Introduction to three rare earth beneficiation methods

Rare earth beneficiation is to enrich rare earth resources by a variety of different methods to obtain high-grade rare earths. In general beneficiation, the beneficiation method of rare earth ore is selected according to the difference in the properties of rare earth and associated minerals. Among them, flotation is the main method, and there are also gravity separation and leaching methods. The magnetic separation method is mainly used to cooperate with the above separation methods to complete the rare earth beneficiation. The following editor will focus on introducing three rare earth ore beneficiation methods.

011. Rare earth ore flotation method

It is one of the main process methods of rare earth ore beneficiation plants, and it is almost inseparable from flotation. This method uses the difference in surface wettability between rare earth and associated minerals for separation. By adding flotation agents and relying on the buoyancy of bubbles, useful rare earth minerals are attached to bubbles and float up to complete the separation and obtain qualified rare earth concentrates.

Generally, flotation is suitable for selecting rare earth ores with finer ore particle size. For example, for the selection of fluorocarbon cerium and monazite, the pH value of the ore pulp is determined to be in the range of 4.5-5.5, alum is added as a monazite inhibitor, and phthalic acid is used as a collector for fluorocarbon cerium. After a flotation process of one roughing-two fines-two sweeps, better fluorocarbon cerium and monazite concentrates can be obtained.

022. Rare earth ore gravity separation method

The gravity separation method selects rare earth ores, which is mainly a process in which minerals are separated based on density differences in a certain fluid medium. It is generally used in small and medium-sized rare earth mines. The process is mainly to use the qualified ore particles (-2mm range) obtained after grinding and classification for roughing, and the obtained roughing tailings are swept through a shaking table. The obtained roughing concentrate and scavenging concentrate can be used as the final rare earth concentrate.

The process of selecting rare earth ores by gravity separation is relatively simple, but the resource recovery rate is low, generally only around 60%.

033. Rare earth ore leaching method

Rare earth ore leaching process can be divided into three types, namely barrel leaching, pool leaching and heap leaching. Among them, the barrel leaching method was used earlier, but due to its low efficiency, it has been replaced by pool leaching and heap leaching.

Rare earth ore pool leaching process: When the raw ore is fed with a leaching agent, a rare earth leaching solution is obtained, and then oxalic acid is added for precipitation, and then filtered and washed and burned several times to obtain a qualified rare earth concentrate. This rare earth beneficiation method has a low cost, but the work efficiency is also low. At the same time, more harmful ions will be generated during the leaching process.

Rare earth ore heap leaching process: ammonium sulfate ((NH4)2SO4) is used as a leaching agent. It has strong washing ability and strong selectivity for leached ions. It can effectively reduce the leaching of harmful metal ions such as Ca2+ and Ba2+. In addition, NH4+ hardly precipitates with rare earth ions. Therefore, the efficiency of rare earth ore concentrate separation is relatively high. But overall, the heap leaching method is very destructive to the surrounding environment.

In addition to the above three single rare earth ore dressing processes, there are also a variety of combined beneficiation processes such as magnetic separation, flotation, and gravity separation, which are mainly used to select and purify some complex and difficult rare earth ores. For example: flotation-gravity separation-flotation method, magnetic separation-gravity separation-flotation method and weak magnetic-strong magnetic-flotation method. In actual beneficiation plants, the rare earth ore dressing method needs to be designed according to the nature and complexity of the ore. Therefore, the editor recommends that rare earth ore beneficiation be carried out first, and through analysis, suitable rare earth beneficiation process methods and complete sets of rare earth ore beneficiation equipment should be designed to effectively obtain ideal rare earth ore concentrates.