature water bath: can control the temperature at 80℃～90℃. 4.3.4 Analysis steps
Weigh about 3g of sample (accurate to 0.001g). Place in a 250mL beaker, add 20mL of water, cover with a watch glass, add 1+1 hydrochloric acid solution until the sample is dissolved, and heat to boil. Remove and cool to room temperature, transfer the solution to a 250mL volumetric flask, dilute to scale with water, shake well, and filter.
Use a pipette to transfer 50mL of filtrate, place in a 250mL beaker, add 30mL of disodium ethylenediaminetetraacetic acid solution, add 2 drops of methyl red indicator solution, adjust the test solution to yellow with ammonia solution, and then adjust it to light red with 1+4 hydrochloric acid solution. Add 10mL acetic acid-sodium acetate buffer solution, add water to 100mL, heat to boiling, add 10mL of potassium dichromate solution while stirring, cover with a watch glass, and boil for 10min~15min. Place the beaker and its contents in a water bath at 80℃～90℃ for 1h, remove and let stand for more than 1h. Filter the precipitate with slow filter paper, wash the beaker and precipitate with ammonium acetate solution until 5mL of filtrate is colorless and add 5 drops of silver nitrate. Dissolve the precipitate on the filter paper in the original beaker with 15mL of 1+4 hydrochloric acid solution, then wash with hot water to 100ml., and cool. Add 10ml of potassium iodide solution, stir, and titrate with sodium thiosulfate standard titration solution until the solution turns light yellow, add 2ml of starch indicator solution, and continue titrating until the blue disappears as the end point. Perform a blank test at the same time.
4.3.5 Expression of analysis results
HG/T 2969—1999
The content of BaCO3 (X4) expressed as mass percentage is calculated according to formula (4): x. c(V-V.)X0. 065 78 ×100 m×250
32. 89 c(V-. V.)
Wherein: V—-volume of sodium thiosulfate standard titration solution consumed by titrating the test solution, mL.; V,—volume of sodium thiosulfate standard titration solution consumed by titrating the blank test solution, mL;—actual concentration of sodium thiosulfate standard titration solution, moi/L; m
-mass of the sample, g;
(4))
0.06578—--mass of barium carbonate expressed in grams equivalent to 1.00mL sodium thiosulfate standard titration solution Lc (Na2SzO)-1.000mol/l.
4.3.6 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 0.05%. 4.4 Determination of sodium content
4.4.1 Method summary
On an atomic absorption spectrophotometer, at 330.3nm, use the standard addition method to determine the sodium content in the sample. 4.4.2 Reagents and materials
4.4.2.1 Hydrochloric acid solution: 1+1.
4.4.2.2 Sodium standard solution: 1mL solution contains 0.1mgNa. 4.4.2.3 Potassium standard solution: 1mL solution contains 30mgK. Accurately weigh 57.33g potassium chloride (superior grade), dilute to 1000mL with water, and store in a polyethylene bottle. 4.4.3 Instruments and equipment
Atomic absorption spectrophotometer: equipped with a sodium hollow cathode lamp. 4.4.4 Analysis steps
Use a pipette to take 50mL of test solution A, add 2mL of hydrochloric acid solution and 5mL of potassium standard solution to four 100mL volumetric flasks, respectively, and then add 0.00mL, 5.00mL, 10.00mL, and 20.00mL of sodium standard solution, respectively, dilute to the scale, and shake the hook. On an atomic absorption spectrophotometer, use an air-acetylene flame at a wavelength of 330.3nn, adjust to zero with water, and measure its absorbance. Draw a working curve with the sodium content as the horizontal axis and the corresponding absorbance as the vertical axis. The point where the curve is extended in the opposite direction and intersects with the horizontal axis is the sodium content in the test solution.
4.4.5 Expression of analysis results
The sodium content (in terms of NazO) expressed as a mass percentage (X) is calculated according to formula (5): X = m × 10 × 1. 35 × 100
Wherein: ml
The sodium content in the test solution found from the working curve, mg; The mass of the sample contained in the test solution A, m; m
1.35——The coefficient for converting sodium into sodium oxide. 4.4.6 Allowable difference
The average value of the two determination results is taken as the determination result. The difference between the parallel determination results shall not exceed 0.03%. 4.5 Determination of iron content
4.5.1 Method summary
According to Chapter 2 of GB/T3049-1986.
