4 Different Types Of Solvent Extraction

4 Different Types Of Solvent Extraction

Crude Tall Oil

During the papermaking process the chemicals natural to the pine tree are recovered as coproducts of the pulping process in the form of Crude Tall Oil (CTO) and Crude Sulphate Turpentine (CST).

Rosin is a derivative from Crude Tall Oil, which is formed by acidifying black liquor soap skimmings with sulfuric acid

The Crude Tall Oil has traces of sulphurs which form in that process, they remain in the rosin and can cause crystallisation which makes the rosin difficult to re-melt which limits it’s use in downstream application.

End products:

  • Crude Sulphate Turpentine
  • Crude Tall Oil

Tapping:

Pine trees are tapped in the forest to recover “oleoresin” which is separated into Gum Rosin (GR) and Gum Turpentine (GT).

Oleoresin is extracted from pine trees by using sulphuric acids and growth hormones to keep the tree bleeding these are harmful to the environmental and can leave toxic residues in the end product.

A section of the bark is removed to form a “face” and then cutting into the first several layers of the skin of the tree, generally to the Xylem layer.

There are several different methods of working the face but all are labor intensive. The tree can be “worked” daily, every two to three weeks, or even less often based on the type of process used to keep the oleoresin flowing and collected.

Pine trees are tapped for their useful life and then cut to recover lumber or chips for pulping. The unused portion of the tree is used for fuel. The forest is then replanted for future harvesting.

End products:

  • Gum Turpentine
  • Gum Rosin

Solvent extraction technology

Aged pine tree stumps are pulverized and solvent extracted using hexane or other solvents to produce wood rosin and terpenes.

Hexane is a petrochemical, which has a negative impact on the environment and can leave foreign residues in the end product.

Organic Solvent extraction technology

Leaf Resources process replaces petrochemical synthetic solvents with a natural organic solvent, which does not does not leave any unnatural residues in the final product creating a unique, non crystallising, completely environmentally friendly process that makes our products suitable for all downstream processing, including food grade products.

Furthermore, once the pine chemicals have been extracted the wood chip by-product can be condensed into wood pellets and used for biofuel. Unlike CTO where the pine chemical output is facing competition with the biofuel industry.

End products

  • Natural gum turpentine
  • Natural gum rosin