How lignin can be separated from black liquor?

Answer to question: How lignin can be separated from black liquor

Bountiful Applied Research has a proprietary process for this application. For explanation of process, see BARC-USA web page: http:/www.barc-usa.com.

The separation process is patented, and a follow-on process improvement is in process of being patented (patent applied).

The simple process is addition of a polymer to the alkali black liquor, which carries lignin in colloidal dispersion. After treatment with polymer, the black liquor is brought to low pH (approximately 2.5) where lignin separates with clear supernatant liquor remaining.

With use of phosphoric acid to acidify (noting the dilute phosphoric acid is regenerated), alkali chemicals can be recycled with causticizing, same as process used with conventional recovery process in the paper industry. More detailed information (power-point slide presentation and other) can be provided by contacting hcooper@barc-usa.com.

Harrison Cooper