The extraction methods of lignite wax mainly include the following:

1. Solvent extraction method

Principle: Use solvent to dissolve the waxy components in lignite, and then separate and recover the solvent to obtain lignite wax.

Steps:

• Raw material preparation: Crush the lignite to an appropriate particle size and dry it.
•  
• Solvent extraction: Mix the dried lignite particles with the extraction solvent (such as dichloroethane, ethanol, toluene, glacial acetic acid, etc.), heat, and stir to dissolve the waxy components in the solvent.
•  
• Separation and recovery: Separate the solvent that dissolves the wax from the undissolved lignite residue by filtering, distillation, and other methods, and then recover the solvent to obtain a wax-rich solution.
•  
• Wax precipitation and drying: Cool or evaporate the wax-rich solution to precipitate the waxy components, and then dry it to obtain a crude lignite wax.
•  
• Refining: Further treat the crude lignite wax to remove impurities such as resin and asphalt to obtain refined lignite wax.
• Features: Solvent extraction is one of the most commonly used lignite wax extraction methods, with advantages such as high extraction efficiency and good product quality. However, this method also has disadvantages such as high solvent consumption, high energy consumption, and environmental pollution.

2. Other extraction methods
In addition to solvent extraction, there are some other lignite wax extraction methods, such as ultrasonic-assisted extraction and microwave-assisted extraction. These methods mainly promote the dissolution and extraction of wax components in lignite by solvents through physical means, thereby improving the extraction efficiency. However, these methods still have some problems in practical applications, such as complex equipment, high cost, and unstable extraction efficiency.

3. Extraction process optimization
To improve the extraction efficiency and product quality of lignite wax, the extraction process can also be optimized. For example:

• Selecting a suitable extraction solvent: According to the properties of lignite and the characteristics of wax components, selecting a suitable extraction solvent can improve the extraction efficiency.
• Optimizing extraction conditions: such as increasing the extraction temperature, extending the extraction time, and increasing the number of extractions, can improve the extraction efficiency to a certain extent.
• Using advanced separation technologies: such as supercritical fluid extraction and membrane separation technology, more efficient separation and recovery of solvents can be achieved, thereby reducing production costs.
• Refining treatment: Refining the crude montan wax obtained by extraction can remove impurities and improve product quality.

In summary, there are many methods for extracting montan wax, and the appropriate extraction method and process conditions should be selected according to the actual situation. At the same time, attention should also be paid to environmental protection and cost control to achieve sustainable montan wax production.