Lithium ore dressing methods and equipment

As the main raw material for energy development, lithium ore is widely used in batteries, electronics, chemicals, materials, medical and other fields. In recent years, as the main raw material for lithium battery production, the demand for lithium ore resources has become increasingly greater, and lithium ore dressing technology has also developed rapidly.

Different lithium ores have different properties, and the content of lithium oxide in the minerals is low and the mineral composition is different, so the lithium ore dressing methods are also different. The following mainly introduces several common lithium ore dressing methods and lithium ore dressing equipment.

At present, the main lithium ore dressing methods include flotation, magnetic separation, gravity separation (or heavy suspension) method, hand selection, thermal crushing (cracking) method and combined beneficiation method.

1. Lithium ore flotation method

The lithium ore flotation method is suitable for the extraction of various lithium with industrial value, especially spodumene in the form of fine-grained impregnation.

Spodumene flotation is mainly affected by factors such as ore properties, grinding fineness, stirring operation, adjusting agent ratio, and water hardness. For pure spodumene minerals with uncontaminated surface, it is easy to float with oleic acid and its soap agents. The most suitable pH in the flotation slurry is a weak alkaline near neutral. Generally, before flotation of spodumene, Na2CO3 should be added to eliminate the influence of molten salt ions in the slurry and stir to desludging, and the surface of spodumene ore should be scrubbed in the high alkaline medium formed by adding NaOH (the recovery rate of spodumene is determined by the amount of NaOH).

Lithium ore flotation equipment includes: xcf flotation machine, kyf flotation machine, jjf flotation machine, sf flotation machine and coarse particle flotation machine, etc., which can meet the roughing, scavenging and concentrating operations of various large, medium and small lithium ore concentrators.

2. Lithium ore magnetic separation method

Lithium ore magnetic separation is mainly used to remove iron impurities in lithium concentrate. Generally, magnetic lithium ores are mainly iron lithium mica and spodumene, which have weak magnetism. Therefore, strong magnetic separation technology can be used to remove iron-containing minerals to improve the product quality of spodumene. In the ore dressing plant, magnetic separation is generally used in conjunction with flotation and gravity separation.

Lithium ore magnetic separation equipment includes: permanent magnetic drum magnetic separator, high gradient magnetic separator, eccentric rotating magnetic field dry separator, etc., which can meet various wet and dry environment magnetic separation to select lithium concentrate.

3. Lithium ore gravity separation method

Gravity separation method uses the density difference between spodumene ore and gangue ore for separation, and is mostly used for the separation of spodumene with coarse embedded particle size. Usually, when the density difference between spodumene and gangue ore (quartz, feldspar, biotite, etc.) is above 0.2-0.5g/cm3, shaking table separation or jigging separation can be used.

When the density difference is less than 0.2-0.5g/cm3, the heavy suspension method can be used to mix the lithium minerals after washing and desludging with the heavy medium, and feed them into the heavy medium cyclone at a pressure of 0.05-0.20Mpa for selection.

Lithium ore re-selection equipment includes: shaking table, jig, heavy medium cyclone, etc.

4. Lithium ore hand selection method

Lithium ore hand selection is a method used to select ore containing more waste rock in the original ore, and is mainly used as a pre-selection operation in the ore dressing plant. Generally, lithium ore is mostly silvery white, and there is a color difference with other impurity minerals. Therefore, it can be selected by the difference in the surface properties between lithium ore and gangue minerals to improve the selection grade of lithium ore. There is no need for better site and equipment during ore selection, and it only needs to be carried out on the hand selection belt or hand selection operation table.

5. Lithium ore thermal cracking method

Lithium ore thermal cracking method, also known as thermal crushing method, is a method of selection by heating and cooling, which is suitable for processing spodumene containing non-albite, calcite and mica. Roasting at a certain high temperature transforms lithium minerals from the original α-type to β-type lithium ore, while the gangue minerals remain unchanged, thereby obtaining lithium ore. The process is: crush the minerals to 50~20mm and then screen them. The ore larger than 0.3mm is roasted at 1000~1200℃ for 1~2h, and then cooled and selectively ground, graded and purified. Lithium ore smaller than 0.3mm can be extracted with spodumene through combined separation technology.

Lithium ore thermal cracking equipment includes: roasting equipment, ball mill, classifier, gravity separation equipment, flotation equipment, etc.

6. Lithium ore combined beneficiation method

The combined beneficiation method extracts lithium minerals, mainly for the separation of poor and fine lithium minerals. When a single method fails to obtain qualified lithium concentrate, a combined method is required to obtain higher quality lithium concentrate. The main processes include: flotation-magnetic separation process, flotation-gravity separation-magnetic separation process, etc.

The above are several common lithium ore dressing methods and commonly used lithium ore dressing equipment. In addition, there is also chemical dressing method, which is mostly used to treat salt lake lithium minerals and extract lithium from brine. The methods include precipitation method, extraction method, ion exchange adsorption method, carbonization method, calcination leaching method, Xu method and electrodialysis method.

In the actual lithium ore dressing plant, if you want to obtain the ideal lithium ore grade, it is recommended to conduct a dressing test first, and customize the appropriate dressing method and equipment according to the dressing test, and do not copy and apply.