Treatment of filter cakes, esp. from phosphoric acid purificn. - by drying and heating with inorganic melt

摘要

A process is claimed for treating filter cakes formed during the purificn. of liq. chemicals (esp. during the purificn. of wet-process phosphoric acid for tripolyphosphate mfr.). The process comprises drying the filter cake and heating it in the presence of an inorganic melt. The melt can be a metallurgical slag or the molten dried filter cake itself. Heating is pref. effected at >500 degrees C (esp. 700-1300 degrees C) while agitating to allow the release of C cpds. The treatment reduces the vol. of material to be handled and converts it to a form which can be stored in the open without the risk of pollutants (e.g. heavy metals) being leached out. The prod. can be crushed and used in road making.