Process for the purification of iron salt solutions

Patent metadata

Field	Value
Publication number	US-9242877-B2
Application number	US-201213977313-A
Country	US
Kind code	B2
Filing date	Jan 6, 2012
Priority date	Jan 6, 2011
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

A process is provided for removing metal salt co-constituents from an iron-containing solution comprising: (a) decreasing the free acidity of the solution to produce a slurry; (b) optionally heating the solution or the slurry to a temperature at least 30° C.; (c) optionally aging the slurry; (d) adding one or more cationic polyelectrolyte flocculants to the slurry; and (e) separating a solid-containing portion from a liquid portion of the slurry.

First claim

We claim:

1. A process for removing metal salt co-constituents from an iron-containing solution comprising:
a. decreasing the free acidity of the solution to a pH of between about 0.5 and 1.5 to produce a slurry by adding a reactant selected from steel and a material which comprises Fe 3 O 4 ;
b. optionally heating the solution or the slurry to a temperature at least 30° C.;
c. optionally aging the slurry;
d. adding one or more cationic polyelectrolyte flocculants to the slurry; and
e. separating a solid-containing portion from a liquid portion of the slurry;
wherein the solid-containing portion comprises one or more metal salt co-constituents selected from titanium, zirconium or niobium;
wherein the liquid portion comprises iron-compounds.

2. The process of claim 1 , wherein the reactant is steel.

3. The process of claim 1 , wherein the reactant is a material which comprises Fe 3 O 4 .

4. The process of claim 1 , wherein the solution or slurry is heated to a temperature of at least 30° C.

5. The process of claim 1 , wherein the solution or slurry is heated to a temperature of 30° C. to 90° C.

6. The process of claim 1 , wherein the solution or slurry is further treated to enhance separation of the metal salt co-constituents from the iron-containing solution.

7. The process of claim 1 , wherein the slurry is treated with a cationic polymer that flocculates the solid portion separating it from the liquid portion.

8. The process of claim 1 , wherein the metal salt co-constituents remaining in the liquid portion are less than about 2% the amount of co-constituents in the original iron-containing solution.

9. The process of claim 1 , wherein the metal salt co-constituents remaining in the liquid portion are less than about 1% the amount of co-constituents in the original iron-containing solution.

10. The process of claim 1 , wherein the separation of the liquid portion from the solid portion comprises sedimentation, filtration, centrifugation or a combination thereof.

11. The process of claim 1 , wherein the iron-containing solution comprises about 8 to about 14% (weight/weight) ferric iron.

12. The process of claim 1 , wherein liquid portion comprises at least about 12% (weight/weight) ferrous iron.

13. The process of claim 11 , wherein liquid portion comprises about 12 to about 17% (weight/weight) ferrous iron.

14. The process of claim 1 , wherein the metal salt co-constituents remaining in the liquid portion are less than about 0.01% the amount of co-constituents in the original iron-containing solution.

15. The process of claim 1 , wherein the titanium remaining in the liquid portion are less than about 0.01% the amount of titanium in the original iron-containing solution.

16. The process of claim 1 , wherein the zirconium remaining in the liquid portion are less than about 0.05% the amount of zirconium in the original iron-containing solution.

17. The process of claim 1 , wherein the niobium remaining in the liquid portion are less than about 0.05% the amount of niobium in the original iron-containing solution.

Assignees

• St Amour Sheila
• Pavlicek Jan
• Kemira Oyj

Inventors

• St Amour Sheila
• Pavlicek Jan

Classifications

• C02F1/5245

  using basic salts, e.g. of aluminium and iron · CPC title

• C01G23/0475

  Purification · CPC title

• C02F1/02 Primary

  by heating (methods of steam generation F22B; preheating boiler feed-water or accumulating preheated boiler feed-water F22D) · CPC title

• C02F1/52 Primary

  by flocculation or precipitation of suspended impurities {(C02F1/463 takes precedence)} · CPC title

• C02F2101/20

  Heavy metals or heavy metal compounds · CPC title