Some standard content:
Record number: 10090-2002
HG2939-2001
4.2, 4.3, 4.4 of this standard are mandatory, arsenic and heavy metal indicators in Table 1 are mandatory, and the rest are recommended. This standard is a revision of the mandatory chemical industry standard HG2939-1987 "Feed Grade Potassium Iodide". The main technical differences between this standard and HG2939-1987 are as follows: - The potassium iodide (KI) content is adjusted from 99.0% to 98.0%, and the potassium iodide content calculated as 1 is adjusted from 75.7% to 74.9% accordingly.
- The potassium iodide content is determined by potassium iodate titration instead of silver nitrate method. - The determination of the content of the silver salt method is added to the determination of the content of the silver salt method, and the silver salt method is used as the arbitration method. - The standard is adjusted from mandatory in the whole text to mandatory in the clauses. This standard will replace HG2939-1987 from the date of implementation. This standard was proposed by the Policy and Regulations Department of the former State Administration of Petroleum and Chemical Industry. This standard is under the jurisdiction of the technical unit responsible for the standardization of inorganic salt products in the chemical industry. The drafting units of this standard are: Tianjin Chemical Research and Design Institute, Hebei Huanghua Jinhua Additive Factory. The main drafters of this standard are: Guo Fengxin, Wang Yan, Zhang Xianwen. This standard was first issued as a national standard in 1987, adjusted to a chemical industry standard in 1992, and renumbered as HG2939-1987 in 1997.
This standard is entrusted to the technical unit responsible for the standardization of inorganic salt products in the chemical industry for interpretation. 868
1 Scope
Chemical Industry Standard of the People's Republic of China
Feed grade
Potassium iodide
Feed grade--Potassium iodideHG 2939--2001
Replaces HG2939-1987
This standard specifies the requirements, test methods, inspection rules, marking, labeling, packaging, storage and transportation of feed grade potassium iodide. This standard applies to feed grade potassium iodide. This product is mainly added to feed as an iodine supplement after premixing and dilution. Molecular formula, KI
Relative molecular mass: 166.00 (according to the 1999 international relative atomic mass) 2 Reference 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 will be revised, and parties using this standard should explore the possibility of using the latest version of the following standards. GB/T 601--1988bzxz.net
Chemical reagents-Preparation of standard solutions for titration analysis (volumetric analysis) GB/T 602-1988
GB/T 603-1988
Chemical reagents
Preparation of standard solutions for determination of impurities (neqISO6353-1:1982) Preparation of preparations and products used in chemical reagent test methods (neqISO6353-1:1982) GB/T 6003.1-1997
GB/T 6435--1986
GB/T 6678--1986
GB/T 6682-1992
GB 10648—1999
Wire mesh test sieve
Determination method of moisture in feed
General rules for sampling of chemical products
Specifications and test methods for water used in analytical laboratories (eqvISO3696:1.987)Feed label
GB/T 13079—1999
GB/T15346--1994
3 Requirements
3.1 Appearance: white crystals.
Determination method of total arsenic in feed
Packaging and marking
Chemical reagents
3.2 Feed-grade potassium iodide shall comply with the requirements of Table 1. Table 1 Requirements
Mass fraction of potassium iodide (KI) (on dry basis)Mass fraction of potassium iodide (as I) (on dry basis)Mass fraction of arsenic (As)
Mass fraction of heavy gold eagle (as Pb)
Mass fraction of lock (B3a)
Solubility test
Approved by the State Economic and Trade Commission on January 24, 2002
Solution is clear and transparent
2002 -07-01 Implementation
Loss on drying, %
Fineness, passing 800μm test sieve, %
HG2939—2001
Table 1 (end)
Note: Arsenic and heavy metal content are mandatory items, others are recommended items 4 Test method
The reagents and water used in this standard, unless otherwise specified, refer to analytical reagents and grade 3 water specified in GB/T6682. The standard titration solution, impurity standard solution, preparation 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 hydrochloric acid used in the test is a corrosive reagent, so be careful when handling it. If it splashes on the skin, rinse it with water immediately; chloroform is a toxic and anesthetic reagent, so it should be handled in a fume hood. 4.1 Identification test
