Process for concurrent steam generation and metal recovery

Claim 2

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° F. to 650° 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.

Claim 3

The process according to claim 1, wherein said feed material is fluid coke.

Claim 4

The process according to claim 1, wherein said feed material is fly ash.

Claim 5

The process according to claim 1, wherein said feed material contains sulphides of vanadium and nickel which are oxidized to sulfates in said wet oxidation reactor.

Claim 6

The process according to claim 1, wherein said feed material contains oxides of vanadium and nickel.

Claim 7

The process according to claim 1, wherein extraneous elemental sulphur is slurried with said feed material in step (a).

Claim 8

The process according to claim 1, wherein extraneous carbonaceous materials are slurried with said feed material in step (a).

Claim 9

The process according to claim 1, wherein sulphuric acid is added to said water in which said feed material is slurried.

Claim 10

The process according to claim 1, comprising the further step of supplying sulphur dioxide and/or sulphur trioxide to said wet oxidation reactor as the source of sulphur.

Claim 11

The process according to claim 1, wherein the pH of said slurry within the reactor is controlled at a level between 0.2 and 0.4.

Claim 12

The process according to claim 1, wherein cooling of said reactor offgases comprises recovery of heat to generate process steam at 35 psig or greater pressure.

Claim 13

The process according to claim 1, wherein said oxygen containing gas is compressed air, molecular oxygen or a mixture thereof.

Claim 14

The process according to claim 1, wherein vanadium pentoxide hydrates are precipitated from said liquor in step (c) by the addition of sodium perchlorate as an oxidizing agent.

Claim 15

The process according to claim 13, comprising the further step of adding an alkali to the perchlorate-oxidized slurry to adjust the pH to about 2.0 and accelerate precipitation of vanadium oxide hydrates.

Claim 16

The process according to claim 14, wherein said alkali comprises ammonia.

Claim 17

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° to 650° 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; and (g) filtering precipitated vanadium pentoxide from ammonia adjusted oxidized filtrate.

Claim 18

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° to 650° 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; and (g) filtering precipitated vanadium pentoxide from ammonia adjusted oxidized filtrate.

Claim 19

The process according to claim 16, comprising the further steps of: (h) subjecting the filtrate from step (g) to hydrogen and ammonia at a temperature of about 375° F. and elevated pressure of about 700 psig to precipitate nickel powder; and (i) recovering said nickel powder by filtration.

Claim 20

The process according to claim 17, further comprising the step of recovering ammonium sulphate from the filtrate from step (i).