Experimental Investigation On The Improvement Of Morphology And Performance Of Mine-dust Suppressing Foam By Water- Soluble Polymers

Foam dust suppression is an important way to effectively prevent dust from the source.Starting from the perspective of materials to improve the performance of dust suppression foam and reduce the cost of use is an important development direction of foam dust suppression technology,but the past research in this area is still weak.In order to reduce the cost and increase the efficiency of dust suppression foams,the author studied the topic of improving the morphology and performance of mine-dust suppression foams by water-soluble polymers from both qualitative and quantitative levels.Based on the theory of interfacial rheology,this paper uses a combination of experimental research and theoretical analysis to focus on the relationship between the interfacial rheology and foam performance,and the quantitative impact of watersoluble polymers on the morphological characteristics and key performance of dust suppression foam,and explore its mechanism to comprehensively evaluate the costsaving and synergistic effect of water-soluble polymers on dust suppression foam.The main results and conclusions of the paper are as follows:The relationship between the surface viscoelastic modulus and the foaming performance and stability of the foam was studied.First of all,the viscoelastic modulus of the foam liquid film usually decreases with the increase of the blowing agent concentration(FAC)(0.1 ~ 1.0wt.‰).The reason for this change is the change in the surface tension gradient and the nonionic surface The viscoelastic modulus of the agent is significantly smaller than the anionic type.Secondly,there is a negative correlation between foaming properties and viscoelastic modulus.The degree of negative correlation varies greatly between different types of foaming agents due to the difference in surface active molecular structure and properties.The viscoelastic modulus of the foaming agent has a good promotion effect on the stability of the foam.Due to the effect on the film strength and foam drainage,the surface viscoelasticity improves the foam life.This synergistic effect is particularly significant when FAC is below the critical micelle concentration.The effect of cellulose ether polymer(CMC-Na)on the average bubble size,distribution and uniformity of dust suppression foam was studied and analyzed.When the foam is formed,due to the change in surface tension,the average bubble size of the foam decreases with the increase of the concentration of the foaming agent AOS(0.01 ~ 0.5%),and the uniformity of the foam increases.It should be noted that when the AOS concentration exceeds 0.1%,the average bubble size and uniformity begin to change slowly,the data gradually stabilizes,and the minimum average bubble radius is about 0.13 ~ 0.16 mm.As the bubble decays,the bubble continuously increases bubble size and decreases uniformity as the decay time increases.At different AOS concentrations,the relationship between average bubble size / uniformity and AOS concentration is similar to when foam is formed.fter the addition of CMC-Na,the change of both morphological parameters has a turning point(0.1% AOS),of which 500 ~ 800 mg / L CMC-Na added AOS at the turning point concentration has the most significant effect on the foam morphology.The average radius can reach a minimum of 0.13 mm,and the uniformity reaches the highest.When the concentration of AOS is higher than the turning point,the addition of CMC-Na has less effect on the foam morphology during foam formation and recession.Experiments show that adding 500 ~ 800mg/L CMC-Na in 0.1% AOS is the best way to optimize the morphology of dustsuppression foam.The effects of different types and concentrations of polymers(HPAM,HEC,PVA)on the key properties of dust suppression foams were studied.The addition of polymers to the foaming agent reduces the wettability of the foam to coal dust.This is because the surfactant molecules are attracted to the hydrophobic groups of the polymer and increase the surface tension of the mixed solution.And as the polymer concentration increases,this change becomes more obvious.At the same time,the addition of polymer significantly improves the surface viscosity of the solution.Due to the viscosity of the polymer itself and the interaction of its molecular chain with surfactant micelles,the viscosity modulus of the surfactant / polymer solution is effectively increased as the polymer concentration increases.The polymer improves the stability of the foam.Due to the strong liquid carrying capacity of the polymer,the liquid content of the foam is significantly increased compared to the pure surfactant foam,and the viscosity of the solution added with the polymer is increased,the foam drainage rate is reduced,and the foam life is increased.Through comparison analysis,it is found that the addition of low concentration(not more than 0.3 ‰)of the polymer will have less effect on the wettability of the foaming agent,and can improve the foam surface viscosity and stability.When the polymer concentration is higher than 0.3 ‰,the surface viscosity and stability of the foam can be further enhanced,but the wettability performance is relatively poor.At the same time,the polymer also has drag reduction effects on foam transportation and spraying.Under comprehensive evaluation,in the study of foam morphology the addition of 0.5 ~ 0.8 g / L polymer is the most stable form of foam.In the study of foam performance,the addition of polymers with a concentration above 0.3 ‰ will affect the foam wettability to a certain extent.Since the wettability,surface viscosity and stability of the dust suppression foam are all key factors that affect the dust suppression performance,in general,adding water-soluble polymers in an appropriate amount under 0.8 wt.‰(less than 0.8g / L)can effectively increase the cost of the mine dust suppression foam.