4.1.1 Reagents and materials
4.1.1.1 Sodium nitrite solution: 10g/L. 4.1.1.2 Hydrochloric acid solution: 1+10.
4.1.1.3 Starch indicator: 10g/L.
4.1.2 Identification method
4.1.2.1 Identification of iodine ions
Weigh about 0.5g of sample, place it in a 50mL beaker, add 5mL of water to dissolve, add 1mL of hydrochloric acid solution, add 1ml. Starch indicator and add 1ml of sodium nitrite solution, the solution should be blue. 4.1.2.2 Identification of potassium ions
Dip the hydrochloric acid solution with a platinum wire and burn it in a colorless flame until it is colorless. Dip the sample and burn it in a colorless flame, see through the cobalt glass, and the flame will be purple.
4.2 Determination of potassium iodide content
4.2.1 Method summary
In hydrochloric acid medium, use potassium iodate standard titration solution to titrate, potassium iodide is oxidized to elemental iodine, and then continue to titrate with potassium iodate standard titration solution. The end point is determined by the disappearance of the color of iodine in the chloroform layer. 4.2.2 Reagents and materials
4.2.2.1 Hydrochloric acid.
4.2.2.2 Chloroform.
4.2.2.3 Potassium iodate standard titration solution: c(1/6KIOs) is about 0.3mol/L. Prepare and calibrate according to GB/T601.
It can also be prepared directly as follows: accurately weigh 10.700g of standard potassium iodate that has been dried to constant weight at (105±2)℃, place it in a 1000ml volumetric flask, add appropriate amount of water to dissolve, dilute with water to the scale, and shake to hook. 4.2.3 Analysis steps
Weigh 0.5g of the sample that has been dried to constant weight at 105℃ in advance (accurate to 0.0002g). Place it in a 250mL conical flask, add 10ml of water to dissolve, add 35ml of hydrochloric acid, and titrate with potassium iodate standard titration solution. When the solution color is orange-yellow, add 5mL of chloroform, continue titrating, and shake vigorously until the chloroform layer turns colorless, which is the end point. 4.2.4 Expression of analytical results
Potassium iodide (KI) content (X1) expressed as mass fraction is calculated according to formula (1): cV×0.055 33 × 100 = 5.533cVX=
（1）
HG 2939—2001
Potassium iodide content (X2) expressed as mass fraction (based on 1) is calculated according to formula (2): X cV×0.042 30 ×100 4. 230cVm
Wherein: C
actual concentration of potassium iodate standard titration solution, mol/L; m
volume of potassium iodate standard titration solution consumed by titrating the test solution, mL; mass of the sample, g;
·(2)
mass of potassium iodide (KI) equivalent to 1.00mL potassium iodate standard titration solution [c(1/6KIO.)=1.000mol/L] in grams;
0.04230----mass of potassium iodide (in I) equivalent to 1.00ml. potassium iodate standard titration solution [c(1/6KI0)-1.000mol1L] in grams.
4.2.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference (in KI) of the parallel determination results shall not exceed 0.2%. 4.3 Determination of arsenic content
4.3.1 Silver salt method (arbitration method)
4.3.1.1 Method summary
Same as Chapter 2 of GB/T13079-1999.
4.3.1.2 Reagents and materials
Same as Chapter 3 of GB/T13079-1999.
4.3.1.3 Instruments and equipment
Same as Chapter 4 of GB/T13079-1999.
4.3.1.4 Analysis steps
a) Preparation of test solution
Accurately weigh (10±0.01)g of sample, add appropriate amount of water to dissolve, transfer to a 100mL volumetric flask, dilute to scale with water, and shake well. b) Drawing of working curve
Perform the operation according to 5.2 of GB/T13079-1999. c) Determination
Pipette 25mL of test solution, and perform the determination according to 5.3 of GB/T13079-1999 starting from "accurately draw appropriate amount of solution into the arsenic generator".
4.3.1.5 Expression of analysis results
The arsenic (As) content (X:) expressed as mass fraction is calculated according to formula (3): X = mi X10-6
0.0004×m
× 100 m
m×100
Wherein: m-
-the mass of arsenic found from the working curve according to the absorbance of the test solution measured, g; -the mass of the sample, g.
