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US 4,495,165 AGranted
Method of purification of phosphoric acid
OwnerGuillermo R. Gurzainventor
Life of this patent
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Abstract
Appreciable inorganic impurities and organic matter are removed from impure phosphoric acid, particularly wet-process phosphoric acid, by pyrolysis of a mixture containing the raw acid and porous carbonaceous matter, including carbohydrates and chars, then leaching the pyrolyzed residue therefrom with a suitable solvent such as water to extract the purified phosphoric acid.
Claims24
A method for purifying phosphoric acid comprising the steps of:
- mixing a porous carbonaceous material with phosphoric acid having impurities therewith;
- heating and agitating the mixture of carbonaceous material and phosphoric acid at a temperature between about 100.degree. C. and about 300.degree. C. so as to affect dehydration of the mixture;
- and then thereafter heating said mixture of carbonaceous material and phosphoric acid at a temperature between about 200.degree. C. and about 1000.degree. C., and
- after said heating and agitating, then washing said mixture with a solvent to dissolve the phosphoric acid which has thus been purified.
1 more element
A method for purifying phosphoric acid comprising the steps of:
- mixing a sufficient amount of predried porous carbonaceous material with a sufficient amount of phosphoric acid having impurities therewith, so that the phosphoric acid can permeate the carbonaceous material;
- heating for a sufficient time and agitating the mixture of carbonaceous material and phosphoric acid to a sufficient temperature to effect dehydration of the mixture;
- then thereafter heating said mixture of carbonaceous material and phosphoric acid to a temperature of from about 200.degree. C. to about 1000.degree. C.;
- and
- washing the residue of the heated mixture with an amount of solvent sufficient to dissolve the acid which has been purified.
2 more elements
A method for purifying phosphoric acid comprising the steps of:
- mixing from about 0.5 parts by weight to about 5.0 parts by weight phosphoric acid having impurities therewith with about 1 part by weight predried sawdust which has a moisture content of about 5.0% by weight to about 15.0% by weight, so that the phosphoric acid can permeate the carbonaceous material;
- heating and agitating the mixture of carbonaceous material and phosphoric acid to a temperature of from about 160.degree. C. to about 280.degree. C. so as to effect dehydration of the mixture and so that the mixture becomes granular and of a free-flowing consistency;
- then thereafter heating said mixture of carbonaceous material in phosphoric acid to a temperature of from about 400.degree. C. to about 600.degree. C.;
- and
- washing the residue of the heated mixture with a sufficient amount of two streams of phosphoric acid-containing water, which streams flow past each other in opposite directions, to dissolve the acid which has been purified.
2 more elements
Dependencies are inferred from the claim text.