Study On New Colloid Material And Its Characteristics For Prevention And Extinguishment Of Coal Spontaneous Combustion

The existence of fire promotes the progress of human civilization, and promotes the development of the society. Material combustion in the control of man can bring benefits to human beings, but it will bring disaster to the people when it is beyond the control of human beings. The spontaneous combustion of coal is a threat to the life of the mine staff, and the national economy has suffered an immeasurable loss. At present, the coal fires still exist bringing disaster to mankind. Mine fires can increase the temperature causing a lot of coal mine disasters. If coal spontaneous combustion occurs, it not only will produce CO and other toxic and harmful gases, but also cause gas explosion in the high temperature conditions.Mine fire hazard is great, which has become a stumbling block to the progress of coal science and technology. Gel fire prevention material for preventing coal spontaneous combustion can achieve a certain effect but it will produce irritating smell, deterioration of the underground environment which is not conducive to the work of the underground. In order to prevent and control coal spontaneous combustion effectively, to make up for the deficiency of the current majority of gel fire prevention materials, a new fire prevention gel material is developed, which is formed by the polymer, crosslinking agent and coagulant. The material is non-toxic, no pollution, easy to be degraded and has low prices which plays an important role to reduce disaster losses in protecting the underground environment.At first, the appropriate proportion of the gel material is selected through the comparative analysis of the experiment: the suitable ratio of polymer whose mass fraction is 2% and crosslinking agent and coagulant is 100:8:2.The performance of the polymer gel prepared in accordance with the ratio is well. Then according to the characteristics of coal mine fire prevention material the gel time, permeability, thermal stability, strength of gel were analyzed. The gel time test results showed that the coagulant on gel time is larger; in a certain range,gel time decreases with the increase of temperature; When the polymer mass fraction is 2%- 0.5%, effect of polymer concentration on the gelation time is larger. With the increase of mass fraction polymer concentration still has certain effect on the gelation time but gradually weakened. Overall, the gelation time reduces with the polymer concentration increases; In the range of stable colloid, with the increase of the proportion of the crosslinking agent and the polymer, the time of gel formation gradually decreased. The penetration test results showed that the permeability decreased with the increase of the coagulant dosage. The influence of sodium carboxymethyl cellulose on the permeability is more complicated, and the relationship is not obvious. Thermal stability of thermal stability experiments showed that the gel’s thermal stability is better: with the increase of temperature polymer gel and water loss rate increase; under the different temperature, the polymer gel loss rate is lower than the water loss rate; The higher temperature is, the more lower gel polymer fluid loss rate than the water loss rate is.The gel strength test showed that the content of sodium carboxymethyl cellulose has a great influence on the gel strength and the resistance characteristics of polymer gel to coal sample were obtained: the different effect of the gel on the resistance of different coal samples is not the same, which may be related to the degree of coal metamorphism, in general, the gel has a good resistance to oxidation of coal. Finally mine fire was simulated in the laboratory: the burning of the coal body was perfused with the gel and record the temperature of coal body and analyze the gas collection from the burning coal. Through a certain period of time, the temperature and the gas concentration of the index are all reduced to the level of the coal before and the coal fire is inhibited which indicates that the polymer gel is reliable and has a good anti fire characteristics. The polymer gel studied in this paper provides a new technical means for the prevention and control of coal spontaneous combustion which has a broad development prospects.