Mineral processing method for enrichment of platinum group metals

Mineral enrichment of platinum group metals (dressing co ncentration of platinum group me tal)

The process of sorting out platinum group metal concentrates from ore by beneficiation method, one of the platinum group metal enrichment methods. It mainly uses flotation and re-election, and in some cases is supplemented by amalgamation method (see gold extraction by mercury amalgamation or silver extraction by amalgamation method). Mined sand PGE deposits mainly containing a platinum group metal and platinum mines symbiotic copper-nickel sulfide ore, which contained little amount of platinum group metal, with the main multi-copper, nickel-copper-nickel flotation concentrate in the fine In the mine. Platinum group metals platinum mines mineral sand mainly natural platinum, iron ore platinum, iridium, osmium ore, mostly free state output, coarse particle size, high density (up to 15000kg / m ^3), generally with re-election Enrichment .

The sand ore beneficiation is generally obtained by re-election to obtain high-grade concentrate. Mining the placer after washing, jigging chute and enrichment, to give a crude platinum-containing magnetite ore, chromium ore or the like. The crude platinum concentrate is re-used with a shaker, magnetic separation and wind selection, and the concentrate produced can contain up to 80% to 90% of the platinum group metals. The crude platinum concentrate with low grade is then extracted by amalgamation. In South Africa, the re-election of gold concentrates is treated by amalgamation. The tailings often contain a lot of antimony ore, which is recovered by a shaker or a suede chute. The coarse concentrate is sequentially removed with nitric acid and caustic soda to remove impurities such as iron and tungsten carbide. The composition of the antimony ore concentrate (mass fraction ω/%) is: 锇33～36, 铱29～36, nail 12～15, platinum 8-13, 铑 1, other 7～9.

Platinum group metals containing platinum group metal copper-nickel symbiotic sulfide ore are usually symbiotic with copper and nickel, and platinum metal is mainly recovered when copper and nickel grade is low. For example, the Merensky vein in South Africa contains 4-15 g/t of platinum group metals and is treated by a combination of re-election and flotation. After the finely ground ore chute and shaking first with suede reselection, platinum output 30% to 35%, 4% to 6% of palladium, gold, 2% to 3%, 0.5% ruthenium reselection high grade concentrates. The re-election of the tailings is then processed by a flotation circuit. For deep ore containing more sulfides, the coarse-grained sulfide is recovered by single-tank flotation. The flotation circuit includes rough selection, sweep selection and multiple selections. Xanthate is used as a collector , cresylic acid is used as a foaming agent, and copper sulfate is used as an activator. When the ore contains talc , inhibitors such as carboxymethyl cellulose, dextrin and guar gum may be added. The flotation concentrate contains 66g/t of platinum group metal, and the recovery rate is 82%-85%. This concentrate is then selected by James Shaker to obtain a platinum group metal concentrate containing 30% to 40% of platinum group metals, which is directly sent to refining.

China's Jinchuan produced platinum-containing metal copper-nickel symbiotic sulfide ore containing more than 1% nickel, more than 0.5% copper, and 0.6g/t of platinum group metal. There are dozens of platinum group minerals in the deposit, but the content is small, the particle size is fine, and the copper-nickel sulfide minerals are intertwined with each other. During the flotation process, copper and nickel are enriched in the copper-nickel concentrate. The enrichment ratio is 3 to 4, and the recovery rate is 70% to 80%, which is lower than the recovery rate of the main metal (copper 82% to 85.%, nickel 89% to 90%).

Platinum-containing metal-copper-nickel symbiotic sulfide ore produced in the Sudbury mine in Canada contains 0.5-0.9 g/t of platinum. During flotation, most of the platinum group metals are enriched in copper-nickel mixed concentrate, copper-nickel The platinum group metal mainly enters the nickel concentrate.

The symbiotic sulfide ore of the Stillwater complex in the United States contains 17 to 28 g/t of palladium, platinum and gold, 0.06% of copper and 0.11% of nickel. The ore is ground in two stages to 60% of the –0.074mm fraction and then floated. The flotation circuit includes rough selection, sweep selection, two selections, and re-grinding of the mine. Primary flotation agent as collector potassium pentyl yellow closing agent and sodium thiosulfate diisobutyl phosphate co 70g / t ,, inhibitor, carboxymethyl cellulose 350g / t and the amount of frother methyl isobutyl Methanol. The flotation concentrate contains 1700g/t of platinum group metal with a recovery rate of 90%.

When the oxidized alteration of the symbiotic sulfide ore is more serious, the formed oxidized ore is difficult to select, and the recovery of nickel, copper and platinum group metals is not high.