AUTO CLAVE, HOT DIGESTION, and

ACID CURING

Kusdinar Davinci3334090821

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OUTLINE

1.Preview of Leaching2.Principal of Auto Clave , Hot

Digestion and Acid Curing3.Application4.Reference

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Preview of Leaching

Leaching is the procees of extracting a soluble constituent from a solid by means of a solvent.

The methods of Leaching is :1. In situ leaching2. Heap/Dump leaching3. Percolation/Vat leaching4. Pulp/agitation leaching5. Auto Clave6. Hot Digestion7. Acid Curing

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Principle of AutoClave

1. In absence oxygena.The ore (Bauxite) is heated with leaching agent at a temperature above boiling point to achieve a high reaction rate.b.The process must be in a closed vessel for keep vapor pressure of solution.c.The example is leaching bauxite with leaching agent NaOH (process Bayer).

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2.In Presence of oxygen :a.In this case the pressure formed from solution plus the oxygen pressure.

b.In this case the rate of leaching depends on the oxygen partial pressure.

c.This method is used mainly for uranium oxide ores

d. The autoclaves are operated at 80-150 psi and at about 120ºC,mounted on a slope (8º)

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Principle of Hot Digestion

1.This method is used highly concentrated solutions ( either acidic or basic).

2.The process used high temperature ( at or near the boiling point of the solution) combined with stirring.

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3.The process is an open vessel, heated externally and its operated batchwise.

4.Example of this process are the leaching of monazite sand in sulfuric acid.The temperature of procees is about 155º-200º C

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Heater

Leaching agentOre

Process of hot digestionStirrer

Principle of Acid Curing

1.The fines ore added water to about 10 % moisture.

2.Then concentrated sulfuric acid is added and material in bin is baked by heating.

3.The cured material is cooled with water and the pregnant solution is separated by filtration.

4.Example this process is leaching for decompose the selenides and tellurides of copper and silver

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Application

1.Example of auto clave methode is leaching of uranium oxide ores.

2.Example of hot digestion is leaching of monazite sand in sulfuric acid.

3.Example of acid curing is leaching for decompose the selenides and tellurides of copper and silver

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Flow sheet of leaching uranium oxide ore (Auto Clave)

Residu Sianidasi 0,02-0,1% U3O8

Leaching

Filtration

Pyrite flotation Roasting

H2SO4 manufacture

H2SO4

MnO2

Solution

Ion Exchange

Uranium Recovery

TailingsPyrite (2-3% of feed)

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uUranium recovery from South African gold ores

Flow sheet Leaching of monazite sand (Hot

Digestion)

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Flow sheet of leaching decompose the selenides and tellurides of copper and

silver (Acid Curing)

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Processing of anodic slimes from an Egyptian copper

Reference

• Fathi Habashi.”Extractive Metallurgy Vol.2 Haydrometallurgy”.

• Soesaptri Oediyani.”Diktat Kuliah Hidrometalurgi”.

• www.google.co.id

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Thank you for your attention

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