Mineral Residue
Inorganic matter determination involves heating a sample of paper or pulp to 525 degrees Celsius to remove all organic components. The procedure defined in iso 1762 ash content allows producers to quantify the amount of fillers and coatings present in the material. This measurement is expressed as a percentage of the original oven-dry weight of the specimen.
Laboratory Procedure
A crucible containing the sample is placed in a muffle furnace until all carbonaceous material has oxidized and disappeared. Careful weighing before and after the combustion process is required to ensure the precision of the iso 1762 ash content value. If the temperature is too high, certain minerals like calcium carbonate may decompose, which leads to an inaccurate result.
The cooling process must occur in a desiccator to prevent the ash from absorbing moisture from the air.
Paper Property
High levels of mineral filler improve the opacity and smoothness of the sheet but can reduce its overall tensile strength. Monitoring the iso 1762 ash content helps mills verify that the correct amount of clay or calcium carbonate has been added to the furnish. It also serves as a check for the efficiency of the de-inking process in recycled fibre mills.
Excessive ash can cause dusting issues during printing or accelerate the wear of cutting knives. Accurate mineral tracking is necessary for consistent sheet quality.
