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Industry-Government-University Cooperative Research Program for the Development of Structural Materials from Sulfate-Rich FGD Scrubber Sludge

Description: The main aim of our project was to develop technology, which converts flue gas desulfurization (FGD) sulfate-rich scrubber sludge into value-added decorative materials. Specifically, we were to establish technology for fabricating cost effective but marketable materials, like countertops and decorative tiles from the sludge. In addition, we were to explore the feasibility of forming siding material from the sludge. At the end of the project, we were to establish the potential of our products by generating 64 countertop pieces and 64 tiles of various colors. In pursuit of our above-mentioned goals, we conducted Fourier transform infrared (FTIR) and differential scanning calorimetry (DSC) measurements of the binders and co-processed binders to identify their curing behavior. Using our 6-inch x 6-inch and 4-inch x 4-inch high pressure and high temperature hardened stainless steel dies, we developed procedures to fabricate countertop and decorative tile materials. The composites, fabricated from sulfate-rich scrubber sludge, were subjected to mechanical tests using a three-point bending machine and a dynamic mechanical analyzer (DMA). We compared our material's mechanical performance against commercially obtained countertops. We successfully established the procedures for the development of countertop and tile composites from scrubber sludge by mounting our materials on commercial boards. We fabricated more than 64 pieces of countertop material in at least 11 different colors having different patterns. In addition, more than 100 tiles in six different colors were fabricated. We also developed procedures by which the fabrication waste, up to 30-weight %, could be recycled in the manufacturing of our countertops and decorative tiles. Our experimental results indicated that our countertops had mechanical strength, which was comparable to high-end commercial countertop materials and contained substantially larger inorganic content than the commercial products. Our moisture sensitivity test suggested that our materials were non-water wettable and did not disintegrate on submerging the product ...
Date: August 31, 2003
Creator: Malhotra, V. M. & Chugh, Y. P.
Partner: UNT Libraries Government Documents Department

Design and fabrication of advanced materials from Illinois coal wastes. Quarterly report, 1 December 1994--28 February 1995

Description: The main goal of this project is to develop a bench-scale procedure to design and fabricate advanced brake and structural composite materials from Illinois coal combustion residues. During the first two quarters of the project, the thrust of the work directed towards characterizing the various coal combustion residues and FGD residue, i.e., scrubber sludge. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), differential thermal analysis (DTA), and transmission-Fourier transform infrared (FTIR) were conducted on PCC fly ash (Baldwin), FBC fly ash (ADK unit l-6), FBC fly ash (S.I. coal), FBC spent bed ash (ADM, unit l-6), bottom ash, and scrubber sludge (CWLP) residues to characterize their geometrical shapes, mineral phases, and thermal stability. Our spectroscopic results indicate that the scrubber sludge is mainly composed of a gypsum-like phase whose lattice structure is different from the lattice structure of conventional gypsum, and sludge does not contain hannebachite (CaSO{sub 3}.0.5H{sub 2}O) phase. Our attempts to fabricate brake frictional shoes, in the form of 1.25 inch disks, from PCC fly ash, FBC spent bed ash, scrubber sludge, coal char, iron particles, and coal tar were successful. Based on the experience gained and microscopic analyses, we have now upscaled our procedures to fabricate 2.5 inch diameter disk,- from coal combustion residues. This has been achieved. The SEM and Young`s modulus analyses of brake composites fabricated at 400 psi < Pressure < 2200 psi suggest pressure has a strong influence on the particle packing and the filling of interstices in our composites. Also, these results along with mechanical behavior of the fabricated disks lead us to believe that the combination of surface altered PCC fly ash and scrubber sludge particles, together ed ash particles are ideal for our composite materials.
Date: December 31, 1995
Creator: Malhotra, V.M. & Wright, M.A.
Partner: UNT Libraries Government Documents Department

Effects of particle size on the desorption kinetics of water from Beulah-Zap lignite coal: Differential scanning calorimetry results

Description: The drying kinetics of water from three particle-sized Beulah-Zap lignite coal samples were probed using the differential scanning calorimetry technique at 295 < T < 480 K. The measurements undertaken under flowing N{sub 2} gas environment indicate that water is lost from this coal by two independent but simultaneously operative kinetic mechanisms. Our results suggest that the unimolecular decay kinetics are obeyed by those water molecules which are near the mouths of large pores and/or surround the coal particles. Most of the water, about 80% of the water lost in our experiments, was removed via a 2nd-order diffusion mechanism. As expected, the desorption activation energies of the 2nd-order diffusion kinetics were much larger than the decay mechanism`s activation energies. Our results also suggest, at least for particle sizes < 841 {mu}m, < 106 {mu}m, and < 37 {mu}m, that the coal particle size has little effect on the desorption activation barriers.
Date: March 1996
Creator: Dang, Yuhong; Malhotra, V. M. & Vorres, K. S.
Partner: UNT Libraries Government Documents Department

Design and fabrication of advanced materials from Illinois coal wastes. Quarterly report, 1 March 1995--31 May 1995