4.5.2 Reagents and materials
According to Chapter 3 of GB/T3049-1986 and nitric acid solution: 1+1. (5)
4.5.3 Apparatus and equipment
According to Chapter 4 of GB/T3049-1986.
4.5.4 Analysis steps
4.5.4.1 Drawing of working curve
HG/T 2969---1999
According to the provisions of 5.3 in GB/T3049.--1986, use a 3cm absorption cell and the corresponding iron standard solution to draw the working curve. 4.5.4.2 Preparation of test solution
Weigh about 1g of sample (accurate to 0.001g), put it in a 100mL beaker, add a small amount of water to moisten it, cover the surface with blood, add 5 drops of nitric acid solution. 5ml.1+1 hydrochloric acid solution to dissolve it, heat to boil, filter it with medium-speed qualitative filter paper after cooling, wash it with water, collect the filtrate and washing liquid in a 100ml volumetric flask, add water to the scale, and shake it well. Use a pipette to transfer 50 mL of the test solution into a 100 mL beaker, and use 1+8 ammonia water and 1+3 hydrochloric acid solution to adjust the pH value of the test solution to 2-3 (check with precision pH test paper). 4.5.4.3 Preparation of blank test solution
Except for not adding the test sample, the amount of other reagents added is exactly the same as that of the test solution, and the same treatment is performed at the same time as the test sample. 4.5.4.4 Determination
The test solution and blank test solution are measured according to the provisions of 5.4 of GB/T3049-1986, starting from "When necessary, add water to 60mL\" to "Measure the absorbance of the test solution and the reagent blank solution". Use a 3cm absorption cell and measure the absorbance according to the provisions of 5.4 of GB/T3049--1986. Find the mass of iron in the test solution and blank test solution based on the working curve.
4.5.5 Expression of analysis results
The iron content (in terms of Fe2O3) expressed as mass percentage (X.) is calculated according to formula (6): X. = (mm)×l.43×10-
m×100
wherein.m is the mass of iron in the test solution, mg, m2
is the mass of iron in the blank test solution, mg; the mass of the sample, g;
is the coefficient for converting iron into ferric oxide.
4.5.6 Allowable difference
× 100 = 0. 286 (ml -m2)
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference of the parallel determination results shall not exceed 0.001%. 4.6 Determination of chlorine content
4.6.1 Method summary
·(6)
The sample is dissolved in nitric acid, and silver nitrate solution is added to the test solution to make the chloride ions in the sample form silver chloride precipitate, which is compared with the standard turbidity solution.
4.6.2 Reagents and materials
4.6.2.1 Nitric acid solution: 1+2;
4.6.2.2 Silver nitrate solution: 20g /L;
4.6.2.3 Chlorine standard solution: 1mL solution contains 0.1mgCl. 4.6.3 Analysis steps
Weigh (1.00±0.01)g of sample, place in a 100mL beaker, add 50mL water and 5mL nitric acid solution, boil for 5min, transfer to a 250mL volumetric flask after cooling, dilute to the mark with water, and shake the hook. Dry filter with slow qualitative filter paper. Use a pipette to transfer 25mL of filtrate, place in a 50mL colorimetric tube, add 5mL nitric acid solution and 1mL silver nitrate solution, add water to the mark, and shake the hook. Place in a dark place for 10 min, compared with the standard turbidity solution, the turbidity produced shall not be deeper than the standard. The standard turbidity solution is 1.2mL of chlorine standard solution, placed in a 50mL colorimetric tube, and treated in the same way as the test solution. 944
4.7 Determination of total sulfur content
4.7.1 Summary of method
HG/T2969—1999
Various valence sulfur in the sample reacts with bromine to generate sulfate ions, which react with barium ions in a slightly acidic medium to form barium sulfate precipitation. Under alkaline conditions, use an excess of disodium ethylenediaminetetraacetic acid standard titration solution to dissolve barium sulfate and form a complex with barium ions. The excess disodium ethylenediaminetetraacetic acid standard titration solution is titrated with magnesium chloride standard titration solution. Calculate the total sulfur content. 4.7.2 Reagents and materials
