Recovery Cycle

Our services range from audits and capacity assessments, feasibility studies, capital cost estimates, and design development and specifications, to detailed design for both new installations and upgrades of existing equipment.

Sandwell brings great depth of experience to all aspects of the kraft recovery cycle. Representative assignments include:

  • troubleshooting problems with deposits in a direct contact black liquor evaporator;
  • upgrading a recausticizing system to add pressure filters for white liquor and weak wash, a new precoat filter for the lime mud going to the kiln, and a cooler for lime from the kiln;
  • engineering for the installation of a new green liquor clarifier in an existing recausticizing system, and modifying the other clarifiers.

Several innovations contribute to the quality and cost-effectiveness of our work in this field, including a patented recausticizing process, and proprietory software to evaluate the accumulation or purging of unwanted material like potassium and chlorine in the liquor cycle.

Ahlstrom Recovery Inc., Alpharetta, Georgia

boiler installation

Black liquor recovery boiler installation


Sandwell provided structural and architectural detailed design for this 4.5 million lb/day boiler installation. Our prior involvement with Ahlstrom on a similar project enabled us to shorten our schedule by two months, assisting them to meet an 18-month schedule from the contract's award to first firing of black liquor. The project set a record for Ahlstrom in installations of this kind.