This standard is applicable to the determination of nitrogen content in nitrided ferrochrome. Determination range: ≤1.00～10.0%. This standard complies with GB 1467-78 "General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products". This standard is equivalent to the Japanese Industrial Standard JIS G 1313/1978 "Analysis Method for Ferrochrome". GB/T 5687.4-1985 Chemical Analysis Method for Ferrochrome Neutralization Titration Method for Determination of Nitrogen Content GB/T5687.4-1985 Standard Download Decompression Password: www.bzxz.net

National Standard of the People's Republic of China
Methods for chemical analysis of ferrochromium
Neutralization titration method for thedetermination of nitrogen content
Methods for chemical analysis of ferrochromiumThe neutralization titration method for thedetermination of nitrogen contentThis standard is applicable to the determination of nitrogen content in nitrided ferrochromium. Determination range: 1.00～10.0%. UDC 669.15° 26
：546.17
GB 5687.4--85
This standard complies with GB1467-78 "General Principles and General Provisions of Standards for Chemical Analysis Methods of Metallurgical Products". This standard is equivalent to the Japanese industrial standard JISG1313/1978 "Analysis Method for Ferrochromium". Summary of the method
The sample is decomposed with hydrochloric acid, sodium hydroxide is added to make it alkaline, and it is distilled by steam. The distilled ammonia is absorbed by boric acid solution and then titrated with aminosulfonic acid standard solution.
2 ReagentsWww.bzxZ.net
Sn (small flakes).
Hydrochloric acid (p 1.19g/m1).
Hydrochloric acid (1+1).
Sulfuric acid (1+1)
Phosphoric acid (p 1.70g/m1)
Boric acid solution (2.5%).
Sodium hydroxide solution (50%)
2.8 Mixed indicator: Dissolve 0.125g methyl red and 0.083g of methyl red in ethanol, dilute to 100ml with ethanol, and mix well. Aminosulfonic acid standard solution: Weigh 6.931g of aminosulfonic acid (NH2SO:H) standard reagent (previously placed in a desiccator under reduced pressure sulfuric acid for 48h) and dissolve in water, transfer to a 1000ml volumetric flask, dilute to the mark with water, and mix well. 1 ml of this solution is equivalent to 1.0 mg of nitrogen.
3 Apparatus
The distillation device (see the figure below) is made entirely of hard glass. The steam flask (1), distillation flask (2), funnel (5) and (6), ball chamber (4) and snake condenser (3) are connected through the frosted mouth (7) and secured with springs and clamps. The receiving bottle is a 300 ml conical flask made of hard glass. Note: When using the distillation device discontinuously or when using a new one, the snake tube of the condenser must first be fully washed with water, and then washed with steam for 2 to 3 hours. Issued by the National Bureau of Standards on December 4, 1985
Implemented on October 1, 1986
4 Sample
GB5687.485
Water vapor flask (0)
Purple version
(soonl)
Quantitative loading of nitrogen in steam
Cold condenser (3)
Water vapor flask: 2-flask (500ml): 3-condenser: 4-ball chamber 5-funnel, 6-purifier: 7-water sample should pass through 0.088mm sieve.
5 Analysis steps*
5.1 Sample
Weigh the sample according to Table 1.
★The analysis must be carried out in the test chamber for nitrogen compounds in steam, and the water used should not contain nitrogen compounds. 332
5.2 Empty test
Nitrogen, ".
5687.4-85
Weighing amount of sample, g
Before determining the nitrogen content in the sample, it is necessary to carry out empty tests more than twice according to the same determination steps as when analyzing the sample, and take the average value as the empty value. The empty value should be less than 0.1mg. 5.3 Measurement
5.3.1 Place the sample (5.1) in a 300ml beaker, cover with table blood, add hydrochloric acid (2.3) according to Table 2, and slowly heat until the sample is completely dissolved. If the sample is not completely decomposed by hydrochloric acid, 40ml sulfuric acid (2.4) and 15ml phosphoric acid (2.5) can be added instead of hydrochloric acid (2.3), heated to dissolve, and after smoking, heat on a sand bath for 30min until the sample is completely decomposed. After cooling, Add about 30ml of water, heat to dissolve the salts, and proceed as per 5.3.2 to 5.3.4.
Note: When dissolving a poorly soluble sample, if the time is too long, the acid used for dissolution will evaporate significantly. The sample can be placed in a 300ml conical flask, and after adding the acid, a funnel can be placed on the mouth of the flask to decompose the sample by heating.
Sample amount, g
.0.2000
Add hydrochloric acid (2.2) ml
Add sodium hydroxide solution (2.7) ml
5.3.2After the solution has cooled, transfer it to the distillation flask (2) and clean the beaker or conical flask with a small amount of water. Connect the ball chamber (4) with a frosted mouth (7), fix it with a spring clip, and then clamp the bottom of the flask with a metal mesh. Add 20ml of boric acid solution (2.6 ), insert the lower end of the condenser coil into the solution in the receiving bottle. 5.3.3 Slowly put the sodium hydroxide solution (2.7) from the funnel (6) into the distillation bottle according to Table 2, add water until the solution volume is about 250ml, and pass the water vapor sent from the water vapor generator bottle for distillation. When the total volume of the solution in the receiving bottle reaches 110㎡1, lower the receiving bottle to make the lower end of the condenser coil leave the liquid surface, and continue distilling for a while to wash the inside of the condenser coil. Wash the lower end surface of the condenser coil with water and take out the receiving bottle.
Note: 1. For the water vapor generator bottle tt, 5 to 10g of small tin pieces can be saved to prevent sudden boiling. 2 After putting water into the water vapor generator bottle, it is better to raise the funnel (5) in advance and then boil the water. ③ Before taking out the receiving plate, the funnel on the water vapor generator bottle should be (5) Raise the pressure to allow water vapor to escape, remove the distillation flask from the ball chamber at the frosted mouth, wash it with water and set it aside. 5.3.4 Add 3 drops of mixed indicator (2.8) to the receiving bottle containing the effluent, and titrate with aminosulfonic acid standard solution (2.9) until the solution changes from green to red. Calculation of analysis results
Calculate the percentage of nitrogen according to the following formula:
GB5687,4-85
()×0.0010×100
Where: V--the volume of aminosulfonic acid standard solution consumed when titrating the test solution, ml; 1--the volume of aminosulfonic acid standard solution consumed by the empty test solution, m1; m·-the amount of sample, g:
0.0010-1 ml aminosulfonic acid standard solution is equivalent to the amount of nitrogen, g. 7 Allowable Difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 3: Table 3
1.00~3.00
3.00~6.00
Additional Notes:
This standard was proposed by the Second Ministry of Metallurgy of the People's Republic of China. This standard was drafted by Shanghai Ferroalloy Factory. 331
Allowable Difference
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