Technical Articles

Last updated: 2026-11-02 Zinc calcine leaching typically transfers 85-92% of the zinc in roasted concentrate into solution before iron precipitation, and the iron residue route you commit to — jarosite, goethite, or hematite — locks in most of that number before the first tank is ever built. This guide walks the full roast-leach-electrowin flowsheet, the…

Last updated: 2026-11-02 For a typical 500 t/d gold plant treating 25% solids pulp, the leach residence time that delivers 90% recovery in four agitated tanks is about 5.7 hours total, or 1.4 hours per tank, using a 0.55 per hour rate constant from bottle roll test work. This guide converts that kinetics figure into…

Last updated: 2026-11-02 Silica gel formation — not total dissolved silica — is behind roughly 60-80% of chronic filtration failures in acid leach circuits treating clay-rich, saprolitic, or silicate-gangue ores. This guide explains the polymerization chemistry, lists seven causes with symptoms and fixes, and shows how to restore filtration rate before gelation forces a shutdown…

Last updated: 2026-11-02 Thiosulfate leaching typically recovers 85-95% of gold from carbonaceous and copper-bearing ores where cyanidation falls below 60%, at an indicative reagent cost of USD 110-400 per ounce recovered versus USD 55-175 per ounce for cyanide on free-milling ore. This page gives process engineers the chemistry, cost structure, recovery routes, equipment deltas, and…

Last updated: 2026-11-02 For most sulfide concentrate projects between 300 and 3,000 t/d, atmospheric chloride leaching in a train of four rubber-lined or FRP agitated reactors with titanium Gr2 internals — sized at roughly 2 h residence and 0.8–1.2 kW/m³ installed agitator power — is the most practical starting point. This guide covers reactor sizing,…

Last updated: 2026-11-01 Red mud washing is the largest single lever on caustic soda consumption in a Bayer alumina plant: a well-designed countercurrent wash train recovers more than 95% of the NaOH and dissolved alumina entrained in the residue, while a poorly washed underflow can export the equivalent of 50-100 kg of Na2O per tonne…

Last updated: 2026-11-01 An OSLO crystallizer is the design of choice when a specification calls for coarse, low-fines crystals — typically a d50 of 0.5-3 mm (0.02-0.12 in), several times coarser than forced circulation delivers. Supersaturation is generated away from the bed and released gently in an upward liquor flow, so crystals grow rather than…

Last updated: 2026-11-01 Phase disengagement is the process by which the organic-aqueous dispersion created in a mixer breaks and coalesces back into two clean layers, and in a well-run mixer-settler it should be substantially complete within 60-120 seconds of quiescent residence. When it slows, entrainment rises in both directions: organic carries into the aqueous raffinate…

Last updated: 2026-11-01 A vacuum belt filter is the default choice when a hydrometallurgical plant must dewater and wash fast-draining cakes continuously, typically achieving 90-95 percent solute removal in two or three countercurrent washes at 40-70 kPa of vacuum. This guide covers belt filter selection and sizing: duty matching, design parameters, a worked area calculation,…

Last updated: 2026-11-01 Resin in pulp is a gold and uranium recovery process that adsorbs dissolved metal onto ion exchange resin beads suspended directly in unfiltered leach slurry, typically across five to eight agitated stages. Because anion exchange resin adsorbs aurocyanide two to four times faster than activated carbon, RIP circuits often reach target recovery…