Chilean forestry company Celulosa Arauco has selected Veolia Water Technologies’ HPD® CRP/ECRP™ technology for its Valdivia mill. The Enhanced Chloride Removal Process (ECRP) is a new patented technology developed to allow mills with a high potassium input to achieve high removal rates of chloride and potassium while minimizing sodium losses.

Arauco’s dissolving pulp project for its Valdivia pulp mill is a $185 million dollar investment to produce a range of products such as textile fiber, cellophane paper and filters. The project will involve treatment of a portion of the precipitator ash from the recovery boiler to remove chloride and potassium without significant loss of sodium or sulfate from the system. In this manner, chloride and potassium levels in the recovery cycle can be controlled to minimize fouling of the recovery boiler and the associated operating costs.

The ECRP is a two-stage crystallizer system. The first stage consists of a conventional CRP system operating close to atmospheric pressure. Sodium salts are crystallized in the first stage and returned to the recovery cycle. The second stage crystallizer operates at lower temperature to take advantage of the reduced solubility of the remaining salt where potassium is aggregated. Crystallized solids from the second stage are dewatered in a centrifuge for subsequent disposal or otherwise further processed for production of SOP fertilizer.