What are the common beneficiation methods for platinum group metals？Based on years of experience, Fodamon engineer summarized：
At present, gravity separation, flotation and their combined processes are mainly used in the industry for the extraction of platinum group metals, among which flotation is the most widely used.
(1) The density of gravity separation platinum group metal minerals is more than 7 g / cubic centimeter, especially the natural metals and metal intermetallic compounds are more than 10 g / cubic centimeter. The common natural platinum, crude platinum ore and hungry ore are as high as 15 ~ 22 g / cubic centimeter, which is not only much higher than the common gangue (the general density is 2.5 ~ 2.75 g / cubic centimeter, and a few can be up to 4.3 g / cubic centimeter), It is higher than common base metal minerals (the general density is 3.6 ~ 5.5g/cm3, and only some minerals such as galena are 7.2 ~ 7.6g/cm3, but it is rare in platinum ore). Therefore, as long as the particle size is large (generally greater than 0.04 mm) and the monomer can be dissociated, it can be enriched by gravity separation method. It is generally used to treat platinum group metals with large particle size in placer platinum ore and raw ore. For some platinum ores, mercury mixing or magnetic separation process is often supplemented to improve concentrate grade and recovery.
(2) Flotation platinum group minerals are mostly hydrophobic and can be attached to bubbles. In most of the resources mined now, fine platinum group minerals are usually symbiotic with copper, nickel and sulfur minerals. Therefore, flotation has become the most important and widely used beneficiation means of platinum group minerals. However, due to the high density of platinum group minerals, when the particle size is large, gravity separation method is supplemented, that is, the combined process of gravity and flotation can be used for more effective and comprehensive recovery. At present, flotation is mainly used to treat copper sulfide and recover platinum group minerals together with copper and nickel sulfide. The separation effect of platinum group metal minerals is related to many factors, such as grinding fineness, medium acidity, reagent type and dosage, process arrangement and so on. Generally, experiments need to be carried out according to the characteristics of different ores to determine the reasonable process flow and technical conditions.
(3) For the ore with large particle size of platinum group minerals, the combined gravity separation and flotation process can make full use of their advantages and obtain better results. As early as the 1930s, Rustenberg platinum mining company of South Africa used the gravity flotation method to treat platinum containing oxidized and sulfide ores. After flotation in the 1960s, its watwell concentrator used a suede chute for gravity separation to obtain “Rustenberg platinum minerals” (30% ~ 35% platinum, 4% ~ 6% palladium, 2% ~ 3% gold and 0.5% nail) and mixed flotation concentrate (110 ~ 150g / cm3 platinum group metals), The ratio is: Platinum 63%, palladium 24%, nail 5.3%, Lao 3.9%, hungry 3.0%, according to 0.9%), and the total recovery of platinum and palladium is about 90%.