Industrial Scale-Up of Fiber Loading on Deinked Wastepaper, 1996 Pulping Conference Proceedings

Oliver Heise

William Fineran, Jr.

Voith Sulzer, Inc.

John Klungness,F reya Tan, Marguerite Sykes & Said Abubakr

USDA Forest Service

Jacob Eisenwasser

Purvish Shah

Praxair, Inc.

Fiber loading is an efficient method of manufacturing precipi-tated calcium carbonate (PCC). The overall goal of this proj-ect is to demonstrate the technical feasibility and economic and environmental advantages of fiber loading PCC as a filler to upgrade wastepaper pulps for printing and writing papers. This paper presents industrial scale-up data, including deink-ing waste paper and demonstrating the ability of a disperser to convert calcium hydroxide to PCC in situ, partially within the fiber. Conventional deinking mill conditions were simulated, including typical pulping chemistry, deinking process sequence, and process water clarification and recircu-lation. Industrial-scale fiber loading was technically success-ful; calcium hydroxide was completely converted to calcium carbonate and precipitated on the external and internal sur-faces of pulp fibers. However, we found that calcium hydrox-ide must be thoroughly mixed with fiber prior to reaction with carbon dioxide to ensure uniform loading and complete conversion to carbonate. The fiber loading processes used in this trial must be modified to obtain optimum conversion to calcium carbonate. Separate operations for mixing calcium hydroxide into the pulp and chemical reaction with carbon dioxide are required. Another industrial trial that incorporat-es equipment or process modifications found to be essential for improved fiber loading will be run.