Concentration and Purification Processes Using Solvent Extraction
1. Describing relationship between concentration and purification
units with solvent extraction.
Supervisor
Dr . Karimi
Hamid faramarzi
926181008
Imam Khomeini International
University, Qazvin, Iran.
1
2. Content
2
Introduction
Steps for Concentration and purification
Solid-Liquid Separation
Separation & Purification
Solvent extraction
Examples for Concentration and purification
Concentration and purification copper
Concentration and purification zinc
Concentration and purification uranium
Conclusion
Reference
3. 3
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]
3
Introduction
4. 4
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]
4
Introduction
6. Steps for
Concentration
and purification
Separation &
Purification
Ion Exchange Solvent
Extraction
Adsorption
on Carbon
Precipitation
of Impurities
6
[8]
7. 7
Solvent
extraction
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" electrolytes
from dilute, impure pregnant leach solutions. It is a crucial step in the
production of -2.5 million tonnes of metallic copper per year.[9]
8. 8
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]
8
Solvent
extraction
9. 9
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]
9
Solvent
extraction
10. 10
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]
10
Solvent
extraction
11. 11
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]
11
12. 12
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]
12
Concentration
and purification
of copper
13. 13
Copper solvent extraction mixer-settler. The two mixing compartments, the large settler and the organic
overflow/aqueous underflow system are notable.[5]
13
Concentration
and purification
of copper
14. 14
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]
14
Concentration
and purification
of copper
15. One of the main influence impurities in Hydrometallurgical method zinc is producing iron.
Concentration and purification of zinc I done in two steps:
1- sedimenting iron ion
2- eliminating impurities by the powder of zinc . (cementation) [10]
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]
15
Concentration
and purification
of zinc
Removal of iron from the leach solution:
16. 16
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]
16
17. 17
Extraction mechanism equation
Zinc concentration in the aqueous phase (g/lit) [11]
17
Concentration
and purification
of zinc
18. 18
Number of extraction are three stages
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]
18
Concentration
and purification
of zinc
19. 19
Concentration
and purification
of uranium
19
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]
20. 20
20
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]
21. 21
conclusion
1) Solvent extraction is now a very well-established process in hydrometallurgy.
2) Steps for Concentration and purification.
Solid-Liquid Separation
Separation & Purification
3) 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 sulphuric
acid leach liquors.
8) In practice, the chloride concentration in process liquors tends to be limited to <3
g/L chloride.
22. 22
22
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 Habashi
Department 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 336
mixed 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.
