JB/T 9220.11-1999 Chemical analysis of acidic slag from foundry cupola furnaces - Combustion-potassium iodate volumetric method for determination of sulfur content
Some standard content:
JB/T9220.11—1999
This standard is a revision of JB/Z284.1187 "Chemical analysis method of acidic slag of foundry cupola furnace - determination of sulfur content by combustion-potassium iodate volumetric method"
. During the revision, the original standard was edited and the main technical content remained unchanged. This standard replaces JB/Z284.11--87 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Foundry Standardization. The drafting units of this standard are: Shanghai Diesel Engine Factory, Nanchang Diesel Engine Factory, Guiyang Foundry, Shenyang Foundry, Shanghai Tractor Company, Huafeng Steel, Wuxi Diesel Engine Factory, Changzhou Diesel Engine Factory, etc. The main drafters of this standard are: Wang Zhihan, etc. 159
1 Scope
Standard of the Machinery Industry of the People's Republic of China
Chemical analysis methods for acid slay of cupolaDetermination of sulphur by volumetric methodusing combustion of potassium iodateJB/T 9220.111999
Replaces JB/Z28.1.1187
This standard specifies the determination of sulfur content in chemical analysis methods. Determination range: 0.020%-1.00%. This standard is applicable to the analysis of the composition of acid slag of cupola. 2 Test conditions
The sample is placed in a high-temperature tubular furnace and burned with oxygen at 1250°C ± 20°C in the presence of a flux, so that the sulfide is converted into sulfur oxide, which is absorbed by the acid precipitation powder solution and titrated with potassium iodate standard solution. 3 Reagent preparation
3.1 Sulfuric acid (density 1.84g/ml).
3.2 Alkali asbestos.
3.3 Anhydrous calcium fluoride.
3.4 Starch absorption liquid: Weigh 10g soluble starch, mix it into a paste with a small amount of water, add 500mL boiling water, stir, and heat to boil. Remove, cool, add 500ml water, 2ml hydrochloric acid (density 1.19g/ml.), stir well and let stand to clarify. When using, take 25ml..l: clear liquid, add 15mL hydrochloric acid (density 1.19g/mL), dilute to 1000ml with water, and mix. Note: It is best to use sweet potato powder because it has high sensitivity and the end point color is blue without reddish phenomenon. 3.5 Fluxbzxz.net
3.5.1 Flux A0.8~1.2g reduced iron powder plus 0.3~~0.5g vanadium pentoxide; 3.5.2 Flux B0.8~1.2g reduced iron powder plus 0.5~~0.8g tin particles. Note: Vanadium pentoxide needs to be burned in a high-flow furnace at 600℃ for more than 2h, and placed in a wide-mouth bottle for use after cooling; otherwise, the small amount of water in the oxide will lead to low results.
3.6 Potassium iodate standard solution
3.6.10.01000N, extract 0.3560g potassium iodate (reference reagent) and dissolve it in water, add 1mL hydroxide solution (10%), transfer to a 1000ml volumetric flask, dilute to the scale with water, and mix with a spoon. 3.6.2 0.001500N, transfer 150.00mL potassium iodate standard solution (3.6.1), place it in a 1000ml volumetric flask, add 1.5% potassium iodide to dissolve it, dilute it to the mark with water, and mix it. This solution is used to determine the sample with a sulfur content of less than 0.5%. 3.6.3 0.003000N, transfer 300.00ml potassium iodate standard solution (3.6.1), place it in a 1000ml volumetric flask, add 3g iodide to dissolve it, dilute it to the mark with water, and mix it. This solution is used to determine the sample with a sulfur content greater than 0.5%. 3.6.4 Determination of T value: Weigh three standard samples with sulfur content similar to that of the sample, and proceed as follows 5.4.1~5.4.2. The extreme difference in the number of milliliters of potassium iodate standard solution consumed in the titration of the three standard samples shall not exceed 0.20ml. Take the average value. Approved by the State Bureau of Machinery Industry on June 24, 1999, 460
Implemented on January 1, 2000
JB/T9220.11
Blank tests of porcelain boats and flux are carried out at the same time. The titer of potassium iodate standard solution on sulfur is calculated according to formula (1): S standard %Xm
(VV)x100
Wherein: T\—titer of potassium iodate standard solution on sulfur, g/mL; S standard % white sulfur content in standard sample, %; V—average volume of potassium iodate standard solution consumed during calibration, ml.; V. —volume of potassium iodate standard solution consumed in blank test, mL; m—sample weight in g.
4 Instrument
The instrument device is shown in Figure 1.
