What Is TCF Wood Pulp?

Pulping

• About one-fourth of the mass of dry wood is composed of lignin, a chemical compound that strengthens wood. Lignin has to be removed to produce pulp suitable for making paper. Commonly used Kraft pulping uses sulphur compounds to remove the lignin. Kraft, meaning “strong” in German, produces strong paper suitable for magazines, graphics paper and grocery bags. Mechanical grinding or heating shreds trees into a weaker pulp commonly used for newspapers. Pulp is bleached to make it white and bright.

Bleaching

• Wood pulp was first bleached with sodium hypochlorite, otherwise known as household bleach. Chlorine gas replaced sodium hypochlorite in the 1930s. Responding to environmental concerns about toxic dioxins, paper mills began using chlorine dioxide instead of chlorine gas, resulting in ECF (Elemental Chlorine Free) pulp. Using chlorine dioxide, as a bleaching agent, reduces, but does not eliminate, the release of dioxins. TCF, a less efficient method of bleaching pulp, uses ozone oxygen and hydrogen peroxide as bleaching agents. As of 2011, ECF accounted for more than 80 percent of worldwide production of bleached wood pulp. In 2009, a mill in Eureka, CA that made chlorine-free toilet paper closed its doors. It was the last TCF mill in the U.S.

TCF Basics

• While the production of TCF pulp does not introduce dioxins to the environment, the paper it produces is generally less whiter and brighter than ECF pulp. TCF generally uses more wood than ECF to produce the same amount of pulp; and since it requires more heat to produce, TCF pulp yields weaker paper than ECF.

AOX

• Adsorbable Organic Halides (AOX) are highly reactive elements called halogens that include bromine, chlorine, fluorine and iodine. These elements bond with organic substances, contaminating the food chain and environment. Chlorine, the most common halogen in pulp mills, is detected by an AOX test that measures chlorine that stick to particles of carbon in a filter. The Stockholm Convention on Persistent Organic Pollutants sets standards and monitors the release of dioxin pollutants internationally. Environmental organizations continue to exert pressure on paper manufacturers to cease production of ECF in favor of TCF.