Five Common Ilmenite Beneficiation Methods - Ilmenite Recovery Methods

In nature, ilmenite resources can be divided into two categories: primary ilmenite and sand-type ilmenite. Primary ilmenite is often associated with titanomagnetite and vanadium-titanium magnetite. Its reserves are large and concentrated, making it suitable for large-scale mining. However, it has a high gangue content, low recovery, and poor selectivity. Sand-type ilmenite is a secondary ore, characterized by a loose structure and good selectivity, but also has a low ore grade and is prone to mudification. Therefore, different ilmenite ore characteristics impose different requirements on ilmenite beneficiation methods.

Currently, the main common ilmenite beneficiation methods include gravity separation, magnetic separation, electrostatic separation, flotation, and combined methods.

I. Gravity Separation for Ilmenite Recovery

Gravity separation is suitable for coarse-grained and fine-grained ilmenite. After primary and secondary crushing, it can be processed through gravity separation equipment, such as spiral chutes and shaking tables, to discard large amounts of gangue and desludging.

II. Magnetic Separation for Ilmenite Recovery

Ilmenite is a weakly magnetic mineral with a higher specific magnetic susceptibility and density than gangue minerals. For minerals of the same particle size, it has a much greater volume magnetization intensity than gangue minerals. Therefore, during magnetic separation under a certain field strength (electric field strength and direction), gangue minerals and some fine-grained iron-containing silicate minerals in the ilmenite are easily discarded into the tailings. High-intensity magnetic separation can effectively separate the ilmenite from the gangue, achieving the goal of enriching titanium metal and processing ilmenite that is difficult to enrich through gravity separation. This method is commonly used in beneficiation and tailings discarding.

III. Flotation for Ilmenite Recovery

Flotation, a high-precision and effective separation method, is primarily used in the beneficiation of primary titanium ore or the separation of fine-grained ilmenite. Methods include conventional flotation, flocculation flotation, and agglomeration flotation. 1. Common collectors used in conventional ilmenite flotation include oleic acid and its soaps, oxidized paraffin soaps, tall oil, and newer collectors such as TAO, R-2, H1717, ZY, RST, and TOB. Oleic acid and its soaps are the most commonly used ilmenite collectors, with proven and reliable technology. Their collection performance can be improved by increasing the temperature, increasing the oxygen content, or adding emulsifiers. However, their disadvantages are high reagent consumption and poor selectivity. Oxidized paraffin soaps, produced by the oxidation and saponification of paraffin, are widely available and low-cost alternatives to oleic acid. However, they require emulsification at room temperature to enhance their collection efficiency, resulting in low concentrate quality and unstable grades. 2. Flocculation Flotation of Ilmenite: Flocculation flotation primarily involves selective flocculation and hydrophobic flocculation. Selective flocculation is a method of agglomerating and flocculating one mineral from a dispersed system of two or more minerals. Hydrophobic flocculation refers to the phenomenon in which hydrophobic particles suspended in water attract each other and form clumps due to their hydrophobic interaction. Hydrophobic flocculants are achieved by adding a collector and neutral oil under high-speed stirring. Ilmenite flocculation flotation uses flocculants such as polyacrylamide to selectively flocculate fine ilmenite particles, forming flocs followed by flotation. 3. Ilmenite agglomeration flotation: Agglomeration flotation uses a collector adsorbed on the ilmenite surface to render it hydrophobic. The capillary attraction of the liquid bridge allows the particles to aggregate and float for separation. Strong agitation is crucial during agglomeration flotation. It imparts more energy to the particles, overcomes the energy barrier between the particles, and renders the surface hydrophobic, inducing flocculation and ultimately achieving ilmenite beneficiation.

IV. Electrostatic Separation for Ilmenite Recovery

Electrostatic separation primarily processes coarse concentrates containing non-conductive impurities such as pyroxene, produced by gravity and magnetic separation. It is widely used in the beneficiation process. Electrostatic separation has specific particle size requirements for ilmenite, with a lower limit of 0.04mm. Pretreatment, such as heating and radiation exposure, is required before electrostatic separation to ensure the proper functioning of the electrostatic separation process, avoid unnecessary problems, and improve the efficiency of the mineral processing technology.

V. Combined Methods for Ilmenite Recovery

Combined methods often achieve better recovery results than single methods. The main methods include magnetic separation-flotation, gravity separation-flotation, magnetic separation-gravity separation, and gravity separation-magnetic separation-flotation-electrostatic separation. For combined magnetic separation-flotation methods, recovering fine-grained ilmenite has always been a key and challenging task. Flotation can generally recover ilmenite down to a particle size of -0.02mm, but large amounts of gangue, such as quartz, can affect flotation performance. Strong magnetic pre-discarding can improve the flotation environment. The combined gravity separation and flotation process primarily uses gravity separation equipment such as spiral chutes and shaking tables for roughing and concentrating to obtain qualified rough concentrates. This is then followed by flotation desulfurization to ultimately produce titanium concentrate and sulfur concentrate, achieving comprehensive utilization of mineral resources. While placer titanium ore can be enriched through simple gravity or magnetic separation, the combined magnetic separation and gravity separation process offers improved performance while reducing costs. For ores whose gangue is primarily composed of titanopyroxene and plagioclase, along with sulfide minerals, the combined gravity separation, magnetic separation, flotation, and electrostatic separation process can remove plagioclase through gravity separation, desulfurize through flotation, and remove titanopyroxene through electrostatic separation.

In short, the choice of ilmenite beneficiation method primarily depends on the material properties. Because titanium minerals have a higher specific gravity than non-metallic gangue minerals, gravity separation can be used for pretreatment or roughing tailings removal. It can also be used to enrich ilmenite with lower gangue minerals. Magnetic separation is widely used for iron removal to improve the concentrate grade of ilmenite. Electrostatic separation is often used to purify titanium concentrates obtained through other processes when they contain various non-conductive minerals. Flotation is more suitable for the beneficiation of fine-grained primary ilmenite ore. Combined beneficiation methods leverage the strengths of various beneficiation methods based on the ilmenite's ore properties, ensuring optimal beneficiation performance and economic benefits. Due to the complex and varying properties of ilmenite, appropriate beneficiation processes and equipment must be determined through beneficiation trials to ensure optimal beneficiation results in production.