The specifications for limestone powder used in a paper mill can vary depending on the requirements of the paper being produced, but generally include the following attributes:
Purity: Typically, high-calcium limestone with a purity of 95% calcium carbonate (CaCO3) or higher is preferred.
Particle size: The particle size can vary, but fine grades, often below 2 microns, are commonly used for smoothness and opacity in paper production. Granule sizes may range from 0.1 to 10 microns.
Whiteness: High whiteness, usually above 90% ISO, to ensure the paper has the desired level of brightness.
Moisture content: Ideally, the moisture content should be low, generally less than 0.5%, to prevent any adverse effects during processing.
pH level: The powder should have a neutral to slightly alkaline pH, typically around 8 to 9, to help with paper strength and brightness.
Specific gravity: This often ranges between 2.7 and 2.9 g/cm³.
Consistency: Limestone powder should be consistently milled and free from impurities like silica, iron, and other minerals which can affect the paper quality.
Always ensure that the limestone powder being used meets the specific standards and requirements of your paper mill.
