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The Evaluation of Paper Sludge (PS) for Zeolite synthesis (Part 1)

2003; Japan Technical Association of the Pulp and Paper Industry; Volume: 57; Issue: 7 Linguagem: Inglês

10.2524/jtappij.57.1055

1881-1000

Takao Ando, Masato Saito, Shigeo Muramatsu, Kimio Hiyoshi, Junsuke Haruna, Naoto Matsue, Teruo Henmi,

Enzyme Production and Characterization

Paper sludge (PS) discharged from the paper mills in Fuji city, Shizuoka prefecture reach about 1, 018, 000 tons/year. The development of the zeolite synthesis technique is essential from the viewpoint of recycling of wasting materials.Generally. PS ash contains not only Si and Al, but also significant amount of Ca. From our previous study on the interaction between Ca in calcite and Si as well as Al in kaolinite during the zeolite synthesis, the following results became clear.(1) The metakaolinite that was heated at 600°C is converted to zeolite by the alkaline (NaOH) hydrothermal treatment at 100°C for 4 hours.(2) Co-existing Ca is expec-d to inhibit the formation of zeolite, since the amorphous Ca-silicate hydrate will form preferentially and Si-O-Al bonds will not.(3) Chemical and mineralogical characterization of the zeolite synthesized by the mixture of Ca (OH) 2 and metakaolinite led us the supposition that the chemical formula of the amorphous Ca-silicate hydrate was Ca3Al2 (SiO4) 3X (OH) 4X. From these results, we cleared the conversion rate of LTA (Linde Type A) zeolite, and the ideal mineralogical composition range of PS for the zeolite synthesis was obtained.In this study, the practical PS ashes were mineralogical and chemical characterized and their possibility as starting materials for the zeolite synthesis, was examined. The 20 PS ashes from paper mills in Fuji city were heated at 600°C for 12 hours and a X-ray fuluorescence (XRF) measurements were tested.The talc, kaolinite, calcite constitution ratios of them were determined by the normative method from a X-ray diffraction (XRD) profiles obtained, and were compared with the above ideal composition range. It was found that 50% of the PS ashes could be directly used for the zeolite synthesis and the others could by addition of Si compounds.