Coal preparation refers to the process of removing gangue and other impurities from coal using various physical, chemical, or physicochemical methods to improve coal quality. The following is a detailed description and introduction to the entire coal preparation process: 1.Raw Coal Preparation Coal Crushing and Screening: Raw coal is first crushed by crushers into particles suitable for coal preparation. The crushed coal is then fed into screening equipment for particle size classification, where different-sized coal particles are directed to corresponding coal preparation devices. The screening process can be divided into multiple stages to ensure that coal of various particle sizes receives optimal treatment. 2.Pre-selection Impurity Removal Equipment: Before the formal coal preparation process, devices like magnetic separators and de-ironing equipment are used to remove metal impurities and large chunks of gangue from raw coal. The goal of the pre-selection stage is to reduce the impurity content entering the subsequent coal preparation processes and enhance preparation efficiency. 3.Coal Jigging Jigging Separation: Coarse-grade coal is separated through a jigging machine. The jigging machine uses the pulsating action of water to stratify coal and impurities by density. Coal with a lower density rises to the upper layer, while denser gangue and impurities sink to the bottom. The coal enters the jigging machine's feed hopper, mixing with water to form a slurry. Under the jigging machine's action, coal and impurities are stratified. The clean coal is collected via the overflow channel or discharge device, while impurities are discharged through the outlet. 4.Heavy Medium Coal Preparation Heavy Medium Separation: Medium-grade coal is separated using a heavy medium separator. In the heavy medium slurry, coal with a lower density floats to the top, and impurities with a higher density sink to the bottom, thus separating coal from impurities. Magnetite powder or other heavy medium materials are mixed with water to form a slurry of a specific density. The separated heavy medium slurry is then processed through a magnetic separator to recover magnetite, which is reused. 5.Coal Flotation Grinding: Fine-grade coal needs further grinding before entering the flotation machine to achieve the required particle size for flotation (usually below 0.1 mm). Flotation Separation: The ground coal slurry is mixed with water, and flotation reagents (such as collectors, frothers, and modifiers) are added before it is fed into the flotation cell. Mechanical agitation and air injection form bubbles, onto which the coal particles adhere. These bubbles rise to the surface of the slurry, forming a foam layer. The foam layer is collected to obtain high-purity clean coal. 6.Clean Coal Treatment De-watering: The clean coal from jigging, heavy medium separation, and flotation contains some moisture, which needs to be removed through de-watering equipment (such as dewatering screens, centrifuges, or filter presses) to reduce moisture content and improve coal quality. Storage and Transport: After de-watering, clean coal is stored and transported. To prevent dampness and spontaneous combustion during storage and transport, protective measures, such as using coal sheds or sealed storage yards, should be implemented. 7.Tailings Treatment Tailings Discharge: Tailings (mainly gangue and impurities) produced during jigging, heavy medium, and flotation processes are discharged through a discharge system and sent to the tailings treatment area. Tailings Dewatering and Wastewater Treatment: The moisture in the tailings must be further processed. After dewatering by concentrators or filters, solid tailings are either stored or further treated. Wastewater generated during flotation is treated and either reused or discharged after meeting environmental standards, reducing environmental pollution. 8.Environmental Protection and Safety Measures Environmental Protection Measures: Coal preparation plants should implement dust control, wastewater treatment, and other environmental protection measures to minimize environmental impact. Wastewater, after treatment, can be recycled or discharged in compliance with standards, reducing water resource consumption. Safety Measures: Safety regulations should be developed and implemented, with regular safety checks and training sessions. Protective equipment and emergency rescue systems should be provided to ensure worker safety.

Premium coal (cleaned coal) refers to coal that has undergone mechanical processing at a coal washery, reducing ash and sulfur content and removing some impurities, making it a high-quality coal suitable for specific uses.