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D5709-22 – Standard Test Method Technical Guide
📐 Scope and Material Requirements
ASTM D5709-22 specifies a standardized dry sieving procedure for determining the particle size distribution of petroleum coke. The test method covers green petroleum coke with a topsize of no more than 75 mm and size fractions down to 4.75 mm. For calcined petroleum coke, it covers materials with a topsize of no more than 25 mm and size fractions down to 75 µm. These limits ensure the method aligns with industry standard sieve sets and sample preparation capabilities.
All sieves used in this test must conform to the requirements of ASTM E11 (Specification for Woven Wire Test Sieve Cloth and Test Sieves). The standard dictates that SI units are regarded as the standard unit of measurement, and sieve sizes are reported according to the U.S.A. standard test series.
| 📏 Parameter | 🟦 Green Petroleum Coke | 🎯 Calcined Petroleum Coke |
|---|---|---|
| Maximum Topsize | 75 mm (approx. 3 in.) | 25 mm (approx. 1 in.) |
| Minimum Sieve Fraction | 4.75 mm (No. 4) | 75 µm (No. 200) |
| Referenced Sampling Practice | D8145 | D6970 |
| Referenced Preparation Practice | D2013 | D6969 |
⚠️ Critical Note: The standard explicitly states the values stated in SI units are to be regarded as standard. When converting sieve sizes, 75 mm is approximately equivalent to a nominal sieve opening of 3 in., and 25 mm is equivalent to 1 in. Likewise, 4.75 mm converts to approximately 0.187 in., and 75 µm converts to approximately 0.0029 in. per Specification E11.
⚙️ Sample Preparation and Test Procedure
The primary objective of the test method is to divide a representative coke sample into designated size fractions by the use of a series of square-holed sieves. Proper sampling and preparation are prerequisites to a valid test. The sampling process must adhere to Practice D8145 for green petroleum coke and Practice D6970 for calcined petroleum coke. Sample preparation must follow Practice D2013 for green coke and Practice D6969 for calcined coke.
The test apparatus consists of sieves nested in order of decreasing opening size. The representative sample is placed on the top sieve and agitated mechanically or manually until the mass retained on each sieve reaches a constant value. The mass retained on each sieve and the bottom pan is recorded to determine the cumulative percentage retained. A minimum initial sample mass based on the lot topsize is required to ensure statistical representation of the particle size distribution.
✅ Good Practice: The standard calls for sieving to continue until no more than a trace amount (typically 0.1% of the total sample mass) passes through a given sieve during one minute of continuous hand sieving.
📊 Key Terminology and Measured Properties
The standard provides precise terminology to ensure consistency. The most critical parameter defined is the Topsize. This is formally defined as “the size of the smallest opening of one sieve of a series upon which is cumulatively retained a total of less than 5 % of the sample.” This defined topsize is distinct from the size of the largest particle in a lot. The final result of the test is a complete particle size distribution report, detailing the cumulative weight percentages for each size fraction.
| 📌 Term | 🎯 Official Definition (Section 3, D5709-22) |
|---|---|
| Topsize | Smallest sieve opening retaining less than 5% of the sample cumulatively. |
| Bulk Sample | The reduced and divided representative portion of the gross sample as prepared for the laboratory. |
| Gross Sample | The original, uncrushed, representative portion taken from a shipment or lot of coke. |
Representative Sample
📥 Standard Documents Download |