Process for the recovery of waste sulphuric acid
AssigneeCecebe Technologies Inc.
InventorGordon M. Cameron
Life of this patent
Estimating the term…
Abstract
A process for concentrating a waste sulphuric acid stream containing metal sulphates including iron sulphate comprises the steps of subjecting the stream to an ion exchange operation to produce an acid-rich stream and a salt-rich stream and, concentrating the acid-rich stream to produce a concentrated sulphuric acid stream.
Claims21
In a process for concentrating a waste sulphuric acid stream from a plant, said stream containing metal sulphates including iron sulphate, the concentration of said sulphates in said waste sulphuric acid stream being less than the solubility limit of said sulphates, the steps of:
- (i) subjecting said stream to an ion exchange operation to produce an acid-rich stream and a salt-rich stream, said operation being conducted to produce an acid-rich stream having an acid concentration above the concentration at which iron sulphate precipitates out as iron sulphate heptahydrate;
- and,
- (ii) concentrating said acid-rich stream to produce a concentrated sulphuric acid-rich stream
- whereby, during said steps, iron sulphate which precipitates out is in its monohydrate form.
A process comprising the steps of:
- (iii) providing a waste sulphuric acid stream containing metal sulphates including iron sulphate, said waste acid stream having a concentration of sulphates therein less than the solubility limit of said sulphates in said stream;
- (iv) subjecting said stream to an ion exchange operation to produce an acid-rich stream having a sulphuric acid concentration greater than about 50 wt. % and a salt-rich stream;
- and,
- (v) concentrating said acid-rich stream to produce a concentrated sulphuric acid-rich stream
- whereby, during said steps, iron sulphate which precipitates out is in its monohydrate form.
Dependencies are inferred from the claim text.