4.3.1.6 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 0.0001%. 4.3.2 Arsenic spot method
4.3.2.1 Method summary
In an acidic medium, potassium iodide and stannous chloride reduce As (V) to As (II), which reacts with new hydrogen to form arsenic hydrogen. Arsenic hydrogen forms an arsenic spot on the mercuric bromide test paper, which is compared with the standard arsenic spot. 4.3.2.2 Reagents and materials
a) Hydrochloric acid.
b) Potassium iodide.
c) Arsenic-free metallic zinc.
d) Stannous chloride hydrochloric acid solution: 400g/L. HG 2939—2001
e) Arsenic standard solution: 1mL of solution contains 0.001mgAs. Use a pipette to transfer 1.00mL of the standard solution prepared according to GB/T602, place it in a 100mL volumetric flask, dilute to the mark with water, and shake to hook. The solution is prepared before use. f) Mercuric bromide test paper.
g) Lead acetate cotton.
4.3.2.3 Apparatus and equipment
Arsenic analyzer.
4.3.2.4 Analysis steps
Use a pipette to transfer 10 mL of the test solution [4.3.1.4a)] and place it in the wide-mouth bottle of the arsenic analyzer, and add 70 mL of water. Add 6 mL of hydrochloric acid, shake well, add 1 g of potassium iodide and 0.2 mL of stannous chloride hydrochloric acid solution, shake well, and place for 10 minutes, add 2.5 g of arsenic-free metal zinc, and immediately plug the test tube pre-filled with lead acetate cotton and mercuric bromide test paper, and place it in a dark place at 25℃～30℃ for 1h～1.5h. The brown-yellow color of the mercuric bromide test paper shall not be darker than the color produced by the standard. The standard is to use a pipette to transfer 2 mL of the arsenic standard solution, place it in the wide-mouth bottle of the arsenic analyzer, and dilute it to 70 mL with water. Add 6ml. hydrochloric acid, and perform the following operations in the same way as the sample. 4.4 Determination of heavy metal content
4.4.1 Method summary
In a weakly acidic medium, the heavy metals in the sample react with hydrogen sulfide to form a brown sulfide precipitate, which is compared with the standard solution. 4.4.2 Reagents and materials
4.4.2.1 Ammonia solution: 2+3.
4.4.2.2 Sulfuric acid solution: 1+1.
4.4.2.3 Acetic acid solution: 1+2.
4.4.2.4 Sodium sulfide glycerol solution: 10g/L. Weigh 5g of sodium sulfide (NazS·9H20) and dissolve it in a mixture of 10mL of water and 40mL of glycerol. 4.4.2.5 Lead standard solution: 1mL of solution contains 0.01mgPb. Use a pipette to transfer 10mL of the lead standard solution prepared according to GB/T602, place it in a 100mL volumetric flask, dilute it with water to the mark, and shake it well.
4.4.3 Instruments and equipment
Colorimetric tube: 50mL.
4.4.4 Analysis steps
Weigh (2±0.01)g of the sample, place it in a porcelain evaporating dish, add 2mL of sulfuric acid solution, slowly heat until the sulfuric acid vapor escapes, cool, dissolve it with a small amount of water, transfer it to a colorimetric tube, adjust the pH value of the solution to 4 with ammonia solution (check with pH test paper), add 0.2mL of acetic acid solution, dilute it with water to 25mL, add 2 drops of sodium sulfide glycerol solution, dilute it with water to the mark, shake it well, and place it in a dark place for 10min. The color of the solution shall not be darker than the standard.
The standard is to use a pipette to transfer 2mL of the lead standard solution, place it in a colorimetric tube, add 0.2mL of acetic acid solution, and perform the following operations in the same way as the sample.
4.5 Determination of content
4.5.1 Summary of method
The barium in the sample reacts with sulfate ions to form a white fine barium sulfate precipitate, making the solution turbid, and compared with the standard solution. 4.5.2 Reagents and materials
4.5.2.1 95% ethanol.
