THE PAPER Trail: Mixed Paper

The recovered paper grade, mixed paper, is a combination of many types of paper and paperboard. It is made from a variety of fiber types, including mechanical, semi-chemical, chemical, unbleached, bleached, coated and uncoated grades.

For years, mixed paper was not "purposefully" produced - its generation actually was avoided because of its low value. However, with increased U.S. residential recycling collection and high recovery rates of old corrugated cardboard (OCC), mixed paper now is produced consistently.

There are vast quantities of mixed paper available for recovery, and both the domestic and export use of this grade is expected to continue to grow.

Mixed Paper Facts and Figures: There are two standard mixed paper definitions. They allow for some of the highest levels of prohibitive and outthrow materials of any recovered paper grade. The Washington, D.C.-based Institute of Scrap Recycling Industries' Paper Stock Industry has the following definitions for these grades:

* PSI #1 - Soft Mixed Paper. Consists of a mixture of various paper qualities not limited to the baling type or fiber content. Prohibitive materials may not exceed 2%.Total outthrows may not exceed 10%.

* PSI #2 - Mixed Paper. Consists of a baled clean, sorted mixture of various qualities of paper containing less than 10% of groundwood content. Prohibitive materials may not exceed 11/42 of 1%. Total outthrows may not exceed 3%.

Because of its diverse composition, mixed paper is difficult to use. It has the least recovery of all the major paper grades in the United States and is the lowest priced grade of recovered paper. Compared to OCC and old newspapers (ONP) that have recovery levels of 80% and 70%, the current estimated recovery rate of mixed paper is less than 25%.

However, as OCC recovery rates and prices continue to climb, more mills are experimenting with using cheaper mixed paper as a substitute.