4.7.2.1 Hydrochloric acid solution: 1+1.
4.7.2.2 Sodium hydroxide solution: 4g/L.
4.7.2.3 Bromine water: saturated aqueous solution at room temperature. 4.7.2.4 Barium chloride solution: 100g/1.
4.7.2.5 Ammonia solution: 1+2.
4.7.2.6 Silver nitrate solution: 20g/L.
4.7.2.7 Ammonia-ammonium chloride buffer solution A: pH~10. 4.7.2.8 Ethylenediaminetetraacetic acid disodium standard titration solution. c(EDTA) about 0.02mol/L. 4.7.2.9 Magnesium chloride standard titration solution: c(MgCl2) about 0.02mol/L. Preparation: Weigh 4.20g magnesium chloride (accurate to 0.01g), dissolve in 1000mL water, add 1mL 1+1 hydrochloric acid solution. After standing for 1 month, filter with a crucible filter (filter plate pore size 5μm~15μm). Calibration: Use a pipette to transfer 25 mL of the magnesium chloride solution to be calibrated, add 70 mL of water, 10 mL of ammonia-ammonium chloride buffer solution A, and an appropriate amount of chrome black T indicator, and titrate with disodium ethylenediaminetetraacetic acid standard titration solution until the solution changes from purple-red to pure blue as the end point. At the same time, perform a blank test.
The concentration c2 of the standard ethylenediaminetetraacetic acid solution is calculated according to formula (7): c2 = iV)
Wherein: C -- the actual concentration of the standard ethylenediaminetetraacetic acid solution, mol/L; V1-the volume of the standard ethylenediaminetetraacetic acid solution consumed in the calibration, mL; V2
-the volume of the standard ethylenediaminetetraacetic acid solution consumed in the titration of the blank test solution, mL; V--the volume of the standard ethylenediaminetetraacetic acid solution transferred, mL. 4.7.2.10 Methyl orange indicator, 1 g/L. 4.7.2.11 Chrome black T indicator.
4.7.3 Instruments and equipment
4.7.3.1 Porous constant temperature water bath: can control the temperature between 95℃ and 100℃; 4.7.3.2 Microburette: graduation value 0.02mL. 4.7.4 Analysis steps
·(7)
Weigh about 2g of sample (accurate to 0.001g) and place it in a 250mL beaker. Add 30mL of water and 10ml of bromine water in a fume hood. Cover with a watch glass and heat to boil for 2min to 3min. After cooling, add 6mL of hydrochloric acid solution to dissolve it. Heat and boil until all the bromine is gone (the solution is colorless), cool, add 3 drops of methyl orange indicator solution, add ammonia solution until the solution just turns yellow, add 1mL of hydrochloric acid solution, add water to 100mL, heat to boiling, and add 10mL of hot barium chloride solution at a trickle column speed while stirring. After heating and boiling for 3-5 minutes, place in boiling water in a porous constant temperature water bath and keep warm for 2 hours. After cooling, filter with slow quantitative filter paper and wash with water until there is no chloride ion (check with silver nitrate solution). Put the filter paper with precipitate into the original beaker, add 15mL of disodium ethylenediaminetetraacetic acid standard titration solution, 10mL of sodium hydroxide solution and 50mL of water with a pipette. Heat and boil until the precipitate dissolves. After cooling, add 10mL of ammonia-ammonium chloride buffer solution A and an appropriate amount of chrome black T indicator, and titrate with magnesium fluoride standard titration solution until the solution changes from blue to purple-red as the end point. 4.7.5 Expression of analysis results
The total sulfur content (in terms of SO4) expressed in mass percentage (X,) is calculated according to formula (8):945
HG/T 2969—1999
X, =(GV-cVe)×0.096 06
X 100
9.606 (c V1 - c V2)
Wherein: c1—-actual concentration of disodium ethylenediaminetetraacetic acid standard titration solution, mol/L; V
the volume of disodium ethylenediaminetetraacetic acid standard titration solution added, mL; 2
the actual concentration of magnesium chloride standard titration solution, mol/L; V—the volume of magnesium chloride standard titration solution consumed in titration, mL; m—
0.096 06
Mass of the sample, g;
（8）
Mass of silver sulfate in grams equivalent to 1.00 mL of standard titration solution of disodium ethylenediaminetetraacetic acid [c(EDTA)=1.000 mol/LI].
