Introduction to the coal washing plant process flow

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Brief introduction to the process flow diagram of the coal washing plant: Coal processing, gangue treatment, and the transportation of materials and equipment constitute the surface system of the mine. The surface coal processing system consists of main stages such as coal reception, screening, crushing, sorting, storage, and loading. It is the main entity for production at the mine surface. Coal reception involves installing coal silos of a certain capacity near the mine entrance to receive the coal lifted from underground to the surface, thereby ensuring balanced and continuous production both above and below the mine entrance. Screening is the process of separating mixtures with particles of different sizes into various size categories using a sieve with holes. The machine used for grading is called a screener or sieve. In coal preparation plants, screening operations are widely used in the preparation and processing of raw coal. Based on the screening method, it is divided into dry screening and wet screening. Crushing is the process of breaking large pieces of material into smaller particles. A machine used for crushing is called a crusher. The main requirements for crushing operations in coal preparation plants are as follows: 1) Meeting the requirements of the particles to be fed into the process ； The size range of coal particles that can be processed by selected machinery is limited; larger pieces exceeding this range must be crushed before they can be washed and processed. 2) Some coal lumps are actually mixed coal containing gangue; in order to separate the high-quality coal from this mixture, it is necessary to crush them into smaller particles so that the coal and gangue can be separated. 3) To meet the customer’s requirements regarding particle size, the selected product or coal lumps are crushed to a specific particle size. Material crushing is primarily carried out using mechanical methods, including compression, splitting, breaking, crushing, and grinding. Coal washing involves using the different physical and physico-chemical properties of coal compared to other substances, and employing mechanical methods in coal washing plants to remove impurities mixed in with the raw coal, thereby separating it into products of varying quality and specifications to meet the needs of different customers. Based on the location relative to the coal mine, coal preparation plants can be classified into: mine-based coal preparation plants, group-mine coal preparation plants, central coal preparation plants, and customer-specific coal preparation plants ； Most of the coal washing plants in our country are mine-based coal washing plants. A modern coal washing plant is a continuous mechanical processing process consisting of many operations. Jig coal sorting is a process of separating coal particles based on differences in their density, carried out in a vertically pulsating medium. The medium used in jig coal washing is water or air; occasionally, suspensions are also used. Hydraulic jigging is the most common method in coal washing. A jig is a device that utilizes the principle of jig sorting to separate the feed material into products such as clean coal, medium coal, and gangue coal, based on their density. Heavy media coal washing is a method of coal separation that involves using a medium with a density greater than 1 g/cm³, and separating coal particles based on differences in their density; this process is known as heavy media coal washing. The heavy media used in coal washing fall into two categories: heavy liquids and heavy flotation fluids. The main advantage of heavy medium coal separation is its high separation efficiency compared to other coal separation methods ； The range of particle sizes that can be processed is wide: the feed particles for the separator range from 1000 to 6 mm, while those for the cyclone range from 80 to 0.15 mm. Production control can be easily automated. The disadvantages of heavy medium coal washing are complex production processes, high production costs, rapid equipment wear, and extensive maintenance needs. Heavy medium coal separation is generally carried out with staged feeding. Bituminous coal sorting is generally carried out using a heavy media separator under the action of gravity ； The separation of foamed coal is carried out using a heavy medium cyclone under the action of centrifugal force. Coal storage silo: A silo with a certain capacity that is designed to address any imbalances between production, transportation, and sales, thereby ensuring normal and balanced operations in the mine and transportation sectors. It receives the coal that has been produced, ensuring that it can be shipped out smoothly and reach the final loading stage. Loading: includes loading (onto ships), cranes, and metering. Coal washing plant flow chart 1 Coal washing plant flow chart 2