SH/T 0651-1997 Determination of Tin Content in Reforming Catalysts (Atomic Absorption Spectrometry)

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Card type: Test method

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

• Standard number: SH/T 0651-1997
• Chinese full title: Determination of Tin Content in Reforming Catalysts (Atomic Absorption Spectrometry)
• English name: Standard Test Method for Tin in Reforming Catalysts by Atomic Absorption Spectrometry
• Replacement relationship: not provided in the available source
• Other: approved by 1997-10-27, implemented by 1998-07-01; the source text marks "(201□ year confirmation)" (the year handwriting requires confirmation against the source standard (source-text extraction))
• Responsible body: Research Institute of Petroleum Processing, China Petrochemical Corporation
• Drafting unit: Fushun Petroleum Institute
• Main drafter: Jin Shan

2. Scope of application and non-applicability

• Applicable to fresh platinum-tin reforming catalysts with alumina as the carrier that do not contain other impurities.
• Tin content range: 0.170% (m/m) to 0.540% (m/m).
• Not applicable: the source text only specifies "does not contain other impurities" and "fresh" samples; other non-applicable situations are not provided in the available source.

3. Method principle

After the sample is dissolved at high temperature in a pressure dissolution bomb with hydrochloric acid, a sample solution is prepared. The tin standard solution and the sample solution are measured with an atomic absorption spectrometer, and the tin content in the sample is determined by the working curve method.

4. Reagents and materials (purity / preparation)

4.1 Reagents

• 4.1.1 Distilled water: meets the requirements for GB/T 6682 grade three distilled water.
• 4.1.2 Hydrochloric acid: analytical reagent, prepared as 5% (V/V) and 10% (V/V) hydrochloric acid solutions (the source text "0% (V/V)" requires confirmation against the source standard (source-text extraction); based on 6.1, 6.2 and 7.1, it is inferred to be 10%).
• 4.1.3 Tin granules: purity 99.99%.
• 4.1.4 Nitric acid: analytical reagent.
• 4.1.5 Aluminum chloride (AlCl₃·6H₂O): analytical reagent.

4.2 Materials

• 4.2.1 Air: compressed air that has been purified, oil-free and water-free.
• 4.2.2 Acetylene gas: purity not lower than 99.9%.

Standard solution preparation

• 6.1 1 mg/mL Tin standard stock solution: weigh 1 g±0.1 mg tin granules into a 250 mL beaker, add 7 mL nitric acid and 21 mL hydrochloric acid, cover with a watch glass, and heat slowly on an electric furnace until about 2 mL of solution remains; then add 7 mL nitric acid and 21 mL hydrochloric acid until the tin granules are completely dissolved, and evaporate to near dryness. After cooling, wash the watch glass and the beaker wall several times with 10% (V/V) hydrochloric acid solution, quantitatively transfer to a 1000 mL volumetric flask, dilute to the mark with 10% (V/V) hydrochloric acid solution, and mix well. Each milliliter contains 1 mg tin.
• 6.2 Standard solutions: into six 50 mL volumetric flasks, respectively add 0, 0.5, 1.0, 1.5, 2.0 and 2.5 mL tin standard stock solution; to simulate the aluminum content in the sample solution, add an appropriate amount of aluminum chloride (taking the weighed sample amount approximately as entirely aluminum oxide, calculate how many grams of aluminum chloride should be added, accurate to 1 mg), dilute to the mark with 10% (V/V) hydrochloric acid solution, and mix well.

5. Instruments and equipment

• 5.1 Atomic absorption spectrometer: wavelength range 190 nm to 900 nm; when the absorbance is 0.1, the repeatability is ±0.0007.
• 5.2 Tin hollow cathode lamp.
• 5.3 Analytical balance: precision 0.1 mg.
• 5.4 High-temperature furnace: 1000℃±25℃.
• 5.5 Porcelain crucible: 30 mL.
• 5.6 Oven: temperature range 0 to 300℃.
• 5.7 Pressure dissolution bomb: polytetrafluoroethylene inner cup volume 45 mL; can operate under conditions of 0 to 200℃ temperature and 0 to 1 MPa pressure.
• 5.8 Desiccator: desiccant is color-changing silica gel.
• 5.9 Weighing bottle.
• 5.10 Beaker: 250 mL.
• 5.11 Watch glass: diameter 85 mm.
• 5.12 Volumetric flask: 50 and 1000 mL.
• 5.13 Pipette: 5 mL.

