Lithium extraction process from lepidolite

The process for extracting lithium from lepidolite usually includes the following steps:

Crushing: Crushing lepidolite ore into appropriate particle sizes for subsequent processing.

Flotation: Lepidolite is separated from other impurities by flotation. During the flotation process, chemicals are used to make the surface of lepidolite hydrophobic, thereby separating it from other impurities.

Roasting: Roast the lepidolite after flotation to remove organic matter and moisture. Roasting is usually carried out at high temperatures, usually around 800-1000°C.

Leaching: Contact the roasted lepidolite with acid or alkali solution to dissolve the lithium element into the solution. Commonly used leaching agents include sulfuric acid, hydrochloric acid, sodium hydroxide, etc.

Precipitation: Separate the lithium element in the leach solution through precipitation. Commonly used precipitants include sodium carbonate, sodium bicarbonate, etc.

Filtration: Separate the precipitated lithium salt through filtration to obtain the lithium salt product. 

Drying: Dry the lithium salt product to remove moisture and obtain a dry lithium salt product.

In addition, there are many different methods for extracting lithium from lepidolite, such as sulfuric acid beneficiation method, sulfate roasting beneficiation method, limestone beneficiation method, etc. Among them, the sulfuric acid leaching method in the sulfuric acid beneficiation method avoids high-temperature roasting, has low energy consumption and low reaction temperature. It is a relatively efficient lithium extraction process with a small amount of waste residue. The sulfate roasting method is mainly to mix lepidolite and sulfate and then roast it at high temperature. The high temperature is used to destroy the mineral phase structure of lepidolite and make the lithium ore structure loose. The sodium, potassium, etc. in the sulfate are mixed with the lepidolite. The lithium ions near the aluminosilicate core undergo a high-temperature displacement reaction to displace the lithium and convert it into soluble lithium sulfate, which is then leached with water or dilute acid and filtered to extract the lithium.

The entire process of extracting lithium from lepidolite can be simply divided into two steps: the first step is to turn the lithium-containing raw ore into lepidolite concentrate; the second step is to turn the lepidolite concentrate into lithium carbonate after deep processing. The completion of these steps requires professional equipment and technology to ensure the efficiency and product quality of lithium extraction from lepidolite.