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The separation of iron ore in a prototype batch jig separator developed by Mintek in South Africa, referred

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Beneficiation of iron ore by flotation is widely used in Brazil, India and China. In Africa, however, this practice is not yet commercially developed.The aim of this test work is to serve as a starting point by establishing suitable pH conditions for the development of a practically implementable reagent suite, which will then be included in a larger beneficiation circuit for producing high-grade iron ore sinter feed.In the literature, African iron ore types are graded as low-grade (60.0-62.9% Fe; 8.6-12.5% SiO 2 and insolubles), high-grade (66.0-69.9% Fe; 0.8-4.5% SiO 2 and insolubles), and meduim-grade as the remaining portion (Astrup et al., 1998). The low-grade ore used in this work contains less than 60% Fe.For Brazilian ores consisting of a combination of haematite and quartz, it is common to use corn starch as a depressant and ether amine blends as collectors with additional frothing characteristic (Araujo et al., 2005). Work by Turrer and Peres (2010) shows the possibility of using other depressants successfully as well.The main mechanism of the reverse flotation of quartz from iron ore is based on the electrostatic theory of flotation. This is due to the strong pH dependence of the zeta potential of the mineral edge planes on silicate particles (Fuerstenau and Pradip. 2005).An electrical double layer, (inner and outer Helmotz planes), as illustrated in Figure 1, forms on the surface of particles submerged in a solution. The charge in the outer Helmotz plane is depicted by the potential-determining ions on the mineral surface. The ion type that is predominantly concentrated on the surface is determined by the solution pH.In general, a higher quartz recovery to the froth phase is attained at pH 9, which is attributed mainly to the largest negative surface charge at this pH, (Vieira and Peres, 2007), as indicated in Figure 2. Hydrophobicity of quartz increases as the zeta potential becomes more negative, due to the increased force between the negatively charged quartz surface and the positively charged amine molecule.Sirkeci (2000) attributed the increased quantities of silicate minerals reporting to the froth phase to the equilibrium between ionized and molecular amine species at pH 9.3.A low-grade haematite ore from Africa was utilized for this flotation test work. Ore characterization consisted of particle size distribution, mineralogical characterization, and compositional characterization. Sample splitting and blending at a representative level were conducted to produce feed samples for laboratory-scale flotation tests.The flotation reagent suite included 150 g/t combined isodecyl ether propylene amine/amino acetate and 1,3-P-propanediamine, N-(3-(C10-C16-alkyloxy) propyl)-derivatives collector and a causticized corn starch, with solution concentration of 2.0% by

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