University of Kentucky UKnowledge Theses and Dissertations--Mining Engineering Mining Engineering 2019 OPERATION AND PROCESS CONTROL DEVELOPMENT FOR A PILOT-SCALE LEACHING AND SOLVENT EXTRACTION CIRCUIT RECOVERING RARE EARTH ELEMENTS FROM COAL-BASED SOURCES Douglas Kweku Addo University of Kentucky, [email protected] Author ORCID Identifier: https://orcid.org/0000-0003-4417-0813 Digital Object Identifier: https://doi.org/10.13023/etd.2019.257 Right click to open a feedback form in a new tab to let us know how this document benefits ou.y Recommended Citation Addo, Douglas Kweku, "OPERATION AND PROCESS CONTROL DEVELOPMENT FOR A PILOT-SCALE LEACHING AND SOLVENT EXTRACTION CIRCUIT RECOVERING RARE EARTH ELEMENTS FROM COAL- BASED SOURCES" (2019). Theses and Dissertations--Mining Engineering. 50. https://uknowledge.uky.edu/mng_etds/50 This Master's Thesis is brought to you for free and open access by the Mining Engineering at UKnowledge. 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Douglas Kweku Addo, Student Dr. Joshua Werner, Major Professor Dr. Zach Agioutantis, Director of Graduate Studies OPERATION AND PROCESS CONTROL DEVELOPMENT FOR A PILOT-SCALE LEACHING AND SOLVENT EXTRACTION CIRCUIT RECOVERING RARE EARTH ELEMENTS FROM COAL-BASED SOURCES ________________________________________ THESIS ________________________________________ A thesis submitted in partial fulfillment of the requirement for the degree of Master of Science in Mining Engineering in the College of Engineering at the University of Kentucky By Douglas Kweku Addo Lexington, Kentucky Director: Dr. Joshua Werner, Assistant Professor of Mining Engineering Lexington, Kentucky 2019 Copyright © Douglas Kweku Addo 2019 ABSTRACT OF THESIS OPERATION AND PROCESS CONTROL DEVELOPMENT FOR A PILOT-SCALE LEACHING AND SOLVENT EXTRACTION CIRCUIT RECOVERING RARE EARTH ELEMENTS FROM COAL-BASED SOURCES The US Department of Energy in 2010 has identified several rare earth elements as critical materials to enable clean technologies. As part of ongoing research in REEs (rare earth elements) recovery from coal sources, the University of Kentucky has designed, developed and is demonstrating a ¼ ton/hour pilot-scale processing plant to produce high-grade REEs from coal sources. Due to the need to control critical variables (e.g. pH, tank level, etc.), process control is required. To ensure adequate process control, a study was conducted on leaching and solvent extraction control to evaluate the potential of achieving low-cost REE recovery in addition to developing a process control PLC system. The overall operational design and utilization of Six Sigma methodologies is discussed. Further, the application of the controls design, both procedural and electronic for the control of process variables such as pH is discussed. Variations in output parameters were quantified as a function of time. Data trends show that the mean process variable was maintained within prescribed limits. Future work for the utilization of data analysis and integration for data-based decision-making will be discussed. KEYWORDS: Rare earth elements, Process Control, programmable logic controller, Leaching, PID Douglas Kweku Addo 06/20/2019 Date OPERATION AND PROCESS CONTROL DEVELOPMENT FOR A PILOT-SCALE LEACHING AND SOLVENT EXTRACTION CIRCUIT RECOVERING RARE EARTH ELEMENTS FROM COAL-BASED SOURCES By Douglas Kweku Addo Dr. Joshua Werner Director of Thesis Dr. Zach Agioutantis Director of Graduate Studies 06/20/2019 Date DEDICATION This work is dedicated to my wife Anita Nti-Addo for her encouragement and patience and everlasting love, my father, and all my family members for their support, love and trust. ACKNOWLEDGMENTS This completion of this thesis was made possible by the advice, support and direction of many people. The following thesis, while an individual work, benefited from the insights and direction of several people. First, my Thesis Chair, Dr. Joshua Werner, exemplifies the high quality scholarship to which I aspire. In addition, Dr. Werner provided timely and instructive comments and evaluation at every stage of the thesis process, allowing me to complete this project on schedule. I am also deeply thankful to Dr. Rick Honaker for all the help and guidance in dealing with challenges in both research work and life in general. I would like to acknowledge David Threlkeld of Alliance Coal for his selfless technical support, guidance and supervision in my entire research work. Next, I wish to thank the complete Thesis Committee, and outside reader, respectively: Dr. Thomas Novak and Dr. Rick Honaker. Each individual provided insights that guided and challenged my thinking, substantially improving the finished product. In addition to the technical and instrumental assistance above, I received equally important assistance from family, friends and colleagues. Many thanks to Vaibhav Srivastava, Xinbo Yang, Alind Chandra, Kayla Mayfield, Wencai Zhang, and Alireza Valian for providing encouragement and emotional support throughout the thesis process, as well as technical assistance critical for completing the project in a timely manner. iii TABLE OF CONTENTS ACKNOWLEDGMENTS ............................................................................................... iii LIST OF TABLES ........................................................................................................... vi LIST OF FIGURES ......................................................................................................... iii CHAPTER 1.GENERAL INTRODUCTION................................................................. 1 1.1 Introduction and Background ................................................................................. 1 1.2 Project Deliverables ................................................................................................ 2 1.3 Project Organization ............................................................................................... 3 CHAPTER 2.LITERATURE REVIEW ......................................................................... 5 2.1 Introduction ............................................................................................................. 5 2.2 Process Control ....................................................................................................... 5 2.2.1 Why Process Control ...................................................................................... 6 2.2.2 Industrial Control Systems and Strategies .................................................... 10 2.2.3 PID Controls (Widely Used Controller) ....................................................... 14 2.2.4 Methods of Tuning PID ................................................................................ 17 2.3 Implementation of Industrial control systems....................................................... 21 2.3.1 Programmable Logic Controllers (PLC) ....................................................... 23 2.3.2 PLC versus Industrial PC .............................................................................. 26 2.3.3 Limitations and Benefits of PLC .................................................................. 27 2.4 Process Control in Metallurgical Industries .......................................................... 29 2.4.1 Leaching process controls ............................................................................. 30 2.4.2 Solvent Extraction process controls .............................................................. 32 2.4.3 Effluent controls............................................................................................ 35 CHAPTER 3.PILOT-SCALE PLANT DEVELOPMENT ......................................... 36 3.1 Control Theory ...................................................................................................... 36 3.1.1 Assumptions .................................................................................................