Outotec (Finland) Oy

John O'Callaghan

Timo Haakana

Riina Ahtiainen

Mari Lundström

Janne Karonen

Risto Pieviläinen

Provided is a method of recovering gold, and optionally silver, from gold-bearing, and optionally silver-bearing, double refractory raw material, comprising the steps of (a) leaching the gold-bearing, and optionally silver-bearing, double refractory raw material in a chloride containing leaching solution to dissolve gold and to obtain a leach solution comprising gold, and optionally silver, in solution, whereby the redox of leaching solution in the chloride leaching step is above 550 mV vs. Ag/AgCl; and simultaneously contacting the leach solution comprising gold, and optionally silver, in solution with a re-sorptive material to obtain a gold-containing, and optionally silver-containing, re-sorptive material; and (b) recovering gold and optionally silver from the gold-containing, and optionally silver-containing, re-sorptive material.

Method for recovering gold

Provided is a process for recovery of gold from gold-bearing raw materials comprising (a) leaching said gold-bearing raw material in a chloride containing leaching solution containing a total concentration of less than 120 g/L of halide ions, whereby the total concentration of chloride ions is less than 120 g/L of to dissolve gold and to obtain a leach solution comprising gold in solution; and simultaneously contacting the leach solution comprising gold in solution with a re-sorptive material to obtain a leach solution comprising gold-bearing re-sorptive material; and (b) recovering gold and optionally silver from the said gold-bearing re-sorptive material.

Process for recovering gold

The invention relates to a method for recovering energy and water from pressure oxidation flash steam where first flash steam directly obtained from a flash vessel is contacted with a first recirculating condensate having a first low condensate temperature to condense at least part of the water vapor in the first dirty flash steam and simultaneously to heat the first recirculating condensate to obtain a first recirculating condensate having a first high condensate temperature and a first vent steam. The invention further relates to a pressure oxidation arrangement adapted for use in the method.

Energy and water recovery from pressure oxidation flash vessel steam

The present invention relates to a method and an arrangement for pressure and temperature let down of autoclave discharge slurry, in particular in pressure oxidation or high pressure acid leach of metal containing ore. The method of the invention comprises a step of providing autoclave vent gas obtained from the autoclave to the top-entry flash vessel for inducing overpressure to the top-entry flash vessel and preventing boiling of the slurry during the transfer to next top-entry flash vessel. The invention further relates to an autoclave and pressure let-down arrangement adapted for providing autoclave vent gas to one or more top-entry flash vessels.

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Victoria, Australia

John O'Callaghan