KRAFT PAPER MILL BLACK LIQUOR, AND ALMOST ALL OF THIS POTENTIALLY RECOVERABLE NATURAL POLYMER IS SIMPLY BURNED WITHOUT SEPARATION OM FURNACES.

KRAFT PAPER MILL BLACK LIQUOR, AND ALMOST ALL OF THIS POTENTIALLY RECOVERABLE NATURAL POLYMER IS SIMPLY BURNED WITHOUT SEPARATION OM FURNACES. THE HIGH COST OCCURS BECAUSE, WHEN THE LIGNIN IS MADE INSOLUBLE BY ACID ADDITION,THE LIGNIN PARTICLES FORMED ARE SUBMICRON IN SIZE, AND EVEN WHEN COAGULATED BY HEATING AND MIXING, THE LIGNIN IS DIFFICULT TO FILTER AND IS CONTAMINATED BY BLACK LIQUOR. TEDIOUS AND ENERGY-INTENSIVE PURIFICATION STEPS ARE NEEDED. RESEARCH IS PROPOSED TO FURTHER DEVELOP A METHOD WE HAVE DEVELOPED FOR ECONOMICALLY SEPARATING THE LIGNIN. AN ORGANIC LIQUID WITH LOW SOLUBILITY IN BLACK LIQUOR IS ADDED PRIOR TO ACIDIFICATION. AS THE SUBMICRON PARTICLES FORM, THEY RAPIDLY AGGLOMERATE INTO LARGE, FLUFFY, COMPACTS WHICH FLOAT UPWARD. LIGNIN PARTICLES ARE DISCHARGED INTO A LAYER OF THE ORGANIC LIQUID AT THE TOP OF THE BLACK LIQUOR, FORMING A SLURRY. A FREE-FLOWING LIGNIN POWDER OF HIGH PURITY IS RECOVERED BY SPRAY DRYING THE SLURRY. THERMAL ENERGY LOST FROM THE BLACK LIQUOR IS REPLACED BY PULVERIZED COAL.