Comprehensive recovery of high-value elements from oil and gas produced water: Technologies and an integrated engineering case

The discharge volume of oil and gas produced water continues to grow, with treatment costs accounting for 5 %-15 % of total oil and gas production costs. Meanwhile, produced water is enriched in high-value elements (Li: 50–200 mg/L, K: 800–4800 mg/L, Br: 50–250 mg/L, B: 100–500 mg/L) meeting industrial standards, but current research lacks mature full-component recovery technologies and replicable engineering cases. To address this gap, this study systematically reviewed resource recovery technologies for produced water and in-depth analyzed the world’s first industrial project (100 m 3 /d) realizing full-component extraction of Li, K, Br, and B from real gas produced water (TDS: 3 ×10 5 -1.5 ×10 7 mg/L, petroleum hydrocarbons: 8–30 mg/L). The integrated process included pretreatment (desulfurization, advanced oxidation), selective separation (adsorption, electrooxidation), mechanical vapor recompression, and boron/bromine recovery. After the project was implemented, high-purity products (Li 2 CO 3 : 99.5 %, KCl: 98 %, H 3 BO 3 : 99 %, NaBr: 98 %), high total resource recovery rate (>95 %), high water conservation rate (>30 %), and zero wastewater discharge have been achieved. We recommend future efforts focus on developing low-cost anti-pollution adsorbents/electrode materials, intensifying process integration, and establishing national resource recovery standards to promote industrialization of produced water valorization. The world’s first demonstration project that achieves full-component extraction of Li, K, Br and B from gas produced water • Integrated CIX, MVR, acid/IX, electro-oxidation enables full-value recovery from produced water. • Station-scale continuous operation (1000 m 3 /d) achieves near-zero liquid discharge. • Reported the world’s first industrial project for full-component recovery of from produced water.