The main method for determining particle size is based on national standards (GB/T) and international standards (such as ASTM, ISO). The methods for determining granular carbon and powder carbon are completely different.The activated carbon products must undergo strict testing before they can be put into use and production.
Method 1: Suitable for the determination of granular activated carbon - Mechanical vibration sieving method
This is the most classic and authoritative method for determining the particle size distribution of granular carbon.
Core principle: Take a certain mass of activated carbon sample, pass it through a series of standard sieves with increasing pore sizes from top to bottom, and vibrate it on a vibrating screen for a certain period of time. Then, weigh the carbon remaining on each layer of the sieve and calculate the mass fraction.
Equipment and materials:
1. Standard vibrating screen: Ensure the standardization of the sieving action.
2. A set of standard test sieves:with specific sieve hole sizes. For example, to determine 8×30 mesh carbon, 8 mesh, 12 mesh, 16 mesh, 30 mesh, and the base plate will be used.
3. Precision balance.
4. Stopwatch.
Key steps:
1. Sampling: Take a representative sample, dry it to constant weight at 105±5°C, and cool it.
2. Sieving: Place the standard sieves with increasing pore sizes from top to bottom on the vibrating screen, add the dried sample. Cover with a top cover and fix it on the vibrating screen. Vibrate for 15-20 minutes.
3. Weighing: Remove each sieve layer one by one, weigh the carbon on each layer of the sieve and the base plate separately.
4. Calculation: Calculate the total mass. Calculate the particle size distribution: the mass of carbon on a certain sieve layer as a percentage of the total mass.
Report the cumulative percentage of the main particle size range (8×30 mesh). For example, "8×30 mesh accounts for ≥ 90%".
Advantages: Intuitive, simple equipment, good reproducibility, and it is the benchmark method for trade and acceptance.
Notes: The sample quantity, vibration time, and mechanical parameters of the vibrating screen must be strictly consistent; otherwise, the results will fluctuate. Activated carbon products must be measured strictly according to these steps.
Method 2: Suitable for the determination of powder activated carbon - Laser diffraction method
Powder carbon particles are extremely fine and cannot be effectively measured by the sieving method. The laser diffraction method is the mainstream method.
Notes: The dispersion effect is the key to measurement accuracy. Powders are hydrophobic and prone to agglomeration, so it is necessary to select an appropriate dispersion medium and dispersing agent (such as adding surface active agents dropwise), and optimize the ultrasonic energy and time.
There are many other indicators that the activated carbon products meet. If you have any questions, please feel free to contact us for further assistance.