Feasibility, technical status and prospects of lithium recovery from produced water in oil and gas fields

The contradiction between high demand and low production of lithium resources makes it urgent to develop new lithium resources. The produced water of oil and gas fields is rich in lithium elements, which is a potential liquid lithium resource. Therefore, it is of great practical significance to analyze the feasibility of lithium extraction from produced water of oil and gas field and propose a feasible technical route. First, the composition of produced water in oil and gas fields was analyzed, and the water quality characteristics of the produced water in oil and gas fields were defined. Then, the lithium resource endowment of major basins in China was analyzed, and the challenges of lithium extraction due to the high concentration of organic matter and rich ion composition in the complex organic-inorganic hybrid system were emphasized. Finally, the water characteristics, water treatment technology and high-efficient lithium extraction technology were comprehensively analyzed and the applicability of those lithium recovery technologies (precipitation, adsorption, extraction and membrane separation) for produced water was discussed. Combined with the practice of lithium extraction and the current situation of the industry, it was recommended to develop a lithium extraction technical route of "pretreatment + enrichment concentration (adsorption/extraction-membrane separation) + precipitation".