Pulp & Paper

'Pulp and Paper' is the generic name for the industry in which wood is processed into paper, pulp, paperboard, and other cellulose-based products. Lime is one of the most essential products used in this application. It is applied in the cellulose extraction process, in bleaching (formation of Calcium Hypochlorite) and in water treatment processes. This reagent is the key in the most commonly used "Kraft process", where lime is used in a closed loop for the causticization process.


The causticization process is a transformation from the sodium carbonate 'by-product' formed to caustic soda. The recovered sodium hydroxide is re-used in the process. The recalcification (conversion of limestone to lime) of the calcium carbonate produced achieves a lime yield of 90 to 97%.  To compensate for the losses, a replenishment of high purity quicklime (from an external source) is required.