I= EXPLOITATION OF THE NATURAL RESOURCES OF PAKISTAN FOR THE RECOVERY OF METALS USED IN NUCLEAR REACTORS
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Title of Thesis
EXPLOITATION OF THE NATURAL RESOURCES OF PAKISTAN FOR THE RECOVERY OF METALS USED IN NUCLEAR REACTORS

Author(s)
Muhammad Haleem Khan
Institute/University/Department Details
Institute of Chemistry/ University of the Punjab
Session
1992
Subject
Chemistry
Number of Pages
322
Keywords (Extracted from title, table of contents and abstract of thesis)
natural resources, nuclear reactors, nuclear reactor technology, uranium, zirconium, thorium

Abstract
To evaluate the feasibility of the material used in nuclear x-ray reactor technology, seventy one metal bearing ore samples were collected from various localities of Pakistan These were analyzed by employing various instrumental analytical techniques such as atomic absorption, visible spectrophotometer fluorescence, flame photometry, radiometry and inductively coupled plasma-emission spectrometry €˜ICP€™. The Concentrations of uranium, thorium and zirconium were found upto 0.190%, 10.5% and 3.3% respectively. Calcium, magnesium, sodium, potassium, iron, aluminium and silica were the major ore constituents, while manganese, strontium, barium, zinc, hafnium and lead were present at trace levels in these samples.

The solvent extraction methods for the extraction of thorium and zirconium from their ore leached solutions using 30% and 40% (v/v) di-n-butylsulfoxide (OB50) in xylene from 2M HNO3 and 7M HNO3 aqueous solutions have been developed respectively. 95Zr radiotracer was used to follow the extraction of zirconium while, a spectrophotometric method has been developed and employed for the determination of thorium using 0.05%(w/v) thorin in 3M HCIO4 acid solution as chromogenic reagent. Absorbance was measured at 544 nm. Thorium-thorin complex was found quite stable for more than two months. Beer's law is obeyed from 1-26 µg/g of thorium in perchloric acid solution with molar absorptivity of ((544=1.69x104 dm3 mole-1 cm-1 at 26±2oC. Optimal conditions for solvent to metal ion concentration, equilibration time and temperature were established. The effect of various cations and anions on the extraction of these metals were also Separation factors (β) for these metals with respect mineral impurities present in the local ores were also calculated and discussed. The stoichiometric compositions of the complexes of thorium and zirconium with DBSO were determined by slope analysis and found to be 1:2 and 1:1 respectively. The process of thorium extraction was found exothermic in the temperature range studied (30-55°C) whereas, negligible effect on the extraction of zirconium was noted upto 50°C. Thermodynamic functions such as free energy (ˆ†G), enthalpy (ˆ†H) and entropy (ˆ†S) changes for thorium extraction have been determined. Deionized water and 1% ammonium bifluoride aqueous solution were found very effective for the back-extraction of thorium and zirconium respectively. The percent purity for extracted thorium was found to be > 98% whereas, for zirconium and zirconium it was noted >96%.

The recycling capacity of the organic solvent for the thorium and zirconium have been checked and found to be quite satisfactory. On the basic of data obtained at laboratory scale extraction studies, pilot plant schemes for the extraction and refining of these metals from their ores have been worked out. On the basis of analytical data, different areas of the country such as Dera Ghazi Khan, Isakhel and Rajanpur for uranium, Badar and Landhi for thorium and sonmiani, Mekran Coast for zirconium have been identified and suggested for ore exploitation.

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2020.92 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
93.46 KB
2 1 Introduction 1
106.69 KB
  1.1 The Economic Development And Energy Crisis In Pakistan 1
  1.2 Energy Resources 6
  1.3 Rationale For The Work Presented In This Thesis 13
  1.4 Thesis Layout 14
3 2 Nuclear Reactor Technology 15
198.25 KB
  2.1 Nuclear Reactor Technology 15
  2.2 Nuclear Reactors 16
  2.3 The Chemistry Of Nuclear Reactor Materials 25
  2.4 Uranium Ores And Minerals 32
  2.5 Zirconium As Reactor Structural Material 33
4 3 Extraction And Refining Of Metals 38
170.19 KB
  3.1 Extraction And Refining Of Metals 39
  3.2 The Liquid-Liquid Extraction 44
  3.3 Extraction Equilibrium In Chelate Extraction System 50
  3.4 Ion Association Complexes 53
  3.5 Extraction By Salvation Process 55
  3.6 Types Of Extraction Techniques 56
  3.7 Factors Of Prime Importance In Solvent Extraction To Metallurgical Processing 58
5 4 Procurement And Analysis Of Thorium, Uranium And Zirconium Bearing Ores From Various Locations Of Pakistan 65
365.27 KB
  4.1 Introduction 65
  4.2 Experimental 68
  4.3 Qualitative Analysis Of Ore Samples 75
  4.4 Quantitative Analysis Of Thorium, Uranium And Zirconium Bearing Ore Samples 79
  4.5 General Determination Procedures 88
  4.6 Procession And Accuracy In Determination Of Various Minerals Constituents In Ore Samples 100
  4.7 Results And Discussion 115
6 5 Spectrophotomertic Method For The Determination Of Thorium From Ore Samples 127
182.71 KB
  5.1 Introduction 127
  5.2 Experimental 130
  5.3 Optimization Of Thorium Determination Parameters 133
  5.4 Determination Of Thorium In ( Nbl ) Standard Ore Samples 138
  5.5 Results And Discussion 145
7 6 Studies On The Solvent Extraction/ Separation Of Thorium From Nitric Acid Solutions By Di -N-Butyl Sulfoxide In Xylene As An Extractant 155
366.08 KB
  6.1 Introduction 155
  6.2 Experimental 161
  6.3 Optimization Of The Parameters For Thorium Extraction 165
  6.4 Extraction Behaviour Of Impurities 175
  6.5 General Procedure For Thorium Extraction/Separation From Its Ores 179
  6.7 Stoichiometric Composition Of Thorium- Dbso Complex 182
  6.8 Extraction Of Thorium With 30% Dbso In Xylene From Hydrochloric Acid Solutions 184
  6.9 Results And Discussion 188
8 7 Solvent Extraction / Separation Of Zirconium From Nitric Acid Solution With Dibutylsulfoxide In Xylene As An Extractant 210
270.48 KB
  7.1 Introduction 210
  7.2 Experimental 215
  7.3 Optimization Of Parameters For The Extraction Of Zirconium 217
  7.4 Stoichiometric Composition Of Zirconium- Dbso Complex 225
  7.5 Test For The Efficiency Of Solvent Extraction Method 225
  7.6 Results And Discussion 231
9 8 Summary 248
54.18 KB
10 9 References 253
171.04 KB