At the end of this module, you will be able to:
- 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
The following key questions are answered in this module:
What is recausticizing?
Recausticizing is the process of converting the chemicals in spent cooking liquor back to their original form so that they can be re-used in the kraft pulping process.
What is the ABC test?
The ABC test is titration with three endpoints which give the concentrations of sodium hydroxide, sodium sulfide and sodium carbonate.
What are some measures of alkality that can come from the ABC test?
There are several measures of alkalinity; they include Total Titratable Alkali (TTA), Active Alkali (AA), Effective Alkali (EA), and Activity.
What is sulfidity?
Sulfidity is a measure of the ratio of sodium sulfide to the other sodium species in the green or white liquor.
What are the primary chemicals found in white liquor?
The primary chemicals in cooking liquor, or white liquor, are sodium hydroxide and sodium sulfide.
Below is a transcript of the video sample provided for this module:
The primary test used to measure the chemicals in both green and white liquor is a titration test called the ABC test. A B C are the names given to the three end points in the titrations. The test is conducted in a laboratory under controlled conditions, and provides information about the concentration of cooking chemicals in the green and white liquors. Another test that is conducted is the density measurement of the liquors. This is sometimes reported as specific gravity, the ratio of liquor density to water density. These tests monitor the recausticizing reaction or the conversion of green liquor to white liquor. The concentration of cooking chemicals in white liquor is used to determine the flow of white liquor sent to or charged to the digesters.
Use the additional resources and links below to learn more about this topic: