Process for concurrent steam generation and metal recovery
AssigneeZimpro Inc.
InventorSong-P. Sit
Life of this patent
Estimating the term…
Abstract
Vanadium and nickel are recovered from fluid coke or fly ash concurrently with cogeneration of steam by a wet oxidation process at 500.degree.-650.degree. F. and elevated pressure, with a leaching pH of approximately 0.3 maintained by generation of sulfuric acid in situ. Vanadium products are precipitated by oxidation with for example sodium perchlorate with concurrent or subsequent pH adjustment to about pH 2. Following separation of the vanadium pentoxide, nickel powder is preferentially recovered by reduction with hydrogen and ammonia. Steam is generated by recovery of the thermal energy present in the offgases.
Claims18
A process for concentrating and recovering vanadium and nickel from feed material which contains vanadium, nickel, carbon, and sulphur, comprising the steps of:
- (a) slurrying said feed material in water and subjecting said material to temperatures of 500.degree. F. to 650.degree. F. and pressures of 1000 psig to 4000 psig in the presence of oxygen, while controlling the pH at a level of less than 1.0 in a wet oxidation reactor to generate, in situ, a liquor containing sulphuric acid and soluble compounds of vanadium and nickel, and simultaneously produce heat for co-generation of steam;
- (b) removing suspended solids from said liquor;
- (c) sequentially precipitating, removing and recovering vanadium and nickel products in concentrated form from said liquor;
- and
- (d) cooling the reactor offgases.
A process for concurrent steam generation and the recovery of vanadium and nickel from fly ash, comprising the steps of:
- (a) slurrying said fly ash and elemental sulphur in water and subjecting said slurry to temperatures of 500.degree. to 650.degree. F. and pressures of 1000 to 4000 psig in the presence of air or oxygen within a wet oxidation reactor;
- (b) regulating the addition of elemental sulphur to said slurry of fly ash to result in a pH value of 0.2-0.3 within said reactor;
- (c) discharging off-gases from the reactor at elevated pressure and temperature to a heat exchanger to generate steam;
- (d) withdrawing oxidized slurry from said reactor and removing suspended solids therefrom by filtration to produce a filtrate containing vanadium and nickel compounds;
- (e) adding sodium perchlorate to said filtrate to oxidize vanadium oxides to the pentoxide state;
- (f) adding ammonia to oxidized filtrate to achieve pH about 2 to precipitate vanadium pentoxide;
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- (g) filtering precipitated vanadium pentoxide from ammonia adjusted oxidized filtrate.
Dependencies are inferred from the claim text.