leaching stem from a combination of elevated operating temperature and oxygen overpressure both of which increase reaction kinetics. Increased operating temperatures above the ambient boiling point can only be achieved by increasing pressure. Early Applications of Pressure Leaching The earliest applications of pressure leaching were low

A conceptual flowsheet for heap leaching of platinum group

In this scenario the highgrade concentrate streams will be processed via standard smelting of concentrate acid pressure leaching of the matte and high pressure chloride leaching of high grade PGM residue. In parallel the lowgrade concentrate streams will be processed as follows Download Download fullsize image Fig. 5. Flowsheet.

Direct leach approaches to Platinum Group Metal (PGM

and selective pressure leaching of base metals and sulfur (2) a roasting pretreatment step to render PGMs and particularly Pt amenable to leaching and (3) chlorination of precious metals

High pressure sulfuric acid/oxygen leaching of platinum

There is however a understanding of the behaviour of PGMs in the high pressure leaching process. Consequently this process is controlled based on operators' intuition despite its

Recovery of PGMs from an oxide ore by flotation and leaching

Recovery of PGMs from an oxide ore by flotation and leaching Msc Research Thesis Prepared by Relebohile Sefako Student number 1420412 Submitted to School of Chemical and Metallurgical Engineering Faculty of Engineering and the Built Environment University of the Witwatersrand Johannesburg South Africa Supervised by Prof. Vusumuzi Sibanda

Direct leach approaches to Platinum Group Metal (PGM) ores

The Kell process is a patented hydrometallurgical alternative to PGM smelting. This process is a mixed chloride/sulfate based technology where base metals are removed by sulfuric acid pressure leaching and PGMs are leached after roasting with Cl 2 /HCl as commonly used in PGM refining. However the solution concentrations of PGMs for the Kell process tend to be lower.

High Pressure Sulfuric Acid/Oxygen Leaching of Platinum

the first stage leach (high pressure or atmospheric leaching or a combination of the two) which is followed by second stage high pressure sulphuric acid/oxygen leaching to dissolve copper and the remaining nickel. PGMs are recovered from the leaching residue in downstream processes and their

Leaching and recovery of platinum group metals from UG2

A PLATSOLtype leach was used at Mintek in an attempt to recover Pd (23 g/t) from a material derived from a sulphidic ore. The PGM (Pd:Pt = 4:1) included arsenide and bismuth tellurides. Leaching conditions included high temperature (220°C) oxygen overpressure of 7 bar (total pressure at temperature 30 bar) leach time of 36 hours

Upgrading of PGMrich leach residue by high pressure

Mass transfer tests were conducted using the sodium sulphite method at 60°C 100 kPa oxygen partial pressure and agitation speed of between 500 to 1000 rev/min. Cobalt(II) was used as the catalyst with a concentration range of 1 to 5 mg/L. Oxidation of amphoteric elements was investigated by leaching of PGMrich leach residue (residue from