What are the common mineral processing methods for platinum group metals?

Currently in terms of extracting platinum group metals, used mainly in industry re-election, flotation and their joint process, which is the most widely used flotation.

(1) a platinum group metal reselection mineral density are 7 g / cc or more, especially natural metal and an intermetallic compound more than 10 g / cm, common natural platinum, platinum mines crude, osmium, iridium ore as high as 15 ~22 g / cm3, not only much higher than the common gangue (generally 2.5 ~ 2.75 g / cm3, a few up to 4.3 g / cm3), and higher than the common base metal minerals (generally density 3.6 to 5.5 g / cc, only individual minerals such as galena 7.2 to 7.6 g / cc, but is rare in platinum ores). Therefore, as long as the particle size is large (generally greater than 0.04 mm), the monomer can be dissociated and can be enriched by a re-election method. It is generally used to treat platinum group metals with larger particle size of platinum group metals in gab mines and ore. For some platinum ores, it is often supplemented by amalgamation or magnetic separation processes to improve concentrate grade and recovery.

(2) Flotation of platinum group minerals is more hydrophobic and can adhere to the bubbles, and among most of the resources currently mined, fine-grained platinum group minerals are usually symbiotic with copper and nickel- sulfur minerals, so flotation has become today Platinum-containing minerals are the most important and the most widely used mineral processing tool. However, due to the high density of the platinum group minerals, when the particle size is large, the re-election method is supplemented, that is, the heavy and floating combined processes can be more effectively and comprehensively recovered. Flotation is currently mainly used to treat copper sulfide ore, so that platinum group minerals and copper and nickel sulfides are recovered together. The sorting effect of platinum group metal minerals is related to various factors such as grinding fineness, medium acidity, type and amount of medicament, and process arrangement. Experiments are often required on the characteristics of different ores to determine reasonable process and technical conditions.

(3) Combined process of heavy and floating For the ore with larger particle size of platinum group minerals, the combination method of re-election and flotation can make full use of the advantages of both and obtain better results. The Russenberg Platinum Company of South Africa used the heavy-floating combined method to treat platinum-containing oxidized and sulfided ore in the 1930s. After the flotation of the Wattwell plant in the 1960s, it was re-elected with a suede chute. “Russenburg Platinum Minerals” (containing platinum 30% to 35%, palladium 4% to 6%, gold 2% to 3%, 钌 0.5%) and mixed flotation concentrates (containing platinum group metals 110 to 150 g/cubic In centimeters, the ratio is: platinum 63%, palladium 24%, 钌 5.3%, 铑 3.9%, 锇 3.0%, 铱 0.9%), and the total recovery of platinum and palladium is about 90%.

Platinum group elements are easy to form alloys or intermetallic compounds with various transition metals, and have the properties of sulfophilic and non-oxygen (but the ruthenium and osmium are easily oxidized and volatilized), so that high-temperature chemical reaction can be used to enrich platinum. Group metal products are separated from other substances. Among the commonly used methods are melting and volatilization.

(1) Platinum group metal traps mainly include lead trapping agent, iron nickel copper trapping agent, sulfur trapping agent, tin , aluminum and other metals as a trapping agent.

(2) smelting and blowing.

(3) Volatile (gasification) enrichment of lanthanum and cerium in platinum group metals is easy to volatilize, and almost all platinum group metals can form volatile chlorides. According to this feature, the platinum group metal can be enriched or recovered from the ore or metallurgical intermediate product. Conversely, other metal compounds can also be volatilized to allow the platinum group metal to remain in the non-volatile material for enrichment. Common methods are: hydrazine, oxime oxidation, chlorination and carbonyl removal of nickel.

(4) Desulfurization by hot filtration and vacuum distillation.

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