Coal gangue roasting, deironing and whitening method and whitened coal gangue material prepared through coal gangue roasting, deironing and whitening method

Abstract

The invention provides a coal gangue roasting, deironing and whitening method, and belongs to the technical field of comprehensive utilization of coal gangue solid waste resources. The coal gangue powder is roasted and decarbonized in advance, so that carbon in the coal gangue is converted into carbon dioxide, and meanwhile, kaolinite minerals in the coal gangue are converted into metakaolinite; in the low-temperature roasting process, ammonium salt is decomposed and reacts with metal iron oxide in the decarburized coal gangue to generate soluble iron salt, then colored iron metal can be removed after rinsing, iron removal under the low-temperature condition is achieved, and the whiteness is improved; color development impurities (carbon and iron impurities) in the coal gangue are removed through two times of roasting, the roasting temperature is low, and the energy consumption in the coal gangue treatment process is greatly reduced. The result of the embodiment shows that the whiteness of the whitened coal gangue prepared by the method provided by the invention reaches 75-85%, and the content of Fe2O3 in the coal gangue is less than or equal to 0.75 wt.%.

Description

technical field [0001] The invention relates to the technical field of comprehensive utilization of coal gangue solid waste resources, in particular to a method for roasting coal gangue to remove iron and whiten it and the whitened coal gangue material prepared therefrom. Background technique [0002] After years of rapid development of the coal industry, the stockpile of coal gangue has increased significantly, and it is still growing rapidly at an annual rate of about 200 million tons. The massive stockpiling of coal gangue has brought about a series of problems, such as a large amount of land occupation, harmful substances polluting the soil, atmosphere, groundwater and other environmental problems, potential surface subsidence, causing landslides, debris flows and other ecological environmental problems. However, in addition to its harmfulness, the existence of various minerals and valuable elements in coal gangue shows its resourceful side. For coal gangue, a bulk soli...

AI Technical Summary

Problems solved by technology

[0004] However, in the coal gangue resource recovery method disclosed above, the calcination of coal gangue is carried out at a high temperature above 900°C, that is, at a time close to or even exceeding the crystal phase transformation of metakaolinite to mullite and silicoalumina spinel. Calcination at high temperature can achieve impurity removal and whitening, high energy consumption