SH/T 0267-1992 Test method for acidification of sodium hydroxide extract from lubricating oil

AI-translated method card — human verification pending. This is not an official translation of the standard. Unclear source values remain unverified; check the original standard and product certificate before use.

Card type: Test method

1. Method number / full title / English name / replacement relationship

• Standard number: SH/T 0267—92 (confirmed in 2004)
• Chinese title: Test method for acidification of sodium hydroxide extract from lubricating oil
• English title: not provided in the available source
• Replacement relationship: replaces SY 2651—77 (88)
• Approval/implementation: approved by China Petrochemical Corporation 1992-05-20, implemented on 1992-05-20
• First issued: 1953 year

2. Scope of application and non-applicability

• Scope of application: This standard applies to lubricating oil.
• Purpose: specifies a test method for checking the degree of cleanliness of impurities in lubricating oil.
• Non-applicability: not provided in the available source.

3. Method principle

The impurities in the sample become an extract present in the alkaline solution; when the extract is acidified with hydrochloric acid, the impurities precipitate as a turbid substance.

4. Reagents and materials (purity / preparation)

• 4.1 Sodium hydroxide: chemically pure, prepared as a 6 g/L solution. During preparation, dissolve 6 g sodium hydroxide in 1 L distilled water; when acid is added to this solution until it shows an acidic reaction, the solution must not become turbid.
  • Note: The sodium hydroxide solution must be very clear. If the sodium hydroxide solution needs to be filtered through filter paper, the first 100~150 mL of filtrate must be discarded.
• 4.2 Hydrochloric acid: chemically pure, density 1.18 g/mL.

5. Apparatus and equipment

• 3.1 Glass test tube: diameter 30 mm ± 2 mm, height 250–300 mm; and diameter 15 mm ± 1 mm, height 140–150 mm.
• 3.2 Pipette: 15~25 mL.
• 3.3 Dropper.
• 3.4 Water bath.
• 3.5 Mercury thermometer: 0–100 ℃ (original text is “0–100 seven”, requires confirmation against the source standard (source-text extraction)).

6. Recommended operating conditions

• Boiling time: 3 min, with vigorous shaking at the same time.
• Water bath temperature: 80 ℃.
• Standing requirement: until the liquid layers in the tube are completely separated and the oil layer is transparent.
• Acidification observation time: within the first 1 min after acidification.
• Observation method: in reflected light, with the line of sight perpendicular to the axis of the tube, observe through the liquid layer the Chinese phonetic alphabet letters closely attached to the rear wall of the test tube.
• Judgment letters: 6 number and 5 number Chinese phonetic alphabet letters.

7. Sampling and sample preparation

• Into a test tube with diameter 30 mm, inject the sample and an equal volume of sodium hydroxide solution (total injected height about 60 mm).
• Other sampling and sample preparation requirements: not provided in the available source.

8. Analysis procedure

1. Into a test tube with diameter 30 mm, inject the sample and an equal volume of sodium hydroxide solution (total injected height about 60 mm).
2. Boil the mixed liquid for 3 min, while shaking vigorously.
3. Immerse the test tube in a 80 ℃ water bath and let it stand until the liquid layers in the tube are completely separated and the oil layer is transparent.
4. After standing, carefully draw out the alkaline liquid with a pipette and transfer it into a test tube with diameter 15 mm ± 1 mm until the liquid layer height in that test tube reaches 40 mm.
   • Note: When transferring the alkaline extract, it must be prevented that the sample falls into the test tube with diameter 15 mm ± 1 mm.
5. Add 3~5 drops of hydrochloric acid to the alkaline extract, until an acidic reaction is shown.
6. Carry out grade judgment according to Section 9.

9. Qualitative and quantitative determination and calculation formula

• If the acidified extract remains completely transparent when observed against light within the first 1 min (when observed in reflected light, a slight milky white appearance in the tube is allowed), the sample is classified as grade 1.
• In reflected light, with the line of sight perpendicular to the axis of the tube, and within the first 1 min after acidification, observe through the liquid layer the two kinds of Chinese phonetic alphabet letters closely attached to the rear wall of the test tube. If the 6 number Chinese phonetic alphabet letters can be read, the sample is classified as grade 2.
• If only the 5 number Chinese phonetic alphabet letters can be read, the sample is classified as grade 3.
• If the acidified extract is already so turbid that the 5 number Chinese phonetic alphabet letters cannot be read, the sample is classified as grade 4.
• Calculation formula: not provided in the available source.

10. Precision

not provided in the available source.

11. Report

not provided in the available source.

12. Referenced documents

not provided in the available source.

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick reference Q&A