SH/T 0270-1992 Determination of calcium content in additives and additive-containing lubricating oils

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 0270-92
• Chinese title: Determination of calcium content in additives and additive-containing lubricating oils
• English title: not provided in the available source
• Replacement relationship: replaces SY 2659-65 (82)
• Approval/implementation: approved by China Petrochemical Corporation 1992-05-20, implemented on 1992-05-20

2. Scope of application and non-applicability

• Scope of application: This standard specifies a method for determining the calcium content in additives and additive-containing lubricating oils; it is applicable to additives and additive-containing lubricating oils.
• Not applicable: not provided in the available source.

3. Method principle

The sample is ashed and dissolved with hydrochloric acid. Calcium is caused to form sparingly soluble calcium oxalate, which is precipitated from the solution and filtered. The precipitate is dissolved with sulfuric acid and titrated with a standard potassium permanganate volumetric solution.

4. Reagents and materials (purity / preparation)

• 5.1 Hydrochloric acid: analytical reagent, prepared as a solution with a hydrochloric acid to water volume ratio of 1:1.
• 5.2 Ammonium chloride: analytical reagent.
• 5.3 Ammonia water: analytical reagent.
• 5.4 Citric acid: analytical reagent, prepared as a 70 g/L citric acid solution.
• 5.5 Ammonium oxalate: analytical reagent, prepared as a 40 g/L ammonium oxalate solution.
• 5.6 Silver nitrate: analytical reagent, prepared as a 30 g/L silver nitrate solution.
• 5.7 Sulfuric acid: analytical reagent, prepared as a solution with a sulfuric acid to water volume ratio of 1:2.
• 5.8 Potassium permanganate: analytical reagent, prepared as a c(1/5 KMnO₄)=0.1 mol/L standard volumetric solution, standardized with sodium oxalate. (The concentration symbol source-text extraction at this point in the source text is doubtful; requires confirmation against the source standard (source-text extraction))
• 4.2 Materials: quantitative filter paper 90~110 mm, medium speed.

5. Instruments and equipment

• 4.1.1 Porcelain crucible: 25, 100 mL.
• 4.1.2 High-temperature furnace.
• 4.1.3 Beaker: 250 mL.
• 4.1.4 Burette: 25 or 50 mL, graduation force 0.1 mL. ("graduation force" is suspected to be "graduation value"; requires confirmation against the source standard (source-text extraction))
• 4.1.5 Wash bottle: 500 mL.
• 4.1.6 Watch glass.
• 4.1.7 Funnel: diameter 60~70 mm.

6. Recommended operating conditions

• Ashing: carry out according to GB/T 508.
• Hydrochloric acid dissolution and heating: boil for 5~10 min.
• Precipitate aging: keep in a water bath at 60–70 ℃ for 3–4 h, or let stand at room temperature for more than 12 h.
• Titration temperature: heat to 90 ℃.
• Titration endpoint retention: the rose-red color remains for 30 s without disappearing.

7. Sampling and sample preparation

• 6.1 Weigh the sample in a porcelain crucible: 40~50 g, weighed to the nearest 0.01 g; for additives, weigh 1 g, weighed to the nearest 0.001 g. Then ash according to GB/T 508.

8. Analytical procedure

• 6.2 Add 20 mL 1:1 hydrochloric acid solution to the crucible containing the ash, cover with a watch glass, and heat to boiling for 5~10 min.
• 6.3 Cool the solution, carefully transfer it to a 250 mL beaker, and wash the residue in the crucible into the beaker with distilled water so that the total volume of the solution is about 100 mL.
• 6.4 Add 10 g ammonium chloride. Heat the solution to boiling and add ammonia water until precipitation is complete (if no phosphorus is present, no precipitate will form, and the test may be continued according to clause 6.5 of this standard).
• 6.5 Add citric acid solution dropwise until the precipitate has just dissolved, then add 15 mL citric acid solution (if there is no precipitate, directly add 15 mL citric acid solution).
• 6.6 Heat the solution to boiling, add 30 mL hot ammonium oxalate solution, and continue boiling for 5 min. Then place on a 60–70 ℃ water bath and keep for 3–4 h, or let stand at room temperature for more than 12 h.
• 6.7 Filter the calcium oxalate precipitate with quantitative filter paper, and wash the beaker and filter paper with 30~50 mL ammonium oxalate solution. Then wash with a small amount of distilled water until no chloride ions are present.
• 6.8 Wash the filter paper together with the calcium oxalate precipitate in it into a beaker with distilled water. Pour 100 mL distilled water and 20 mL 1:2 sulfuric acid solution into the beaker. Carefully break up the filter paper with a glass rod.
• 6.9 Heat the solution in the beaker to 90 ℃, and while shaking vigorously, titrate with c(1/5 KMnO₄)=0.1 mol/L potassium permanganate standard volumetric solution until a rose-red color appears and remains for 30 s without disappearing.

9. Qualitative and quantitative determination and calculation formula

The calcium content in the sample X〔% (m/m)〕is calculated according to the following formula:

X = (V₁ - V₂) × 0.020045 × 100 × c / m

Where:

• V₁ — the volume of potassium permanganate standard volumetric solution consumed in titrating the sample, mL;
• V₂ — the volume of potassium permanganate standard volumetric solution consumed in the blank test, mL;
• the mass of calcium, expressed in grams, equivalent to 0.020045—— and 1.00 mL potassium permanganate standard volumetric solution [c(KMnO₄)=1.000 mol/L];
• the actual concentration of the c—— potassium permanganate standard volumetric solution, mol/L;
• the mass of the m—— sample, g.

(The original formula source-text extraction contains noise, such as "Y-V:00.020045 ×100 XC"; the above formula has been arranged according to the context and requires confirmation against the source standard (source-text extraction))

10. Precision

• 8.1 Repeatability
• 8.1.1 For repeated determination of calcium content in additives, the difference between two results shall not exceed 0.5% (m/m) of their arithmetic mean.
• 8.1.2 For repeated determination of calcium content in lubricating oils, the difference between two results shall not exceed 5% (m/m) of their arithmetic mean.

11. Report

Take the arithmetic mean of two repeated determination results as the calcium content of the sample.

12. Referenced documents

• GB/T 508 Determination of ash in petroleum products

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