Describing relationship between concentration and purification units with solvent extraction.

Supervisor

Dr . Karimi

Hamid faramarzi926181008

Imam Khomeini International University, Qazvin, Iran.

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Content

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Introduction

Steps for Concentration and purification

Concentration and purification copperConcentration and purification zincConcentration and purification uranium

Reference

Conclusion

Solid-Liquid Separation Separation & Purification

Examples for Concentration and purification

Solvent extraction

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Leaching processes are rarely, if ever, completely selective and, therefore, pregnant leach solutions contain impurities and will almost always require purification prior to final metal winning.[4]

Solvent extraction is now a very well-established process in hydrometallurgy. It is used for the hydrometallurgical processing of copper, nickel, cobaIt, zinc,uranium and etc.[4]

Iron removal from nickel-cobalt process liquors, is one case.[4]

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Introduction

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solution purification which obtained from depending on the number and concentration of interfering ions in solution is done in many different ways had the concentration of impurities in solution obtaind from leaching process be specific excessive it would caused some problems in electrowining recovery.[2]

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Introduction

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Steps for Concentration

and purification

Solid-Liquid Separation

Filtration (incl micro-and nano -filtration)

Thickening & clarification

(inclcoagulation, flocculation)

Counter-current

decantationFlocculation

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[8]

Steps for Concentration

and purification

Ion Exchange Solvent Extraction

Adsorption on Carbon

Precipitation of Impurities

Separation & Purification

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[8]

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The net result of the technology involving the three principal stages, namely, extraction, scrubbing and stripping, is the separation of an impure aqueous stream into two aqueous streams, one containing most of the impurities and the other containing most of the valuable metal ions.

Solvent extraction provides the means for producing pure, high Cu" electrolytesfrom dilute, impure pregnant leach solutions. It is a crucial step in theproduction of -2.5 million tonnes of metallic copper per year.[9]

Solvent extraction

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Solvent extraction is used for separation and concentration of metal ions in aqueous solutions. The method is based on that an extraction agent, diluted with an organic solvent, is mixed by stirring or shaking with an aqueous solution containing the desired metal. The extraction agent and the organic solvent are both insoluble in water..

By mixing the aqueous and organic phase, the metal ion binds to the extraction agent and is transferred to the organic phase. Thereafter, the organic and aqueous phases are allowed to disengage and then the two phases are separated.[9]

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Solvent extraction

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The organic extractant removes Cu++ from pregnant leach solution by the reaction

So contact of dilute H2so4 aqueous pregnant leach solution with organic gives extraction of Cu from the aqueous phase into the organic phase.[5]

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Solvent extraction

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From the reactions above it is apparent that the pH dependence for extraction and

stripping is greater for Fe3+ than for Cu2+,. By using a pH between 1.5 and 2.0 Cu2+

can be extracted selectively.[3]

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Solvent extraction

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Concentration and purification

of copper

The pregnant leach solutions produced by most leaching operations are:(a) too dilute in Cu (1-6 kg Cu/m3) and: (b) too impure (1 - 10 kg Fe/m3)for direct electrodeposition of high purity cathode copper.[5]

This high concentration of Cu:

(a) ensures that CU++ ions are always available for plating at the cathode surface

(b) gives smooth, dense, high purity, readily marketable cathode copper.[5]

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Schematic plan view of copper solvent extraction circuit.

Solvent extraction circuit that has been perturbed by receiving 3.3 kg Cu/ M3 pregnant leach solution.[5]

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Concentration and purification

of copper

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Copper solvent extraction mixer-settler. The two mixing compartments, the large settler and the organic overflow/aqueous underflow system are notable.[5]

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Concentration and purification

of copper

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Rejection of Fe and other impurities

An efficient extractant must carry Cu forward from pregnant leach solution to electrolyte while not forwarding impurities, particularly Fe, Mn and CI. [9]

Industrial electrowinning requires pure, Cu-rich electrolytes with >35 kg Cu/m3.Electrowinning. [9]

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Concentration and purification

of copper

One of the main influence impurities in Hydrometallurgical method zinc is producing iron.

