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D2862-16 – Standard Test Method Technical Guide
📐 Overview and Scope
The ASTM D2862-16 (Reapproved 2022) standard provides a definitive test method for determining the particle size distribution of granular activated carbon. This standard is essential for ensuring material consistency and performance in various industrial applications.
Per the scope of the standard, granular activated carbon is specifically defined as a material where a minimum of 90 % of the sample weight is retained on a 180 µm (U.S. Mesh 80) standard sieve. The standard also cautions that for extruded carbons with a high length-to-diameter (L/D) ratio, the validity of the test method might be affected.
⚠️ Important Units Note: While the standard states that values in inch-pound units are regarded as standard, all mass measurements are conducted exclusively in SI units (grams). Sieve diameters are typically 8 in. (203 mm).
The procedure yields data that can be utilized to calculate the weight percent retained on each sieve, the mean particle diameter (MPD), the effective size, and the uniformity coefficient.
| 📊 Parameter | 📐 Specification / Requirement |
|---|---|
| Granular Definition | ≥ 90 % retained on 180 µm (U.S. Mesh 80) |
| Standard Sieve Size | 8 in. (203 mm or equivalent) per ASTM E11 |
| Mass Measurement | Exclusively SI units (grams) |
| Applicability Caution | Extruded carbons (high L/D ratio may affect results) |
⚙️ Test Procedure and Apparatus
The apparatus required is a mechanical sieve shaker that imparts a uniform rotating and tapping motion to the stack of sieves. The shaker must be adjusted to accommodate the required number of 8-inch (203 mm) sieves, a bottom receiver pan, and a sieve cover.
The test procedure involves placing a known weight of granular activated carbon on the top sieve of a stacked set of U.S. Standard sieves. The stack is then shaken under standard conditions for a specific time period. Following the shaking, the weight percent of the total sample retained on each sieve and the bottom pan is determined.
💡 Pro Tip: Carefully following the apparatus setup guidelines ensures that the rotating and tapping motion is consistent, directly impacting the reproducibility of the test results between different laboratories.
Referenced documents critical to this procedure include ASTM D2854 (Apparent Density of Activated Carbon), ASTM E11 (Specification for Woven Wire Test Sieves), and ASTM E300 (Practice for Sampling Industrial Chemicals).
📊 Key Measured Properties and Significance
Knowing the distribution of particle sizes is crucial for ensuring proper contact of gases or liquids with the carbon in a packed bed. Changes in this distribution can significantly affect the pressure drop across the bed and the overall rate of adsorption.
| 🎯 Property | ⚡ Application / Influence |
|---|---|
| Particle Size Distribution | Gas/liquid contact in packed bed, pressure drop, adsorption rate |
| Mean Particle Diameter (MPD) | Direct influence on pressure drop across the bed |
| Effective Size | Critical for municipal water treatment applications |
| Uniformity Coefficient | Critical for municipal water treatment applications |
The data obtained from this test method provides the foundation for calculating Mean Particle Diameter (MPD), which directly influences pressure drop. Additionally, the effective size and uniformity coefficient derived from the cumulative distribution curve are of particular interest in municipal water treatment facilities seeking to control particle size for optimal filtration.
✅ Precision and Bias: For information regarding the precision of this test method, users should refer to an interlaboratory study conducted in accordance with ASTM E691 (Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method).
❓ Frequently Asked Questions
🔍 What defines “granular” activated carbon under this standard?
Granular activated carbon is defined as a material where a minimum of 90% of the sample weight is