Novel Process to Prepare a Vanadium Electrolyte from a Calcification Roasting–Acid Leaching Solution of Vanadium Slag

The vanadium battery has received great attention in recent years as one of the most viable energy-storage technologies for large-scale applications. As an important part of the vanadium battery, the vanadium electrolyte occupies most of the cost of the vanadium battery. How to prepare a vanadium electrolyte at a low cost has become a hot topic for researchers all over the world. Herein, an efficient method for the preparation of a vanadium electrolyte from a calcification roasting–acid leaching solution of vanadium slag (CRAL) is proposed based on TMAC extraction to the treatment of CRAL and recycling of Mn and Mg resources. The influence of various factors on vanadium extraction efficiency has been investigated, including the extractant concentration, phase ratio A/O, contact time, and temperature. Furthermore, the principle of extraction and stripping has been illustrated, and the recyclability of the organic phase has been evaluated. Under optimum conditions, 99.91% of vanadium is recovered from CRAL to prepare the vanadium battery, confirming the efficient separation of vanadium. This study highlights a new approach for separating vanadium from other impurities to prepare a vanadium electrolyte and provides a new outlook for other leaching solutions and new perspectives on the resource-comprehensive utilization of liquor.