was added a slurry comprised of 800 grams of north dakota lignite and 800 milliliters of water over a one hour period the mixture was held at 60 u00b0 c for three hours cooled to room temperature and then removed from the reactor and filtered the recovered solids were washed three times with water 1000 cubic centimeters of water each time dried in a vacuum oven resulting in the production of 560 grams of particulate polycyclic polycarboxylic acids the north dakota lignite used analyzed as follows 33 weight percent water 45 7 weight percent carbon 2 8 weight percent hydrogen 11 3 weight percent oxygen 0 6 weight percent sulfur 0 6 weight percent nitrogen and 6 0 weight percent metals a number of suspensions was prepared as follows into a waring blender there were placed water coal carboxylate prepared above and pellets of sodium hydroxide these materials were mixed at low speeds about 500 rpm for about five minutes sufficient to obtain a reaction between the coal carboxylate and the base to the resulting solution there was added particulate coal that had passed a 40 mesh u s series sieve and the resulting mixture was mixed at high speed about 20 000 rpm for about.