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US 10,189,710 B2Granted
Method of purifying phosphoric acid
AssigneeTenova Advanced Technologies Ltd.
InventorJonathan Lipp
Life of this patent
Estimating the term…
Abstract
A method of purifying phosphoric acid solution produced in wet process using nanofiltration. The claimed method contains the following: (a) providing wet phosphoric feed (b) subjecting the said feed to a first nanofilter (c) produce sulfate solids (d) removing the solids (e) subjecting a second nanofilter.
Claims20
A method of purifying phosphoric acid comprising:
- (a) providing a pre-treated wet phosphoric acid feed containing:
- (i) 2-62% phosphoric acid, expressed as a percent weight of P2O5 in said feed;
- (ii) a sulfate concentration of at least 15 ppm, per each 1 percent weight of said P2O5 in said feed;
- and
- (iii) metallic impurities including iron, aluminum, calcium, magnesium, and chromium, a total feed concentration of said iron, aluminum, calcium, magnesium, and chromium being at least 10 ppm, per each 1 percent weight of said P2O5 in said feed;
- (b) subjecting said pre-treated wet phosphoric acid feed to a first nanofilter in at least a first nanofiltration stage, to obtain a first permeate and a first reject;
- (c) treating said first permeate to produce sulfate solids in a partially treated phosphoric acid stream;
- (d) removing at least a portion of said solids from said phosphoric acid stream to produce a sulfate-depleted phosphoric acid stream;
- and
- (e) subjecting said sulfate-depleted phosphoric acid stream to at least a second nanofilter in at least one additional nanofiltration stage, to obtain a purified phosphoric acid in a second permeate, and a second reject, said second permeate containing:
- (i) a concentration of 2-62% phosphoric acid, expressed as a percent weight of P2O5 in said second permeate;
- (ii) a sulfate concentration of less than 10 ppm per each 1 percent weight of said P2O5 in said second permeate;
- and
- (iii) metallic impurities including iron, aluminum, calcium, magnesium, and chromium, a total concentration of said iron, aluminum, calcium, magnesium, and chromium in said second permeate being at most 5 ppm, per each 1 percent weight of said P2O5 in said second permeate.
11 more elements
A method of purifying phosphoric acid comprising:
- (a) providing a pre-treated wet phosphoric acid feed containing:
- (i) 20-62% phosphoric acid, expressed as a percent weight of P2O5 in said feed;
- (ii) a sulfate concentration of at least 15 ppm, per each 1 percent weight of said P2O5 in said feed;
- and
- (iii) metallic impurities including iron, aluminum, calcium, magnesium, and chromium, a total feed concentration of said iron, aluminum, calcium, magnesium, and chromium being at least 10 ppm, per each 1 percent weight of said P2O5 in said feed;
- (b) subjecting said pre-treated wet phosphoric acid feed to a first nanofilter in at least a first nanofiltration stage, to obtain a first permeate and a first reject;
- (c) treating said first permeate with a barium salt to produce sulfate solids in a partially treated phosphoric acid stream;
- (d) removing at least a portion of said solids from said phosphoric acid stream;
- and
- (e) subjecting said phosphoric acid stream to at least a second nanofilter in at least one additional nanofiltration stage, to obtain a purified phosphoric acid in a second permeate, and a second reject, said second permeate containing:
- (i) a concentration of 20-62% phosphoric acid, expressed as a percent weight of P2O5 in said second permeate;
- (ii) a sulfate concentration of less than 10 ppm per each 1 percent weight of said P2O5 in said second permeate;
- and
- (iii) metallic impurities including iron, aluminum, calcium, magnesium, and chromium, a total concentration of said iron, aluminum, calcium, magnesium, and chromium in said second permeate being at most 5 ppm, per each 1 percent weight of said P2O5 in said second permeate;
- said second permeate containing at most 0.05 ppm of barium, per each 1 percent weight of P2O5 in said second permeate.
12 more elements
Dependencies are inferred from the claim text.