Preparation And Properties Of Waterborne Polymeric Dust Suppressant

Air pollution is still serious,causing extreme harm to humans and the environment.Dust emission is one of the main factors.In this paper,waterborne polymers were synthesized,with backfill soil,iron ore and coal as the application object.Through Zeta potential,compressive strength,surface morphology and pore structure,the moisturizing and consolidation mechanism of the polymer dust suppressant were discussed,and the dust suppression efficiency of the polymer dust suppressant was studied through laboratory and field.Styrene-acrylates copolymer dust suppressant was synthesized from acrylic acid(AA),methyl acrylate(BA),methyl methacrylate(MMA)and styrene(St).The wetting,moisturizing and aggregation effects of polymers on backfill soil were studied.And the effect of polymer on the composition,crystal structure,consolidation state and moisture content of iron ore were studied.Dust suppression efficiency of the dust suppressant on-site application was studied.The results show that the acrylic acid could reduce the contact angle between the polymer and the backfill soil,and decrease the Zeta potential on the surface of the backfill soil.Dust suppressant promoted the aggregation of particles and improved the cohesion by hydrogen bonding.It could moisturize and delay the evaporation of water in the wet state,and tightly seal powder in the dry state.Backfill soil under 35?,45%relative humidity equilibrium moisture content was 2.3 times higher than that of watered.The compressive strength of dust suppression sample reached 4.97 MPa in 28 days,3.9 times of the watered sample,which could effectively reduce wind erodibility.The field results show that the dust suppression efficiency of PM₁₀ and PM_2.5 reached 67.41%and 53.68%after 24 hours,respectively.At the temptrue of 30?,relative humidity of 35%,the equilibrium moisture content of suppressed iron ore was 1.2 times higher than watered.Fe³⁺was adsorbed on the polymer and acted with hydrogen bond to increase the cohesion between iron ore particles.Iron ore was compact densely and its compressive strength reached 3.59 MPa in 28 days.The results of FTIR,XRD and XRF show that the dust suppressant would not change the structure and composition of iron ore and had no adverse effect on the quality.After 24hours of on-site dust suppression,the dust suppression efficiency of PM_2.5 and PM₁₀ was75.0%and 80.95%,respectively.Acrylic acid(AA)and acrylamide(AM)were used as main monomers to prepared an waterborne acrylic copolymer dust suppressant.The moisture content change,emission factor and compressive strength of coal were studied.The wet suppression ability was evaluated with dust-suppressing duration and dust suppression efficiency at the higher moisture content.The dry suppression ability was evaluated with compressive strength.The application performance was evaluated by field results.The results show that the dust suppression time of coal with high moisture content was2.7 times of watered,which significantly delayed water vaporization,and the dust suppression efficiency reached 85.18%at low moisture content.Owing to fine particles agglomeration by polymer,coal surface was sealed levelly and particles stacked densely in SEM morphology.The 28th day compressive strength reached 1.40 MPa.On open coal piles,field application shows that the compacted seal formed stably,and on the 5th day,dust suppression efficiency of PM_2.5 and PM₁₀ was more than 60%.