Recaust Liquor Testing

The kraft chemical pulping process produces strong pulp because of the special characteristics of the cooking liquor. The presence of sodium sulfide (Na2S) in combination with the sodium hydroxide (NaOH) in the cooking liquor, protects the pulp fibers from degradation during the cooking process. The control of the chemical composition of the cooking liquor is critical for production of strong pulp fibers. The liquor testing in the recausticizing process provides critical information for that control. This module provides information about the liquor testing in the recausticizing process, what those test results mean, and why it is important to the processes involved.

•Identify and describe green and white liquors •Describe where the green and white liquors are produced and used •Describe the chemicals measured by the ABC test •Define TTA, AA, EA, sulfidity, and specific gravity •Explain how the chemical characteristics of the green and white liquors are controlled •Identify typical sampling points for green and white liquors •Identify hazards and safety considerations when working with green and white liquors