This standard specifies the technical requirements and relevant inspection methods and rules for annealing, quenching and tempering of 55SiMoVA and 55SiMoA steel rolling bearing parts. JB/T 6366-1992 Technical conditions for heat treatment of 55SiMoVA steel rolling bearing parts JB/T6366-1992 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Surface active agents
Determination of mineral sulfate content-Titrimetric methodbZxz.net
Surface active agents-Determination of mineral sulfate content-Titrimetric methodGB/T6366-92
Replaces GB6366-86
This standard refers to and adopts the international standard ISO68441983 "Determination of inorganic sulfate content of surfactants-Titration method". 1 Subject content and scope of application
This standard specifies the method for determining the content of inorganic sulfate in surfactants. This standard is applicable to anionic surfactants containing sodium sulfate, ammonium sulfate, alkanolamine and sulfate. This standard is not applicable to products containing other compounds that will generate slightly soluble lead salts under the test conditions, such as phosphates or large amounts of chlorides, nor is it applicable to products containing large amounts of weak acid salts (for example: soap or succinic acid monoester sulfonate) that will prevent accurate pH adjustment. 2 Reference standards
GB601 Preparation of standard solutions for chemical reagent titration analysis (volume analysis). 3 Principle of the method
This titration method uses dithiothionate as an indicator and uses lead nitrate standard solution to titrate the buffered acetone solution of the sample. 4 Reagents and materials
4.1 Laboratory distilled water (GB6682): Grade 3 water; 4.2 Acetone (GB686): Chemically pure;
4.3 Nitric acid (GB626): 63g/L;
4.4 Sodium hydroxide (GB629) solution: 40g/L; 4.5 1,5-diphenylthiothionate (dithiothionate) (CHg·NH·NHCSH: NCgH) solution: 0.5g/L acetone solution. After preparation, the dithiothionate solution should be stored in a brown bottle and should be re-prepared after 3 to 5 days. 4.6 Ammonium difluoroacetate buffer solution: Add 67mL dichloroacetic acid to about 250mL water, use a pH meter or precision test paper, and carefully neutralize (about 80mL) with 18% (m/m) ammonia solution (GB631) to pH7. After cooling, add 33mL dichloroacetic acid and dilute with water to 600mL, at which time the solution pH is 1.5-1.6. The pH of the solution in 70%-85% (V/V) acetone medium should be 4.1±0.2. 4.7 Lead nitrate (HG31070) c(Pb(NO))=0.0100mol/L. Prepare and calibrate according to Article 4.18 of GB601. 5 Instruments and equipment
5.1 Beaker: 50mL;
5.2 Volumetric flask: 50, 100mL;
5.3 Conical flask: 250mL;
Approved by the State Administration of Technical Supervision on December 10, 1992 and implemented on October 1, 1993
5.4 Single-scale pipette: 5, 10, 15, 20mL; 5.5 Scale pipette 1, 2mL,
5.6 Brown acid burette: 10, 25mL; 5.7 Volumetric tube: 25, 100mL.
Analysis steps
6366-92
For colorless and light-colored surfactants, weigh the sample amount specified in Table 1 (accurate to 0.001g) into a beaker according to the expected sodium sulfate content.
Expected sodium sulfate content in the sample, %
Sample mass, g
Note: 1) If the sodium sulfate content of the sample is greater than 6%, the sample mass should contain 0.1-0.3g sodium sulfate. Dissolve the sample with about 50mL warm water (not exceeding 50℃), transfer it to a 100mL volumetric flask, dilute it with water to the scale, shake it well, and set it aside. According to the expected sodium sulfate content listed in Table 2, use a pipette (5.4) to transfer the corresponding volume. Table 2
Expected sodium sulfate content, %
Taken volume, mL
For darker surfactants, according to the expected sodium sulfate content, weigh the sample specified in Table 3 (accurate to 0.001g), dilute it to 500mL according to the above dissolution method, shake it well, and then use a pipette (5.4) to transfer the corresponding volume. Table 3
Expected sodium sulfate content\, %
Sample mass + g
Note: 1) If the sodium sulfate content of the sample is greater than 10%, the sample mass weighed should contain 0.2~0.3g sodium sulfate. Absorbed volume, ml.
Place the sample solution absorbed according to Table 2 (or Table 3) into a conical flask and add water to 20mL. Add 1mL of dithiol (4.5) solution. If the solution is green, add sodium hydroxide solution (4.4) dropwise until red appears, then add nitric acid solution (4.3) dropwise until green appears, then add 2mL of ammonium dichloroacetate buffer solution (4.6) and 80mL of acetone (4.2). Immediately after adding acetone, titrate with lead nitrate standard solution (4.7) until the green color of the solution disappears and turns into dark red that can be stable for 15s, which is the end point. Expression of analysis results
For colorless and lighter colored surfactants, the mass percentage X of inorganic sulfate expressed as sodium sulfate is calculated according to formula (1): GB/T6366-92
X, = V·c × 0.142 × 10
m. .V.
For darker colored surfactants, the mass percentage X of inorganic sulfate expressed as sodium sulfate is calculated according to formula (2): X: = V c × 0.142 × 5 × 10mo·V.
Where: m. —-mass of the sample, g;
V.一The volume taken during the determination, mL;
V—--The volume of lead nitrate solution consumed in the titration, mL; -The actual concentration of the lead nitrate standard solution, mol/L0.142-
. (1)
-The mass of sodium sulfate in grams equivalent to 1.00mL of lead nitrate standard solution (c(Pb(NO.)2)=1.000mol/L).
Additional remarks:
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of Shanghai Dyestuff Research Institute. This standard was drafted by Shanghai Dyestuff Research Institute. The main drafters of this standard are Ji Jufen, Xiao Yi and Zhuang Yongbin.
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