Technical Articles

Last updated: 2026-10-31 Ammonium paratungstate production turns one tonne of 65% WO3 wolframite concentrate into roughly 0.71 t of APT, and the spread between a well-run and a poorly run digestion stage is about six points of WO3 recovery — 97% against 91%. That spread is worth more than the reagent bill, so the autoclave,…

Last updated: 2026-10-31 Twenty tonnes per hour evaporated from a sodium sulfate brine at 80 °C carries 13.06 MW; at U = 1,000 W/(m² K) and an effective 33 K, the evaporator heat transfer area is 396 m², or 501 m² after a 15% fouling allowance and a 10% design margin — 700 tubes of…

Last updated: 2026-10-31 When fill time climbs past roughly 1.4 times its commissioning value — 22 to 31 minutes with feed solids and pressure unchanged — filter cloth blinding is the first hypothesis to test, not the last. Measure air permeability drop and dry cloth mass gain before touching pump curves or plate alignment: both…

Last updated: 2026-10-31 Lime neutralization wins on cost for high-volume water where 1-2 mg/L residual metals is acceptable; sulfide precipitation wins wherever the discharge limit sits below roughly 0.5 mg/L. The deciding number is the residual itself: hydroxide chemistry stalls near 0.1-1 mg/L for nickel, cobalt and cadmium, while a sulfide stage routinely reaches 0.01-0.05…

Last updated: 2026-10-31 Three tanks, 45 minutes of total residence and 2.0-2.5 kg of zinc dust per cubic meter take a neutral leach solution from about 600 mg/L copper to below 1 mg/L. That is the envelope most zinc purification circuits converge on, and what decides whether it holds is not tank volume but the…

Last updated: 2026-10-30 Gold recovery from oxide ore is achieved by cyanide leaching, and route choice sets the outcome: well-matched projects report 65–85% recovery by heap leaching and 88–94% by agitated CIL (indicative ranges, dry-tonne basis, to be confirmed by test work). This guide explains what makes oxidized gold ores chemically and physically different, how…

Last updated: 2026-10-30 The thickening area calculation for a 120 t/h feed of 28% w/w solids thickened to 62% w/w closes at 0.123 m² of settling surface per tonne of dry solids per day — 355 m² on test data, 426 m² after a 1.2 design factor, and a standard 24 m diameter thickener running…

Last updated: 2026-10-30 Bioleaching copper circuits rarely fail suddenly — they stall, and in the stalls we have audited, recovery losses of 15–30 percentage points trace back to one of seven diagnosable field faults rather than to the biology itself. This guide gives process engineers the mechanism, the diagnostic parameters, and the seven fixes, ordered…

Last updated: 2026-10-30 Hydrometallurgy vs pyrometallurgy comes down to one planning number first: an acid-leach route such as heap leach plus SX-EW can deliver cathode copper at roughly 15–25 GJ per tonne, against roughly 40–60 GJ per tonne for the concentrate-smelting route, but only when your ore, impurities and permits allow it. This page turns…

Last updated: 2026-10-30 The right size for a filter press for mining duty falls out of the cake, not the catalogue: a duty of 40 t/h of dry solids at 18% cake moisture and a 90-minute cycle needs roughly 2,800 m² of effective filtration area — delivered as two large presses of about 1,400 m²…