Description: The main goal of this project is to develop a bench-scale procedure to design and fabricate advanced brake and structural composite materials from Illinois coal combustion residues. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), differential thermal analysis (DTA), and transmission-Fourier transform infrared (FTIR) were conducted on PCC fly ash (Baldwin), FBC fly ash (ADM unit1-6), FBC fly ash (S.I. coal), FBC spent bed ash (ADM unit1-6), bottom ash, and scrubber sludge (CWLP) residues to characterize their geometrical shapes, mineral phases, and thermal stability. Our spectroscopic results indicate that the scrubber sludge is mainly composed of a gypsum-like phase whose lattice structure is different from the lattice structure of conventional gypsum, and sludge does not contain hannebachite (CaSO{sub 3}0.5H{sub 2}O) phase. In the second and third quarters the focus of research has been on developing protocols for the formation of advanced brake composites and structural composites. Our attempts to fabricate brake frictional shoes, in the form of 1.25 inch disks, from PCC fly ash, FBC spent bed ash, scrubber sludge, coal char, iron particles, and coal tar were successful. Based on the experience gained and microscopic analyses, we have now upscaled our procedures to fabricate 2.5 inch diameter disks from coal combustion residues. The SEM and Young`s modulus analyses of brake composites fabricated at 400 psi < Pressure < 2200 psi suggest pressure has a strong influence on the particle packing and the filling of interstices in our composites.
Date: December 31, 1995
Creator: Malhotra, V.M. & Wright, M.A.
Partner: UNT Libraries Government Documents Department

Design and fabrication of advanced materials from Illinois coal wastes. [Quarterly] technical report, September 1--November 30, 1994

Description: The main goal of this project is to develop a bench-scale procedure to design and fabricate advanced brake and structural composite materials from Illinois coal combustion residues. During the first quarter of the project, the thrust of the work was directed towards setting up the experimental facilities and undertaking preliminary tests to gauge the ability of coal tar derived binder in fabricating the brake skeletons. In addition systematic scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and differential thermal analysis (DTA) were conducted on PCC fly ash (Baldwin), fly ash (ADM), FBC fly ash, FBC spent bed bottom ash, bottom ash (ADM), and scrubber sludge residues to characterize their geometrical shape and thermal stability. The PCC fly ash particles being highly spherical in shape and thermally inert up to 1100{degrees}C will make an excellent raw material for our composites. This is born out by fabricating brake skeletons from PCC fly ash colloids. Unlike the PCC fly ash and FBC fly ash, the scrubber sludge particles are not suitable hosts for our brake lining materials because of a whisker-like particle structure. Six different compositions of various combustion residues were tested in the fabrication of brake skeletons, and our tar derived binder shows great promise in the fabrication of composite materials.
Date: December 31, 1994
Creator: Malhotra, V.M. & Wright, M.A.
Partner: UNT Libraries Government Documents Department

Drying of Beulah Zap lignite

Description: Recent results on the kinetics of water's desorption from Beulah-Zap lignite coal, as determined by thermogravimetric analysis (TGA) and the differential scanning calorimetry (DSC) technique were reported. The kinetic analysis of DSC was further complimented by determining the mechanism of air drying of lignite coal with the help of an in-situ Desorption Kinetics via Fourier transform infrared (ISDK-FTIR) technique. 17 refs., 5 figs., 1 tab.
Date: January 1, 1991
Creator: Vorres, K.S.; Molenda, D. (Argonne National Lab., IL (USA)); Dang, Y. & Malhotra, V.M. (Southern Illinois Univ., Carbondale, IL (USA). Dept. of Physics)
Partner: UNT Libraries Government Documents Department

Clean, premium-quality chars: Demineralized and carbon enriched. Final technical report, September 1, 1991--August 31, 1992

Description: The overall objective of this two-year project is to evaluate methods of preparing demineralized and carbon enriched chars from Minois Basin coal. There are two processing steps: physical cleaning of the coal and devolatilization of coal under different environments (He, H{sub 2}, He/O{sub 2}, CH{sub 4}, and CH{sub 4}/O{sub 2}) to form chars. Also, as-received and clean coal samples were mixed with hectorite, Ca-montmorillonite, and kaolinite to evaluate the potential effects of these clays on chars yield and agglomeration during devolatilization processes. Three different techniques were used: thermogravimetric analysis, differential thermogravimetric analysis, differential scanning calorimetry (DSC), and in-situ diffuse reflectance FTIR (ISDR-FTIR). Thermogravimetric measurements showed that reactive gases (except He) dissolve in the softened coal. Also, these gases convert some of the coal mineral matter into catalyst by chemical reduction and oxidation. Coal reactivity increases by adding clays because they may be catalyst for methane activation, may prevent coal agglomeration, and may modify the geometric structure of the coal surface. DSC measurements show that clean coal devolatilizes at a lower temperature than as-received sample and preoxidation lowers the devolatilization temperature. Additionally, kaolinite addition increase yields of chars from IBC-102 coal in He. In-situ diffuse reflectance FTIR experiments show that thermal decomposition of coal either increases -CH{sub 3}, content in char or alters the physical structure of -CH{sub 3}. Also, phenol groups of the coal play an important role in cross-linkage the coal structure when coal is thermally treated.
Date: December 31, 1992
Creator: Smith, G. V.; Malhotra, V. M. & Wiltowski, T.
Partner: UNT Libraries Government Documents Department