Concentration and purification of zinc I done in two steps:

1- iron prevent from dissolution some parts of zinc and reduce the recovery

2- iron ion act as a disrupting thing.[10]

The best qualification of ph for sedimenting ferric hydroxide is 5-5.5

With iron residual most of impurities such as As , Sb , Ge , will sediment.[11]

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Concentration and purification

of zinc

Removal of iron from the leach solution:

1- sedimenting iron ion 2- eliminating impurities by the powder of zinc . (cementation) [10]

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Mn impurities in the pregnant solution reduces recovery of the organic phase and electrolyte Raffinate.

Element name g/l

Cadmium 0.002 - 0.004

Copper 0.0001 – 0.0005

Iron 0.02 – 0.03

Arsenic 0.0001

Antimony 0.0001

Cobalt 0.003 – 0.007

Manganese Less than 0.7

Concentration and purification

of zinc

Permitted levels of elements in the input solution Electro wining [11]

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Extraction mechanism equation

Zinc concentration in the aqueous phase (g/lit) [11]17

Concentration and purification

of zinc

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ion manganese iron copper zinc

Concentration( g / lit)

0.154 0.0094 0.001 15

The final concentration of electrolyte ions in the washing of the organic phase .[11]

Number of extraction are three stages

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Concentration and purification

of zinc

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Concentration and purification

of uranium

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Solvent extraction is a common technique used to recover uranium from sulphuric acid leach liquors. The tertiary amines are selective for uranium in the presence of impurities such as iron thorium , phosphate and rare earths.[6]

[7]

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Concentration and purification

of uranium

The presence of chloride in Sulfuric acid leach liquors has a negative impact on the solvent extraction process for the recovery of uranium using tertiary amine reagents.[1]

In practice, the chloride concentration in process liquors tends to be limited to <3 g/L chloride, so as not to significantly affect uranium solvent loading.[11]

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conclusion

1) Solvent extraction is now a very well-established process in hydrometallurgy.

2) Steps for Concentration and purification.Solid-Liquid Separation Separation & Purification3) is the separation of an impure aqueous stream into two aqueous streams, one

containing most of the impurities and the other containing most of the valuable metal ions.

4) By mixing the aqueous and organic phase, the metal ion binds to the extraction agent and is transferred to the organic phase .

5) An efficient extractant must carry Cu forward from pregnant leach solution to electrolyte while not forwarding impurities, particularly Fe, Mn and CI.

6) One of the main influence impurities in Hydrometallurgical method is producing iron.

7) Solvent extraction is a common technique used to recover uranium from sulphuricacid leach liquors.

8) In practice, the chloride concentration in process liquors tends to be limited to <3 g/L chloride.

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References

[1] Concentration–Purification of Uranium from an Acid LeachingSolution.H. Guettaf*, A.Becis, K. Ferhat, K. Hanou, D. Bouchiha, K. Yakoubi and F. Ferrad. 2009

[2] A short history of hydrometallurgy Fathi HabashiDepartment of Mining, Metallurgical, and Materials Engineering, Laval University.

[3] Hydrometallurgy solvent extraction of Cu2+ using LIX-984

[4] Unit processes in extractive metallurgy , Robert D. Pehlke.

[5] Extractive Metallurgy of Copper, W.G.Davenport , M. king , M.schlesinger , A.K. biswas.

[6] Solvent extraction of uranium from saline leach liquors using DEHPA/Alamine 336mixed reagent James E. Quinn, Deborah Wilkins, Karin H. Soldenhoff,Hydrometallurgy vol 134–135 (2013) 74–79

[7] Uranium Extraction Technology , International Atomic Energy Agency , VIENNA ,1993.

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[8] http://www.parkercentre.com.au/hydrometallurgy/classification-of-processes-in-hydrometallurgy

[9] Chemical Metallurgy , Chiranjib Kumar Gupta , 2003

1378,سعید مرادی دانشجوی ارشد تربیت مدرس ,تولید فلز روی به روش هیدرومتالورژی [10]

منوچهر ,عوامل موثر بر استخراج حاللی روی از محلول حاوی یونهای آهن و منگنز محمد رضا بلور فرش [11]

1386 ,خداکرم غریبی,اولیازاده

References

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Thank from your attention.

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