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Retrofitting existing plants for low cost production of high performance building boards

Deliverables

Development of gypsum boards in conventional production line incorporating cellulose fibres and zeolite in the recipe (KNAUF.ABEE) - Assessment of energy saving potentials (NTUA)
Assessment of potential to "foam" zeolite in industrial environment (NTUA and IGME) A pilot scale expansion furnace (scale-down of industrial facility) appropriate for dynamic thermal treatment of minerals has been used and commissioned for the purposes of the project. NTUA performed experiments to investigate the possibility of thermal treatment of zeolites (foaming) based on similar results found in open literature. Four different types of Italian zeolites and eight types of Greek zeolites have been exposed to abrupt heating up to 11000C. Experiments were performed at heating temperatures of 6000C, 9000C and 11000C, and for two particle size distributions of the raw material, corresponding to 0 - 0.3mm and 0.3 - 0.9mm. Size distribution and dry density (specific weight) of all the treated samples have been measured before and after treatment. Results indicated that, for the conditions under which the experiments were performed, direct heating of zeolite particles up to 11000C does not result to apparent foaming of the material. Selected thermally treated samples were analysed by IGME using XRD. Results indicate: - Smectite, is destroyed during thermal expansion process - Heulandite-2 lattice appears in almost complete destruction - Some of clinoptilolite and mordenite seems to remain during thermal expansion procedure - Kaolinite and calcite, if present, they are entirely destroyed by the thermal process. - Possibly new phases are formed not clearly detected by XRD From the LOI analytical results it is concluded that in the samples containing heulandite-2 lose over 80% of LOI during the procedure of expansion due mainly to the destruction of the zeolite lattice. In the samples containing clinoptilolite and mordenite that are more stable in high temperatures than heulandite-2 (clinoptilolite, mordenite) a greater percentage of LOI remain after thermal expansion. Representative samples of Greek and Italian zeolites were analysed for their natural radionuclide content using gamma spectroscopy and for radon exhalation rate (ìBqkg-1s-1). The 226Ra content of the Zeolites examined (40-160BqKg-1) lies within the 226 Ra content of European building materials, i.e. 4 - 4000BqKg-1. The Radon exhalation rate of the zeolites examined (80 - 115ìBqKg-1s-1) lies within the range of Greek black cement or fly ashes, i.e. 10 - 110ìBqKg-1s-1, but it is much lower than that of internationally reported values. Measured radon exhalation rate from gypsum boards containing up to 10% zeolite was very low.
Mapping of Italian zeolite deposits (VERDI s.r.l.) and full characterisation of raw materials (VERDI s.r.l., CSTB) (1)Review of the literature data to assess the more appropriate zeolite type and the methods to remove undesirable impurities (2)Identification of the main zeolite deposits in Italy and evaluation of the mining capacity, quality and compositional uniformity of the zeolite bearing rocks from the different quarries. A Geological Survey and Mapping was performed on the SE area of the zeolitic body of Piandirena, and confirmed the estimation of the geological resevoir of at least 9.000.000 m3 of zeolite rich tuff. The zeolite bearing lithostratigraphic unit, corresponding to the "Sorano Formation" extends SE far beyond the mapped area. A rough estimation of potential resource is in the order of about 50Mt. (3) Collection of about 12-15 representative samples (50Kg apiece) from different selected quarries. (4) Characterisation of each sample with qualitative and quantitative mineralogical analysis using the X-ray Rietveld method, chemical composition by XRF and TG analysis and cation exchange capacity using the 1N NH4 and 1N NaCl solutions, and comparison of the results with those obtained for the Greek zeolite rich rocks. (5) Chemical composition and morphological characterisation of the zeolite crystals by electron microprobe analysis (EPMA) and scanning electron microscopy (SEM), respectively; (6) Determination of relevant physical properties (DTA, DTG, TG, cation exchange capacity) of the samples; (7) In order to define the optimum conditions of firing of the mineral, quantitative phase analysis on the fired samples (yield of reaction) can be accomplished using the Rietveld-RIR methods in our laboratories. (8) Supply of zeolite samples (about 20Kg) in two different granulometries: raw material < 1cm and sieved material < 1mm.
