Black Liquor Soap

A natural intermediate byproduct of kraft pulping, black liquor soap is the rosin and fatty acid content that floats to the top as black liquor is left to settle. It is skimmed off and can be used as a raw material for tall oil production. Black liquor soap can be somewhat abrasive and range in viscosity from 22 to 5500 cP, depending on the temperature it is handled at.