Iron oxide precipitation from acidic iron salt solutions
AssigneeMetalox International, LLC
InventorsDarren Koningen, William J. Freund, David Bruce Dreisinger
Life of this patent
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Abstract
Improved methods for treating metallurgical compositions involve reacting a metallurgical composition with an aqueous nitric acid solution. The reaction is performed at a pressure or at least about 220 psig and at a temperature of at least 100° C. The metallurgical composition comprises iron and one or more non-ferrous metals. The reaction dissolves at least a portion of the non-ferrous metal compositions into the solution which is in contact with solid ferric oxide. The reaction can be repeated on the isolated solids to increase the purity of ferric oxide in the solids. Zinc can be removed from mixed metal solutions obtained from furnace dust by adding base to precipitate zinc hydroxide.
Claims21
A process for the production of ferric oxide precipitates having a particle size from about 0.1 to about 10 microns, the process comprising
- (a) obtaining an aqueous feed solution comprising iron solubilized in one member selected from the group consisting of nitric acid, sulfuric acid, and hydrochloric acid, the aqueous feed solution having a pH ranging from about 0.25 to about 2.5;
- and
- (b) subjecting the aqueous feed solution to a combination of
- (i) a temperature from about 100° C. to about 300° C.,
- (ii) a seeding ratio from about 20% to about 2000%, wherein the seeding ratio is a ratio of a weight of a seed solid to a weight of an expected unseeded precipitate product, and wherein the particle size of the ferric oxide precipitates is smaller than a particle size of the ferric oxide precipitates obtained with a seeding ratio of 0%, and
- pressures ranging from about 40 psig to about 1300 psig
- to obtain ferric oxide precipitates of the particle size from about 0.1 to about 10 microns.
Dependencies are inferred from the claim text.