SH/T 0067-1991 Determination of ash content of engine coolants and rust inhibitors

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 name / English name / replacement relationship

• Method number: SH/T 0067-91
• Full name: Determination of ash content of engine coolants and rust inhibitors
• English name: not provided in the available source
• Replacement relationship: not provided in the available source (the source text marks "(200() year confirmation", suspected to be "(2000 year confirmation)", requires confirmation against the source standard (source-text extraction))
• Reference adoption: ASTM D1119-85 "Test method for ash content of engine coolants and rust inhibitors"
• Approval/implementation: approved by China Petrochemical Corporation 1991-06-28, implemented 1992-07-01

2. Scope of application and non-applicability

• Applicable to unused or used commercial engine coolants and liquid rust inhibitors.
• Can be used to identify the type of coolant and rust inhibitor.
• Cannot be used to determine the total inhibitor content.

3. Method principle

A weighed sample is evaporated or burned under specified conditions, then ignited and ashed in a strong heat source, and the solid residue is calcined to constant weight.

4. Reagents and materials (purity / preparation)

• Hydrochloric acid: chemically pure, prepared into 1:4 (by volume ratio) hydrochloric acid solution.
• Quantitative filter paper: diameter 9cm.

5. Instruments and equipment

• Crucible: high-silica glass or porcelain, with lid, 50mL.
• Crucible tongs: one large and one small.
• Clay triangle.
• Electric heating plate or electric furnace (with asbestos mesh).
• High-temperature furnace: capable of heating to a constant temperature of 750～900℃.
• Desiccator: without desiccant.
• Analytical balance: sensitivity 0.1mg.

6. Recommended operating conditions

• High-temperature furnace ignition temperature: 750～900℃.
• Crucible pretreatment calcination: 750～900℃ for at least 10min.
• Ashing and ignition: at least 1h.
• Desiccator cooling: 1h.
• Weighing precision: 0.0001g (general sample); when ash content is relatively high, sample 5～10g, weighing precision 0.01g.
• Sample weighing: 20g±0.5 (the weighing tolerance is unclear in the source transcription; verify both its value and unit against the original); for volatile samples take 20～25mL and weigh directly, weigh to 0.1g.

7. Sampling and sample preparation

• According to the requirements of SH/T 0065, take a certain amount of representative sample into a sample bottle (the amount must not exceed three-quarters of the bottle volume), shake evenly, and set aside for use.

8. Analysis steps

8.1 Crucible constant weight: Place the crucible in a beaker containing hydrochloric acid solution and boil for 5min, wash with distilled water. After drying, place in a high-temperature furnace, calcine at 750～900℃ for at least 10min, take out and place in air for 3min, transfer to a desiccator. After cooling for 1h, weigh to 0.0001g. Repeat calcination, cooling and weighing until the difference between consecutive weighings is not greater than 0.0005g. When taking the crucible, be extremely careful and use safety tools such as safety glasses, gloves and crucible tongs. 8.2 Weighing sample: In a crucible that has reached constant weight, weigh 20g±0.5g of a well-mixed sample. For volatile samples, take 20～25mL, add to a crucible that has reached constant weight and weigh directly, weigh to 0.1g, record the mass of the sample. Note: The above sampling amount is suitable for most samples. If the ash content of the sample is known to be relatively high, the sampling amount can be reduced to 5～10g; in this case the weighing precision is 0.01g. 8.3 Evaporation: Cover the crucible containing the sample with a lid (leave a gap between the lid and the crucible), place in a cold sand bath, place on an electric heating plate or an electric furnace with asbestos mesh and raise the temperature until the liquid is completely evaporated. If the sample ignites, remove the heat source until the flame goes out, then heat again. Note: Many types of coolants and rust inhibitors tend to splash when heated, causing sample loss and inaccurate results; the laboratory should take preventive measures. It is particularly important to use a well-functioning fume hood when evaporating the sample to avoid inhaling any exhaust gas. 8.4 Bumping treatment: Some coolants tend to bump when heated; in this case, use filter paper to cover for evaporation instead of evaporating with the crucible lid on. The method is as follows: Fold a piece of quantitative filter paper in half, roll into a cone shape, use scissors to cut off the top part from 5～10mm from the tip, and place into the crucible. Insert the rolled conical filter paper steadily upright into the coolant in the crucible, covering most of the sample surface. Carry out evaporation as described in clause 7.2 (i.e., 8.3 of this card). 8.5 Ashing: When the liquid has evaporated or burned completely and the crucible is dry, transfer the crucible into a high-temperature furnace (to prevent spattering loss caused by rapid burning or residual small amounts of evaporation, the temperature of the high-temperature furnace should be lower than 200℃ when transferring into the furnace), raise the temperature to 750～900℃ as quickly as possible, and ignite for at least 1h. Then take out and place in air for 3min, transfer to a desiccator to cool for 1h, weigh to 0.0001g. Then transfer into the high-temperature furnace again, repeat calcination, cooling, and weighing until the difference between consecutive weighings is not greater than 0.0005g. Calculate the mass percentage of ash.

9. Qualitative and quantitative and calculation formula

The ash content of the sample X[% (m/m)] is calculated according to the following formula:

X = (M1 / m) × 100

Where:

• M1—— mass of ash, g;
• m—— mass of sample, g.

10. Precision

Use the following provisions to judge the reliability of test results (95% confidence level).

• Repeatability (tentative): The difference between two repeated determination results shall not be greater than 9% of their arithmetic mean.
• Reproducibility: For engine coolants and certain liquid rust inhibitors, the difference between two results submitted by different laboratories shall not be greater than 20% of their arithmetic mean.

11. Report

Take the arithmetic mean of two repeated determination results as the ash of the sample. Report the result to 0.01% (m/m).

12. Referenced documents

• SH/T 0065 Sampling of test samples of engine coolants or rust inhibitors and preparation of their aqueous solutions
• ASTM D1119-85 (reference adoption)

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 Q&A