Recently Thermo Black Clawson of Middletown, Ohio has started promoting a new, patented recycling process. The system, trade named Xtrax, is used to recycle wax-coated corrugated containers. Inland Paperboard and Packaging Inc. is a partner with Thermo Black Clawson in the development.

Wax-coated corrugated containers have largely replaced wooden crates for transporting produce and fruit. The tonnage of these cartons produced per year is quite large: an estimated 1,500,000 tons. We were surprised to learn that, by weight, these cartons are 30% wax.

Paper machines at normal OCC (Old Corrugated Container) recycling mills can tolerate up to about 3% wax. Because of the problems caused to the paper machine clothing by excess wax, the wax-coated boxes are segregated. Up until now the great majority of them have been incinerated or landfilled.

The new Thermo Black Clawson process features the addition of steam to the hydrapulper. The heat melts the wax. Then a conterflow series of TBC Reverse Screens are used to wash the wax from the flow. In the end the furnish has less than 1% wax.

In April of 1998 Vincent Corporation was honored to be invited to a Trial Demonstration held at the Middletown laboratory of TBC. Representatives from ten paper companies attended along with engineers from Poseidon (clarifiers), BetzDearborn (flocculents), Brown & Root (consultants), and CITGO (waxes).

Vincent screw presses were used in two phases of the process. One CP-4 was used for primary, first wash dewatering. Testing was done at 165º, 185º and 150º. The wax content in all press cake samples was on the high side, 4-1/2%; we feel that this can be improved by using higher cone pressures.

A second CP-4 was used on the DAF sludge coming from a unique Poseidon clarifier. Most clarifiers are very large in diameter and of relatively short height. The Poseidon machine was shaped more like a grain silo, with up-side-down umbrellas on the inside. Flocculated wastewater is pumped into the side, at the bottom. The clarified water makes a U-turn into the umbrellas and drains from the bottom. The sludge floats to the top and over a weir. Excellent results were achieved pressing this sludge by greatly reducing the rpm of our press.