Patent ID: 9394173
Filing Date: 2016-07-19
CPC Classification: C01B,C02F

Claim Text:
1. A process for recovery of phosphorus values and salt impurities from an aqueous waste stream comprising one or more organic phosphorus compounds and salt impurities, the process comprising: oxidizing one or more organic phosphorus compounds containing phosphorus and organic carbon present in a feed stream comprising components of the aqueous waste stream to produce a phosphate-containing cake, wherein the one or more organic phosphorus compounds are selected from the group consisting of N-(phosphonomethyl)glycine (glyphosate) and salts thereof, N-(phosphonomethyl)iminodiacetic acid (PMIDA) and salts thereof, aminomethylphosphonic acid and salts thereof, hydroxymethylphosphonic acid and salts thereof, N-formyl-N-(phosphonomethyl)glycine and salts thereof, N-methyl-N-(phosphonomethyl)glycine and salts thereof, methyl aminomethylphosphonic acid and salts thereof, and combinations thereof, and wherein the oxidizing one or more organic phosphorus compounds within the feed stream and containing phosphorus and organic carbon comprises calcination of the feed stream and/or combustion of the one or more compounds within the feed stream and containing phosphorus and organic carbon, wherein any combustion of the one or more compounds containing phosphorus and organic carbon is conducted at a temperature of at least about 500° C.; contacting within an acidification zone the phosphate-containing cake and an acidic liquid medium to form a solution comprising at least one inorganic salt and phosphoric acid; and precipitating salt crystals from the salt-containing solution to form an aqueous product mixture comprising salt crystals and a mother liquor comprising phosphoric acid.