Rare earth ore flotation process

Fatty acid collector flotation method

Fatty acid collectors are a type of rare earth collector that has been used earlier and more widely. Its molecular structure contains polar groups such as carboxyl (-COOH) and long-chain non-polar hydrocarbon groups. During the flotation process, polar groups such as carboxyl can react chemically with metal ions on the surface of rare earth minerals to form chemical adsorption or chemical bonding, while non-polar hydrocarbon groups face outward, making the surface of rare earth minerals hydrophobic, thereby achieving separation from gangue minerals. For example, oleic acid is a typical fatty acid collector that can react with rare earth ions in rare earth minerals to make rare earth minerals floatable.

This method is suitable for treating rare earth ores with low rare earth grade and gangue minerals mainly composed of silicates. It has strong collection ability, good selectivity for rare earth minerals, and can obtain a higher rare earth recovery rate; however, it is sensitive to impurity ions such as calcium ions and magnesium ions in the ore pulp, which is easily disturbed, resulting in fluctuations in flotation indicators. In addition, under low temperature conditions, the solubility and activity of fatty acid collectors will decrease, affecting the flotation effect.

Phosphonic acid collector flotation method

The molecules of phosphonic acid collectors contain active groups such as phosphonic acid groups (-PO(OH)₂). During the flotation process, the phosphonic acid group can form a stable chelate with the metal ions on the surface of the rare earth mineral, thereby firmly adsorbing on the surface of the rare earth mineral and making the surface of the rare earth mineral hydrophobic. Due to its special chemical structure, phosphonic acid collectors have good selectivity and collection performance for rare earth minerals.

It is often used to treat complex ores containing a variety of rare earth minerals, as well as rare earth ores that coexist with iron, titanium and other minerals. It has good selectivity, strong collection ability for rare earth minerals, and is relatively less affected by impurity ions in the ore pulp. However, the synthesis process is relatively complex and the cost is high, and some phosphonic acid collectors have poor water solubility, requiring special treatment and formulation to be better used in the flotation process.

Amine collector flotation method

Amine collector molecules contain basic groups such as amino groups (-NH₂). Under acidic or weakly acidic pulp conditions, amino groups can combine with hydrogen ions in the pulp to form positively charged ammonium ions (-NH₃⁺). The surface of rare earth minerals usually carries a negative charge under such conditions. Positively charged amine collectors are adsorbed on the surface of rare earth minerals through electrostatic attraction. At the same time, the non-polar hydrocarbon group of the amine collector faces outward, making the surface of the rare earth mineral hydrophobic, thereby achieving flotation separation.

This flotation method is suitable for treating rare earth ores with silicate minerals as the main gangue, and for removing gangue minerals such as quartz from rare earth ores in the reverse flotation process. Its advantages are that it has good collection performance for certain rare earth minerals under acidic conditions, good foaming properties, and can reduce the amount of frother; but the selectivity is relatively poor, and it is easily interfered by other ions in the slurry, and amine collectors have certain toxicity and have certain impacts on the environment. Safety and environmental protection issues need to be paid attention to during use.

Chelating collector flotation method

Chelate collectors are a class of organic compounds containing multiple coordinated atoms, which can form chelates with ring structures with rare earth ions. These coordinating atoms such as oxygen, nitrogen, and sulfur can react with metal ions on the surface of rare earth minerals to form stable chelate bonds, so that the collector is firmly adsorbed on the surface of rare earth minerals, thereby realizing the flotation of rare earth minerals.

It is mainly used to treat rare earth ores with low rare earth grade and complex mineral composition, especially for ores containing multiple rare earth elements and complex symbiotic relationships. In the flotation recovery of some ionic rare earth ores, chelating collectors also have certain applications, which can effectively improve the recovery rate and grade of rare earths. This method has high selectivity, can form stable chelates with rare earth ions, and has a good capture effect on rare earth minerals; but the synthesis cost is high, and the water solubility and stability of some chelating collectors need to be further improved. In practical applications, they need to be reasonably selected and formulated according to the different properties of the ore.

Combined Collector Flotation Method

Combined collector flotation method is to mix two or more different types of collectors in a certain proportion and use the synergistic effect between different collectors to improve the collection effect and selectivity of rare earth minerals. Different collectors have different adsorption modes and action mechanisms on the surface of rare earth minerals. By using them in combination, they can give play to their respective advantages and enhance the collection capacity and selectivity of rare earth minerals.

It can be widely used in the flotation of various types of rare earth ores, especially for complex and difficult rare earth ores. By reasonably selecting and matching collector combinations, the flotation index of rare earth can be significantly improved. When processing mixed ores containing multiple rare earth minerals and gangue minerals, the combined collector flotation method can better achieve the separation and enrichment of rare earth minerals.