1-Oxygen cylinder; 2-Oxygen pressure reducing gauge; 3-~buffer bottle; 4-gas washing bottle; 5-drying tower; 6-...tube furnace; 7-thyristor temperature automatic controller (or voltage regulator); 8--spherical lower drying tube; 9--absorption cup; 10-burette (25mL); 11-porcelain tube; 12-porcelain boat; 13-daylight lamp (8W); 14-oxygen flow meter Figure 1
4.2 Gas washing bottle: Concentrated sulfuric acid (3.1) is filled in, and the amount filled is about one-third of the height of the bottle (1)
4.3 Drying tower: Alkaline asbestos (3.2) is filled in the upper layer, and calcium chloride (3.3) is filled in the lower layer, with glass wool in the middle, and the bottom and top are also covered with glass wool. 4.4 Tubular furnace: with thermocouple pyrometer. 4.5 Spherical drying tube: Contain dry absorbent cotton. 4.6 Absorption cup [see Figure 2a), Figure 2b)]. 4.7 Burette: 25ml.
4.8 Bottle tube: 600mm long, 23mm inner diameter (ordinary porcelain tube or high-aluminum porcelain tube). 4.9 Porcelain boat: 88mm or 97mm long.
Note: The porcelain boat is pre-burned in a high-temperature furnace at 1000℃ for more than 1h, and stored in a desiccator without grease after cooling for standby use. 4.10 Oxygen pressure reducer: QY6, P1:150, P20.02~0.25MPa. 4.11 Oxygen flowmeter: glass rotor gas flowmeter (LZB-4, 16~160L/h). 461
5 Analysis steps
5.1 Sample quantity
The 4
grit in the glass should be
full of water.
It can automatically
move downward in the liquid
and
extract the sample quantity according to Table 1.
Sulfur content
0. 020~0. 050
>0. 050~0.100
>0.100~0.200
>0.200~1. 00
5.2 Blank test
Carry out a blank test together with the sample.
5.3 Preparation
JB/T9220.111999
5.3.1 Raise the temperature of the tube furnace (4.4) to 1250℃±20℃460
per 22-23
flour frosting
0. 10000.2000
5.3.2 Preparation of starch absorption liquid: Add 40mL starch absorption liquid (3.4) into the absorption cup. Pass oxygen [adjust the oxygen pressure reducer (4.10) P2 to 0.02～0.04MPa, and the gas flow meter (4.11) to 90L/h). Titrate with potassium iodate standard solution (3.6) until light blue does not fade, which is the end point color. Turn off the oxygen.
JB/T9220.11-1999
5.3.3 Check whether the porcelain tube (4.8) and the instrument are tight and leak-proof. And proceed according to 5.4.1~5.4.2, analyze two non-standard samples, 5.4 Determination
5.4.1 Evenly distribute the sample (5.1) in the porcelain boat (4.9), add the flux (3.5), open the rubber stopper, put the porcelain boat in the porcelain tube (4.8), push it to the high temperature with a long hook, immediately plug the rubber stopper, and preheat for 1 min. 5.4.2 Pass oxygen, and the mixed gas after combustion is introduced into the absorption cup (4.6). The blue color of the starch absorption solution (3.4) begins to fade. Immediately titrate with potassium iodate standard solution (3.6) and keep the liquid surface blue. When the starch absorption solution (3.4) fades slowly, the titration speed should also be slowed down accordingly. When the color of the starch absorption solution does not change, it is the end point. Turn off the oxygen, open the rubber stopper, pull out the porcelain boat with a long hook, read the volume of potassium iodate standard solution (3.6) consumed in the titration, and drain the absorption cup (4.6).6) solution. Note
When titrating high-sulfur samples, if the titration speed cannot keep up, the result will be low. Therefore, when the combustion is intense (about 10°), the titration should be placed directly or some potassium iodate standard solution should be appropriately added at the beginning to prevent sulfur dioxide from "escaping". However, the pre-addition amount should not be too much when the room temperature is high to avoid the potassium iodate itself from volatilizing and losing and causing the result to be high.
2 Pull out the porcelain boat to observe the combustion situation. The sample should be completely melted, the slag surface should be flat and smooth, and there should be no bubbles on the fracture. Otherwise, it needs to be re-measured. 3. The porcelain boat with a lot of slag should not be used, otherwise the result will fluctuate. 6 Calculation of analysis results
Calculate the percentage of sulfur according to formula (2):
S=V=V)×100%
Where: T…the titration degree of potassium iodate standard solution on sulfur, g/mL; the volume of potassium iodate standard solution consumed in titration, m..V-the volume of potassium iodate standard solution consumed in the air test.mI.m--the amount of sample·g.
7 Tolerance
The difference in analysis results between laboratories should not be greater than the tolerance listed in Table 2. When calibrated with standard specimens, the deviation shall not exceed 1/2 of the tolerance listed in Table 2,
Sulfur content
0.020~0.050
0.050-0.100
≥ 0.100~0.200
≥0.200~0.500
>0.500～1.00
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