Coal gangue is a mixture of various mineral rocks that is co-occurred with the coal seam during the production process of coal preparation plant. Generally speaking, carbon clay rocks, sandstone, carbonate and aluminous rocks are the main components of coal gangue. At present, we need to strengthen the development of coal gangue, explore its potential function, transform waste into treasure and realize the sustainable use of coal resources.
With a large number of coal mining activities, the total amount of coal gangue produced each year gradually increases, which causes a variety of harmful effects on the environment. They are mainly in the following aspects:
Coal gangue contains a lot of carbon, sulfur, hydrogen and oxygen. After a period of stacking, it can oxidize with air and spontaneously ignite, then releasing a lot of harmful gases such as sulfur dioxide, hydrogen sulfide, and carbon monoxide in the air. In addition, weathered coal gangue surface may produce some dust suspending in the air, so as to cause air pollution.
Influenced by rainfall and long-term immersion, some harmful elements in coal gangue, especially the soluble heavy metals such as mercury, lead, cadmium, and arsenic will gradually flow into the soil and water. Therefore, the soil and water environment can be polluted, and the health of human body can be harmed through daily food.
A large amount of coal gangue is discharged each year, which takes up a large area of land for storage it. It influences the surrounding land resources and leads to the surrounding land to be contaminated or the soil fertility is reduced and cannot be used.
According to the test result, coal gangue contains various necessary trace elements for plant growth. The content of nitrogen, phosphorus, potassium and trace elements of coal gangue are several times that of the soil. The PH value and the number of harmful elements of coal gangue are moderate.
Thus, we can use coal gangue as raw materials to produce organic fertilizer. Ordinarily, we need to use the crushing and screening equipment to lessen the granularity of coal gangue, and add moderate additives and active agents as needed.
There are often the pyrite, gallium and other rare-earth metal elements in coal gangue. For the coal gangue with 60g/t of gallium grade, its comprehensive utilization should be centered on the recycling gallium.
In order to recycle the pyrite product from coal gangue, we should use the PE jaw crusher and two-stage crusher to crush it firstly, and then use the corresponding mining equipment to recycle the pyrite from coal gangue.
The content of silica and aluminum oxide in gangue is the highest. Therefore, we can use a physical or chemistry method to extract the silicon and aluminum in coal gangue, and apply them to the production of silicon and aluminum materials. For example, we can use the high-alumina coal gangue and fly ash as raw materials, and adopt the electric heating method to directly produce alsimin.
In recent years, it develops rapidly to produce building materials with coal gangue. As far as the current utilization situation of coal gangue, the more mature approach is to make bricks, hollow block, cement raw materials, and lightweight aggregate.
Coal gangue contains carbon, hydrogen, oxygen, and other calorific components. Using coal gangue to generate electricity is an important way to realize the comprehensive use of coal gangue. In order to promote energy conservation and emission reduction, encourage the use of coal gangue, many countries have specialized policy for coal gangue power generation. At present, there are some power projects which use the coal gangue to generate power, which has produced good economic benefit and environmental benefit.
The comprehensive utilization of coal gangue is a complex project involving multi-disciplinary field and a variety of technical fields, which must be analyzed with the chemical composition of coal gangue. The related information of stone crusher machines, please contact us for inquiry.