Recent Advances in Gallium Recovery from Zinc Metallurgical Residues and Integrated Zn–Pb Materials: From Process Deportment to Selective Recovery and Industrial Integration (2020–2026)

Gallium recovery from zinc-processing residues has expanded rapidly, yet the evidence remains heterogeneous and heavily weighted toward laboratory studies. This structured critical narrative review examines 95 publications issued from January 2020 to July 2026 on gallium deportment, residue formation, characterization, pretreatment, leaching, purification, separation, and product recovery in zinc metallurgical residues and integrated Zn–Pb materials. The corpus was assembled using reproducible keyword combinations, DOI- and title-based deduplication, single-reviewer screening, and study-level evidence coding. Seventy-three empirical or mechanistic publications were graded by evidence type (A = 4, B = 8, C = 20, D = 22, and E = 19), while 22 review, contextual, thesis, or proceedings publications were retained as supporting evidence; only a small minority used continuous, factory, or industrially representative operations. Quantitative comparisons show that host-phase control is decisive: industrial optimization increased gallium leaching from 77.83% to 96.46% when jarosite-associated gallium was addressed, while selected downstream operations achieved 97.9% iron removal before gallium extraction, up to 99% gallium recovery in staged membrane contact, and 98.6% adsorption after six resin cycles. Zinc-refinery and replacement residues provide the strongest evidence. Data for primary lead residues remain insufficient and are therefore treated as complementary evidence from integrated Zn–Pb materials rather than as an equivalent evidence base. High-confidence conclusions concern the importance of mineral hosting, iron control, complete mass balance, and multimetal integration. Claims regarding universal flowsheets, economic thresholds, and industrial circularity remain low confidence because continuous campaigns, reagent recycle, product qualification, and comparable techno-economic or life-cycle data are scarce.