4.5.2.2 Ascorbic acid.
4.5.2.3 Sulfuric acid solution: 1+8.
HG 2939--2001
4.5.2.4 Barium standard solution: 1mL solution contains 0.01mgBa. Use a pipette to transfer 10ml of the barium standard solution prepared according to GB/T602, place it in a 100mL volumetric flask, dilute it to the mark with water, and shake it.
4.5.3 Instruments and equipment
Colorimetric tube: 50ml.
4.5.4 Analysis steps
Weigh (2±0.01)g of sample. Place in a colorimetric tube, add 25ml of water to dissolve the sample, add 5ml of 95% ethanol, 0.3g of ascorbic acid, and 1ml of sulfuric acid solution, and place for 10 min; the turbidity should not be greater than the standard. The standard is to use a pipette to transfer 2mlL of barium standard solution and place it in a colorimetric tube. The following operations are carried out at the same time as the sample. 4.6 Solubility test
Weigh (1±0.01)g of sample, place in a test tube, add 10mL of water to dissolve it, and observe immediately. The solution should be clear and transparent. 4.7 Determination of loss on drying
Determine according to GB/T6435.
4.8 Determination of fineness
4.8.1 Instruments and equipment
Metal wire mesh test sieve: R40/3 series. Φ200mm×50mm/0.800mm. 4.8.2 Analysis steps
Weigh about 50g of sample (accurate to 0.01g), place it in a metal wire mesh test sieve that meets GB/T6003.1 for sieving, and weigh the sieve material (accurate to 0.01g).
4.8.3 Expression of analysis results
The fineness (X4) expressed as the mass fraction of the sieve material is calculated according to formula (4): X4= ml×100
Where: mi is the mass of the test sieve material, g; m---the mass of the sample, g.
4.8.4 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 0.2%. 5 Inspection rules
5.1 All items specified in this standard are factory inspection items. 5.2 Each batch of products shall not exceed 500kg.
：（4）
5.3 Determine the number of sampling units in accordance with the provisions of 6.6 of GB/T6678-1986. Each bottle is a packaging unit. When sampling, insert the mouth of the white packaging container of the sampler obliquely to 3/4 of the depth of the material layer to take a sample. After mixing the collected samples, reduce them to no less than 500g by quartering method, and pack them into two clean and dry wide-mouth bottles with stoppers and seal them. Paste labels on the bottles, indicating the manufacturer's name, product name, batch number, sampling date and name of the sampler. One bottle is used for inspection and the other is kept for three months for future reference. 5.4 Feed-grade potassium iodide shall be inspected by the quality inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer shall ensure that all feed-grade potassium iodide shipped from the factory meets the requirements of this standard. 5.5 The user has the right to inspect and accept the received feed-grade potassium iodide products in accordance with the provisions of this standard. The inspection time shall be within... months from the date of arrival of the goods.
5.6 If any index of the test result does not meet the requirements of this standard, samples should be taken from twice the amount of packaging for re-testing. If even one index of the re-test result does not meet the requirements of this standard, the entire batch of products shall be unqualified. 873
6 Marking and labeling
HG 2939—2001
6.1 The packaging of feed-grade potassium iodide shall be firmly and clearly marked, including the manufacturer's name, address, product name, trademark, "feed-grade", net content, batch number or production date, this standard number and the "moisture-averse" and "sunscreen" marks specified in GB191. 6.2 Each batch of feed-grade potassium iodide shipped out of the factory should be accompanied by a firm and clear label printed in accordance with the requirements of GB10648. 7 Packaging, storage, and transportation
7.1 Feed-grade potassium iodide is packaged in brown glass bottles or plastic bottles, with a net content of 0.5kg or 1kg per bottle. A certain number of glass bottles or plastic bottles are packed into cartons, and the performance and inspection methods of the packaging should comply with the provisions of 7.1 and 7.4 in GB/T15346-1994. 7.2 When feed-grade potassium iodide is packaged in glass bottles or plastic bottles, the inner and outer covers must be tightly covered, pressed, and tightened. 7.3 Feed-grade potassium iodide should be stored in a dark, dry place, sealed, and strictly prohibited from being stored together with toxic substances. 7.4 Feed-grade potassium iodide must not be inverted during transportation to prevent sun exposure and rain. It is strictly prohibited to be transported together with toxic substances. 7.5 The shelf life is two years.
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