in situ and hot digestion

8/6/2019 In Situ and Hot Digestion

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SALAMUALAIKUM WR.

Sit back, Relax, and Enjoy.

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IMAM FAZRI PATAR M (3334081621))(INSITU AND HOT DIGESTIONLEACHING

May 24, 2011 :

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Outline

Preface

In Situ Leaching

Hot Digestion Leaching

References

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Preface

Hydrometallurgy :

1. Leaching

2. Solid Liquid Separation

3. Recovery

Leaching :a process to extract certain mineral as much as

possible from an ore and to dissolve gangue as lowas possible and it use certain solvent called leachingagent.

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IN SITU LEACHING

In Situ Leaching (ISL), it is leaching in place.

Leaching in where mineral located

It take a long time

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Step of Process

Injection

Well

Production

Well

Injection

Well

Soil

Orebody

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This is the method to take thepregnant solution without pump tool.


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The flow of groundwater is determined by differences in water

pressure. Thus, if the injection of solutions were to lead to

excessive pressures in the mining zone, this increases the

chances of those solutions escaping since the pressure gradients

would be away from the injection/extraction well system. To

overcome this, ISL mines always extract more water than they

inject. This tries to ensure that there is an overall decrease of

pressure in the local area of injection and extraction and water

will always flow towards the extraction well. The amount of this

excess extraction generally ranges between 0.5 to 5% of the

water injected. This extra water is known as the bleed solution

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This is the method to take pregnant solutionwith submersible pump

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Click to edit Master text stylesSecond level Third level Fourth level Fifth level


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In recovery well a submersible pump(2-10 Hp) is placed just above the orezone to pump out leached out solutionto the surface.

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What do the next after the pregnant

solution pump out to the surface?

The solution is brought to the surfaceprocessing plant. Here, it is treated with

chemicals that cause the uranium fromthe solution to precipitate from thesolution. The remaining solution is

returned underground from where itoriginally came.

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This is the complete picture ofISL

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Factor of Process

2. Access of theleaching

agent to oresurface

1. Soluble anddissolublemineral

3. Occurrence ofthe ore

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The occurence of orebody

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The deposits that typically meet these criteria are usually found in

sandstones or in the sands of palaeochannels (old river beds). The

uranium is dissolved from an area of primary mineralisation (ie - the

original source rocks that contain uranium) and transported through

flowing groundwater. In order to dissolve the uranium, the water must

be oxidising. When the water reaches a part of the aquifer that is

reducing, the uranium precipitates out of solution to form insoluble

minerals such as coffinite (USiO4) or uraninite (UO2). The deposition of

uranium occurs on the surface of sand grains as the oxidising

groundwater flows through the reducing part of the aquifer,

progressively enriching the deposit. Such deposits are known as roll

front or geochemical cell type ores, and are typically long and narrow

and tens of metres thick

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Advantage

Can extract the low grade ore

Reduce the environmentaldamage

Reduce the risk for thepersonel

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The technique of in-situ leaching is a relatively unknown

method in India, though it is largely practiced and

successfully implemented in almost all mineral-rich

countries of the world. Extraction in this method is

accomplished through the dissolution of natural inplace

metal in underground and recovery of the leached solution

from underground for further processing. This is achieved

by introducing a suitable solvent liquid into the ore body

through the wells, allowing the liquid to pass through the

ore body for desired period so as to dissolve the metal and

finally recovering the pregnant liquor through other wells.

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Application

Uranium leaching with Sulfuric Acid asleaching agent

UO3 + H2SO4 UO2SO4 + H2O

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LOGO Hot DigestionLeaching

It is a leaching process in hot openvessel and it use acid or basic

leaching agent.

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LOGO

1. High Temperature

2. High concentration

leaching agent

3. Use

stirring

process

4. Faster time of leaching

5. Batch system Characteristicsof process

Characteristics

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LOGO

2121

Batch system is not continous system. It

means one process to the other process in

difference place. After one process is finish,it must move to the other to go to the next

process.


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LOGO Step of Process

Ore

Leaching agent

Heater

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LOGO

2323

In this methode, it use tank for leaching not

vessel. Because this process without added

pressure. If we use adding pressure we must use

vessel.


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LOGO Factors of Process

Factors

Concentration

of leaching

agent

Leaching

time

Temperature

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LOGO Application

Vanadium leaching and it use H2 SO4as leaching agent.

2 V2O3 + 4 H2SO4 + O2 4 VOSO4 + 4 H2O

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References

1. Beri, K.K and Sarangi, A.K. Uranium Mining By In Situ Leaching.

2000 : 1-8. [May 20, 2011]

2. Habashi, Fathi. 1980. Extractive Metallurgy. London : Gordon

and Breach

3. Xian-yang, Chen, etc. Leaching Vanadium By High Concentration

Sulfuric Acid From Stone Coal. 2009 : 1-4.7. Mud, Gavin. The Case Against Uranium Solution Mining. 2008

9. International Atomic Agent Agency. Manual of Acid In Situ Leach

Uranium Mining Technology. 2001

10. World Nuclear Association. In Situ Leach (ISL) Mining ofUranium. 2010. http://www.world-nuclear.org/. [May 25, 2011]

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http://www.world-nuclear.org/http://www.world-nuclear.org/http://www.world-nuclear.org/


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L/O/G/O

Thank You !

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