Coal preparation refers to the process of removing shale and other impurities from coal through various physical, chemical, or physicochemical methods to improve the quality of coal. The following is a detailed description and introduction of the entire coal preparation production process in China:\n1. Raw coal preparation\nCoal crushing and screening:\nRaw coal is first crushed into suitable particle sizes for coal preparation using crushers. The crushed coal then enters screening equipment for particle size classification, directing the coal with different particle sizes into the corresponding coal preparation equipment.\nThe screening process can be divided into several stages to ensure that coal of different particle sizes can achieve the best processing results.\n2. Pre-selection equipment: Before official coal preparation, use magnetic separators, iron removers, and other equipment to remove metal impurities and large pieces of gangue from the raw coal. The objective of the pre-selection stage is to reduce the impurity content entering the subsequent coal preparation processes, thereby improving the efficiency of coal preparation. Coal jigging\nJigging separation:\nCoarse coal is sorted through a jigging machine. The jigging machine utilizes the pulsating action of water to stratify coal and impurities by density. The cleaner coal, with a lower density, rises to the upper layer, whereas the gangue and impurities with higher density sink to the lower layer. \nCoal enters the mineral hopper of the jigging machine, mixes with water to form pulp. Under the action of the jigging machine, the Premium coal and impurities stratify; Premium coal is collected via overflow槽 or discharge device, and impurities are discharged through the discharge port. Heavy medium coal preparation Heavy medium separation: Medium-sized coal is sorted through a heavy medium separator. In the heavy medium suspension, coal with lower density floats up, while impurities with higher density sink down, thereby achieving the separation of coal and impurities. Magnetite powder or other heavy medium materials are mixed with water to create a heavy medium suspension of a certain density. The heavy medium suspension after classification is processed through magnetic separators to recover the magnetite powder for recycling and reuse. 5. Coal flotation Grinding: Fine coal needs to be further ground before entering the flotation machine to achieve the appropriate particle size for flotation (usually 0. The coal powder less than 1 millimeter).\nCoal flotation:\nThe ground coal powder is mixed with water to form a slurry. After adding flotation reagents (such as collectors, frothers, and modifiers), it is sent into the flotation cell. Through mechanical agitation and aeration, bubbles are formed. The coal powder particles adhere to these bubbles, which rise to the surface of the slurry, forming a foam layer. This foam layer is collected to obtain high-purity premium coal.\n6. Premium coal processing Dehydration processing: The premium coal obtained from coal jigging, heavy medium coal preparation, and flotation coal preparation contains a certain amount of moisture. It needs to be processed by dehydration equipment (such as dewatering screens, centrifuges, or filter presses) to reduce the moisture content and improve the quality of the premium coal. Storage and transportation: The dehydrated premium coal is then stored and transported. To prevent moisture and spontaneous combustion during storage and transportation, protective measures need to be taken, such as using coal sheds or sealed stockpiles for storage. Tailings processing\nTailings discharge:\nThe tailings (mainly gangue and impurities) generated in the coal jigging, heavy medium coal preparation, and coal flotation processes are discharged through a discharge device and sent to the tailings processing area.\nDewatering of tailings and wastewater treatment:\nThe moisture in the tailings needs further processing, dewatered through a thickener or filter, the solid tailings are stockpiled or further processed. The wastewater produced during the flotation process is treated and reused or discharged up to standard, reducing environmental pollution. Environmental Protection and Safety Measures\\nEnvironmental protection measures:\\nThe coal preparation plant should take environmental protection measures such as dust control and wastewater treatment to reduce environmental impacts. Treated wastewater can be reused or discharged up to standards, reducing water resource consumption.\\nSafety measures:\\nFormulate and implement safety production rules and regulations, carry out regular safety inspections and training, provide protective equipment and emergency rescue systems to ensure the safety of workers.

Thermal coal refers to coal used as a power material. In a narrow sense, it generally refers to coal used for thermal power generation. Broadly speaking, any coal used for the purpose of power generation, locomotive propulsion, boiler combustion, etc., falls under the category of thermal coal, which is simply referred to as thermal coal.