Evaluation of reuse of old paperboards on the quality of the new gypsum-fibre board. The quality features of an old newspaper grade typical of Southern Europe were determined in terms of its physical properties after dry and wet pulping. In addition, the properties of the paperboard part of old gypsum boards and wet-pulped old newspapers were studied for refining-induced changes in their fibre morphology and strength properties. Results: - Fibrous material has to be sufficiently disintegrated to distribute the fibres uniformly throughout the gypsum substrate. - Drainage resistance (SR) increases with the disintegration time owing to fibre swelling phenomena. - Pulp refining is intended to enlarge the specific fibre surface via fibrillation and to activate the reactive OH groups. An increase in the specific refining energy brings about the following changes to the fibre properties: increased water retention (WRV) of the pulp and increased drainage resistance (SR) on the wire, enhanced tensile strength and elastic modulus (Young's modulus). - Dry-pulped newspaper exhibited the highest short-fibre content (> 0.5mm). Reused gypsum paperboard exhibited the highest length-weighted average fibre length (1.17mm) among all samples tested. Another important result of the project was that finely ground zeolite integrated into gypsum plasterboard was found to be capable of taking up formaldehyde and benzene - both are tobacco smoke emissions - thus removing them from the ambient air. In co-operation with KNAUF.GIPS, the PTS pilot paper machine successfully produced plasterboard samples containing 30% by weight of zeolite of different origins. These highly filled papers had greater pore volume and enhanced air permeability. The plasterboard (paper covering) therefore no longer acted as a barrier layer, but actively contributed to improving air quality.
Mapping of Greek zeolite deposits (IGME) and full characterisation of raw materials (IGME, CSTB) Bulk samples were taken from various zeolite deposits in Evros and Rhodopi Prefectures, Thrace, NE Greece. The criteria for the zeolite deposits selection were the size of the deposit, the type of zeolitic alteration and the knowledge status of each deposit. According to their chemical assays, zeolitic tuffs are characterized as rhyodacitic to dacitic in composition. The collected samples of altered tuffs, according to zeolite type prevailing, can be classified in tuffs altered to (a) Clinoptilolite , (b) Heulandite-2 +/- mordenite, (c) Mordenite, (d) Analcime. Due to their mineralogical composition, C.E.C. of the working samples range from deposit to deposit. The main exchangeable cation is calcium, except in the case of Petrota. This is attributed to the Na-rich clinoptilolite being its main alteration mineral, whereas in the other tuffs alteration to Ca-rich heulandite-2 prevails. All working samples show similar behaviour in thermal treatment. Almost in all of them, the weight loss has been achieved at a temperature lower than 500oC. During quick thermal expansion at various temperatures, some mineralogical changes, as well as formation of new minerals take place. The samples for industrial applications were collected from Pentalofos. Chemical composition of selected zeolite for the four production tests is almost the same and their moisture depends on ambient temperature. CSTB measured physical properties (Water vapour adsorption/ desorption, VOC adsorption, density, porosity etc) of four families of Greek natural zeolites.
Technological development for increase of utilization of recovered paper (PTS) In the wake of targeted technological development, recovered paper utilization rates have climbed to an unprecedented high level in the member states of the CEPI Association in Europe. However, the specific rates (based on recovered paper consumptions) vary widely for both the individual grade categories of paper and paperboard and for the countries concerned. Recovered papers and paper industry wastes and residuals are also reused in the building industry. The paper recovery rate represents the waste paper volume in percent of paper and board consumption. A comparison of paper recovery rates of Germany (73%) and Greece (31%) demonstrates the potential higher paper recovery rate in Greece and discloses the fibre material reserves for the new product. The use of waste paper presents considerable financial and ecological advantages compared to the utilization of fresh fibres, which may be terminated. PTS submitted a market survey on recovered paper in Greece, which is based on information derived from paper databases to supplement the market survey conducted by KNAUF.ABEE.
