Solidification of final liquor from ammonia-soda works - by adding flocculant, concentrating and filtering on press

摘要

Sepn. of the solids from the final liquor (I) and conversion to a useful or dumpable form involves treatment using concentrators and chamber filter presses and addn. of flocculants (II). (I) is conc. to 50-250 kg/m3 solids with addn. of (II) then the sludge removed is diluted with 2-20 vol. pts. water. It is then conc. to 100-400 kg/m3 solids, with addn. of more (II), and finally filtered at 2-20 bar. The solids are converted to a form which can be dumped without endangering the environment or ground water and may also be re-usable. The second concn. stage may be omitted and the filter cake washed with water. (II) is an ionic or nonionic high polymer pref. polyacrylamide, poly(meth)acrylates, copolymers of acrylamide and acrylates, polyethylene oxides and/or polysaccharides.