Effect of de-ashing method of recycled paper sludge on its chemical compounds in bio-refinery concept

Paper mill sludge is a solid waste including residual fiber and ash produced in pulping and papermaking processes that is supplied from Neka Pars Kaghaz Co. in mazandaran provience and used in this study as raw material to evaluation of its potantial for high-value added products manufacturing in bio-refinery concept. Mentioned sludge after its chemical compounds measurment was de-ashed in 3 methods by using air, CO2 and stirrer. Then, chemical compounds in each de-ashed sludge was measured and compared with obtained data before mentioned treatment. Also, mineral oxide in recycled paper sludge charecterized with XRF. Results show that de-ashing methods with CO2, stirrer and air can be decreased ash content of recycled paper sludge till 28.4, 61.84 an 70.99 percent, respectively. Accordingly, cellulose content of it in the air de-ashing about 120 percent as well as stirrer method (121percent) compared to CO2 bobles method (64 percent). Also, de-ashing methods were succesfully act in the calcium oxide removal to 13 percent and basically effeciancy of this methods is more in the trace oxides removal. Notable, the much content of ash is including of casium, silisium, aluminium and magnesium oxides. Investigation of mineral and organic compounds of recycled paper sludge show that de-ashing with air has the most efficiancy in ash removal that can be used as pre-treatment before all processes and to obtain of high-value added products in bio-refinery concept.