CRYSTALLIZATION AS RECOVERY PROCESS FOR

HYDROMETALLURGY

Presented By :Miftahul Jannah

33340908591

OUTLINE

Introduction Theory

Applications Conclution Reference

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What is the Meaning Of Crystallization As RECOVERY PROCESS??

INTRODUCTION

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* Crystallization is one kind of many recovery methodes which is this process formation of solid crystals precipitating from a solution , melt or more rarely deposited directly from a gas .

*Recovery Process Is a valuable mineral retrieval process of leach solution

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Types of Recovery Methodes

1. Crystallizations

2. Adsorption

3. Ionic Precepitation

4. Precepitation by gases

5. Precepation by metals / Cementation

6. Ion Flotation and Precipitate Flotation

7. Ion Exchange

8. Solven Extraction

9. Electrolisis

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(Cont) CRYSTALLIZATION

- Crystallization separates a product from a liquid feedstream, often in extremely pure form, by cooling the feedstream or adding precipitants which lower the solubility of the desired product so that it forms crystals.

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Crystallization are Effected By 2 kind of

effect

Temperature&

Solubity

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Thermodynamic Vs

Kinetic Aspecs

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Thermodynamic Aspect

Textbook thermodynamics says that melting occurs because

the entropy , symbolized by “S”, gain in your system by spatial

randomization of the molecules has overcome the enthalpy , “H”, loss

due to breaking the crystal packing forces:

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(Cont)

The entropy decrease due to the ordering of molecules within the system is overcompensated by the thermal randomization of the surroundings, due to the release of the heat of fusion; the entropy of the universe increases.

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Kinetic Aspec Something that is kinetically stable

will desire to stay in the form of reactants, which will require an input of energy to cause the reaction to go forward, converting reactants into products.

It's almost as if a kinetically-stable reaction is stubborn and does not want to be converted into products

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Important  Things of Crystallization:

 1. Crystal Nucleation

2. Crystal growth.

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Crystal Nucleation

1. Primary nucleation

is the initial formation of a crystal where there are no other crystals present or where, if there are crystals present in the system, they do not have any influence on the process.

2. Secondary nucleation is the formation of nuclei attributable to the influence of the existing microscopic crystals.

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Crystal Growth

The pattern of growth resembles the rings of an onion, as shown in the picture, where each colour indicates the same mass of solute; this mass creates increasingly thin layers due to the increasing surface area of the growing crystal.

Fig 1. Crystal Growth 14

APPLICATIONS

Olin Process in Olin Mathieson Chemical Corporation.

In U.S Bureau of Mines of USA

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Flow Chart Olin Process

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Conclusions

Crystallization is one of many kind of Recovery Process which is Formed by leach solution to formation a solid crystal precipitations

The Important steps of Crystallization are : Crystal Nucleation and Crystal Growth

The Nucleation and Crystal Growth are Under kinetical Control rather than Thermodinamic control.

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REFFERENCE A. Mersmann, Crystallization Technology

Handbook (2001) CRC; 2nd ed. Tine Arkenbout-de Vroome, Melt

Crystallization Technology (1995) CRC Glynn P.D. and Reardon E.J. (1990)

"Solid-solution aqueous-solution equilibria: thermodynamic theory and representation". Amer. J. Sci. 290, 164–201.

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THANK YOU

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ANY QUESTIONS???