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Raw Materials: Characterization and Preparation
Published in Ram Pravesh Bhagat, Agglomeration of Iron Ores, 2019
Gravity Separation This is a physical process and exploits the differences in densities of minerals to bring about a separation. The gravity separation of the associated minerals that are present in iron ore is carried out by their relative movement in fluid (normally water) under gravity. The forces affecting their relative movement are: Drag force: Resistance to motion of particles in a fluid due to its viscous effect.Specific gravity of the particles: Iron ore constitutes of ferruginous (hematite/magnetite) and gangue (silica and alumina) constituting minerals. Each group has a different density.
Downstream Processing
Published in Maik W. Jornitz, Filtration and Purification in the Biopharmaceutical Industry, 2019
A particle suspended in a liquid medium of lesser density tends to sediment downward due to the force of gravity. Its passage downwards is opposed by a buoyancy force equivalent to the weight of the displaced liquid, friction between particles and the liquid, and to a certain extent diffusion. Particles whose buoyancy force exceeds the gravitational force acting downwards will tend to rise to the surface and float. Gravity separation can, therefore, be used to sediment heavy particles and float buoyant particles, leaving a partially clarified liquid layer. Conventional gravity separation can be achieved either in a still tank or a stirred vessel. It is rapid and efficient for large particles but slow and inefficient as the particles get smaller, and is therefore only suitable for crude separation steps. More efficient gravity separation can be achieved using a plate separator, which comprises a set of evenly spaced plates usually inclined at an angle to provide a greater settling area in a smaller space. This allows a greater feed flow rate and minimizes the bottleneck during clarification.
Minerals of base metals
Published in Francis P. Gudyanga, Minerals in Africa, 2020
Zirconium occurs in more than 140 minerals; the metal is produced chiefly from zircon but also from baddeleyite and korsnarite. Its other important source is as a by-product in the production of titanium from minerals ilmenite and rutile, and tin from cassiterite. Zircon is recovered from the rest of mineral sands by gravity separation methods such as spiral concentration followed by magnetic separation, which remove the titanium ores ilmenite and rutile.
Pre-separation of low-grade collophane by an enhanced gravity separator
Published in Particulate Science and Technology, 2023
Xuebin Zhang, Youjun Tao, Yushuai Xian
Enhanced gravity separator (Falcon centrifugal separator) can generate 300 g (g is the gravity acceleration) centrifugal acceleration, which has been proved to separate ultrafine materials with similar density differences effectively, such as coal (Oruç, Özgen, and Sabah 2010; Zhu, Tao, and Sun 2016a, 2016b), gold (Lins et al. 1992), electronic waste (Ma, Tao, and Xian, 2021), macerals (Zhang et al. 2019), fly ash (Zhang, Yang, and Tao 2020), and rare earth mineral (Schriner and Anderson 2015) et al. The enhanced gravity separation technology has the advantages of no reagent consumption and less environmental pollution due to using water as sorting medium. However, the application of enhanced gravity separator in the pre-separation of low-grade collophane has never been systematically studied before.
Precious Metals Recovery from Waste Printed Circuit Boards by Gravity Separation and Leaching
Published in Mineral Processing and Extractive Metallurgy Review, 2021
Esra Tanısalı, Mustafa Özer, Fırat Burat
Gravity separation has been used widely for a long time in the mineral processing industry for the separation of valuable minerals from the host rock. Low capital and operating costs draw increased attention for these methods (Burat, Baştürkcü and Özer 2019). A material composed of two or more components having a marked specific gravity difference between them is generally enriched in size ranges of 3 and 0.1 mm using a shaking table. In physical beneficiation studies, a laboratory scale Wilfley type shaking table with a length of 800 mm and a width of 400 mm was employed. Three products, concentrate (heavy), middlings (metal/nonmetal mixture), and tailings (light), were separated using adjustable splitters. Tests were conducted under the following conditions: 10 L/min of wash water flow, 300 cycles per minute frequency, 2 mm of stroke length, 3° of lateral angle, 30 kg/hour of feed rate.
A Detailed study of Applying Gravity Separation to Lead and Zinc Carbonate Ore for Smithsonite Concentration Using DMC
Published in Mineral Processing and Extractive Metallurgy Review, 2020
Ali Ebtedaei, Akbar Farzanegan
Dense medium separation (DMS), heavy medium separation (HMS) or the sink and float process is a mature gravity separation technology used extensively as the main concentration stage for separation of particles based on their settling properties. In all gravity separation methods, the separation is normally affected using the gravity force applied on particles (Das and Sarkar 2018; Wills and Finch 2016) which can be enhanced by adding centrifugal forces as in Knelson Concentrator (Ghaffari and Farzanegan 2017a, 2017b; Katwika et al. 2018) or Falcon Concentrator (Dehaine et al. 2019). Gravity separation is an effective method which has been applied to process many types of minerals such as nickel, tin, barite, and ilmenite (Angadi et al. 2017; Molaei, Razavi and Chehreh Chelgani 2017; Rejith and Sundararajan 2017; Yüce et al. 2007). Mathematical modeling and performance evaluation of the gravity separation process has been discussed by many researchers including Mukherjee (2009), Grimes (2012) and King (2012).