Method for utilizing coal gangue waste

Abstract

The invention relates to a comprehensive utilization method for coal gangue waste combined with spent cathode carbon blocks in the aluminum electrolysis industry. The method comprises the following concrete steps: smashing coal gangue and the spent cathode carbon blocks into powder, drying, then burdening in a certain proportion, removing alkaline soluble impurities in a mixed material by using astrong alkali liquid, washing to be neutral with hot water, drying, then in an inert or reducing atmosphere, heating to 1400-1700 DEG C, carrying out heat preservation for a period of time, so that mixed powder containing silicon carbide is obtained, then oxidizing and combusting the powder in an oxidizing atmosphere for removing residual carbon powder, dispersing the obtained powder into hydrofluoric acid for removing residual silicon dioxide, cleaning, and drying, so that silicon carbide powder can be obtained. The obtained silicon carbide product is high in purity and small in particle sizeand has extremely high industrial application value; meanwhile, industrial solid wastes coal gangue and spent cathode carbon blocks are taken as raw materials, so that the method provided by the invention has positive significance in directions of reducing waste pollution, protecting the environment and recycling resources.

Description

Technical field:

[0001] The invention relates to a utilization method of coal gangue waste, in particular to the technical field of harmless treatment of coal gangue waste combined with waste cathode carbon blocks of the aluminum electrolysis industry and resource regeneration and utilization. Background technique:

[0002] Coal gangue is a rock mixed in the coal-measure strata. It is a black rock with lower carbon content and harder than coal that is associated with the coal seam during the coal-forming process. It is a mixture of inorganic matter and a small amount of organic matter. The accumulation of gangue in my country has reached 7 billion tons, covering an area of ​​70 km 2 , and the annual emissions are increasing at a rate of 150 million tons. However, the comprehensive utilization of coal gangue is still less than 15%, and the remaining coal gangue is mostly stacked naturally and loosely around the mine in a conical or valley dumping manner. It has become one o...