Study On Synthesis And Properties Of Dust Suppressants For Coal Transportation Under Ultrasonic Technology

China is one of the few countries used coal as the main energy source.Due to some people's lack of environmental awareness during the process of mining and transportation,thus the coal resources was wasted and the air is worse and worse.In recent years,fog and haze cover most areas of our country in winter.One of the main causes of this air pollution is that a large amount of coal dust will be produced in the process of coal mining and transportation and the residents will burn coal for heating in winter.Coal dust pollution will not only reduce the air quality greatly,but also seriously affect human health.Therefore,effective control of coal dust pollution in coal transportation is particularly important for environmental protection.This passage in mainly about the coal dust pollution during the transportation.Two kinds of dust suppressants with adhesion and shock resistance were made by ultrasonic polymerization.The specific methods and contents are as follows:(1)Attapulgite is used as the main raw material,butyl acrylate and styrene are used as copolymers,OP-10 and MS-1 are non-ionic and ionic emulsifiers,the ratio is m(OP-10):m(MS-1)=1:1.4.A polymer dust suppressant emulsion was synthesized by seed emulsion polymerization.The effects of monomer ratio,attapulgite dosage,initiator dosage,cross-linking agent dosage,emulsifier dosage and temperature in the reaction process on the properties of the product were discussed.The product was analyzed by Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD),thermogravimetric analysis(TGA)and scanning.The structure of the graft copolymer was characterized by scanning electron microscopy(SEM).The water retention,wind erosion resistance,shock resistance,temperature adaptability and pressure resistance of the dust suppressant prepared by the graft copolymer were tested.The results showed that when the monomer ratio m(BA):m(St)=7:3,the amount of potassium persulfate and sodium bisulfite as initiators(m(KPS):m(NaHSO3)=3:2)was 0.8wt%(for the total mass of monomers,the same below),the amount of DVB,emulsifier and attapulgite were 0.5wt%,5wt%and 2wt%respectively,and the reaction temperature was controlled at 80?.The water retention rate of the prepared dust suppressant can still reach 59.91%after 40 hours at 25?,and only 0.58%of the pulverized coal is lost after 3 hours of continuous blowing,and 3.18%of the pulverized coal is lost after 40 hours of oscillation.Moreover,the comprehensive strength of the pulverized coal model is much greater than 0.02 MPa when the temperature is-20-60?.It can be inferred that the dust suppressant has a high compressive strength.The water-retaining property is very high,and it also shows good wind erosion resistance and strong ability to adapt to the environment.(2)Considering the cost and environmental protection,sodium hydroxypropyl methyl cellulose was used as raw material,acrylamide and acrylic acid were used as copolymers,and a kind of dust inhibitor with good performance was synthesized by ultrasonic-assisted graft co-polymerization.A small amount of other additives were added to improve the flexibility and the stability.A study was made to test the reaction conditions such as monomer ratio,cross linking agent dosage,initiator dosage,ultrasonic power and time under ultrasonic technology.The effects of various technological conditions on the properties of the products were determined.The products were analyzed by FT-IR,XRD and TGA.The structure of the dust proof agent was characterized by analysis,scanning electron microscopy(SEM)and different scanning calorimetry(DSC).The grafting ratio was determined.The forming,water holding,anti-oscillation and anti-wind erosion properties of the products were further tested.The results show that when the ratio of AA to AM is 3:1,the dosage of ammonium persulfate(APS)is 1wt%,the dosage of cross linking agent dimethyl diallylammonium chloride(DMDAAC)is 0.5wt%,and the power is 200 W,the dust suppressant with excellent dust suppression effect is prepared by ultrasonic reaction for 70 minutes.The water retention rate of the prepared dust suppressant can still reach 74.52%after 40 hours at 25?,and only 1.26%of the pulverized coal is lost after 3 hours of continuous blowing.The loss rate of pulverized coal is 4.80%after 40 hours of oscillation,which shows that the water retention,wind erosion resistance and shock resistance of the dust suppressant are all good.