Standard Test Method For Total Ash of Activated Carbon – ASTM D 2866-89

Standard Test Method For Total Ash of Activated Carbon – ASTM D 2866-89

1    Scope.

1.1  This test method describes a procedure for the determination of total ash content of activated carbon.  

1.2  This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine  the applicability of regulatory limitations prior to use

2. Referenced documents

2.1 ASTM Standard

D 2867 Test Method for Moisture in Activated Carbon

E 177 Practice for use of the terms of precision and Bias in ASTM Test Method

E 691 Practice for conducting an Interlaboratory Study to Determine Precision of Test Method.

3. Summary of Test Method

3.1 An accurately weighed sample of dried of activated carbon is placed in controlled-temperature muffle furnace for the period of several hours. When constant weight has been achieved, the crucible is cooled to ambient temperature in a desiccator and reweighed. The weight of the ashed carbon is expressed as a percentage of the weight of original carbon sample.

4. Significance and Use

4.1 In specific end uses, the amount and composition of the ash may influence the capabilities and certain desired properties of activated carbon.

5. Apparatus and Materials

5.1 Muffle Furnace, having air circulation, capable of temperature regulation of ± 25 ⁰C at 650 ⁰C

5.2 High-Temperature Crucible, high-form

5.3 Analytical balance, having a sensitivity of 0.1 mg

5.4 Desiccator

5.5 Oven, force-air circulation, capable of temperature regulation between 145-155 ⁰C

6. Procedure

6.1 Ignite the crucible (cốc nung) in the muffle furnace at 650 ± 25 ⁰C for 1h. Place the crucible in the desiccator. Cool to room temperature and weigh to the nearest 0.1 mg.

6.2 Dry an adequate sample of activated carbon to constant weight at 150 ± 5 ⁰C( 3 hours is usually sufficient)

 NOTE 1-Some carbon can ignite spontaneously (tự phát) at 150 ⁰C. in this case, moist carbon should be used with a correction for moisture(in accordance with Method D 2687) applied in the calculation. In this case, the ashing should be started in a cold muffle furnace.

6.3 Weigh out to the nearest 0.1mg sufficient dried activated carbon, so that the estimated amount of the ash will be 0.1 g to the ignited crucibles and place the crucible in the furnace at 650 ± 25 ⁰C. Ash will require from 3 to 16 hours, depending on the size and the type of activated carbon. Ashing can be considered complete when constant weigh is achieve.

6.4 Place the crucible in the desiccator and allow to cool to room temperature. After the sample has cooled in the desiccator, admit air slowly to avoid loss ash from the crucible. Weigh to the nearest 0.1 mg.

7. Calculation

7.1 Calculate the ash content as follows:

Total Ash, % = [(D-B)/ C-B)] x 100      (1)

Where:

B = weight of crucible, g

C = weight of crucible plus original sample, g, and

D  = weight of crucible plus ashed sample, g

8. Precision and Bias

8.1 Precision

8.1.1 Interlaboratory Test Program-An interlaboratory study was run in which representative sample of three types of activated carbon (coconut-shell base (A), coal-based (B), and wood-based (C) were tested for ash content by six laboratories with each laboratory making three observation of each activated carbon type over three days. Practice E 691 was followed for the design and analysis of the data.

8.1.2 Test Result-The precision information given in Table 1 in units of measurement (percent minus weigh ash content) is for the comparison of two test results, each of which is the average of three test determination.