Nozzle for low pressure flash tanks for ore slurry
AssigneeBarrick Gold Corporation
InventorsRichard Williams, Larry Enloe, Paul Wilmot, David Dixon
Life of this patent
Estimating the term…
Abstract
A wear-resistant flash tank pressure let down nozzle for use in passing an ore slurry into an ore slurry flash tank to release steam from the slurry and reduce the pressure of the slurry. The nozzle has an expansion cone flaring toward the discharge end of the nozzle. The cross-sectional area of a choke section of the nozzle and the exit diameter of the expansion cone are selected to establish a relationship between pressure upstream of the nozzle and pressure in the flash tank so that underflashing, overflashing, and shock waves inside the flash tank are minimized.
Claims20
An ore slurry flash tank apparatus for receiving and holding pressure oxidized ore slurry for reducing the pressure of ore slurry, the apparatus comprising:
- a vessel having a bottom, a top, and side walls;
- a wear-resistant flash tank pressure let down nozzle mounted on said vessel for use in passing ore slurry into said vessel to release steam from the slurry and reduce the pressure of the slurry, the nozzle comprising an inlet end, a discharge end, a tubular passageway extending therebetween for passage of the slurry from a location outside the flash tank in fluid flow communication with said inlet end, the slurry passageway comprising a choke comprising a zone of the passageway in which its cross-sectional area is smallest, the passageway flaring with respect to the axis thereof toward said discharge end to define an expansion cone;
- and
- the cross-sectional area of the choke and the exit diameter of the expansion cone being selected to establish a relationship between pressure upstream of the nozzle and pressure in the flash tank so that shock waves inside the flash tank are weaker than shock waves inside a reference flash tank having identical dimensions and configuration and operating under identical conditions except having a reference pressure let down nozzle consisting of a straight choke.
An ore slurry flash tank apparatus for receiving and holding pressure oxidized ore slurry for reducing the pressure of pressure oxidized gold ore slurry, the apparatus comprising:
- a vessel having a bottom, a top, and side walls;
- a wear-resistant flash tank pressure let down nozzle comprising an inlet end, a discharge end, a tubular passageway extending therebetween for passage of the slurry from a location outside the flash tank in fluid flow communication with said inlet end, the slurry passageway comprising a choke comprising a zone of the passageway in which its cross-sectional area is smallest, the passageway flaring with respect to the axis thereof toward said discharge end to define an expansion cone;
- and
- the cross-sectional area of the choke and the exit diameter of the expansion cone being selected to establish a relationship between pressure upstream of the nozzle and pressure in the flash tank so that shock waves inside the flash tank are weaker than shock waves inside a reference flash tank having identical dimensions and configuration and operating under identical conditions except having a reference pressure let down nozzle consisting of a straight choke.
An apparatus for preheating gold ore slurry prior to pressure oxidation and for reducing the pressure of pressure oxidized gold ore slurry after pressure oxidation, the apparatus comprising:
- a flash tank for receiving a volume of pressure oxidized gold ore slurry, the flash tank comprising a vessel having a bottom, a top, and side walls;
- a nozzle on the top of the vessel for passing ore slurry into the vessel, the nozzle comprising an inlet end, a discharge end, a tubular passageway extending therebetween for passage of the slurry from a location outside the flash tank in fluid flow communication with said inlet end, the slurry passageway comprising a choke comprising a zone of the passageway in which its cross-sectional area is smallest, the passageway flaring with respect to the axis thereof toward said discharge end to define an expansion cone;
- the cross-sectional area of the choke and the exit diameter of the expansion cone being selected to establish a relationship between pressure upstream of the nozzle and pressure in the flash tank so that shock waves inside the flash tank are weaker than shock waves inside a reference flash tank having identical dimensions and configuration and operating under identical conditions except having a reference pressure let down nozzle consisting of a straight choke;
- a steam outlet for passing steam out of the flash tank;
- a splash condenser for contacting ore slurry with steam prior to pressure oxidation of the ore slurry in order to preheat the ore slurry, the splash condenser having a steam inlet;
- and
- conduit for transferring steam from the steam outlet of the flash tank to the splash condenser.
A process for reducing the pressure of pressure oxidized ore slurry from above about 100 psig to about atmospheric, the process comprising passing up to about 500 tons per hour ore slurry comprising between about 30% and about 70% solids by weight through a nozzle into a flash tank, the nozzle disposed on the top of the flash tank and comprising a receiving end and a discharge end, and a slurry passageway extending through the nozzle from the receiving end to the discharge end for passage of the slurry into the flash tank from a location outside the flash tank, the passageway flaring with respect to the axis thereof toward said discharge end to define an expansion cone, and the cross-sectional area of the choke and the exit diameter of the expansion cone being selected to establish a relationship between pressure upstream of the nozzle and pressure in the flash tank so that shock waves inside the flash tank are weaker than shock waves inside a reference flash tank having identical dimensions and configuration and operating under identical conditions except having a reference pressure let down nozzle consisting of a straight choke.
An ore slurry flash tank apparatus for receiving and holding pressure oxidized ore slurry for reducing the pressure of pressure oxidized gold ore slurry from between about 100 psig and about 140 psig to about atmospheric, the apparatus comprising:
- a vessel having a bottom, a top, and side walls;
- a nozzle on the top of the vessel for passing ore slurry into the vessel, the nozzle comprising an inlet end, a discharge end, a tubular passageway extending therebetween for passage of the slurry from a location outside the flash tank in fluid flow communication with said inlet end, the slurry passageway comprising a choke comprising a zone of the passageway in which its cross-sectional area is smallest, the passageway flaring with respect to the axis thereof toward said discharge end to define an expansion cone;
- and
- the nozzle having a choke diameter of between about 3.8 and about 4.1 inches corresponding to the smallest cross-section in the slurry passageway, the straight section having a length of between about 91/2 and about 101/2 inches, an expansion cone exit diameter of between about 7.1 and about 7.4 inches, an expansion cone length of between about 6 inches and about 6.2 inches, and an expansion cone half angle of between about 14.degree. and about 16.degree., to establish a relationship between pressure upstream of the nozzle and pressure in the flash tank so that under a flowrate of up to about 500 tons per hour of ore slurry comprising between about 30% and about 70% solids by weight, shock waves inside the flash tank are weaker than shock waves inside a reference flash tank operating under identical conditions except having a reference pressure let down nozzle comprising a straight choke.
Dependencies are inferred from the claim text.