4.7.6 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 0.02%. 4.8 Determination of moisture
4.8.1 Summary of method
The sample is dried at 105℃～110℃, and the moisture is calculated from the reduced mass of the sample. 4.8.2 Analysis steps
Weigh about 10g of sample (accurate to 0.0002g) and place it in a weighing bottle that has been dried to constant weight at 105℃～110℃ in advance. Dry at 105℃~110℃ to constant weight.
4.8.3 Expression of analysis results
The moisture expressed as mass percentage (X:) is calculated according to formula (9): X. = m=m2 × 100
Wherein: mbzxz.net
--mass of the sample and weighing bottle before drying, g; m2——--mass of the sample and weighing bottle after drying, g; m
mass of the sample, g.
4.8.4 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 0.02%. 4.9 Determination of chromium content
4.9.1 Summary of method
Use hydroxylamine hydrochloride to reduce hexavalent chromium to trivalent chromium, and use aluminum hydroxide as a coprecipitant to enrich it, so that chromium and strontium are separated, and the determination is carried out in an air-acetylene flame using an atomic absorption spectrophotometer. 4.9.2 Reagents and materials
4.9.2.1 Sodium carbonate.
4.9.2.2 Potassium nitrate.
4.9.2.3 Hydrochloric acid solution: 1+1.
4. 9. 2. 4
Ammonia solution: 1+1.
Hydroxylamine hydrochloride solution: 50g/L.
4. 9. 2. 6
Aluminum chloride solution: 20g/L.
4. 9. 2. 7
Sodium sulfate solution: 100g/L.
4.9.2.8 Chromium standard solution: 1mL solution contains 0.01mgCr. Use a pipette to transfer 10mL of the chromium standard solution prepared according to GB/T602 and dilute it to 100mL with water. Prepare this solution before use. 4.9.2.9 Methyl red indicator solution: 1g/.。
4.9.3 Instruments and equipment
4.9.3.1 Platinum crucible;
HG/T 2969—1999
4.9.3.2 Atomic absorption spectrophotometer: equipped with chromium hollow cathode lamp. 4.9.4 Analysis steps
4.9.4.1 Drawing of working curve
Add 0.00mL, 5.00mL, 10.00mL, and 20.00mL of chromium standard solution to four 100mL volumetric flasks, and add 1mL of hydroxylamine hydrochloride solution, 2mL of hydrochloric acid solution, 10mL of sodium sulfate solution, and 5mL of aluminum chloride solution to each flask, shake well, let stand for 5 minutes, and dilute to the scale. On the atomic absorption spectrophotometer, use air-acetylene flame at a wavelength of 357.9nm, adjust to zero with water, and measure its absorbance. Draw a working curve with chromium content as the horizontal axis and the corresponding absorbance as the vertical axis. 4.9.4.2 Determination
Weigh about 10g of sample (accurate to 0.01g), place it in a 300mL beaker, add a small amount of water to moisten it, cover the surface blood, add 30mL of hydrochloric acid solution to dissolve the sample. Heat and boil for 2 minutes, filter with medium-speed quantitative filter paper, wash with water 4 times, and collect the filtrate in a 300mL beaker. After the filter paper and insoluble matter are placed in a platinum crucible for low-temperature ash treatment, 1g sodium carbonate and 0.1g potassium nitrate are added, placed in a high-temperature furnace, melted at 900°C, burned for 30 minutes, taken out and cooled, placed in a 300mL beaker together with the crucible, added with 80ml of water, heated and boiled until the molten block is loose, this solution is combined with the above solution, 5mL of hydroxylamine hydrochloride solution is added, stirred and boiled, removed and added with 5mL of aluminum nitride solution, water is added to about 300ml, 2 drops of methyl red indicator solution are added, and ammonia solution is added to change the solution from red to yellow. Heat on an electric furnace until it is nearly boiling to condense the precipitate, remove and filter with rapid qualitative filter paper, wash the precipitate 2 to 3 times, and move it to the original beaker together with the filter paper. Add 10ml of sodium sulfate solution, 4mL of hydrochloric acid solution, and 20ml of water. Heat to dissolve the precipitate, filter the solution into a 100ml volumetric flask with medium-speed qualitative filter paper, add 1mL of hydroxylamine hydrochloride solution, dilute to the mark, and shake well. Measure the absorbance of the solution on an atomic absorption spectrophotometer under the same test conditions as the working curve. 4.9.5 Expression of analysis results
The chromium oxide (Cr2O,) content (X.) expressed as mass percentage is calculated according to formula (10): X. m X1. 461 5×10-6
Where: m--the chromium content in the test solution found from the working curve according to the absorbance of the test solution, ug; m--the mass of the sample, g;
1.4615--the coefficient for converting chromium to chromium trioxide. 4.9.6 Allowable difference
(10)
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference between two parallel determination results shall not exceed 0.0001%. 4.10 Determination of particle size
