As is known,the presence of chemical additives is very effective for producing high coal loading CWM(Coal Water Mixture). To reduce process cost, natural additive of CWM such as Humic-Acid extracted from low rank coal and lignin obtained by concentrating the pulp waste liquor(black liquor)are noted well now. At the same time,the extraction process and the concentration process deplete a lot of chemical reagent and energy. Further more,the problem of pulp waste liquor disposal or utilization has been attacked from many standpoints, People are still seeking an-economical solution. It was once studied to produce CWM using pulp waste liquor directly, but the dispersing effect only by the lignin contained in the black liquor. Corrosion of black liquor due to its high pH is also a difficult problem for the storage transportation and combustion of CWM. This study attempted to extract low rank coal such as lignite using black liquor,and then,prepare CWM using the extraction liquor directly. It was found that the viscosity of CWM prepared by lignite black liquor extraction was lower than that of CWM prepared using black liquor directly. High coal loading CWM(69wt%)can be prepared by the new method and the pH of CWM was under 9,which is lower than black liquor whose pH is 13.
特集 : 「資源、新エネルギー、環境、防災研究国際セミナー」