Study of use of Beneficiated Pulverized Coal Fly-ash as filler and rice straw fibers in manufacturing of paper, PaperCon 2010 Conference

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Pulverized coal fly ash obtained from the burning of pulverized coal is very fine in particle size. It is available in abundant quantity in India and other countries world wide from coal based thermal power plants as solid wastes. It contains a mixture of oxides consisting of nearly 35-70 % silicon dioxide, 15-30% alumina, 1-10 % magnesium oxide, 1-10% calcium oxide, 5-10% iron oxide and 1-2% titanium dioxide. The fly ash can be beneficiated by different mechanical and chemical processes to give suitable properties as fillers. In this direction, a novel experimental study has been done for use of pulverized coal fly ash. The samples of fly ash taken from coal fired power plants have shown suitable chemical and physical properties which are comparable with that of conventional fillers (kaolin clay, calcium carbonate, alumina and titanium dioxides etc). Fractionation of fly ash was done by magnets and then screening was done for collection of finer size particles which are acceptable for paper making. Residual carbon can be separated to give higher optical properties. The mechanical strength properties, optical properties like brightness and opacity and surface properties of paper hand-sheets were studied for different percentages of fillers. A comparison study has been carried from conventional fillers. The opacity of fly ash (non magnetic fraction) loaded paper was better than conventional fillers. Strength properties were also comparable. Rice straw, a solid agro residue material was processed using catalyzed acetic acid pulping. The rice straw fibers were used for manufacturing of specialty paper where very high brightness was sought but whiteness is not important. This will decrease the production cost of paper significantly. Utilization of rice straw along with coal fly ash will result in sustainable industrial development and environment friendly handling of waste materials.