Nonmetallic Mineral
Coal Washing
One of the most important goals of coal washing is to improve the quality of coal in the preparation of metallurgical coke for the steel industry. The presence of ash and other harmful elements in coal causes undesirable problems in the steel industry such as increasing material consumption, reducing steel production, slag increasing, and decreasing Furnace efficiency.
One of the important issues in the design of coal-washing plants is a complete understanding of the structure and properties of coal. This knowledge will be obtained from the study of representative samples. Hardness, brittleness, humidity, amount of ash, type of minerals that make up ash, type, and number of harmful substances such as sulfur of mineral origin and organic origin, coking properties, and amount of volatile substances. Plastometry, amount and type of Macerals, grade of coal, grain size distribution and particles less than 0.5 mm, coal washing ability by sink and float methods, and many other things are among the parameters that should be investigated and studied first.
Crushing, sizing, floatation, dewatering, and washing of coal by gravity methods are the main processes of coal washing plants
For minerals that reach the appropriate degrees of freedom in coarse dimensions, if there is a sufficient specific mass difference, the most suitable method is the gravity method.
One of the important issues in the design of coal-washing plants is a complete understanding of the structure and properties of coal. This knowledge will be obtained from the study of representative samples. Hardness, brittleness, humidity, amount of ash, type of minerals that make up ash, type, and number of harmful substances such as sulfur of mineral origin and organic origin, coking properties, and amount of volatile substances. Plastometry, amount and type of Macerals, grade of coal, grain size distribution and particles less than 0.5 mm, coal washing ability by sink and float methods, and many other things are among the parameters that should be investigated and studied first.
Crushing, sizing, floatation, dewatering, and washing of coal by gravity methods are the main processes of coal washing plants
For minerals that reach the appropriate degrees of freedom in coarse dimensions, if there is a sufficient specific mass difference, the most suitable method is the gravity method.
The separation mechanism in gravity methods is divided into three categories:
The method based on the vertical movement of particles or the layering of particles, such as Jig
The method is based on the movement of particles on an inclined surface or the flow of a thin layer of water or layered flows of water such as spiral and vibrating tables
The method that is based on the movement of particles in a false fluid with a specific mass in the middle of the specific mass of heavy and light materials (coal), such as Heavy media drum, Heavy media cyclone, and Tri-flow.
The advantages of the gravity method compared to the flotation method include the absence of chemicals (both from the point of operation costs and environmental effects) and the simplicity of the process.