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Location of Anglo Platinum operations in the Bushveld complex. Source: (Groot and Pistorius, 2007) 

Location of Anglo Platinum operations in the Bushveld complex. Source: (Groot and Pistorius, 2007) 

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Conference Paper
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The cleaning of off-gas in the process of producing platinum group metals and the conversion of highly concentrated Sulphur dioxide (SO2) to sulfuric acid (H2SO4) are crucial in the current discussions for attempting to reduce emissions in the entire process of mining platinum metals in South Africa. Emissions of SO2 gas into the atmosphere became...

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... In 2008, South the African overall Bushveld restructuring complex operations is the largest of factories economic in the potential Anglo of American platinum group Platinum metals was (PGM) completed. resources The ever restructuring discovered operations in the world consisted estimated of aligning at about newly 80% owned of the mines world with ’s reserves. the new Anglo strategies American put in place Platinum, by the the company world's largest to improve PGM production, producer, management, operates in the safety Western and limbs environmental of the Bushveld protection Complex by reducing exploiting pollution the world’s and meet largest regulations. known igneous Sulphur complex dioxide (SO that 2 ) extends emissions over were 65,000km identified 2 and the reaches most noticed a depth airborne of about pollution 7km ( Figure 1) to be addressed (Mabiza, 2013). in the recovery process of platinum group metals. Owing to its Precious Metals Refinery (PMR) and Base Metal Refining (BMR) units, the Anglo American Platinum shares ownership of some private mines, acquired by joint-venture agreements or other arrangements, the purchase of concentrates produced by private miners and enabling the company to maintain production up to 2,464 million ounces of PGM in 2009 compared 2,645 million ounces of production in 2008, an unwelcome occurrence in recent years (Anglo Platinum Limited, 2009). In addition, Anglo Platinum American also acquired a 17.5% stake in Johnson Matthey, a global leading producer of platinum electrocatalysts. Furthermore, through the first investment in its Platinum Group Metals Development Fund (PGMD Fund). In 2008, the overall restructuring operations of factories in the Anglo American Platinum was completed. The restructuring operations consisted of aligning newly owned mines with the new strategies put in place by the company to improve production, management, safety and environmental protection by reducing pollution and meet regulations. Sulphur dioxide (SO 2 ) emissions were identified the most noticed airborne pollution to be addressed in the recovery process of platinum group metals. Owing to its Precious Metals Refinery (PMR) and Base Metal Refining (BMR) units, the Anglo American Platinum shares ownership of some private mines, acquired by joint-venture agreements or other arrangements, the purchase of concentrates produced by private miners and enabling the company to maintain production up to 2,464 million ounces of PGM in 2009 compared 2,645 million ounces of production in 2008, an unwelcome occurrence in recent years (Anglo Platinum Limited, 2009). In addition, Anglo Platinum American also acquired a 17.5% stake in Johnson Matthey, a global leading producer of platinum electrocatalysts. Furthermore, through the first investment in its Platinum Group Metals Development Fund (PGMD Fund). An average concentration of PGM of about five grams (5g) can be found in one metric ton (1,000kg) of mined ore which can be sent directly to the Precious Metals Refinery (PMR) unit. The rest of the mined ore undergoes ore concentration operations. Precious metals are completely recovered from the mined ore (Jones, 2006). The concentration unit is used mainly for the separation of valuable contents to rocks and sand. Ores undergo crushing, milling, and wet-screening to obtain pumpable slurry which bears the precious metals. Separation occurs in flotation cells where the reagents (chemicals) are added to aerate slugs carrying high-grade collected PGM (Anglo Platinum Limited, 2009). An approximate composition of a metric ton received at the ore concentration unit of Waterval is given in Table 1 below. The composition of the above concentrate (Table 1), are required, precious metals (PGM plus gold) and metals (nickel (Ni), copper (Cu) and cobalt sulphate (CoSO 4 )) (Anglo Platinum Limited, 2003). Smelting is a part of the process intended to recover precious metals from the concentrate slug by use of furnaces. A simplified smelter process flow schematic at the Waterval is given in Figure 2 below. At an average temperature near to 1500°C, depending on the composition of the concentrate sulphide gangue mineral, a composition of silicate slag and oxide is separated from the inorganic sulphide matte and discarded. Matte then includes base and noble metals. According to Jacobs (2006), the analysis of the composition of furnace matte is as shown in Table 2, in which the iron (Fe) 41% and (S) 27%, both not needed, are still prevailing. In general this is the composition of the matte at this stage of the PGM recovery, in which 95% of the total of the slag is discarded. Smelters have a feed rate ranging from 25 to 54T / h. Subsequently, at elevated temperatures the concentrate melts further and splits into two liquids phases; a lighter molten matte and slag rich in iron, having a density of about 2.7 to 3.3, is separated under the gravity from the molten matte, being denser, with a density of about 4.8 to 5.3 and rich in nickel and copper sulphides and in precious and base metals (Jones, 2006). The lighter molten matte is discarded and undergoes milling and cleaning of slag for possible recovery of PGM, and the molten matte is finally conveyed and discarded to the tailings dam (Figure 2). The converter is designed to further separate the precious metals and base metals from the granulated matte. Because of its rich composition in iron (41%) and in Sulphur (27%) (Table 4), the granulated furnace matte undergoes a converting process in an attempt to completely remove Fe and S. This happens by blowing oxygen-enriched air through the top-submerged lance converter where the oxygen reacts with the furnace matte at high temperatures ranging around 1300°C. The blown oxygen-enriched air can then oxidise Fe and S into iron oxide slag ...