Rare earth recovery from copper ore processing waste and application as fertilizer for tea plants and some vegetables in Da Lat, Lam Dong province

MINISTRY OF EDUCATION AND TRAINING VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY

INSTITUTE OF CHEMISTRY

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Study on Extraction of Cerium and Rare Earth (III) from Total Rare Earth Oxides

“RECOVERY OF RARE EARTH FROM COPPER ORE REFINING WASTE FOR APPLICATION AS FERTILIZER

FOR TEA PLANTS AND SOME VEGETABLES IN DA LAT, LAM DONG ”

Major: Inorganic Chemistry Code: 62.44.01.13

DOCTORAL THESIS IN CHEMISTRY

Scientific guidance team:

1. Associate Professor, Dr. Luu Minh Dai

2. Dr. Pham S

Hanoi, 2014

COMMITMENT

I hereby declare that this is my own research work. The data and results in the thesis are honest and have not been published in any other work.

Thesis author

Nguyen Thanh Anh

ACKNOWLEDGEMENTS

This thesis was conducted at the Inorganic Materials Laboratory, Institute of Materials Science, Vietnam Academy of Science and Technology.

I would like to sincerely thank the Board of Directors of the Vietnam Academy of Science and Technology, the Board of Directors of the Institute of Chemistry, the Institute of Materials Science, the Inorganic Materials Laboratory and the scientists who helped and gave me advice during the process of writing my thesis.

I would like to sincerely thank my family and friends for their encouragement and support during the research of this thesis.

In particular, I would like to express my deep gratitude to Associate Professor, Dr. Luu Minh Dai and Dr. Pham S for their dedicated guidance and help in successfully completing my thesis, Dr. Dao Ngoc Nhiem, Associate Professor, Dr. Nguyen Mong Sinh, Associate Professor, Dr. Dao Quoc Huong, Associate Professor, Dr. Vo Van Tan, Associate Professor, Dr. Vo Quang Mai for their help, comments and discussions with me during the process of experimentation, writing and completing the thesis.

Hanoi, March 20, 2014 Author

Nguyen Thanh Anh

INDEX

INTRODUCTION

Chapter 1. DOCUMENT OVERVIEW

1.1. Rare earth minerals 3

1.1.1. Rare earth minerals in Vietnam 3

1.1.2. Sin Quyen 3 copper mine

1.1.3. Sin Quyen 4 copper ore processing waste

1.2. Rare earth ore processing technology 5

1.2.1. Enrichment of rare earth ores 5

1.2.2. Separation of total rare earth oxides 7

1.2.2.1. Separation of total rare earth oxides from monazite ore 7

1.2.2.2. Separation of total rare earth oxides from basnesite ore 9

1.2.2.3. Separation of total rare earth oxides from other ores 9

1.3. Complex forming ability of NTĐH 9

1.4. Separation of essential oils by liquid-liquid extraction method 12

1.4.1. Theoretical basis of liquid-liquid extraction method 12

1.4.1.1. Concept 12

1.4.1.2. Distribution coefficient 12

1.4.1.3. Extraction percentage (E%) 12

1.4.1.4. Refractive index (Sk ) 13

1.4.1.5. Separation coefficient β 13

1.4.2. Extraction agent 14

1.4.3. Extraction of NTĐH with neutral organophosphorus compounds 15

1.4.4. Effect of salt on extraction efficiency 17

1.5. Applications of NTĐH in agriculture 18

1.6. Introduction to tea plants and some popular vegetables in Dalat 20

1.6.1. Introduction to tea tree 20

1.6.2. Introduction to cabbage 21

1.6.3. Introduction to lettuce 21

Chapter 2: CHEMICALS, INSTRUMENTS AND RESEARCH METHODS

2.1. Main chemicals 24

2.1.1. Extraction agents and dilution solvents 24

2.1.2. Rare earth salt solution 24

2.1.3. Acetate buffer solution 24

2.1.4. DTPA 24 standard solution

2.1.5. Other chemicals 25

2.2. Research methods 25

2.2.1. Method of selecting and enriching rare earth ores from copper ore selection waste Sin Quyen 25

2.2.2. Recovery of total rare earth oxides from the rare earth rich fraction by acid method

................................................................ ................................................................ ..............................................26

2.2.3. Recovery of total rare earth oxides from rare earth rich fraction by alkaline method 27

2.2.4. Method of extraction and separation of essential oils 28

2.2.5. Method of synthesizing rare earth complexes with lactic acid 29

2.2.6. Experimental arrangement method to study the growth stimulation of tea and vegetable plants in Da Lat, Lam Dong by rare earth lactate complex 30

2.2.6.1. For tea plants 30

2.2.6.2. For outdoor cabbage 31

2.2.6.3. For outdoor planting of oro trees 32

2.2.6.4. For Romanian rosewood in 33-degree watering house

2.3. Methods of testing analysis 34

2.3.1. Determination of acid concentration 34

2.3.2. Determination of total content of rare earth elements in concentrate 35

2.3.3. Determination of total content of rare earth elements and thorium in the fractional extraction process

............................................................................................................................................35 2.3.4. Determination of the content of each element...........................................................................36

