CN-119368550-B - Method for high-temperature and high-pressure cooperative treatment of red mud and coal or coal gangue

CN119368550BCN 119368550 BCN119368550 BCN 119368550BCN-119368550-B

Abstract

The invention discloses a high-temperature high-pressure synergistic treatment method of red mud and coal or coal gangue, which comprises the following steps of mixing the red mud, the coal or the coal gangue and placing the mixture into a high-temperature pressure device, introducing oxygen-containing gas or an oxidant, decomposing and reconstructing minerals of the red mud and the coal or the coal gangue under the conditions of high temperature and high pressure, carrying out neutralization reaction on acidic substances produced by oxidizing sulfide minerals and carbon-based minerals in the coal or the coal gangue and alkaline substances in the red mud, and desalting a reaction product of the red mud and the coal or the coal gangue to obtain ecological matrix soil. According to the invention, the decomposition and alkali release of alkaline minerals such as nepheline in the red mud are accelerated at high temperature and high pressure, the oxidation of carbon-based minerals and sulphide minerals in coal or coal gangue and the conversion of humus/humic acid and the like are accelerated, alkaline substances produced by the reaction are neutralized with acidic substances, the rapid dealkalization of the red mud is realized, the oxidation degree of the carbon-based minerals is controlled to improve the organic matter content in reaction products, and thus the full-scale recycling and ecological utilization of the red mud and the coal or coal gangue are realized.

Inventors

HU XUEWEI
SONG HAORAN
ZHAO QUN
XIE ERMAN
TIAN SENLIN

Assignees

昆明理工大学

Dates

Publication Date: 20260508
Application Date: 20241119

Claims (4)

1. The high-temperature and high-pressure co-treatment method for the red mud and the coal or the coal gangue is characterized by comprising the following steps of: S1, mixing red mud, coal or coal gangue and water, and then placing the mixture into a high-temperature pressure device, wherein the mass ratio of the red mud to the coal or the coal gangue is 1:0.03-50, and the addition amount of the water is 0.3-10 times of the total volume of the solid; S2, introducing oxygen-containing gas or an additive oxidant, wherein the additive amount of the oxygen-containing gas or the oxidant is 1-50% of the carbon content of the solid matters, decomposing and reconstructing the red mud and the coal or the coal gangue under the conditions of high temperature and high pressure, and neutralizing acidic matters produced by oxidizing sulfide minerals in the coal or the coal gangue and alkaline matters in the red mud, wherein the additive amount of the oxygen-containing gas or the oxidant is 1-50% of the carbon content of the solid matters, and the high temperature and the high pressure are specifically controlled at 100-380 ℃ and 0.1-20 Mpa; S3, desalting the reaction product of the red mud and the coal or the gangue, wherein the pH value of the reaction product is between 5 and 9, and the organic matter content is between 1 and 8 percent, so that the reaction product is used as ecological matrix soil.
2. The method for high-temperature and high-pressure co-treatment of red mud and coal or coal gangue according to claim 1, wherein the step S2 is characterized in that the oxygen-containing gas or the additive is added by adopting one-time addition, multiple addition or continuous addition.
3. The method for high-temperature and high-pressure co-treatment of red mud and coal or coal gangue according to claim 1, wherein the oxygen-containing gas is air, oxygen-enriched gas or ozone, and the oxidant is sodium oxide, potassium oxide, calcium oxide, hydrogen peroxide or persulfate.
4. The method for high-temperature and high-pressure co-treatment of red mud and coal or coal gangue according to claim 1, wherein the red mud is one or more of bayer process red mud, sintering process red mud and combined process red mud.

Description

Method for high-temperature and high-pressure cooperative treatment of red mud and coal or coal gangue Technical Field The invention belongs to the technical field of solid waste treatment and resource utilization, and particularly relates to a high-temperature and high-pressure co-treatment method for red mud and coal or coal gangue. Background The red mud is used as a large amount of industrial solid waste produced in the alumina production, and has stronger alkalinity because of containing a large amount of alkaline minerals such as nepheline, sodalite and the like, and alkaline substances can be slowly released for a long time in the stacking process, so that environmental pollution is generated to surrounding soil and underground water. The coal and gangue contain multi-type mineral components such as carbon-based minerals, sulphide minerals and the like, the high-sulfur coal is limited in utilization way due to environmental protection, and the gangue is classified as a large amount of industrial solid waste due to low heat value and high ash content. At present, red mud and coal gangue lack effective large-scale digestion approaches. The method is characterized in that the existing method comprises the steps of building material utilization, underground filling, valuable component extraction, piling and landfill and the like, the consumption of the coal gangue building material utilization is limited due to the economic transportation radius and the building market demand, the coal gangue filling goaf has the problems of large investment and influence on mining production safety, the valuable component extraction of the coal gangue has the problems of reduced volume scale, environmental risk of leached slag after extraction and the like, and the problems of limited consumption, high treatment cost and the like in the treatment are all solved. At present, the prior art adopts four red mud disposal modes, namely (1) submarine emission, (2) wet storage, (3) dry storage and (4) ecological restoration. The submarine emission is greatly limited by geographical environment, the risks of groundwater pollution and dam break exist in wet type stockpiling, the dehydration and solidification costs are high in dry type stockpiling, and the ecological restoration purpose has the problems of insufficient maturity of the prior art and the like. Therefore, it is very necessary to develop a method for high-temperature and high-pressure co-treatment of red mud and coal or coal gangue. Disclosure of Invention The invention aims to provide a high-temperature high-pressure cooperative treatment method for red mud and coal or coal gangue. The object of the invention is achieved in that it comprises the following steps: S1, mixing red mud, coal or coal gangue and water, and then placing the mixture into a high-temperature pressure device; S2, introducing oxygen-containing gas or adding an oxidant, decomposing and reconstructing minerals of the red mud and coal or coal gangue under high-temperature and high-pressure conditions, and carrying out neutralization reaction on acidic substances produced by oxidizing sulfide minerals and carbon-based minerals in the coal or coal gangue and alkaline substances in the red mud; s3, desalting the reaction product of the red mud and the coal or the gangue, and taking the desalted product as ecological matrix soil. Wherein, coal refers to peat, lignite, bituminous coal, anthracite, waste rock washing, waste rock tunneling and the like containing coal components. Preferably, the mass ratio of the red mud to the coal or the gangue in the step S1 is 1:0.03-50, and the addition amount of water is 0.3-10 times of the total volume of the solid. Preferably, the addition amount of the oxygen-containing gas or the oxidant in the step S2 is 1% -50% of the carbon content of the solid matters. Preferably, the step S2 is carried out by introducing oxygen-containing gas or adding oxidant by adopting one-time addition, multiple addition or continuous addition. Preferably, the high-temperature and high-pressure condition in the step S2 is specifically that the temperature is controlled to be 100-380 ℃ and the pressure is controlled to be 0.1-20 mpa. Preferably, the oxygen-containing gas is air, oxygen-enriched gas or ozone, and the oxidant is sodium oxide, potassium oxide, calcium oxide, hydrogen peroxide or persulfate. Preferably, the red mud is one or more of Bayer process red mud, sintering process red mud and combined process red mud. The invention adopts the principle that (1) minerals such as nepheline in red mud are decomposed to release a large amount of alkaline substances in a supercritical/subcritical environment, (2) carbon-based minerals (carbon-containing components) in coal or gangue are subjected to oxidative decomposition in a high-temperature and high-pressure aerobic environment and are converted into humic acid substances such as humins, humic acid and fulvic acid, the humic acid sub