6. Recommended operating conditions

Table 2 Instrument working conditions (obtained from Hitachi 180-80 atomic absorption spectrometer, for reference only):

Note: The conditions for different instrument models are not completely the same; the above conditions are for reference only.

7. Sampling and sample preparation

• 7.1 Place the sample that has been ground to powder into a weighing bottle, weigh the sample according to the amount specified in Table 1 (accurate to 0.1 mg) into the polytetrafluoroethylene inner cup of the pressure dissolution bomb, so that the tin content in the sample solution is about 30 μg/mL. Add 5 mL hydrochloric acid with a pipette, seal the pressure dissolution bomb well, place it in an oven at 160℃ to □℃ (the source text "16090-590" requires confirmation against the source standard (source-text extraction), suspected to be 160℃ to 165℃) for constant temperature 4 h, take it out and let it cool naturally, then quantitatively transfer the dissolved sample solution with 5% (V/V) hydrochloric acid solution to a 50 mL volumetric flask, make up to volume, mix well, and set aside for measurement.

Table 1 Sample weighing amount provisions:

• 7.3 Determination of ignition base:
  • 7.3.1 The tin content of the reforming catalyst is calculated on a non-volatile basis. Usually, while weighing the sample, a portion of the sample is weighed out to determine the ignition base.
  • 7.3.2 Weigh three portions of about □g (the source text "about her" requires confirmation against the source standard (source-text extraction); the mass value is not provided in the available source) sample (accurate to 0.1 mg) into three constant-weight porcelain crucibles, cover with a small gap, place in a high-temperature furnace, raise the temperature to 1000℃±25℃, keep at constant temperature for 3 h, then take out, place in a desiccator to cool for 1 h, then weigh, respectively calculate the ignition base B, and take the average of the three determination results as the ignition base B of the sample.

8. Analysis procedure

• 7.2.1 Operate the instrument according to the conditions in Table 2.
• 7.2.2 Zero the instrument with the blank solution.
• 7.2.3 From low content to high content, measure the absorbance of each tin standard solution in sequence.
• 7.2.4 Measure the absorbance of the sample solution, continuously for three times.
• 7.2.5 From high content to low content, measure the absorbance of each tin standard solution in sequence.
• 7.2.6 Repeat steps 7.2.4 to 7.2.5. For each standard solution, take the average of the absorbance obtained from three measurements; for the sample solution, take the average of the absorbance obtained from six measurements performed in two batches.
  • Note: During the interval between the measurement of the standard solutions and the sample solution, continuously aspirate the blank solution to zero the instrument so as to maintain zero stability.
• 7.2.7 Plot the tin standard solution working curve with the concentration values of each standard solution as the abscissa and the corresponding average absorbance as the ordinate.
• 7.2.8 According to the average absorbance of the sample solution, find the corresponding sample solution concentration C (μg/mL) on the tin standard solution working curve, and obtain the tin content of the sample through calculation.

9. Qualitative and quantitative determination and calculation formulas

• 8.1 Ignition base B [% (m/m)] is calculated according to formula (1):

  B = (m₂ − m₀) / m₁ × 100 …… (1)

  Where:

  • m₀ — mass of the empty crucible, g;
  • m₁ — mass of the sample before ignition, g;
  • m₂ — total mass of the sample and the empty crucible after ignition, g.

• 8.2 Tin content in the sample X [% (m/m)] is calculated according to formula (2):

  X = (C × 50) / (m₃ × B) × 10⁻⁶ × 100 …… (2)

  Where:

  • C — concentration of the sample solution, μg/mL;
  • m₃ — mass of the sample, g;
  • B — ignition base of the sample, % (m/m);
  • 50 — volume of the sample solution, mL.

  (Note: In the source formula (2), "I protection" is source-text extraction noise; according to dimensions and context, it is organized as 10⁻⁶, requires confirmation against the source standard (source-text extraction).)

10. Precision

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

• 9.1 Repeatability: the difference between two results obtained by the same operator on the same sample for repeated determination shall not be greater than 0.010% (m/m).
• 9.2 Reproducibility: the difference between two independent results obtained by different laboratories on the same sample shall not be greater than 0.019% (m/m).

11. Report

The tin content determination result of the test sample is taken to three decimal places.

12. Reference documents

• GB/T 6682 Specifications and test methods for water for analytical laboratory use

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 for questions and answers