Various boards based on gypsum and gypsum fibre mix and containing zeolites in the range of 5 - 20%. The feasibility of producing a new gypsum fibreboard containing zeolites, using the process of Result number 9 has been demonstrated at a test production 02/2004 - Grenzebach BSH GmbH. Products: Gypsum fibre boards with mineral wool, processed cellulose fibres, kettle stucco of Knauf Schwarze Pumpe and starch. Aim for the test production: Adjustment of the existing technology to products with high fibre contents. The focus of Knauf Gips KG was mainly directed to indoor-air quality. The effect of zeogyp boards on pollutants (formaldehyde, ammonia, benzene and tobacco fume) was studied in detail. The boards have been used uncovered and covered/laminated. Also perforated boards have been produced and investigated. Experiments included measurements of time-dependent decrease of odour-intensity (deodorization) according to VDI-Richtlinie 3881, I and II and indicated significant reduction of formaldehyde and benzene content (main component of tobacco fumes) in indoor air. No desorption has been observed contrary to normal boards. Further experiments included effects of paper coating, perforation, use of dispersion dye. All experiments demonstrated significant decomposition of formaldehyde within the first 4 days and no recovery after 21 days.
GRENZEBACH BSH (formerly BABCOCK BSH) created and demonstrated the apparatus and plant engineering prerequisites for the production of novel gypsum fibreboards containing natural zeolite and production waste from paper mills and gypsum plasterboard plants. The new production concept is able to use the major proportion of the equipment employed for the older gypsum plasterboards, that noticeably increase the service life of these plants and saves investment costs. The resulting boards are more advantageous for the consumer than conventional gypsum plasterboards: they use recyled materials, whereas surface, bending tensile strength and flexurity of the panels are satisfying regardless of the content of zeolites (up to 10%). The "wet" GRENZEBACH-BSH process being developed, overcomes disadvantages of "dry" processes, by pulping the paper gently with excess water. The water is then removed by means of a lightweight and more favourable filter belt. The resulting board has the same strength although it contains only 10 % paper, instead of 17% (paper costs!) in the "dry" Fels/Siempelkamp process and is also more homogeneous. The disadvantage up to now was that only special or specially treated plasters of Paris could be used. Fine plasters of Paris or gypsum that disintegrate on contact with water could not be used. Within the project, a rotating drum developed by GRENZEBACH-BSH was successfully assessed for stabilisation of the KNAUF.ABEE (Amphilochia) low-grade gypsum. To increase plant capacity, (decisive factor for economic viability of plant) process-engineering modifications included newly developed stabilisation that reduces the disintegration of the gypsum particles and improves dewatering (as well as the use of warm pulp). In addition, based on the experience gained, drawings were made for a forming machine with a working width of 2.5m (instead of 1m) to increase plant capacity. Technical solutions were also developed for reduction of production waste and energy consumption
USAL, working with FCR (fibrous clay residues, i.e. waste from recycling paper), stucco and zeolite has identified a range of high quality building board formulations. The fibrous waste residues that result from recycling waste paper can be combined with gypsum and successfully transformed into high quality building boards for internal use. Board formulations can be tailored to achieve target densities, strengths and stiffnesses. Commercial production may be by pressing or by continuous process.
Critical assessment of process modification potentials to produce gypsum fibreboards with minimum intervention and capital investment. The installation of a gypsum fibreboard Form Machine (BSH) in an existing gypsum board factory has been assessed by KNAUF.ABEE. This evaluation took into account all the possible technical parameters (mixing station, water drainage, press, control systems) so that a form machine can operate alternatively to a gypsum board line. Depending on the layout of various such gypsum board factories, alternative solutions might be opted for. For this reason four alternative scenarios have been studied in the beginning of the project (2001). a. interruption of the gypsum board conveyor belt b. installation of the FM at the mixing station, with backward relocation of the paper feeding station c. installation of the FM parallel to the gypsum board conveyor belt d. installation of the FM parallel to the dryer. The assessment of the four alternatives revealed that direct retrofitting of existing plants was uneconomical and led to reduce plant capacity, when using the equipment available at that time (2001). On the basis of the assessment BSH proceeded with the improvements of the wet process, described in Result 7

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