Coal preparation refers to the process of removing gangue and other impurities from coal through various physical, chemical, or physicochemical methods to improve coal quality. The following is a detailed description and introduction of the entire coal preparation production process in China:\n\n1. Raw coal preparation\n\nCoal crushing and screening:\n\nThe raw coal is first crushed into particles suitable for coal preparation by a crusher. The crushed coal then enters screening equipment for particle size classification, sending coal of different particle sizes to the corresponding coal preparation equipment.\n\nThe screening process can be divided into several stages to ensure that coal of different particle sizes can be processed optimally.\n\n2. Pre-selection\\n\\nImpurity removal equipment:\\n\\nBefore official coal preparation, use magnetic separators, iron removers, and other equipment to remove metal impurities and large gangue from the raw coal.\\n\\nThe goal of the pre-selection stage is to reduce the impurity content entering the subsequent coal preparation process, improving the efficiency of coal preparation. Coal jigging\n\nJigging separation:\n\nCoarse coal is sorted through a jig. The jig uses the pulsation of water to separate coal and impurities by density. The cleaner coal with lower density rises to the upper layer, while the gangue and impurities with higher density sink to the lower layer.\n\nCoal enters the ore feeding hopper of the jig and mixes with water to form pulp. Under the action of the jig, the Premium coal and impurities are separated into layers. The Premium coal is collected through overflow troughs or discharge devices, and impurities are discharged through the discharge port.\n\n4. Heavy medium coal preparation\n\nHeavy medium separation:\n\nMedium-sized coal is sorted through a heavy medium separator. In a heavy medium suspension, coal with lower density floats while impurities with higher density sink, achieving separation of coal and impurities.\n\nUsing magnetite powder or other heavy medium materials mixed with water, a heavy medium suspension of a certain density is produced. After sorting, the heavy medium suspension is passed through a magnetic separator to recover the magnetite powder for recycling.\n\n5. Coal flotation\n\nGrinding:\n\nFine coal needs to be further ground before entering the flotation cell to reach a suitable size for flotation (usually 0. Floatation separation: The ground coal powder, less than 1 millimeter, is mixed with water to form a slurry. After adding flotation reagents (such as collectors, frothers, and modifiers), it is fed into the flotation cell. Through mechanical stirring and air injection, bubbles are formed. Coal particles adhere to the bubbles and rise to the surface of the slurry with the bubbles, forming a foam layer. The foam layer is collected to obtain high-purity premium coal. Premium coal processing\n\nDewatering treatment:\n\nThe premium coal obtained from coal jigging, heavy medium coal preparation, and flotation coal preparation contains a certain amount of moisture. Dewatering treatment through dewatering equipment (such as dewatering screens, centrifuges, or filter presses) is required to reduce the moisture content and improve the quality of the premium coal.\n\nStorage and transportation:\n\nAfter dewatering, the premium coal is stored and transported. To prevent dampness and spontaneous combustion during storage and transportation, protective measures need to be taken, such as storing in coal sheds or sealed stockyards. Tailings processing\n\nTailings discharge:\n\nThe tailings (mainly gangue and impurities) generated from the coal jigging, heavy medium coal preparation, and coal flotation processes are discharged through discharge equipment and sent to the tailings processing area.\n\nTailings dewatering and wastewater treatment:\n\nThe water in the tailings requires further processing. After dewatering through thickeners or filters, the solid tailings are stockpiled or subjected to further processing. The wastewater produced during the flotation process is treated and then reused or discharged up to the standard, thus reducing environmental pollution. Environmental Protection and Safety Measures\\n\\nEnvironmental Protection Measures:\\n\\nThe coal preparation plant should adopt environmental protection measures such as dust control and wastewater treatment to reduce environmental impacts. Treated wastewater can be recycled or discharged up to the standard, thereby reducing water resource consumption. \\n\\nSafety Measures:\\n\\nFormulate and implement safety production rules and regulations, conduct regular safety inspections and training, equip protective devices 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. Among these, medium thermal coal is a product between premium coal and coal gangue. Its quality is inferior to that of premium coal and contains a certain amount of impurities such as ash and sulfur, but it is better than coal gangue and still has a certain calorific value. Medium coal usually contains a higher proportion of ash and can be used in some industrial boilers where coal quality requirements are not particularly high.