4.10.1 Instruments and equipment
4.10.1.1 Test sieve: R40/3 series, with sieve bottom and sieve cover; 4.10.1.2 Screen vibrator.
4.10.2 Analysis steps
Stack the test sieves in order. Weigh 100g of sample (accurate to 0.1g) that has been dried at 105℃～120℃ in advance, place it in the upper sieve, cover the sieve cover, and use the screen vibrator to vibrate the sieve for 1 minute. Weigh the mass of the material on or under the sieve as required (accurate to 0.01g). 4.10.3 Expression of analysis results
The mass percentage of the oversize or undersize (X1.) is calculated according to formula (11): Xio=m×100
wherein; m1——mass of the oversize or undersize of the test sieve, g; m——mass of the test material, g.
4.10.4 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference between the two parallel determination results shall not exceed the user's negotiated provisions. 947
5 Inspection rules
HG/T 2969--1999
5.1 All ten index items in the requirements of this standard are type inspection items, among which strontium barium content, calcium carbonate content, barium carbonate content, sodium content, iron content, chlorine content, total sulfur content, moisture content and particle size are routine inspection items. 5.2 Each batch of products shall not exceed 60t.
5.3 Determine the number of sampling units according to 6.6 of GB/T6678-1986. When sampling, insert the sampler vertically from the center of the packaging bag to 3/4 of the depth of the material layer to take a sample. After mixing the collected samples, divide them into four parts to no less than 1000g, and pack them in two clean and dry wide-mouth bottles with stoppers and seal them. Paste labels on the bottles, indicating the manufacturer's name, product name, model, 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 future reference. 5.4 Industrial strontium carbonate shall be inspected by the quality supervision and inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer shall ensure that each batch of products shipped from the factory meets the requirements of this standard.
5.5 If any indicator of the inspection results does not meet the requirements of this standard, re-sampling should be carried out from twice the amount of packaging for re-inspection. If even one indicator of the re-inspection results does not meet the requirements of this standard, the entire batch of products shall be unqualified. 5.6 Determine whether the test results comply with the standard by the rounded value comparison method specified in 5.2 of GB/T1250. 6 Marking and labeling
6.1 The packaging of industrial strontium carbonate should have firm and clear markings, including the manufacturer's name, address, product name, trademark, model, net content, batch number or production date, the number of this standard and the "moisture-afraid" mark specified in GB191. 6.2 Each batch of industrial strontium carbonate leaving the factory should be accompanied by a quality certificate. The content includes the manufacturer's name, address, product name, trademark, model, net content, batch number or production date, proof that the product quality complies with this standard and the number of this standard. 7 Packaging, transportation, purchase and storage
7.1 Industrial carbonate Strontium is packaged in two ways. 7.1.1 Plastic woven bag packaging: The inner packaging is a polyethylene plastic film bag with a thickness of 0.03mm~0.05mm; the outer packaging is a plastic woven bag. The net content of each bag is 25kg, 50kg, 500kg, 800kg and 1000kg. 7.1.2 Composite woven bag packaging: The inner packaging is a polyethylene plastic film bag with a thickness of 0.03mm~0.05mm; the outer packaging is a composite woven bag. The net content of each bag is 25kg, 50kg, 500kg, 800kg, 1000kg7.2 When industrial strontium carbonate is packaged in plastic woven bags or composite woven bags, the inner bag shall be tied with vinyl rope or other ropes of equivalent quality, or sealed with other equivalent methods; the outer bag shall be folded at a distance of not less than 30mm from the bag edge, and sewed with vinyl thread or other thread of equivalent quality at a distance of not less than 15mm from the bag edge. The stitches shall be neat and the stitch length shall be uniform. There shall be no leakage or skipping of seams. 7.3 Industrial strontium carbonate shall be covered during transportation to prevent rain and moisture. 7.4 Industrial strontium carbonate shall be stored in a dry and cool place to prevent rain and moisture. Prevent heavy pressure. 948
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