Additional Study Information: The main purpose of the study is to find out whether Triferic, when taken by mouth (orally) with Shohls solution, is safe and effective for the treatment of Iron Refractory Iron-Deficiency Anemia (IRIDA). The study drug, ferric pyrophosphate citrate (FPC), is also called Triferic. It is an iron salt that has been approved by the Food and Drug Administration (FDA) for the maintenance of hemoglobin (prevention of anemia/low red blood cell counts) in adults with chronic kidney disease on hemodialysis. It has not yet been tested in patients with iron-refractory iron deficiency anemia (IRIDA), and so its use is considered experimental (investigational) in this study.