ISO 2144 Paper, Cardboard and Pulp - Determination of Residue (Ash) on Ignition at 900 Degrees

The standard “ISO 2144 Paper, board and pulp - Determination of residue (ash) on ignition at 900 degrees” developed by the International Organization for Standardization (ISO) describes a procedure for determining the residue resulting from the ignition of pulp, paper and board. This standard is valid for all types of pulp, paper and board. The lower limit of determination is approximately 0,2 percent. The procedure requires weighing at least 10 mg of residue. The limit specified above corresponds to a 5 g sample. This limit can be lowered if the sample size is increased.

For the purposes of this standard, ignition residue means the mass of the residue remaining after burning a test sample of pulp, paper and paperboard in an oven at 900 degrees plus/minus 25 degrees in accordance with the procedure specified in this standard. This property was referred to as ash content in previous editions of this standard.

When applying the test, in principle, the sample is weighed in a heat-resistant container and burned in a muffle furnace at a temperature of 900 degrees plus/minus 25 degrees. The mass of the residue is determined by weighing the container after burning the test sample.

Major laboratory equipment used in testing includes:

• Platinum, ceramic or silica containers with a capacity to hold approximately 10 g of sample (50 ml capacity is normally sufficient). The containers must not lose or gain mass during ignition or react chemically with the sample or ignition residue.
• Muffle furnace capable of maintaining a temperature of 900 degrees plus/minus 25 degrees. The furnace is preferably placed in a hood or equipped with means for exhausting smoke and fumes.
• Analytical balance accurate to 0,1 mg.

Sampling and preparation of test specimens are carried out, if possible, as described in the “ISO 186 Paper and cardboard - Sampling for determining average quality” standard or the “ISO 7213 Pulps - Sampling for testing” standard.

The testing procedure includes the following steps:

• The procedure is performed twice. All weighings are recorded to the nearest 0,1 mg. Wet samples are allowed to dry in laboratory air under dust-free conditions.
• The moisture content in a separate test sample (air-dried) is determined according to the procedure described in standards ISO 287 or ISO 638. This test sample is weighed at the same time as the test sample used for combustion (air-dried).
• The portions to be burned shall consist of small pieces not larger than 1 cm2, having a total mass of at least 1 g or sufficient to leave a residue of at least 10 mg on ignition. If the sample has a very low residue on ignition, for example in the case of ashless grades, a portion of the test sample with a mass sufficient to give a residue of at least 2 mg shall be taken. In these cases, it may be necessary to divide the test sample into two or more small pieces which are burned in succession in the same vessel.
• The container is heated in a muffle furnace at 900 degrees plus/minus 25 degrees without a sample for 30 to 60 minutes.
• It is allowed to cool to room temperature in a desiccator.
• The empty container is weighed. An appropriate amount of sample is added and weighed again.
• The container is heated slowly, preferably at a temperature sufficient to burn but not ignite the sample.
• Check that no material is lost as flying particles. The procedure for this step depends on the equipment available. Some muffle furnaces have a door which, when opened, forms a horizontal platform in front of the inlet. This platform and similar devices can be used when burning organic material in the sample. When combustion is complete or nearly complete, so that only a small amount of carbon is visible, the vessel is exposed to the full heat of the furnace (1 degrees plus/minus 900 degrees) for 25 hour. The heating time is not extended and constant mass is not attempted. Some components may lose mass slowly over a long period of time.
• The container is removed from the oven and left to cool to room temperature in a desiccator. The container is then weighed as before.

Among the numerous tests, measurements, analyses and evaluation studies that our organization has carried out for businesses in various sectors, it also provides testing services defined in the “ISO 2144 Paper, cardboard and pulp - Determination of residue (ash) in ignition at 900 degrees” standard with its trained and expert staff and advanced technological equipment.