Use of Thermally Converted Paper Residue as a Building Material

Abstract

CDEM, a group of four Dutch paper mills, joined forces to develop a proprietary (patented) process that allows the production of a new type of admixture for use as building material. The process consists of a controlled thermal conversion of de-inking paper residue in a fluidized-bed combustor. The resulting mineral product has both hydraulic and pozzolanic properties. The mineral product is mainly composed of metakaolin and calcium compounds. The mineral product composition depends upon the chemistry of the starting paper residue and the thermal conditions applied. When the raw paper residue is rich in kaolin and the thermal conversion preserves calcium carbonate, a very reactive pozzolan is obtained. When the calcium content increases and decomposition of calcium carbonate occurs, a self-cementing material appears which can replace normal cement in several applications like: masonry blocks, autoclaved products, and backfilling mortars.