Top-entry flash vessel arrangement

Patent metadata

Field	Value
Publication number	US-9920396-B2
Application number	US-201314653238-A
Country	US
Kind code	B2
Filing date	Dec 30, 2013
Priority date	Dec 28, 2012
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

The present invention relates to a method and an arrangement for pressure and temperature let down of autoclave discharge slurry, in particular in pressure oxidation or high pressure acid leach of metal containing ore. The method of the invention comprises a step of providing autoclave vent gas obtained from the autoclave to the top-entry flash vessel for inducing overpressure to the top-entry flash vessel and preventing boiling of the slurry during the transfer to next top-entry flash vessel. The invention further relates to an autoclave and pressure let-down arrangement adapted for providing autoclave vent gas to one or more top-entry flash vessels.

First claim

The invention claimed is:

1. A method for pressure and temperature let-down of a pressure oxidation autoclave discharge slurry, characterized in that the method comprises
(a) receiving an autoclave discharge slurry from an autoclave to a first top-entry flash vessel;
(b) obtaining a first flash steam and a first cooled slurry by allowing the autoclave discharge slurry to flash in the first top-entry flash vessel;
(c) transferring the first cooled slurry from a bottom part of the first top-entry flash vessel to a top part of a second top-entry flash vessel; and
(d) providing, simultaneously with the steps (b) and (c), autoclave vent gas obtained from the autoclave to the said first top-entry flash vessel for inducing overpressure to the first top-entry flash vessel and preventing boiling of the first cooled slurry during the transfer to the second top-entry flash vessel;
(e) obtaining a second flash steam and a second cooled slurry by allowing the first cooled slurry to flash in the second top-entry flash vessel.

2. The method as claimed in claim 1 , wherein step (b) additionally comprises providing supplementary inert gas to the said first flash vessel for providing further overpressure to the first flash vessel.

3. The method as claimed in claim 1 , wherein the overpressure is 20 to 50 kPa.

4. The method as claimed in claim 1 , wherein the first and second flash vessel are substantially at the same horizontal level.

5. The method as claimed in claim 1 , wherein the method further comprises
(f) transferring the second cooled slurry from a bottom part of the second top-entry flash vessel to a top part of a third top-entry flash vessel;
(g) providing, simultaneously with steps (e) and (f), autoclave vent gas obtained from the autoclave to the said second top-entry flash for inducing overpressure to the second top-entry flash vessel and preventing boiling of the second cooled slurry during the transfer to the third top-entry flash vessel.

6. The method as claimed in claim 5 , wherein the first, second and third flash vessel are aligned substantially on the same horizontal level.

7. The method as claimed in claim 1 , wherein no cool water or aqueous liquid is injected to the flash system for preventing boiling of the slurry during transfer from one flash vessel to the next flash vessel.

8. The method as claimed in claim 1 , wherein the pressure oxidation autoclave discharge slurry is obtained from an autoclave adapted for pressure oxidation or high pressure acid leach of metal containing ore.

Assignees

• Outotec Finland Oy

Inventors

• O'Callaghan John

Classifications

• C22B3/02

  Apparatus therefor · CPC title

• B01J3/04

  Pressure vessels, e.g. autoclaves · CPC title

• C22B3/04

  by leaching (C22B3/18 takes precedence) · CPC title

• C02F1/06

  Flash evaporation · CPC title

• C22B3/00 Primary

  Extraction of metal compounds from ores or concentrates by wet processes · CPC title