2.3.4.1. Ion exchange chromatography combined with microquantitative titration 36

2.3.4.2. Quantitative analysis of elements by IP - AES 36

2.3.5. Determination of parameters of rare earth extraction process 37

2.3.5.1. Distribution coefficient D of NTĐH 37

2.3.5.2. Determination of extraction capacity 37

2.3.6. Method for determining the composition and properties of the complex of NTĐH(III) with lactic acid 37

2.3.6.1. Composition of complex 37

2.3.6.2. Conductivity of complex solution 38

2.3.6.3. Thermal analysis method 39

2.3.6.4. Infrared spectroscopy method 40

2.3.7. Method of processing and analyzing data to evaluate crop yield and quality

................................................................ ................................................................ ..............................................41

Chapter 3: RESULTS AND DISCUSSION

3.1. Research on rare earth enrichment from Sin Quyen copper ore processing waste

................................................................ ................................................................ .......................... 42

3.1.1. Results of waste composition analysis 42

3.1.2. Experimental results of rare earth enrichment 43

3.1.3. Results of analysis of rare earth rich fraction 45

3.2. Research on rare earth recovery by acid method 46

3.2.1. Research on rare earth recovery by acid leaching method 46

3.2.1.2. Nitric acid extraction method 47

3.2.1.3. Sulfuric acid extraction method 48

3.2.1.4. Effect of leaching time on rare earth recovery efficiency... 48

3.2.2. Hydrometallurgical method with heating using sulfuric acid solution 49

3.2.2.1. Effect of sulfuric acid concentration on rare earth recovery efficiency at different temperatures 50

3.2.2.2. Effect of H2SO4 ore ratio on rare earth recovery efficiency 51

3.2.2.3. Effect of decomposition time on rare earth recovery efficiency 52

3.2.2.4. Effect of initial ore treatment temperature on rare earth recovery efficiency53

3.2.3. Hydrometallurgical method using sulfuric acid under microwave effect 54

3.2.3.1. Effect of microwave power and acid concentration on rare earth recovery efficiency 54

3.2.3.2. Effect of H2SO4 ore ratio on rare earth recovery efficiency 54

3.2.3.3. Effect of hydrometallurgy time on rare earth recovery efficiency 55

3.2.4. Hydrometallurgical method with sulfuric acid at high temperature 56

3.2.4.1. Effect of H2SO4 ore ratio on rare earth recovery efficiency 56

3.2.4.2. Effect of calcination temperature on rare earth recovery efficiency 57

3.2.4.3. Effect of calcination time on rare earth recovery efficiency 57

3.2.4.4. Effect of solid-liquid ratio in the separation process on rare earth recovery efficiency 58

3.3. Research on rare earth recovery by alkaline method 59

3.3.1. De-metallization method using NaOH solution at normal pressure 59

3.3.1.1. Effect of NaOH solution concentration on rare earth recovery efficiency 59

3.3.1.2. Effect of hydrometallurgy time on rare earth recovery efficiency 60

3.3.1.3. Effect of NaOH ore ratio on rare earth recovery efficiency 61

3.3.1.4. Effect of hydrometallurgical temperature on rare earth recovery efficiency 61

3.3.2. Hydrometallurgical method using NaOH solution at high pressure 62

3.3.2.1. Investigation of the effect of NaOH solution concentration on rare earth recovery efficiency 62

3.3.2.2. Effect of hydrometallurgy time on rare earth recovery efficiency 63

3.3.2.3. Effect of NaOH ore ratio on rare earth recovery efficiency 64

3.3.2.4. Effect of reaction temperature on rare earth recovery efficiency 64

3.3.2.5. Effect of hydrostatic pressure on rare earth recovery efficiency 65

3.4. Extraction of La, Ce, Nd and Y by TPPO in aqueous solution containing 67 push salt

3.4.1. Extraction of La, Ce, Nd by TPPO in aqueous solution containing 67 push salt

3.4.1.1. Effect of the nature of the salt on the distribution coefficient of La, Ce, Nd 67

3.4.1.2. Effect of salt concentration on the distribution coefficient of La, Ce, Nd 68

3.4.1.3. La, Ce, Nd 69 extraction isotherm

3.4.2. Extraction of Y by TPPO in aqueous solution containing 71 push salt

3.4.2.1. Effect of the nature of the salt on the distribution coefficient of Y 71

3.4.2.2. Effect of salt concentration on the distribution coefficient of Y 72

3.4.2.3. Extraction isotherm Y 73

3.4.2.4. extraction conditions Y 74

3.5. Extraction of cerium and rare earth(III) oxides from total rare earth oxides Sin Quyen75

3.5.1. Study on extraction conditions of La, Nd, Y, Ce and Th 75

3.5.2. Study on extraction of Ce(IV) 77

3.5.3. Study on extraction and recovery of cerium and rare earth(III) from total rare earth oxide Sin Quyen

................................................................ ................................................................ .......................................... 78

3.6. Synthesis and study of the structure of rare earth lactate complex 81

3.6.1. Composition of complex 81

3.6.2. Complex 82 research

3.6.2.1. Solubility and conductivity of complex 82

3.6.2.2. Study of complexes by thermal analysis 82

3.6.2.3. Study of complexes by infrared spectroscopy 84

3.7. Experimental results on the effects of rare earth lactate complexes on tea yield and some vegetables in Da Lat, Lam Dong 88

3.7.1. Experimental results on tea plants 88

3.7.1.1. Results of monitoring the growth rate of tea buds 88

3.7.1.2. Results of monitoring tea bud length 89

3.7.1.3. Results of monitoring tea bud density 89

3.7.1.4. Results of monitoring the weight of tea buds 90