Placer Dome Technical Services Limited

Altair Nanomaterials, Inc.

Paul George West-Sells

Jinxing Ji

Ralph Peter Hackl

Christopher Andrew Fleming

Willem P C Duyvesteyn

Timothy Malcome Spitler

Bruce James Sabacky

Andrew Vince

Bernardus Josephus Paulus Maria Huls

James R Burkholder

Dirk Edmund Victor Verhulst

Processes are provided for recovering precious metals from refractory materials using thiosulfate lixiviants. The processes can employ lixiviants that include at most only small amounts of copper and/or ammonia and operate at a relatively low pH, reduction of polythionates, inert atmospheres to control polythionate production, and electrolytic solutions which provide relatively high rates of precious metal recovery.

Method for thiosulfate leaching of precious metal-containing materials

Processes are provided for recovering precious metals from refractory materials using thiosulfate lixiviants. The processes can employ heap leaching or lixiviants that include one or more blinding agents.

A hydrometallurgical process is provided for producing pigment grade TiO from titaniferous mineral ores, and in particular from ilmenite ore. The ore is leached with a hydrochloric acid, preferably a recycled solution at high hydrochloric acid concentration, to form a leachate containing titanium and iron chloride and a residue. The leachate may be filtered to separate the leachate from the residue. The leachate is cooled to a temperature sufficient to form crystals of FeCl , which are separated from the leachate. The leachate may be subjected to a reduction step to reduce Fe to Fe , before crystallizing. The leachate is subjected to a first solvent extraction to form a pregnant strip solution containing titanium and ferric ions and a raffinate containing ferrous ions. This strip solution is subjected to a second solvent extraction to form a second strip solution containing ferric ions and a raffinate containing titanium ions. The first strip solution may be subjected to an oxidization step before the second solvent extraction. The second raffinate containing titanium ions is hydrolyzed. The hydrolysis can be by water addition or spray hydrolysis. Iron chloride is converted to iron oxide and hydrochloric acid. All product streams containing chlorides are recycled, producing gaseous hydrochloric acid that is used for regenerating the leaching solution.

Processing titaniferous ore to titanium dioxide pigment

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Vancouver, Canada

Paul George West-Sells